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Diffstat (limited to 'virt/kvm/kvm_main.c')
| -rw-r--r-- | virt/kvm/kvm_main.c | 6266 |
1 files changed, 6266 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c new file mode 100644 index 000000000..486800a70 --- /dev/null +++ b/virt/kvm/kvm_main.c @@ -0,0 +1,6266 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel-based Virtual Machine driver for Linux + * + * This module enables machines with Intel VT-x extensions to run virtual + * machines without emulation or binary translation. + * + * Copyright (C) 2006 Qumranet, Inc. + * Copyright 2010 Red Hat, Inc. and/or its affiliates. + * + * Authors: + * Avi Kivity <avi@qumranet.com> + * Yaniv Kamay <yaniv@qumranet.com> + */ + +#include <kvm/iodev.h> + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/percpu.h> +#include <linux/mm.h> +#include <linux/miscdevice.h> +#include <linux/vmalloc.h> +#include <linux/reboot.h> +#include <linux/debugfs.h> +#include <linux/highmem.h> +#include <linux/file.h> +#include <linux/syscore_ops.h> +#include <linux/cpu.h> +#include <linux/sched/signal.h> +#include <linux/sched/mm.h> +#include <linux/sched/stat.h> +#include <linux/cpumask.h> +#include <linux/smp.h> +#include <linux/anon_inodes.h> +#include <linux/profile.h> +#include <linux/kvm_para.h> +#include <linux/pagemap.h> +#include <linux/mman.h> +#include <linux/swap.h> +#include <linux/bitops.h> +#include <linux/spinlock.h> +#include <linux/compat.h> +#include <linux/srcu.h> +#include <linux/hugetlb.h> +#include <linux/slab.h> +#include <linux/sort.h> +#include <linux/bsearch.h> +#include <linux/io.h> +#include <linux/lockdep.h> +#include <linux/kthread.h> +#include <linux/suspend.h> + +#include <asm/processor.h> +#include <asm/ioctl.h> +#include <linux/uaccess.h> + +#include "coalesced_mmio.h" +#include "async_pf.h" +#include "kvm_mm.h" +#include "vfio.h" + +#include <trace/events/ipi.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/kvm.h> + +#include <linux/kvm_dirty_ring.h> + + +/* Worst case buffer size needed for holding an integer. */ +#define ITOA_MAX_LEN 12 + +MODULE_AUTHOR("Qumranet"); +MODULE_LICENSE("GPL"); + +/* Architectures should define their poll value according to the halt latency */ +unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT; +module_param(halt_poll_ns, uint, 0644); +EXPORT_SYMBOL_GPL(halt_poll_ns); + +/* Default doubles per-vcpu halt_poll_ns. */ +unsigned int halt_poll_ns_grow = 2; +module_param(halt_poll_ns_grow, uint, 0644); +EXPORT_SYMBOL_GPL(halt_poll_ns_grow); + +/* The start value to grow halt_poll_ns from */ +unsigned int halt_poll_ns_grow_start = 10000; /* 10us */ +module_param(halt_poll_ns_grow_start, uint, 0644); +EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start); + +/* Default resets per-vcpu halt_poll_ns . */ +unsigned int halt_poll_ns_shrink; +module_param(halt_poll_ns_shrink, uint, 0644); +EXPORT_SYMBOL_GPL(halt_poll_ns_shrink); + +/* + * Ordering of locks: + * + * kvm->lock --> kvm->slots_lock --> kvm->irq_lock + */ + +DEFINE_MUTEX(kvm_lock); +LIST_HEAD(vm_list); + +static struct kmem_cache *kvm_vcpu_cache; + +static __read_mostly struct preempt_ops kvm_preempt_ops; +static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu); + +struct dentry *kvm_debugfs_dir; +EXPORT_SYMBOL_GPL(kvm_debugfs_dir); + +static const struct file_operations stat_fops_per_vm; + +static struct file_operations kvm_chardev_ops; + +static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg); +#ifdef CONFIG_KVM_COMPAT +static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg); +#define KVM_COMPAT(c) .compat_ioctl = (c) +#else +/* + * For architectures that don't implement a compat infrastructure, + * adopt a double line of defense: + * - Prevent a compat task from opening /dev/kvm + * - If the open has been done by a 64bit task, and the KVM fd + * passed to a compat task, let the ioctls fail. + */ +static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl, + unsigned long arg) { return -EINVAL; } + +static int kvm_no_compat_open(struct inode *inode, struct file *file) +{ + return is_compat_task() ? -ENODEV : 0; +} +#define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl, \ + .open = kvm_no_compat_open +#endif +static int hardware_enable_all(void); +static void hardware_disable_all(void); + +static void kvm_io_bus_destroy(struct kvm_io_bus *bus); + +#define KVM_EVENT_CREATE_VM 0 +#define KVM_EVENT_DESTROY_VM 1 +static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); +static unsigned long long kvm_createvm_count; +static unsigned long long kvm_active_vms; + +static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask); + +__weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm) +{ +} + +bool kvm_is_zone_device_page(struct page *page) +{ + /* + * The metadata used by is_zone_device_page() to determine whether or + * not a page is ZONE_DEVICE is guaranteed to be valid if and only if + * the device has been pinned, e.g. by get_user_pages(). WARN if the + * page_count() is zero to help detect bad usage of this helper. + */ + if (WARN_ON_ONCE(!page_count(page))) + return false; + + return is_zone_device_page(page); +} + +/* + * Returns a 'struct page' if the pfn is "valid" and backed by a refcounted + * page, NULL otherwise. Note, the list of refcounted PG_reserved page types + * is likely incomplete, it has been compiled purely through people wanting to + * back guest with a certain type of memory and encountering issues. + */ +struct page *kvm_pfn_to_refcounted_page(kvm_pfn_t pfn) +{ + struct page *page; + + if (!pfn_valid(pfn)) + return NULL; + + page = pfn_to_page(pfn); + if (!PageReserved(page)) + return page; + + /* The ZERO_PAGE(s) is marked PG_reserved, but is refcounted. */ + if (is_zero_pfn(pfn)) + return page; + + /* + * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting + * perspective they are "normal" pages, albeit with slightly different + * usage rules. + */ + if (kvm_is_zone_device_page(page)) + return page; + + return NULL; +} + +/* + * Switches to specified vcpu, until a matching vcpu_put() + */ +void vcpu_load(struct kvm_vcpu *vcpu) +{ + int cpu = get_cpu(); + + __this_cpu_write(kvm_running_vcpu, vcpu); + preempt_notifier_register(&vcpu->preempt_notifier); + kvm_arch_vcpu_load(vcpu, cpu); + put_cpu(); +} +EXPORT_SYMBOL_GPL(vcpu_load); + +void vcpu_put(struct kvm_vcpu *vcpu) +{ + preempt_disable(); + kvm_arch_vcpu_put(vcpu); + preempt_notifier_unregister(&vcpu->preempt_notifier); + __this_cpu_write(kvm_running_vcpu, NULL); + preempt_enable(); +} +EXPORT_SYMBOL_GPL(vcpu_put); + +/* TODO: merge with kvm_arch_vcpu_should_kick */ +static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req) +{ + int mode = kvm_vcpu_exiting_guest_mode(vcpu); + + /* + * We need to wait for the VCPU to reenable interrupts and get out of + * READING_SHADOW_PAGE_TABLES mode. + */ + if (req & KVM_REQUEST_WAIT) + return mode != OUTSIDE_GUEST_MODE; + + /* + * Need to kick a running VCPU, but otherwise there is nothing to do. + */ + return mode == IN_GUEST_MODE; +} + +static void ack_kick(void *_completed) +{ +} + +static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait) +{ + if (cpumask_empty(cpus)) + return false; + + smp_call_function_many(cpus, ack_kick, NULL, wait); + return true; +} + +static void kvm_make_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req, + struct cpumask *tmp, int current_cpu) +{ + int cpu; + + if (likely(!(req & KVM_REQUEST_NO_ACTION))) + __kvm_make_request(req, vcpu); + + if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu)) + return; + + /* + * Note, the vCPU could get migrated to a different pCPU at any point + * after kvm_request_needs_ipi(), which could result in sending an IPI + * to the previous pCPU. But, that's OK because the purpose of the IPI + * is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is + * satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES + * after this point is also OK, as the requirement is only that KVM wait + * for vCPUs that were reading SPTEs _before_ any changes were + * finalized. See kvm_vcpu_kick() for more details on handling requests. + */ + if (kvm_request_needs_ipi(vcpu, req)) { + cpu = READ_ONCE(vcpu->cpu); + if (cpu != -1 && cpu != current_cpu) + __cpumask_set_cpu(cpu, tmp); + } +} + +bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req, + unsigned long *vcpu_bitmap) +{ + struct kvm_vcpu *vcpu; + struct cpumask *cpus; + int i, me; + bool called; + + me = get_cpu(); + + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + + for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) { + vcpu = kvm_get_vcpu(kvm, i); + if (!vcpu) + continue; + kvm_make_vcpu_request(vcpu, req, cpus, me); + } + + called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); + put_cpu(); + + return called; +} + +bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, + struct kvm_vcpu *except) +{ + struct kvm_vcpu *vcpu; + struct cpumask *cpus; + unsigned long i; + bool called; + int me; + + me = get_cpu(); + + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + + kvm_for_each_vcpu(i, vcpu, kvm) { + if (vcpu == except) + continue; + kvm_make_vcpu_request(vcpu, req, cpus, me); + } + + called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); + put_cpu(); + + return called; +} + +bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) +{ + return kvm_make_all_cpus_request_except(kvm, req, NULL); +} +EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request); + +void kvm_flush_remote_tlbs(struct kvm *kvm) +{ + ++kvm->stat.generic.remote_tlb_flush_requests; + + /* + * We want to publish modifications to the page tables before reading + * mode. Pairs with a memory barrier in arch-specific code. + * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest + * and smp_mb in walk_shadow_page_lockless_begin/end. + * - powerpc: smp_mb in kvmppc_prepare_to_enter. + * + * There is already an smp_mb__after_atomic() before + * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that + * barrier here. + */ + if (!kvm_arch_flush_remote_tlbs(kvm) + || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH)) + ++kvm->stat.generic.remote_tlb_flush; +} +EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs); + +void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages) +{ + if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages)) + return; + + /* + * Fall back to a flushing entire TLBs if the architecture range-based + * TLB invalidation is unsupported or can't be performed for whatever + * reason. + */ + kvm_flush_remote_tlbs(kvm); +} + +void kvm_flush_remote_tlbs_memslot(struct kvm *kvm, + const struct kvm_memory_slot *memslot) +{ + /* + * All current use cases for flushing the TLBs for a specific memslot + * are related to dirty logging, and many do the TLB flush out of + * mmu_lock. The interaction between the various operations on memslot + * must be serialized by slots_locks to ensure the TLB flush from one + * operation is observed by any other operation on the same memslot. + */ + lockdep_assert_held(&kvm->slots_lock); + kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages); +} + +static void kvm_flush_shadow_all(struct kvm *kvm) +{ + kvm_arch_flush_shadow_all(kvm); + kvm_arch_guest_memory_reclaimed(kvm); +} + +#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE +static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc, + gfp_t gfp_flags) +{ + gfp_flags |= mc->gfp_zero; + + if (mc->kmem_cache) + return kmem_cache_alloc(mc->kmem_cache, gfp_flags); + else + return (void *)__get_free_page(gfp_flags); +} + +int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min) +{ + gfp_t gfp = mc->gfp_custom ? mc->gfp_custom : GFP_KERNEL_ACCOUNT; + void *obj; + + if (mc->nobjs >= min) + return 0; + + if (unlikely(!mc->objects)) { + if (WARN_ON_ONCE(!capacity)) + return -EIO; + + mc->objects = kvmalloc_array(sizeof(void *), capacity, gfp); + if (!mc->objects) + return -ENOMEM; + + mc->capacity = capacity; + } + + /* It is illegal to request a different capacity across topups. */ + if (WARN_ON_ONCE(mc->capacity != capacity)) + return -EIO; + + while (mc->nobjs < mc->capacity) { + obj = mmu_memory_cache_alloc_obj(mc, gfp); + if (!obj) + return mc->nobjs >= min ? 0 : -ENOMEM; + mc->objects[mc->nobjs++] = obj; + } + return 0; +} + +int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min) +{ + return __kvm_mmu_topup_memory_cache(mc, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, min); +} + +int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc) +{ + return mc->nobjs; +} + +void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) +{ + while (mc->nobjs) { + if (mc->kmem_cache) + kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]); + else + free_page((unsigned long)mc->objects[--mc->nobjs]); + } + + kvfree(mc->objects); + + mc->objects = NULL; + mc->capacity = 0; +} + +void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc) +{ + void *p; + + if (WARN_ON(!mc->nobjs)) + p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT); + else + p = mc->objects[--mc->nobjs]; + BUG_ON(!p); + return p; +} +#endif + +static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) +{ + mutex_init(&vcpu->mutex); + vcpu->cpu = -1; + vcpu->kvm = kvm; + vcpu->vcpu_id = id; + vcpu->pid = NULL; +#ifndef __KVM_HAVE_ARCH_WQP + rcuwait_init(&vcpu->wait); +#endif + kvm_async_pf_vcpu_init(vcpu); + + kvm_vcpu_set_in_spin_loop(vcpu, false); + kvm_vcpu_set_dy_eligible(vcpu, false); + vcpu->preempted = false; + vcpu->ready = false; + preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); + vcpu->last_used_slot = NULL; + + /* Fill the stats id string for the vcpu */ + snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d", + task_pid_nr(current), id); +} + +static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu) +{ + kvm_arch_vcpu_destroy(vcpu); + kvm_dirty_ring_free(&vcpu->dirty_ring); + + /* + * No need for rcu_read_lock as VCPU_RUN is the only place that changes + * the vcpu->pid pointer, and at destruction time all file descriptors + * are already gone. + */ + put_pid(rcu_dereference_protected(vcpu->pid, 1)); + + free_page((unsigned long)vcpu->run); + kmem_cache_free(kvm_vcpu_cache, vcpu); +} + +void kvm_destroy_vcpus(struct kvm *kvm) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + kvm_for_each_vcpu(i, vcpu, kvm) { + kvm_vcpu_destroy(vcpu); + xa_erase(&kvm->vcpu_array, i); + } + + atomic_set(&kvm->online_vcpus, 0); +} +EXPORT_SYMBOL_GPL(kvm_destroy_vcpus); + +#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) +{ + return container_of(mn, struct kvm, mmu_notifier); +} + +typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); + +typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start, + unsigned long end); + +typedef void (*on_unlock_fn_t)(struct kvm *kvm); + +struct kvm_hva_range { + unsigned long start; + unsigned long end; + union kvm_mmu_notifier_arg arg; + hva_handler_t handler; + on_lock_fn_t on_lock; + on_unlock_fn_t on_unlock; + bool flush_on_ret; + bool may_block; +}; + +/* + * Use a dedicated stub instead of NULL to indicate that there is no callback + * function/handler. The compiler technically can't guarantee that a real + * function will have a non-zero address, and so it will generate code to + * check for !NULL, whereas comparing against a stub will be elided at compile + * time (unless the compiler is getting long in the tooth, e.g. gcc 4.9). + */ +static void kvm_null_fn(void) +{ + +} +#define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn) + +static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG; + +/* Iterate over each memslot intersecting [start, last] (inclusive) range */ +#define kvm_for_each_memslot_in_hva_range(node, slots, start, last) \ + for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \ + node; \ + node = interval_tree_iter_next(node, start, last)) \ + +static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, + const struct kvm_hva_range *range) +{ + bool ret = false, locked = false; + struct kvm_gfn_range gfn_range; + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + int i, idx; + + if (WARN_ON_ONCE(range->end <= range->start)) + return 0; + + /* A null handler is allowed if and only if on_lock() is provided. */ + if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) && + IS_KVM_NULL_FN(range->handler))) + return 0; + + idx = srcu_read_lock(&kvm->srcu); + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + struct interval_tree_node *node; + + slots = __kvm_memslots(kvm, i); + kvm_for_each_memslot_in_hva_range(node, slots, + range->start, range->end - 1) { + unsigned long hva_start, hva_end; + + slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]); + hva_start = max(range->start, slot->userspace_addr); + hva_end = min(range->end, slot->userspace_addr + + (slot->npages << PAGE_SHIFT)); + + /* + * To optimize for the likely case where the address + * range is covered by zero or one memslots, don't + * bother making these conditional (to avoid writes on + * the second or later invocation of the handler). + */ + gfn_range.arg = range->arg; + gfn_range.may_block = range->may_block; + + /* + * {gfn(page) | page intersects with [hva_start, hva_end)} = + * {gfn_start, gfn_start+1, ..., gfn_end-1}. + */ + gfn_range.start = hva_to_gfn_memslot(hva_start, slot); + gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot); + gfn_range.slot = slot; + + if (!locked) { + locked = true; + KVM_MMU_LOCK(kvm); + if (!IS_KVM_NULL_FN(range->on_lock)) + range->on_lock(kvm, range->start, range->end); + if (IS_KVM_NULL_FN(range->handler)) + break; + } + ret |= range->handler(kvm, &gfn_range); + } + } + + if (range->flush_on_ret && ret) + kvm_flush_remote_tlbs(kvm); + + if (locked) { + KVM_MMU_UNLOCK(kvm); + if (!IS_KVM_NULL_FN(range->on_unlock)) + range->on_unlock(kvm); + } + + srcu_read_unlock(&kvm->srcu, idx); + + /* The notifiers are averse to booleans. :-( */ + return (int)ret; +} + +static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, + unsigned long start, + unsigned long end, + union kvm_mmu_notifier_arg arg, + hva_handler_t handler) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_hva_range range = { + .start = start, + .end = end, + .arg = arg, + .handler = handler, + .on_lock = (void *)kvm_null_fn, + .on_unlock = (void *)kvm_null_fn, + .flush_on_ret = true, + .may_block = false, + }; + + return __kvm_handle_hva_range(kvm, &range); +} + +static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn, + unsigned long start, + unsigned long end, + hva_handler_t handler) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_hva_range range = { + .start = start, + .end = end, + .handler = handler, + .on_lock = (void *)kvm_null_fn, + .on_unlock = (void *)kvm_null_fn, + .flush_on_ret = false, + .may_block = false, + }; + + return __kvm_handle_hva_range(kvm, &range); +} + +static bool kvm_change_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + /* + * Skipping invalid memslots is correct if and only change_pte() is + * surrounded by invalidate_range_{start,end}(), which is currently + * guaranteed by the primary MMU. If that ever changes, KVM needs to + * unmap the memslot instead of skipping the memslot to ensure that KVM + * doesn't hold references to the old PFN. + */ + WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count)); + + if (range->slot->flags & KVM_MEMSLOT_INVALID) + return false; + + return kvm_set_spte_gfn(kvm, range); +} + +static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long address, + pte_t pte) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const union kvm_mmu_notifier_arg arg = { .pte = pte }; + + trace_kvm_set_spte_hva(address); + + /* + * .change_pte() must be surrounded by .invalidate_range_{start,end}(). + * If mmu_invalidate_in_progress is zero, then no in-progress + * invalidations, including this one, found a relevant memslot at + * start(); rechecking memslots here is unnecessary. Note, a false + * positive (count elevated by a different invalidation) is sub-optimal + * but functionally ok. + */ + WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count)); + if (!READ_ONCE(kvm->mmu_invalidate_in_progress)) + return; + + kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn); +} + +void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, + unsigned long end) +{ + /* + * The count increase must become visible at unlock time as no + * spte can be established without taking the mmu_lock and + * count is also read inside the mmu_lock critical section. + */ + kvm->mmu_invalidate_in_progress++; + if (likely(kvm->mmu_invalidate_in_progress == 1)) { + kvm->mmu_invalidate_range_start = start; + kvm->mmu_invalidate_range_end = end; + } else { + /* + * Fully tracking multiple concurrent ranges has diminishing + * returns. Keep things simple and just find the minimal range + * which includes the current and new ranges. As there won't be + * enough information to subtract a range after its invalidate + * completes, any ranges invalidated concurrently will + * accumulate and persist until all outstanding invalidates + * complete. + */ + kvm->mmu_invalidate_range_start = + min(kvm->mmu_invalidate_range_start, start); + kvm->mmu_invalidate_range_end = + max(kvm->mmu_invalidate_range_end, end); + } +} + +static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, + const struct mmu_notifier_range *range) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_hva_range hva_range = { + .start = range->start, + .end = range->end, + .handler = kvm_unmap_gfn_range, + .on_lock = kvm_mmu_invalidate_begin, + .on_unlock = kvm_arch_guest_memory_reclaimed, + .flush_on_ret = true, + .may_block = mmu_notifier_range_blockable(range), + }; + + trace_kvm_unmap_hva_range(range->start, range->end); + + /* + * Prevent memslot modification between range_start() and range_end() + * so that conditionally locking provides the same result in both + * functions. Without that guarantee, the mmu_invalidate_in_progress + * adjustments will be imbalanced. + * + * Pairs with the decrement in range_end(). + */ + spin_lock(&kvm->mn_invalidate_lock); + kvm->mn_active_invalidate_count++; + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e. + * before acquiring mmu_lock, to avoid holding mmu_lock while acquiring + * each cache's lock. There are relatively few caches in existence at + * any given time, and the caches themselves can check for hva overlap, + * i.e. don't need to rely on memslot overlap checks for performance. + * Because this runs without holding mmu_lock, the pfn caches must use + * mn_active_invalidate_count (see above) instead of + * mmu_invalidate_in_progress. + */ + gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end, + hva_range.may_block); + + __kvm_handle_hva_range(kvm, &hva_range); + + return 0; +} + +void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, + unsigned long end) +{ + /* + * This sequence increase will notify the kvm page fault that + * the page that is going to be mapped in the spte could have + * been freed. + */ + kvm->mmu_invalidate_seq++; + smp_wmb(); + /* + * The above sequence increase must be visible before the + * below count decrease, which is ensured by the smp_wmb above + * in conjunction with the smp_rmb in mmu_invalidate_retry(). + */ + kvm->mmu_invalidate_in_progress--; +} + +static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, + const struct mmu_notifier_range *range) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + const struct kvm_hva_range hva_range = { + .start = range->start, + .end = range->end, + .handler = (void *)kvm_null_fn, + .on_lock = kvm_mmu_invalidate_end, + .on_unlock = (void *)kvm_null_fn, + .flush_on_ret = false, + .may_block = mmu_notifier_range_blockable(range), + }; + bool wake; + + __kvm_handle_hva_range(kvm, &hva_range); + + /* Pairs with the increment in range_start(). */ + spin_lock(&kvm->mn_invalidate_lock); + wake = (--kvm->mn_active_invalidate_count == 0); + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * There can only be one waiter, since the wait happens under + * slots_lock. + */ + if (wake) + rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait); + + BUG_ON(kvm->mmu_invalidate_in_progress < 0); +} + +static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + trace_kvm_age_hva(start, end); + + return kvm_handle_hva_range(mn, start, end, KVM_MMU_NOTIFIER_NO_ARG, + kvm_age_gfn); +} + +static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + trace_kvm_age_hva(start, end); + + /* + * Even though we do not flush TLB, this will still adversely + * affect performance on pre-Haswell Intel EPT, where there is + * no EPT Access Bit to clear so that we have to tear down EPT + * tables instead. If we find this unacceptable, we can always + * add a parameter to kvm_age_hva so that it effectively doesn't + * do anything on clear_young. + * + * Also note that currently we never issue secondary TLB flushes + * from clear_young, leaving this job up to the regular system + * cadence. If we find this inaccurate, we might come up with a + * more sophisticated heuristic later. + */ + return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn); +} + +static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long address) +{ + trace_kvm_test_age_hva(address); + + return kvm_handle_hva_range_no_flush(mn, address, address + 1, + kvm_test_age_gfn); +} + +static void kvm_mmu_notifier_release(struct mmu_notifier *mn, + struct mm_struct *mm) +{ + struct kvm *kvm = mmu_notifier_to_kvm(mn); + int idx; + + idx = srcu_read_lock(&kvm->srcu); + kvm_flush_shadow_all(kvm); + srcu_read_unlock(&kvm->srcu, idx); +} + +static const struct mmu_notifier_ops kvm_mmu_notifier_ops = { + .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start, + .invalidate_range_end = kvm_mmu_notifier_invalidate_range_end, + .clear_flush_young = kvm_mmu_notifier_clear_flush_young, + .clear_young = kvm_mmu_notifier_clear_young, + .test_young = kvm_mmu_notifier_test_young, + .change_pte = kvm_mmu_notifier_change_pte, + .release = kvm_mmu_notifier_release, +}; + +static int kvm_init_mmu_notifier(struct kvm *kvm) +{ + kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops; + return mmu_notifier_register(&kvm->mmu_notifier, current->mm); +} + +#else /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */ + +static int kvm_init_mmu_notifier(struct kvm *kvm) +{ + return 0; +} + +#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ + +#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER +static int kvm_pm_notifier_call(struct notifier_block *bl, + unsigned long state, + void *unused) +{ + struct kvm *kvm = container_of(bl, struct kvm, pm_notifier); + + return kvm_arch_pm_notifier(kvm, state); +} + +static void kvm_init_pm_notifier(struct kvm *kvm) +{ + kvm->pm_notifier.notifier_call = kvm_pm_notifier_call; + /* Suspend KVM before we suspend ftrace, RCU, etc. */ + kvm->pm_notifier.priority = INT_MAX; + register_pm_notifier(&kvm->pm_notifier); +} + +static void kvm_destroy_pm_notifier(struct kvm *kvm) +{ + unregister_pm_notifier(&kvm->pm_notifier); +} +#else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */ +static void kvm_init_pm_notifier(struct kvm *kvm) +{ +} + +static void kvm_destroy_pm_notifier(struct kvm *kvm) +{ +} +#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */ + +static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot) +{ + if (!memslot->dirty_bitmap) + return; + + kvfree(memslot->dirty_bitmap); + memslot->dirty_bitmap = NULL; +} + +/* This does not remove the slot from struct kvm_memslots data structures */ +static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + kvm_destroy_dirty_bitmap(slot); + + kvm_arch_free_memslot(kvm, slot); + + kfree(slot); +} + +static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots) +{ + struct hlist_node *idnode; + struct kvm_memory_slot *memslot; + int bkt; + + /* + * The same memslot objects live in both active and inactive sets, + * arbitrarily free using index '1' so the second invocation of this + * function isn't operating over a structure with dangling pointers + * (even though this function isn't actually touching them). + */ + if (!slots->node_idx) + return; + + hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1]) + kvm_free_memslot(kvm, memslot); +} + +static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc) +{ + switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) { + case KVM_STATS_TYPE_INSTANT: + return 0444; + case KVM_STATS_TYPE_CUMULATIVE: + case KVM_STATS_TYPE_PEAK: + default: + return 0644; + } +} + + +static void kvm_destroy_vm_debugfs(struct kvm *kvm) +{ + int i; + int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + + kvm_vcpu_stats_header.num_desc; + + if (IS_ERR(kvm->debugfs_dentry)) + return; + + debugfs_remove_recursive(kvm->debugfs_dentry); + + if (kvm->debugfs_stat_data) { + for (i = 0; i < kvm_debugfs_num_entries; i++) + kfree(kvm->debugfs_stat_data[i]); + kfree(kvm->debugfs_stat_data); + } +} + +static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname) +{ + static DEFINE_MUTEX(kvm_debugfs_lock); + struct dentry *dent; + char dir_name[ITOA_MAX_LEN * 2]; + struct kvm_stat_data *stat_data; + const struct _kvm_stats_desc *pdesc; + int i, ret = -ENOMEM; + int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + + kvm_vcpu_stats_header.num_desc; + + if (!debugfs_initialized()) + return 0; + + snprintf(dir_name, sizeof(dir_name), "%d-%s", task_pid_nr(current), fdname); + mutex_lock(&kvm_debugfs_lock); + dent = debugfs_lookup(dir_name, kvm_debugfs_dir); + if (dent) { + pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name); + dput(dent); + mutex_unlock(&kvm_debugfs_lock); + return 0; + } + dent = debugfs_create_dir(dir_name, kvm_debugfs_dir); + mutex_unlock(&kvm_debugfs_lock); + if (IS_ERR(dent)) + return 0; + + kvm->debugfs_dentry = dent; + kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries, + sizeof(*kvm->debugfs_stat_data), + GFP_KERNEL_ACCOUNT); + if (!kvm->debugfs_stat_data) + goto out_err; + + for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) { + pdesc = &kvm_vm_stats_desc[i]; + stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT); + if (!stat_data) + goto out_err; + + stat_data->kvm = kvm; + stat_data->desc = pdesc; + stat_data->kind = KVM_STAT_VM; + kvm->debugfs_stat_data[i] = stat_data; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm->debugfs_dentry, stat_data, + &stat_fops_per_vm); + } + + for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) { + pdesc = &kvm_vcpu_stats_desc[i]; + stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT); + if (!stat_data) + goto out_err; + + stat_data->kvm = kvm; + stat_data->desc = pdesc; + stat_data->kind = KVM_STAT_VCPU; + kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm->debugfs_dentry, stat_data, + &stat_fops_per_vm); + } + + ret = kvm_arch_create_vm_debugfs(kvm); + if (ret) + goto out_err; + + return 0; +out_err: + kvm_destroy_vm_debugfs(kvm); + return ret; +} + +/* + * Called after the VM is otherwise initialized, but just before adding it to + * the vm_list. + */ +int __weak kvm_arch_post_init_vm(struct kvm *kvm) +{ + return 0; +} + +/* + * Called just after removing the VM from the vm_list, but before doing any + * other destruction. + */ +void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm) +{ +} + +/* + * Called after per-vm debugfs created. When called kvm->debugfs_dentry should + * be setup already, so we can create arch-specific debugfs entries under it. + * Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so + * a per-arch destroy interface is not needed. + */ +int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm) +{ + return 0; +} + +static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) +{ + struct kvm *kvm = kvm_arch_alloc_vm(); + struct kvm_memslots *slots; + int r = -ENOMEM; + int i, j; + + if (!kvm) + return ERR_PTR(-ENOMEM); + + /* KVM is pinned via open("/dev/kvm"), the fd passed to this ioctl(). */ + __module_get(kvm_chardev_ops.owner); + + KVM_MMU_LOCK_INIT(kvm); + mmgrab(current->mm); + kvm->mm = current->mm; + kvm_eventfd_init(kvm); + mutex_init(&kvm->lock); + mutex_init(&kvm->irq_lock); + mutex_init(&kvm->slots_lock); + mutex_init(&kvm->slots_arch_lock); + spin_lock_init(&kvm->mn_invalidate_lock); + rcuwait_init(&kvm->mn_memslots_update_rcuwait); + xa_init(&kvm->vcpu_array); + + INIT_LIST_HEAD(&kvm->gpc_list); + spin_lock_init(&kvm->gpc_lock); + + INIT_LIST_HEAD(&kvm->devices); + kvm->max_vcpus = KVM_MAX_VCPUS; + + BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX); + + /* + * Force subsequent debugfs file creations to fail if the VM directory + * is not created (by kvm_create_vm_debugfs()). + */ + kvm->debugfs_dentry = ERR_PTR(-ENOENT); + + snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d", + task_pid_nr(current)); + + if (init_srcu_struct(&kvm->srcu)) + goto out_err_no_srcu; + if (init_srcu_struct(&kvm->irq_srcu)) + goto out_err_no_irq_srcu; + + refcount_set(&kvm->users_count, 1); + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + for (j = 0; j < 2; j++) { + slots = &kvm->__memslots[i][j]; + + atomic_long_set(&slots->last_used_slot, (unsigned long)NULL); + slots->hva_tree = RB_ROOT_CACHED; + slots->gfn_tree = RB_ROOT; + hash_init(slots->id_hash); + slots->node_idx = j; + + /* Generations must be different for each address space. */ + slots->generation = i; + } + + rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]); + } + + for (i = 0; i < KVM_NR_BUSES; i++) { + rcu_assign_pointer(kvm->buses[i], + kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT)); + if (!kvm->buses[i]) + goto out_err_no_arch_destroy_vm; + } + + r = kvm_arch_init_vm(kvm, type); + if (r) + goto out_err_no_arch_destroy_vm; + + r = hardware_enable_all(); + if (r) + goto out_err_no_disable; + +#ifdef CONFIG_HAVE_KVM_IRQFD + INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list); +#endif + + r = kvm_init_mmu_notifier(kvm); + if (r) + goto out_err_no_mmu_notifier; + + r = kvm_coalesced_mmio_init(kvm); + if (r < 0) + goto out_no_coalesced_mmio; + + r = kvm_create_vm_debugfs(kvm, fdname); + if (r) + goto out_err_no_debugfs; + + r = kvm_arch_post_init_vm(kvm); + if (r) + goto out_err; + + mutex_lock(&kvm_lock); + list_add(&kvm->vm_list, &vm_list); + mutex_unlock(&kvm_lock); + + preempt_notifier_inc(); + kvm_init_pm_notifier(kvm); + + return kvm; + +out_err: + kvm_destroy_vm_debugfs(kvm); +out_err_no_debugfs: + kvm_coalesced_mmio_free(kvm); +out_no_coalesced_mmio: +#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) + if (kvm->mmu_notifier.ops) + mmu_notifier_unregister(&kvm->mmu_notifier, current->mm); +#endif +out_err_no_mmu_notifier: + hardware_disable_all(); +out_err_no_disable: + kvm_arch_destroy_vm(kvm); +out_err_no_arch_destroy_vm: + WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); + for (i = 0; i < KVM_NR_BUSES; i++) + kfree(kvm_get_bus(kvm, i)); + cleanup_srcu_struct(&kvm->irq_srcu); +out_err_no_irq_srcu: + cleanup_srcu_struct(&kvm->srcu); +out_err_no_srcu: + kvm_arch_free_vm(kvm); + mmdrop(current->mm); + module_put(kvm_chardev_ops.owner); + return ERR_PTR(r); +} + +static void kvm_destroy_devices(struct kvm *kvm) +{ + struct kvm_device *dev, *tmp; + + /* + * We do not need to take the kvm->lock here, because nobody else + * has a reference to the struct kvm at this point and therefore + * cannot access the devices list anyhow. + */ + list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) { + list_del(&dev->vm_node); + dev->ops->destroy(dev); + } +} + +static void kvm_destroy_vm(struct kvm *kvm) +{ + int i; + struct mm_struct *mm = kvm->mm; + + kvm_destroy_pm_notifier(kvm); + kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm); + kvm_destroy_vm_debugfs(kvm); + kvm_arch_sync_events(kvm); + mutex_lock(&kvm_lock); + list_del(&kvm->vm_list); + mutex_unlock(&kvm_lock); + kvm_arch_pre_destroy_vm(kvm); + + kvm_free_irq_routing(kvm); + for (i = 0; i < KVM_NR_BUSES; i++) { + struct kvm_io_bus *bus = kvm_get_bus(kvm, i); + + if (bus) + kvm_io_bus_destroy(bus); + kvm->buses[i] = NULL; + } + kvm_coalesced_mmio_free(kvm); +#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) + mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm); + /* + * At this point, pending calls to invalidate_range_start() + * have completed but no more MMU notifiers will run, so + * mn_active_invalidate_count may remain unbalanced. + * No threads can be waiting in kvm_swap_active_memslots() as the + * last reference on KVM has been dropped, but freeing + * memslots would deadlock without this manual intervention. + */ + WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait)); + kvm->mn_active_invalidate_count = 0; +#else + kvm_flush_shadow_all(kvm); +#endif + kvm_arch_destroy_vm(kvm); + kvm_destroy_devices(kvm); + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + kvm_free_memslots(kvm, &kvm->__memslots[i][0]); + kvm_free_memslots(kvm, &kvm->__memslots[i][1]); + } + cleanup_srcu_struct(&kvm->irq_srcu); + cleanup_srcu_struct(&kvm->srcu); + kvm_arch_free_vm(kvm); + preempt_notifier_dec(); + hardware_disable_all(); + mmdrop(mm); + module_put(kvm_chardev_ops.owner); +} + +void kvm_get_kvm(struct kvm *kvm) +{ + refcount_inc(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm); + +/* + * Make sure the vm is not during destruction, which is a safe version of + * kvm_get_kvm(). Return true if kvm referenced successfully, false otherwise. + */ +bool kvm_get_kvm_safe(struct kvm *kvm) +{ + return refcount_inc_not_zero(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm_safe); + +void kvm_put_kvm(struct kvm *kvm) +{ + if (refcount_dec_and_test(&kvm->users_count)) + kvm_destroy_vm(kvm); +} +EXPORT_SYMBOL_GPL(kvm_put_kvm); + +/* + * Used to put a reference that was taken on behalf of an object associated + * with a user-visible file descriptor, e.g. a vcpu or device, if installation + * of the new file descriptor fails and the reference cannot be transferred to + * its final owner. In such cases, the caller is still actively using @kvm and + * will fail miserably if the refcount unexpectedly hits zero. + */ +void kvm_put_kvm_no_destroy(struct kvm *kvm) +{ + WARN_ON(refcount_dec_and_test(&kvm->users_count)); +} +EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy); + +static int kvm_vm_release(struct inode *inode, struct file *filp) +{ + struct kvm *kvm = filp->private_data; + + kvm_irqfd_release(kvm); + + kvm_put_kvm(kvm); + return 0; +} + +/* + * Allocation size is twice as large as the actual dirty bitmap size. + * See kvm_vm_ioctl_get_dirty_log() why this is needed. + */ +static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot) +{ + unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot); + + memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT); + if (!memslot->dirty_bitmap) + return -ENOMEM; + + return 0; +} + +static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id) +{ + struct kvm_memslots *active = __kvm_memslots(kvm, as_id); + int node_idx_inactive = active->node_idx ^ 1; + + return &kvm->__memslots[as_id][node_idx_inactive]; +} + +/* + * Helper to get the address space ID when one of memslot pointers may be NULL. + * This also serves as a sanity that at least one of the pointers is non-NULL, + * and that their address space IDs don't diverge. + */ +static int kvm_memslots_get_as_id(struct kvm_memory_slot *a, + struct kvm_memory_slot *b) +{ + if (WARN_ON_ONCE(!a && !b)) + return 0; + + if (!a) + return b->as_id; + if (!b) + return a->as_id; + + WARN_ON_ONCE(a->as_id != b->as_id); + return a->as_id; +} + +static void kvm_insert_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *slot) +{ + struct rb_root *gfn_tree = &slots->gfn_tree; + struct rb_node **node, *parent; + int idx = slots->node_idx; + + parent = NULL; + for (node = &gfn_tree->rb_node; *node; ) { + struct kvm_memory_slot *tmp; + + tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]); + parent = *node; + if (slot->base_gfn < tmp->base_gfn) + node = &(*node)->rb_left; + else if (slot->base_gfn > tmp->base_gfn) + node = &(*node)->rb_right; + else + BUG(); + } + + rb_link_node(&slot->gfn_node[idx], parent, node); + rb_insert_color(&slot->gfn_node[idx], gfn_tree); +} + +static void kvm_erase_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *slot) +{ + rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree); +} + +static void kvm_replace_gfn_node(struct kvm_memslots *slots, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int idx = slots->node_idx; + + WARN_ON_ONCE(old->base_gfn != new->base_gfn); + + rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx], + &slots->gfn_tree); +} + +/* + * Replace @old with @new in the inactive memslots. + * + * With NULL @old this simply adds @new. + * With NULL @new this simply removes @old. + * + * If @new is non-NULL its hva_node[slots_idx] range has to be set + * appropriately. + */ +static void kvm_replace_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int as_id = kvm_memslots_get_as_id(old, new); + struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id); + int idx = slots->node_idx; + + if (old) { + hash_del(&old->id_node[idx]); + interval_tree_remove(&old->hva_node[idx], &slots->hva_tree); + + if ((long)old == atomic_long_read(&slots->last_used_slot)) + atomic_long_set(&slots->last_used_slot, (long)new); + + if (!new) { + kvm_erase_gfn_node(slots, old); + return; + } + } + + /* + * Initialize @new's hva range. Do this even when replacing an @old + * slot, kvm_copy_memslot() deliberately does not touch node data. + */ + new->hva_node[idx].start = new->userspace_addr; + new->hva_node[idx].last = new->userspace_addr + + (new->npages << PAGE_SHIFT) - 1; + + /* + * (Re)Add the new memslot. There is no O(1) interval_tree_replace(), + * hva_node needs to be swapped with remove+insert even though hva can't + * change when replacing an existing slot. + */ + hash_add(slots->id_hash, &new->id_node[idx], new->id); + interval_tree_insert(&new->hva_node[idx], &slots->hva_tree); + + /* + * If the memslot gfn is unchanged, rb_replace_node() can be used to + * switch the node in the gfn tree instead of removing the old and + * inserting the new as two separate operations. Replacement is a + * single O(1) operation versus two O(log(n)) operations for + * remove+insert. + */ + if (old && old->base_gfn == new->base_gfn) { + kvm_replace_gfn_node(slots, old, new); + } else { + if (old) + kvm_erase_gfn_node(slots, old); + kvm_insert_gfn_node(slots, new); + } +} + +static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) +{ + u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; + +#ifdef __KVM_HAVE_READONLY_MEM + valid_flags |= KVM_MEM_READONLY; +#endif + + if (mem->flags & ~valid_flags) + return -EINVAL; + + return 0; +} + +static void kvm_swap_active_memslots(struct kvm *kvm, int as_id) +{ + struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id); + + /* Grab the generation from the activate memslots. */ + u64 gen = __kvm_memslots(kvm, as_id)->generation; + + WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS); + slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS; + + /* + * Do not store the new memslots while there are invalidations in + * progress, otherwise the locking in invalidate_range_start and + * invalidate_range_end will be unbalanced. + */ + spin_lock(&kvm->mn_invalidate_lock); + prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait); + while (kvm->mn_active_invalidate_count) { + set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock(&kvm->mn_invalidate_lock); + schedule(); + spin_lock(&kvm->mn_invalidate_lock); + } + finish_rcuwait(&kvm->mn_memslots_update_rcuwait); + rcu_assign_pointer(kvm->memslots[as_id], slots); + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * Acquired in kvm_set_memslot. Must be released before synchronize + * SRCU below in order to avoid deadlock with another thread + * acquiring the slots_arch_lock in an srcu critical section. + */ + mutex_unlock(&kvm->slots_arch_lock); + + synchronize_srcu_expedited(&kvm->srcu); + + /* + * Increment the new memslot generation a second time, dropping the + * update in-progress flag and incrementing the generation based on + * the number of address spaces. This provides a unique and easily + * identifiable generation number while the memslots are in flux. + */ + gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS; + + /* + * Generations must be unique even across address spaces. We do not need + * a global counter for that, instead the generation space is evenly split + * across address spaces. For example, with two address spaces, address + * space 0 will use generations 0, 2, 4, ... while address space 1 will + * use generations 1, 3, 5, ... + */ + gen += KVM_ADDRESS_SPACE_NUM; + + kvm_arch_memslots_updated(kvm, gen); + + slots->generation = gen; +} + +static int kvm_prepare_memory_region(struct kvm *kvm, + const struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + int r; + + /* + * If dirty logging is disabled, nullify the bitmap; the old bitmap + * will be freed on "commit". If logging is enabled in both old and + * new, reuse the existing bitmap. If logging is enabled only in the + * new and KVM isn't using a ring buffer, allocate and initialize a + * new bitmap. + */ + if (change != KVM_MR_DELETE) { + if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) + new->dirty_bitmap = NULL; + else if (old && old->dirty_bitmap) + new->dirty_bitmap = old->dirty_bitmap; + else if (kvm_use_dirty_bitmap(kvm)) { + r = kvm_alloc_dirty_bitmap(new); + if (r) + return r; + + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) + bitmap_set(new->dirty_bitmap, 0, new->npages); + } + } + + r = kvm_arch_prepare_memory_region(kvm, old, new, change); + + /* Free the bitmap on failure if it was allocated above. */ + if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap)) + kvm_destroy_dirty_bitmap(new); + + return r; +} + +static void kvm_commit_memory_region(struct kvm *kvm, + struct kvm_memory_slot *old, + const struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + int old_flags = old ? old->flags : 0; + int new_flags = new ? new->flags : 0; + /* + * Update the total number of memslot pages before calling the arch + * hook so that architectures can consume the result directly. + */ + if (change == KVM_MR_DELETE) + kvm->nr_memslot_pages -= old->npages; + else if (change == KVM_MR_CREATE) + kvm->nr_memslot_pages += new->npages; + + if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) { + int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1; + atomic_set(&kvm->nr_memslots_dirty_logging, + atomic_read(&kvm->nr_memslots_dirty_logging) + change); + } + + kvm_arch_commit_memory_region(kvm, old, new, change); + + switch (change) { + case KVM_MR_CREATE: + /* Nothing more to do. */ + break; + case KVM_MR_DELETE: + /* Free the old memslot and all its metadata. */ + kvm_free_memslot(kvm, old); + break; + case KVM_MR_MOVE: + case KVM_MR_FLAGS_ONLY: + /* + * Free the dirty bitmap as needed; the below check encompasses + * both the flags and whether a ring buffer is being used) + */ + if (old->dirty_bitmap && !new->dirty_bitmap) + kvm_destroy_dirty_bitmap(old); + + /* + * The final quirk. Free the detached, old slot, but only its + * memory, not any metadata. Metadata, including arch specific + * data, may be reused by @new. + */ + kfree(old); + break; + default: + BUG(); + } +} + +/* + * Activate @new, which must be installed in the inactive slots by the caller, + * by swapping the active slots and then propagating @new to @old once @old is + * unreachable and can be safely modified. + * + * With NULL @old this simply adds @new to @active (while swapping the sets). + * With NULL @new this simply removes @old from @active and frees it + * (while also swapping the sets). + */ +static void kvm_activate_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + int as_id = kvm_memslots_get_as_id(old, new); + + kvm_swap_active_memslots(kvm, as_id); + + /* Propagate the new memslot to the now inactive memslots. */ + kvm_replace_memslot(kvm, old, new); +} + +static void kvm_copy_memslot(struct kvm_memory_slot *dest, + const struct kvm_memory_slot *src) +{ + dest->base_gfn = src->base_gfn; + dest->npages = src->npages; + dest->dirty_bitmap = src->dirty_bitmap; + dest->arch = src->arch; + dest->userspace_addr = src->userspace_addr; + dest->flags = src->flags; + dest->id = src->id; + dest->as_id = src->as_id; +} + +static void kvm_invalidate_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Mark the current slot INVALID. As with all memslot modifications, + * this must be done on an unreachable slot to avoid modifying the + * current slot in the active tree. + */ + kvm_copy_memslot(invalid_slot, old); + invalid_slot->flags |= KVM_MEMSLOT_INVALID; + kvm_replace_memslot(kvm, old, invalid_slot); + + /* + * Activate the slot that is now marked INVALID, but don't propagate + * the slot to the now inactive slots. The slot is either going to be + * deleted or recreated as a new slot. + */ + kvm_swap_active_memslots(kvm, old->as_id); + + /* + * From this point no new shadow pages pointing to a deleted, or moved, + * memslot will be created. Validation of sp->gfn happens in: + * - gfn_to_hva (kvm_read_guest, gfn_to_pfn) + * - kvm_is_visible_gfn (mmu_check_root) + */ + kvm_arch_flush_shadow_memslot(kvm, old); + kvm_arch_guest_memory_reclaimed(kvm); + + /* Was released by kvm_swap_active_memslots(), reacquire. */ + mutex_lock(&kvm->slots_arch_lock); + + /* + * Copy the arch-specific field of the newly-installed slot back to the + * old slot as the arch data could have changed between releasing + * slots_arch_lock in kvm_swap_active_memslots() and re-acquiring the lock + * above. Writers are required to retrieve memslots *after* acquiring + * slots_arch_lock, thus the active slot's data is guaranteed to be fresh. + */ + old->arch = invalid_slot->arch; +} + +static void kvm_create_memslot(struct kvm *kvm, + struct kvm_memory_slot *new) +{ + /* Add the new memslot to the inactive set and activate. */ + kvm_replace_memslot(kvm, NULL, new); + kvm_activate_memslot(kvm, NULL, new); +} + +static void kvm_delete_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Remove the old memslot (in the inactive memslots) by passing NULL as + * the "new" slot, and for the invalid version in the active slots. + */ + kvm_replace_memslot(kvm, old, NULL); + kvm_activate_memslot(kvm, invalid_slot, NULL); +} + +static void kvm_move_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + struct kvm_memory_slot *invalid_slot) +{ + /* + * Replace the old memslot in the inactive slots, and then swap slots + * and replace the current INVALID with the new as well. + */ + kvm_replace_memslot(kvm, old, new); + kvm_activate_memslot(kvm, invalid_slot, new); +} + +static void kvm_update_flags_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new) +{ + /* + * Similar to the MOVE case, but the slot doesn't need to be zapped as + * an intermediate step. Instead, the old memslot is simply replaced + * with a new, updated copy in both memslot sets. + */ + kvm_replace_memslot(kvm, old, new); + kvm_activate_memslot(kvm, old, new); +} + +static int kvm_set_memslot(struct kvm *kvm, + struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + struct kvm_memory_slot *invalid_slot; + int r; + + /* + * Released in kvm_swap_active_memslots(). + * + * Must be held from before the current memslots are copied until after + * the new memslots are installed with rcu_assign_pointer, then + * released before the synchronize srcu in kvm_swap_active_memslots(). + * + * When modifying memslots outside of the slots_lock, must be held + * before reading the pointer to the current memslots until after all + * changes to those memslots are complete. + * + * These rules ensure that installing new memslots does not lose + * changes made to the previous memslots. + */ + mutex_lock(&kvm->slots_arch_lock); + + /* + * Invalidate the old slot if it's being deleted or moved. This is + * done prior to actually deleting/moving the memslot to allow vCPUs to + * continue running by ensuring there are no mappings or shadow pages + * for the memslot when it is deleted/moved. Without pre-invalidation + * (and without a lock), a window would exist between effecting the + * delete/move and committing the changes in arch code where KVM or a + * guest could access a non-existent memslot. + * + * Modifications are done on a temporary, unreachable slot. The old + * slot needs to be preserved in case a later step fails and the + * invalidation needs to be reverted. + */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) { + invalid_slot = kzalloc(sizeof(*invalid_slot), GFP_KERNEL_ACCOUNT); + if (!invalid_slot) { + mutex_unlock(&kvm->slots_arch_lock); + return -ENOMEM; + } + kvm_invalidate_memslot(kvm, old, invalid_slot); + } + + r = kvm_prepare_memory_region(kvm, old, new, change); + if (r) { + /* + * For DELETE/MOVE, revert the above INVALID change. No + * modifications required since the original slot was preserved + * in the inactive slots. Changing the active memslots also + * release slots_arch_lock. + */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) { + kvm_activate_memslot(kvm, invalid_slot, old); + kfree(invalid_slot); + } else { + mutex_unlock(&kvm->slots_arch_lock); + } + return r; + } + + /* + * For DELETE and MOVE, the working slot is now active as the INVALID + * version of the old slot. MOVE is particularly special as it reuses + * the old slot and returns a copy of the old slot (in working_slot). + * For CREATE, there is no old slot. For DELETE and FLAGS_ONLY, the + * old slot is detached but otherwise preserved. + */ + if (change == KVM_MR_CREATE) + kvm_create_memslot(kvm, new); + else if (change == KVM_MR_DELETE) + kvm_delete_memslot(kvm, old, invalid_slot); + else if (change == KVM_MR_MOVE) + kvm_move_memslot(kvm, old, new, invalid_slot); + else if (change == KVM_MR_FLAGS_ONLY) + kvm_update_flags_memslot(kvm, old, new); + else + BUG(); + + /* Free the temporary INVALID slot used for DELETE and MOVE. */ + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) + kfree(invalid_slot); + + /* + * No need to refresh new->arch, changes after dropping slots_arch_lock + * will directly hit the final, active memslot. Architectures are + * responsible for knowing that new->arch may be stale. + */ + kvm_commit_memory_region(kvm, old, new, change); + + return 0; +} + +static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, + gfn_t start, gfn_t end) +{ + struct kvm_memslot_iter iter; + + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { + if (iter.slot->id != id) + return true; + } + + return false; +} + +/* + * Allocate some memory and give it an address in the guest physical address + * space. + * + * Discontiguous memory is allowed, mostly for framebuffers. + * + * Must be called holding kvm->slots_lock for write. + */ +int __kvm_set_memory_region(struct kvm *kvm, + const struct kvm_userspace_memory_region *mem) +{ + struct kvm_memory_slot *old, *new; + struct kvm_memslots *slots; + enum kvm_mr_change change; + unsigned long npages; + gfn_t base_gfn; + int as_id, id; + int r; + + r = check_memory_region_flags(mem); + if (r) + return r; + + as_id = mem->slot >> 16; + id = (u16)mem->slot; + + /* General sanity checks */ + if ((mem->memory_size & (PAGE_SIZE - 1)) || + (mem->memory_size != (unsigned long)mem->memory_size)) + return -EINVAL; + if (mem->guest_phys_addr & (PAGE_SIZE - 1)) + return -EINVAL; + /* We can read the guest memory with __xxx_user() later on. */ + if ((mem->userspace_addr & (PAGE_SIZE - 1)) || + (mem->userspace_addr != untagged_addr(mem->userspace_addr)) || + !access_ok((void __user *)(unsigned long)mem->userspace_addr, + mem->memory_size)) + return -EINVAL; + if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM) + return -EINVAL; + if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) + return -EINVAL; + if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + + /* + * Note, the old memslot (and the pointer itself!) may be invalidated + * and/or destroyed by kvm_set_memslot(). + */ + old = id_to_memslot(slots, id); + + if (!mem->memory_size) { + if (!old || !old->npages) + return -EINVAL; + + if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages)) + return -EIO; + + return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE); + } + + base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT); + npages = (mem->memory_size >> PAGE_SHIFT); + + if (!old || !old->npages) { + change = KVM_MR_CREATE; + + /* + * To simplify KVM internals, the total number of pages across + * all memslots must fit in an unsigned long. + */ + if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) + return -EINVAL; + } else { /* Modify an existing slot. */ + if ((mem->userspace_addr != old->userspace_addr) || + (npages != old->npages) || + ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) + return -EINVAL; + + if (base_gfn != old->base_gfn) + change = KVM_MR_MOVE; + else if (mem->flags != old->flags) + change = KVM_MR_FLAGS_ONLY; + else /* Nothing to change. */ + return 0; + } + + if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) && + kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages)) + return -EEXIST; + + /* Allocate a slot that will persist in the memslot. */ + new = kzalloc(sizeof(*new), GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->as_id = as_id; + new->id = id; + new->base_gfn = base_gfn; + new->npages = npages; + new->flags = mem->flags; + new->userspace_addr = mem->userspace_addr; + + r = kvm_set_memslot(kvm, old, new, change); + if (r) + kfree(new); + return r; +} +EXPORT_SYMBOL_GPL(__kvm_set_memory_region); + +int kvm_set_memory_region(struct kvm *kvm, + const struct kvm_userspace_memory_region *mem) +{ + int r; + + mutex_lock(&kvm->slots_lock); + r = __kvm_set_memory_region(kvm, mem); + mutex_unlock(&kvm->slots_lock); + return r; +} +EXPORT_SYMBOL_GPL(kvm_set_memory_region); + +static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, + struct kvm_userspace_memory_region *mem) +{ + if ((u16)mem->slot >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + return kvm_set_memory_region(kvm, mem); +} + +#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT +/** + * kvm_get_dirty_log - get a snapshot of dirty pages + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * @is_dirty: set to '1' if any dirty pages were found + * @memslot: set to the associated memslot, always valid on success + */ +int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, + int *is_dirty, struct kvm_memory_slot **memslot) +{ + struct kvm_memslots *slots; + int i, as_id, id; + unsigned long n; + unsigned long any = 0; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + *memslot = NULL; + *is_dirty = 0; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + *memslot = id_to_memslot(slots, id); + if (!(*memslot) || !(*memslot)->dirty_bitmap) + return -ENOENT; + + kvm_arch_sync_dirty_log(kvm, *memslot); + + n = kvm_dirty_bitmap_bytes(*memslot); + + for (i = 0; !any && i < n/sizeof(long); ++i) + any = (*memslot)->dirty_bitmap[i]; + + if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n)) + return -EFAULT; + + if (any) + *is_dirty = 1; + return 0; +} +EXPORT_SYMBOL_GPL(kvm_get_dirty_log); + +#else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ +/** + * kvm_get_dirty_log_protect - get a snapshot of dirty pages + * and reenable dirty page tracking for the corresponding pages. + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * + * We need to keep it in mind that VCPU threads can write to the bitmap + * concurrently. So, to avoid losing track of dirty pages we keep the + * following order: + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Upon return caller flushes TLB's if needed. + * + * Between 2 and 4, the guest may write to the page using the remaining TLB + * entry. This is not a problem because the page is reported dirty using + * the snapshot taken before and step 4 ensures that writes done after + * exiting to userspace will be logged for the next call. + * + */ +static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int i, as_id, id; + unsigned long n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + bool flush; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; + + dirty_bitmap = memslot->dirty_bitmap; + + kvm_arch_sync_dirty_log(kvm, memslot); + + n = kvm_dirty_bitmap_bytes(memslot); + flush = false; + if (kvm->manual_dirty_log_protect) { + /* + * Unlike kvm_get_dirty_log, we always return false in *flush, + * because no flush is needed until KVM_CLEAR_DIRTY_LOG. There + * is some code duplication between this function and + * kvm_get_dirty_log, but hopefully all architecture + * transition to kvm_get_dirty_log_protect and kvm_get_dirty_log + * can be eliminated. + */ + dirty_bitmap_buffer = dirty_bitmap; + } else { + dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot); + memset(dirty_bitmap_buffer, 0, n); + + KVM_MMU_LOCK(kvm); + for (i = 0; i < n / sizeof(long); i++) { + unsigned long mask; + gfn_t offset; + + if (!dirty_bitmap[i]) + continue; + + flush = true; + mask = xchg(&dirty_bitmap[i], 0); + dirty_bitmap_buffer[i] = mask; + + offset = i * BITS_PER_LONG; + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, + offset, mask); + } + KVM_MMU_UNLOCK(kvm); + } + + if (flush) + kvm_flush_remote_tlbs_memslot(kvm, memslot); + + if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n)) + return -EFAULT; + return 0; +} + + +/** + * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot + * @kvm: kvm instance + * @log: slot id and address to which we copy the log + * + * Steps 1-4 below provide general overview of dirty page logging. See + * kvm_get_dirty_log_protect() function description for additional details. + * + * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we + * always flush the TLB (step 4) even if previous step failed and the dirty + * bitmap may be corrupt. Regardless of previous outcome the KVM logging API + * does not preclude user space subsequent dirty log read. Flushing TLB ensures + * writes will be marked dirty for next log read. + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Flush TLB's if needed. + */ +static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, + struct kvm_dirty_log *log) +{ + int r; + + mutex_lock(&kvm->slots_lock); + + r = kvm_get_dirty_log_protect(kvm, log); + + mutex_unlock(&kvm->slots_lock); + return r; +} + +/** + * kvm_clear_dirty_log_protect - clear dirty bits in the bitmap + * and reenable dirty page tracking for the corresponding pages. + * @kvm: pointer to kvm instance + * @log: slot id and address from which to fetch the bitmap of dirty pages + */ +static int kvm_clear_dirty_log_protect(struct kvm *kvm, + struct kvm_clear_dirty_log *log) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int as_id, id; + gfn_t offset; + unsigned long i, n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + bool flush; + + /* Dirty ring tracking may be exclusive to dirty log tracking */ + if (!kvm_use_dirty_bitmap(kvm)) + return -ENXIO; + + as_id = log->slot >> 16; + id = (u16)log->slot; + if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) + return -EINVAL; + + if (log->first_page & 63) + return -EINVAL; + + slots = __kvm_memslots(kvm, as_id); + memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; + + dirty_bitmap = memslot->dirty_bitmap; + + n = ALIGN(log->num_pages, BITS_PER_LONG) / 8; + + if (log->first_page > memslot->npages || + log->num_pages > memslot->npages - log->first_page || + (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63))) + return -EINVAL; + + kvm_arch_sync_dirty_log(kvm, memslot); + + flush = false; + dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot); + if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n)) + return -EFAULT; + + KVM_MMU_LOCK(kvm); + for (offset = log->first_page, i = offset / BITS_PER_LONG, + n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--; + i++, offset += BITS_PER_LONG) { + unsigned long mask = *dirty_bitmap_buffer++; + atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i]; + if (!mask) + continue; + + mask &= atomic_long_fetch_andnot(mask, p); + + /* + * mask contains the bits that really have been cleared. This + * never includes any bits beyond the length of the memslot (if + * the length is not aligned to 64 pages), therefore it is not + * a problem if userspace sets them in log->dirty_bitmap. + */ + if (mask) { + flush = true; + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, + offset, mask); + } + } + KVM_MMU_UNLOCK(kvm); + + if (flush) + kvm_flush_remote_tlbs_memslot(kvm, memslot); + + return 0; +} + +static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, + struct kvm_clear_dirty_log *log) +{ + int r; + + mutex_lock(&kvm->slots_lock); + + r = kvm_clear_dirty_log_protect(kvm, log); + + mutex_unlock(&kvm->slots_lock); + return r; +} +#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ + +struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn) +{ + return __gfn_to_memslot(kvm_memslots(kvm), gfn); +} +EXPORT_SYMBOL_GPL(gfn_to_memslot); + +struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu); + u64 gen = slots->generation; + struct kvm_memory_slot *slot; + + /* + * This also protects against using a memslot from a different address space, + * since different address spaces have different generation numbers. + */ + if (unlikely(gen != vcpu->last_used_slot_gen)) { + vcpu->last_used_slot = NULL; + vcpu->last_used_slot_gen = gen; + } + + slot = try_get_memslot(vcpu->last_used_slot, gfn); + if (slot) + return slot; + + /* + * Fall back to searching all memslots. We purposely use + * search_memslots() instead of __gfn_to_memslot() to avoid + * thrashing the VM-wide last_used_slot in kvm_memslots. + */ + slot = search_memslots(slots, gfn, false); + if (slot) { + vcpu->last_used_slot = slot; + return slot; + } + + return NULL; +} + +bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) +{ + struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn); + + return kvm_is_visible_memslot(memslot); +} +EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); + +bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return kvm_is_visible_memslot(memslot); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn); + +unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct vm_area_struct *vma; + unsigned long addr, size; + + size = PAGE_SIZE; + + addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL); + if (kvm_is_error_hva(addr)) + return PAGE_SIZE; + + mmap_read_lock(current->mm); + vma = find_vma(current->mm, addr); + if (!vma) + goto out; + + size = vma_kernel_pagesize(vma); + +out: + mmap_read_unlock(current->mm); + + return size; +} + +static bool memslot_is_readonly(const struct kvm_memory_slot *slot) +{ + return slot->flags & KVM_MEM_READONLY; +} + +static unsigned long __gfn_to_hva_many(const struct kvm_memory_slot *slot, gfn_t gfn, + gfn_t *nr_pages, bool write) +{ + if (!slot || slot->flags & KVM_MEMSLOT_INVALID) + return KVM_HVA_ERR_BAD; + + if (memslot_is_readonly(slot) && write) + return KVM_HVA_ERR_RO_BAD; + + if (nr_pages) + *nr_pages = slot->npages - (gfn - slot->base_gfn); + + return __gfn_to_hva_memslot(slot, gfn); +} + +static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn, + gfn_t *nr_pages) +{ + return __gfn_to_hva_many(slot, gfn, nr_pages, true); +} + +unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, + gfn_t gfn) +{ + return gfn_to_hva_many(slot, gfn, NULL); +} +EXPORT_SYMBOL_GPL(gfn_to_hva_memslot); + +unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) +{ + return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL); +} +EXPORT_SYMBOL_GPL(gfn_to_hva); + +unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva); + +/* + * Return the hva of a @gfn and the R/W attribute if possible. + * + * @slot: the kvm_memory_slot which contains @gfn + * @gfn: the gfn to be translated + * @writable: used to return the read/write attribute of the @slot if the hva + * is valid and @writable is not NULL + */ +unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot, + gfn_t gfn, bool *writable) +{ + unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false); + + if (!kvm_is_error_hva(hva) && writable) + *writable = !memslot_is_readonly(slot); + + return hva; +} + +unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return gfn_to_hva_memslot_prot(slot, gfn, writable); +} + +unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return gfn_to_hva_memslot_prot(slot, gfn, writable); +} + +static inline int check_user_page_hwpoison(unsigned long addr) +{ + int rc, flags = FOLL_HWPOISON | FOLL_WRITE; + + rc = get_user_pages(addr, 1, flags, NULL); + return rc == -EHWPOISON; +} + +/* + * The fast path to get the writable pfn which will be stored in @pfn, + * true indicates success, otherwise false is returned. It's also the + * only part that runs if we can in atomic context. + */ +static bool hva_to_pfn_fast(unsigned long addr, bool write_fault, + bool *writable, kvm_pfn_t *pfn) +{ + struct page *page[1]; + + /* + * Fast pin a writable pfn only if it is a write fault request + * or the caller allows to map a writable pfn for a read fault + * request. + */ + if (!(write_fault || writable)) + return false; + + if (get_user_page_fast_only(addr, FOLL_WRITE, page)) { + *pfn = page_to_pfn(page[0]); + + if (writable) + *writable = true; + return true; + } + + return false; +} + +/* + * The slow path to get the pfn of the specified host virtual address, + * 1 indicates success, -errno is returned if error is detected. + */ +static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, + bool interruptible, bool *writable, kvm_pfn_t *pfn) +{ + /* + * When a VCPU accesses a page that is not mapped into the secondary + * MMU, we lookup the page using GUP to map it, so the guest VCPU can + * make progress. We always want to honor NUMA hinting faults in that + * case, because GUP usage corresponds to memory accesses from the VCPU. + * Otherwise, we'd not trigger NUMA hinting faults once a page is + * mapped into the secondary MMU and gets accessed by a VCPU. + * + * Note that get_user_page_fast_only() and FOLL_WRITE for now + * implicitly honor NUMA hinting faults and don't need this flag. + */ + unsigned int flags = FOLL_HWPOISON | FOLL_HONOR_NUMA_FAULT; + struct page *page; + int npages; + + might_sleep(); + + if (writable) + *writable = write_fault; + + if (write_fault) + flags |= FOLL_WRITE; + if (async) + flags |= FOLL_NOWAIT; + if (interruptible) + flags |= FOLL_INTERRUPTIBLE; + + npages = get_user_pages_unlocked(addr, 1, &page, flags); + if (npages != 1) + return npages; + + /* map read fault as writable if possible */ + if (unlikely(!write_fault) && writable) { + struct page *wpage; + + if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) { + *writable = true; + put_page(page); + page = wpage; + } + } + *pfn = page_to_pfn(page); + return npages; +} + +static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault) +{ + if (unlikely(!(vma->vm_flags & VM_READ))) + return false; + + if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE)))) + return false; + + return true; +} + +static int kvm_try_get_pfn(kvm_pfn_t pfn) +{ + struct page *page = kvm_pfn_to_refcounted_page(pfn); + + if (!page) + return 1; + + return get_page_unless_zero(page); +} + +static int hva_to_pfn_remapped(struct vm_area_struct *vma, + unsigned long addr, bool write_fault, + bool *writable, kvm_pfn_t *p_pfn) +{ + kvm_pfn_t pfn; + pte_t *ptep; + pte_t pte; + spinlock_t *ptl; + int r; + + r = follow_pte(vma->vm_mm, addr, &ptep, &ptl); + if (r) { + /* + * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does + * not call the fault handler, so do it here. + */ + bool unlocked = false; + r = fixup_user_fault(current->mm, addr, + (write_fault ? FAULT_FLAG_WRITE : 0), + &unlocked); + if (unlocked) + return -EAGAIN; + if (r) + return r; + + r = follow_pte(vma->vm_mm, addr, &ptep, &ptl); + if (r) + return r; + } + + pte = ptep_get(ptep); + + if (write_fault && !pte_write(pte)) { + pfn = KVM_PFN_ERR_RO_FAULT; + goto out; + } + + if (writable) + *writable = pte_write(pte); + pfn = pte_pfn(pte); + + /* + * Get a reference here because callers of *hva_to_pfn* and + * *gfn_to_pfn* ultimately call kvm_release_pfn_clean on the + * returned pfn. This is only needed if the VMA has VM_MIXEDMAP + * set, but the kvm_try_get_pfn/kvm_release_pfn_clean pair will + * simply do nothing for reserved pfns. + * + * Whoever called remap_pfn_range is also going to call e.g. + * unmap_mapping_range before the underlying pages are freed, + * causing a call to our MMU notifier. + * + * Certain IO or PFNMAP mappings can be backed with valid + * struct pages, but be allocated without refcounting e.g., + * tail pages of non-compound higher order allocations, which + * would then underflow the refcount when the caller does the + * required put_page. Don't allow those pages here. + */ + if (!kvm_try_get_pfn(pfn)) + r = -EFAULT; + +out: + pte_unmap_unlock(ptep, ptl); + *p_pfn = pfn; + + return r; +} + +/* + * Pin guest page in memory and return its pfn. + * @addr: host virtual address which maps memory to the guest + * @atomic: whether this function can sleep + * @interruptible: whether the process can be interrupted by non-fatal signals + * @async: whether this function need to wait IO complete if the + * host page is not in the memory + * @write_fault: whether we should get a writable host page + * @writable: whether it allows to map a writable host page for !@write_fault + * + * The function will map a writable host page for these two cases: + * 1): @write_fault = true + * 2): @write_fault = false && @writable, @writable will tell the caller + * whether the mapping is writable. + */ +kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible, + bool *async, bool write_fault, bool *writable) +{ + struct vm_area_struct *vma; + kvm_pfn_t pfn; + int npages, r; + + /* we can do it either atomically or asynchronously, not both */ + BUG_ON(atomic && async); + + if (hva_to_pfn_fast(addr, write_fault, writable, &pfn)) + return pfn; + + if (atomic) + return KVM_PFN_ERR_FAULT; + + npages = hva_to_pfn_slow(addr, async, write_fault, interruptible, + writable, &pfn); + if (npages == 1) + return pfn; + if (npages == -EINTR) + return KVM_PFN_ERR_SIGPENDING; + + mmap_read_lock(current->mm); + if (npages == -EHWPOISON || + (!async && check_user_page_hwpoison(addr))) { + pfn = KVM_PFN_ERR_HWPOISON; + goto exit; + } + +retry: + vma = vma_lookup(current->mm, addr); + + if (vma == NULL) + pfn = KVM_PFN_ERR_FAULT; + else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) { + r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn); + if (r == -EAGAIN) + goto retry; + if (r < 0) + pfn = KVM_PFN_ERR_FAULT; + } else { + if (async && vma_is_valid(vma, write_fault)) + *async = true; + pfn = KVM_PFN_ERR_FAULT; + } +exit: + mmap_read_unlock(current->mm); + return pfn; +} + +kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn, + bool atomic, bool interruptible, bool *async, + bool write_fault, bool *writable, hva_t *hva) +{ + unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault); + + if (hva) + *hva = addr; + + if (addr == KVM_HVA_ERR_RO_BAD) { + if (writable) + *writable = false; + return KVM_PFN_ERR_RO_FAULT; + } + + if (kvm_is_error_hva(addr)) { + if (writable) + *writable = false; + return KVM_PFN_NOSLOT; + } + + /* Do not map writable pfn in the readonly memslot. */ + if (writable && memslot_is_readonly(slot)) { + *writable = false; + writable = NULL; + } + + return hva_to_pfn(addr, atomic, interruptible, async, write_fault, + writable); +} +EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot); + +kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault, + bool *writable) +{ + return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, false, + NULL, write_fault, writable, NULL); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn_prot); + +kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn) +{ + return __gfn_to_pfn_memslot(slot, gfn, false, false, NULL, true, + NULL, NULL); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot); + +kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn) +{ + return __gfn_to_pfn_memslot(slot, gfn, true, false, NULL, true, + NULL, NULL); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic); + +kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic); + +kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) +{ + return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn); + +kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn); + +int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn, + struct page **pages, int nr_pages) +{ + unsigned long addr; + gfn_t entry = 0; + + addr = gfn_to_hva_many(slot, gfn, &entry); + if (kvm_is_error_hva(addr)) + return -1; + + if (entry < nr_pages) + return 0; + + return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages); +} +EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic); + +/* + * Do not use this helper unless you are absolutely certain the gfn _must_ be + * backed by 'struct page'. A valid example is if the backing memslot is + * controlled by KVM. Note, if the returned page is valid, it's refcount has + * been elevated by gfn_to_pfn(). + */ +struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) +{ + struct page *page; + kvm_pfn_t pfn; + + pfn = gfn_to_pfn(kvm, gfn); + + if (is_error_noslot_pfn(pfn)) + return KVM_ERR_PTR_BAD_PAGE; + + page = kvm_pfn_to_refcounted_page(pfn); + if (!page) + return KVM_ERR_PTR_BAD_PAGE; + + return page; +} +EXPORT_SYMBOL_GPL(gfn_to_page); + +void kvm_release_pfn(kvm_pfn_t pfn, bool dirty) +{ + if (dirty) + kvm_release_pfn_dirty(pfn); + else + kvm_release_pfn_clean(pfn); +} + +int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map) +{ + kvm_pfn_t pfn; + void *hva = NULL; + struct page *page = KVM_UNMAPPED_PAGE; + + if (!map) + return -EINVAL; + + pfn = gfn_to_pfn(vcpu->kvm, gfn); + if (is_error_noslot_pfn(pfn)) + return -EINVAL; + + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + hva = kmap(page); +#ifdef CONFIG_HAS_IOMEM + } else { + hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB); +#endif + } + + if (!hva) + return -EFAULT; + + map->page = page; + map->hva = hva; + map->pfn = pfn; + map->gfn = gfn; + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_map); + +void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty) +{ + if (!map) + return; + + if (!map->hva) + return; + + if (map->page != KVM_UNMAPPED_PAGE) + kunmap(map->page); +#ifdef CONFIG_HAS_IOMEM + else + memunmap(map->hva); +#endif + + if (dirty) + kvm_vcpu_mark_page_dirty(vcpu, map->gfn); + + kvm_release_pfn(map->pfn, dirty); + + map->hva = NULL; + map->page = NULL; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_unmap); + +static bool kvm_is_ad_tracked_page(struct page *page) +{ + /* + * Per page-flags.h, pages tagged PG_reserved "should in general not be + * touched (e.g. set dirty) except by its owner". + */ + return !PageReserved(page); +} + +static void kvm_set_page_dirty(struct page *page) +{ + if (kvm_is_ad_tracked_page(page)) + SetPageDirty(page); +} + +static void kvm_set_page_accessed(struct page *page) +{ + if (kvm_is_ad_tracked_page(page)) + mark_page_accessed(page); +} + +void kvm_release_page_clean(struct page *page) +{ + WARN_ON(is_error_page(page)); + + kvm_set_page_accessed(page); + put_page(page); +} +EXPORT_SYMBOL_GPL(kvm_release_page_clean); + +void kvm_release_pfn_clean(kvm_pfn_t pfn) +{ + struct page *page; + + if (is_error_noslot_pfn(pfn)) + return; + + page = kvm_pfn_to_refcounted_page(pfn); + if (!page) + return; + + kvm_release_page_clean(page); +} +EXPORT_SYMBOL_GPL(kvm_release_pfn_clean); + +void kvm_release_page_dirty(struct page *page) +{ + WARN_ON(is_error_page(page)); + + kvm_set_page_dirty(page); + kvm_release_page_clean(page); +} +EXPORT_SYMBOL_GPL(kvm_release_page_dirty); + +void kvm_release_pfn_dirty(kvm_pfn_t pfn) +{ + struct page *page; + + if (is_error_noslot_pfn(pfn)) + return; + + page = kvm_pfn_to_refcounted_page(pfn); + if (!page) + return; + + kvm_release_page_dirty(page); +} +EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty); + +/* + * Note, checking for an error/noslot pfn is the caller's responsibility when + * directly marking a page dirty/accessed. Unlike the "release" helpers, the + * "set" helpers are not to be used when the pfn might point at garbage. + */ +void kvm_set_pfn_dirty(kvm_pfn_t pfn) +{ + if (WARN_ON(is_error_noslot_pfn(pfn))) + return; + + if (pfn_valid(pfn)) + kvm_set_page_dirty(pfn_to_page(pfn)); +} +EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty); + +void kvm_set_pfn_accessed(kvm_pfn_t pfn) +{ + if (WARN_ON(is_error_noslot_pfn(pfn))) + return; + + if (pfn_valid(pfn)) + kvm_set_page_accessed(pfn_to_page(pfn)); +} +EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed); + +static int next_segment(unsigned long len, int offset) +{ + if (len > PAGE_SIZE - offset) + return PAGE_SIZE - offset; + else + return len; +} + +static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn, + void *data, int offset, int len) +{ + int r; + unsigned long addr; + + addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); + if (kvm_is_error_hva(addr)) + return -EFAULT; + r = __copy_from_user(data, (void __user *)addr + offset, len); + if (r) + return -EFAULT; + return 0; +} + +int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, + int len) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return __kvm_read_guest_page(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_GPL(kvm_read_guest_page); + +int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, + int offset, int len) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return __kvm_read_guest_page(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page); + +int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_read_guest_page(kvm, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_GPL(kvm_read_guest); + +int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest); + +static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn, + void *data, int offset, unsigned long len) +{ + int r; + unsigned long addr; + + addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); + if (kvm_is_error_hva(addr)) + return -EFAULT; + pagefault_disable(); + r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len); + pagefault_enable(); + if (r) + return -EFAULT; + return 0; +} + +int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa, + void *data, unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + int offset = offset_in_page(gpa); + + return __kvm_read_guest_atomic(slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic); + +static int __kvm_write_guest_page(struct kvm *kvm, + struct kvm_memory_slot *memslot, gfn_t gfn, + const void *data, int offset, int len) +{ + int r; + unsigned long addr; + + addr = gfn_to_hva_memslot(memslot, gfn); + if (kvm_is_error_hva(addr)) + return -EFAULT; + r = __copy_to_user((void __user *)addr + offset, data, len); + if (r) + return -EFAULT; + mark_page_dirty_in_slot(kvm, memslot, gfn); + return 0; +} + +int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, + const void *data, int offset, int len) +{ + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + + return __kvm_write_guest_page(kvm, slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_GPL(kvm_write_guest_page); + +int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, + const void *data, int offset, int len) +{ + struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + + return __kvm_write_guest_page(vcpu->kvm, slot, gfn, data, offset, len); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page); + +int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, + unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_write_guest_page(kvm, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_GPL(kvm_write_guest); + +int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data, + unsigned long len) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + data += seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest); + +static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots, + struct gfn_to_hva_cache *ghc, + gpa_t gpa, unsigned long len) +{ + int offset = offset_in_page(gpa); + gfn_t start_gfn = gpa >> PAGE_SHIFT; + gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT; + gfn_t nr_pages_needed = end_gfn - start_gfn + 1; + gfn_t nr_pages_avail; + + /* Update ghc->generation before performing any error checks. */ + ghc->generation = slots->generation; + + if (start_gfn > end_gfn) { + ghc->hva = KVM_HVA_ERR_BAD; + return -EINVAL; + } + + /* + * If the requested region crosses two memslots, we still + * verify that the entire region is valid here. + */ + for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) { + ghc->memslot = __gfn_to_memslot(slots, start_gfn); + ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn, + &nr_pages_avail); + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + } + + /* Use the slow path for cross page reads and writes. */ + if (nr_pages_needed == 1) + ghc->hva += offset; + else + ghc->memslot = NULL; + + ghc->gpa = gpa; + ghc->len = len; + return 0; +} + +int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + gpa_t gpa, unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len); +} +EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init); + +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned int offset, + unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + int r; + gpa_t gpa = ghc->gpa + offset; + + if (WARN_ON_ONCE(len + offset > ghc->len)) + return -EINVAL; + + if (slots->generation != ghc->generation) { + if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) + return -EFAULT; + } + + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + + if (unlikely(!ghc->memslot)) + return kvm_write_guest(kvm, gpa, data, len); + + r = __copy_to_user((void __user *)ghc->hva + offset, data, len); + if (r) + return -EFAULT; + mark_page_dirty_in_slot(kvm, ghc->memslot, gpa >> PAGE_SHIFT); + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached); + +int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len); +} +EXPORT_SYMBOL_GPL(kvm_write_guest_cached); + +int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned int offset, + unsigned long len) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + int r; + gpa_t gpa = ghc->gpa + offset; + + if (WARN_ON_ONCE(len + offset > ghc->len)) + return -EINVAL; + + if (slots->generation != ghc->generation) { + if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) + return -EFAULT; + } + + if (kvm_is_error_hva(ghc->hva)) + return -EFAULT; + + if (unlikely(!ghc->memslot)) + return kvm_read_guest(kvm, gpa, data, len); + + r = __copy_from_user(data, (void __user *)ghc->hva + offset, len); + if (r) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_read_guest_offset_cached); + +int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_read_guest_offset_cached(kvm, ghc, data, 0, len); +} +EXPORT_SYMBOL_GPL(kvm_read_guest_cached); + +int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len) +{ + const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0))); + gfn_t gfn = gpa >> PAGE_SHIFT; + int seg; + int offset = offset_in_page(gpa); + int ret; + + while ((seg = next_segment(len, offset)) != 0) { + ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, len); + if (ret < 0) + return ret; + offset = 0; + len -= seg; + ++gfn; + } + return 0; +} +EXPORT_SYMBOL_GPL(kvm_clear_guest); + +void mark_page_dirty_in_slot(struct kvm *kvm, + const struct kvm_memory_slot *memslot, + gfn_t gfn) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + +#ifdef CONFIG_HAVE_KVM_DIRTY_RING + if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm)) + return; + + WARN_ON_ONCE(!vcpu && !kvm_arch_allow_write_without_running_vcpu(kvm)); +#endif + + if (memslot && kvm_slot_dirty_track_enabled(memslot)) { + unsigned long rel_gfn = gfn - memslot->base_gfn; + u32 slot = (memslot->as_id << 16) | memslot->id; + + if (kvm->dirty_ring_size && vcpu) + kvm_dirty_ring_push(vcpu, slot, rel_gfn); + else if (memslot->dirty_bitmap) + set_bit_le(rel_gfn, memslot->dirty_bitmap); + } +} +EXPORT_SYMBOL_GPL(mark_page_dirty_in_slot); + +void mark_page_dirty(struct kvm *kvm, gfn_t gfn) +{ + struct kvm_memory_slot *memslot; + + memslot = gfn_to_memslot(kvm, gfn); + mark_page_dirty_in_slot(kvm, memslot, gfn); +} +EXPORT_SYMBOL_GPL(mark_page_dirty); + +void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + struct kvm_memory_slot *memslot; + + memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + mark_page_dirty_in_slot(vcpu->kvm, memslot, gfn); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty); + +void kvm_sigset_activate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + /* + * This does a lockless modification of ->real_blocked, which is fine + * because, only current can change ->real_blocked and all readers of + * ->real_blocked don't care as long ->real_blocked is always a subset + * of ->blocked. + */ + sigprocmask(SIG_SETMASK, &vcpu->sigset, ¤t->real_blocked); +} + +void kvm_sigset_deactivate(struct kvm_vcpu *vcpu) +{ + if (!vcpu->sigset_active) + return; + + sigprocmask(SIG_SETMASK, ¤t->real_blocked, NULL); + sigemptyset(¤t->real_blocked); +} + +static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + unsigned int old, val, grow, grow_start; + + old = val = vcpu->halt_poll_ns; + grow_start = READ_ONCE(halt_poll_ns_grow_start); + grow = READ_ONCE(halt_poll_ns_grow); + if (!grow) + goto out; + + val *= grow; + if (val < grow_start) + val = grow_start; + + vcpu->halt_poll_ns = val; +out: + trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old); +} + +static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + unsigned int old, val, shrink, grow_start; + + old = val = vcpu->halt_poll_ns; + shrink = READ_ONCE(halt_poll_ns_shrink); + grow_start = READ_ONCE(halt_poll_ns_grow_start); + if (shrink == 0) + val = 0; + else + val /= shrink; + + if (val < grow_start) + val = 0; + + vcpu->halt_poll_ns = val; + trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old); +} + +static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) +{ + int ret = -EINTR; + int idx = srcu_read_lock(&vcpu->kvm->srcu); + + if (kvm_arch_vcpu_runnable(vcpu)) + goto out; + if (kvm_cpu_has_pending_timer(vcpu)) + goto out; + if (signal_pending(current)) + goto out; + if (kvm_check_request(KVM_REQ_UNBLOCK, vcpu)) + goto out; + + ret = 0; +out: + srcu_read_unlock(&vcpu->kvm->srcu, idx); + return ret; +} + +/* + * Block the vCPU until the vCPU is runnable, an event arrives, or a signal is + * pending. This is mostly used when halting a vCPU, but may also be used + * directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI. + */ +bool kvm_vcpu_block(struct kvm_vcpu *vcpu) +{ + struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); + bool waited = false; + + vcpu->stat.generic.blocking = 1; + + preempt_disable(); + kvm_arch_vcpu_blocking(vcpu); + prepare_to_rcuwait(wait); + preempt_enable(); + + for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + + if (kvm_vcpu_check_block(vcpu) < 0) + break; + + waited = true; + schedule(); + } + + preempt_disable(); + finish_rcuwait(wait); + kvm_arch_vcpu_unblocking(vcpu); + preempt_enable(); + + vcpu->stat.generic.blocking = 0; + + return waited; +} + +static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start, + ktime_t end, bool success) +{ + struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic; + u64 poll_ns = ktime_to_ns(ktime_sub(end, start)); + + ++vcpu->stat.generic.halt_attempted_poll; + + if (success) { + ++vcpu->stat.generic.halt_successful_poll; + + if (!vcpu_valid_wakeup(vcpu)) + ++vcpu->stat.generic.halt_poll_invalid; + + stats->halt_poll_success_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns); + } else { + stats->halt_poll_fail_ns += poll_ns; + KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns); + } +} + +static unsigned int kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + + if (kvm->override_halt_poll_ns) { + /* + * Ensure kvm->max_halt_poll_ns is not read before + * kvm->override_halt_poll_ns. + * + * Pairs with the smp_wmb() when enabling KVM_CAP_HALT_POLL. + */ + smp_rmb(); + return READ_ONCE(kvm->max_halt_poll_ns); + } + + return READ_ONCE(halt_poll_ns); +} + +/* + * Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc... If halt + * polling is enabled, busy wait for a short time before blocking to avoid the + * expensive block+unblock sequence if a wake event arrives soon after the vCPU + * is halted. + */ +void kvm_vcpu_halt(struct kvm_vcpu *vcpu) +{ + unsigned int max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu); + bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); + ktime_t start, cur, poll_end; + bool waited = false; + bool do_halt_poll; + u64 halt_ns; + + if (vcpu->halt_poll_ns > max_halt_poll_ns) + vcpu->halt_poll_ns = max_halt_poll_ns; + + do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns; + + start = cur = poll_end = ktime_get(); + if (do_halt_poll) { + ktime_t stop = ktime_add_ns(start, vcpu->halt_poll_ns); + + do { + if (kvm_vcpu_check_block(vcpu) < 0) + goto out; + cpu_relax(); + poll_end = cur = ktime_get(); + } while (kvm_vcpu_can_poll(cur, stop)); + } + + waited = kvm_vcpu_block(vcpu); + + cur = ktime_get(); + if (waited) { + vcpu->stat.generic.halt_wait_ns += + ktime_to_ns(cur) - ktime_to_ns(poll_end); + KVM_STATS_LOG_HIST_UPDATE(vcpu->stat.generic.halt_wait_hist, + ktime_to_ns(cur) - ktime_to_ns(poll_end)); + } +out: + /* The total time the vCPU was "halted", including polling time. */ + halt_ns = ktime_to_ns(cur) - ktime_to_ns(start); + + /* + * Note, halt-polling is considered successful so long as the vCPU was + * never actually scheduled out, i.e. even if the wake event arrived + * after of the halt-polling loop itself, but before the full wait. + */ + if (do_halt_poll) + update_halt_poll_stats(vcpu, start, poll_end, !waited); + + if (halt_poll_allowed) { + /* Recompute the max halt poll time in case it changed. */ + max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu); + + if (!vcpu_valid_wakeup(vcpu)) { + shrink_halt_poll_ns(vcpu); + } else if (max_halt_poll_ns) { + if (halt_ns <= vcpu->halt_poll_ns) + ; + /* we had a long block, shrink polling */ + else if (vcpu->halt_poll_ns && + halt_ns > max_halt_poll_ns) + shrink_halt_poll_ns(vcpu); + /* we had a short halt and our poll time is too small */ + else if (vcpu->halt_poll_ns < max_halt_poll_ns && + halt_ns < max_halt_poll_ns) + grow_halt_poll_ns(vcpu); + } else { + vcpu->halt_poll_ns = 0; + } + } + + trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu)); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_halt); + +bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu) +{ + if (__kvm_vcpu_wake_up(vcpu)) { + WRITE_ONCE(vcpu->ready, true); + ++vcpu->stat.generic.halt_wakeup; + return true; + } + + return false; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up); + +#ifndef CONFIG_S390 +/* + * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode. + */ +void kvm_vcpu_kick(struct kvm_vcpu *vcpu) +{ + int me, cpu; + + if (kvm_vcpu_wake_up(vcpu)) + return; + + me = get_cpu(); + /* + * The only state change done outside the vcpu mutex is IN_GUEST_MODE + * to EXITING_GUEST_MODE. Therefore the moderately expensive "should + * kick" check does not need atomic operations if kvm_vcpu_kick is used + * within the vCPU thread itself. + */ + if (vcpu == __this_cpu_read(kvm_running_vcpu)) { + if (vcpu->mode == IN_GUEST_MODE) + WRITE_ONCE(vcpu->mode, EXITING_GUEST_MODE); + goto out; + } + + /* + * Note, the vCPU could get migrated to a different pCPU at any point + * after kvm_arch_vcpu_should_kick(), which could result in sending an + * IPI to the previous pCPU. But, that's ok because the purpose of the + * IPI is to force the vCPU to leave IN_GUEST_MODE, and migrating the + * vCPU also requires it to leave IN_GUEST_MODE. + */ + if (kvm_arch_vcpu_should_kick(vcpu)) { + cpu = READ_ONCE(vcpu->cpu); + if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) + smp_send_reschedule(cpu); + } +out: + put_cpu(); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_kick); +#endif /* !CONFIG_S390 */ + +int kvm_vcpu_yield_to(struct kvm_vcpu *target) +{ + struct pid *pid; + struct task_struct *task = NULL; + int ret = 0; + + rcu_read_lock(); + pid = rcu_dereference(target->pid); + if (pid) + task = get_pid_task(pid, PIDTYPE_PID); + rcu_read_unlock(); + if (!task) + return ret; + ret = yield_to(task, 1); + put_task_struct(task); + + return ret; +} +EXPORT_SYMBOL_GPL(kvm_vcpu_yield_to); + +/* + * Helper that checks whether a VCPU is eligible for directed yield. + * Most eligible candidate to yield is decided by following heuristics: + * + * (a) VCPU which has not done pl-exit or cpu relax intercepted recently + * (preempted lock holder), indicated by @in_spin_loop. + * Set at the beginning and cleared at the end of interception/PLE handler. + * + * (b) VCPU which has done pl-exit/ cpu relax intercepted but did not get + * chance last time (mostly it has become eligible now since we have probably + * yielded to lockholder in last iteration. This is done by toggling + * @dy_eligible each time a VCPU checked for eligibility.) + * + * Yielding to a recently pl-exited/cpu relax intercepted VCPU before yielding + * to preempted lock-holder could result in wrong VCPU selection and CPU + * burning. Giving priority for a potential lock-holder increases lock + * progress. + * + * Since algorithm is based on heuristics, accessing another VCPU data without + * locking does not harm. It may result in trying to yield to same VCPU, fail + * and continue with next VCPU and so on. + */ +static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT + bool eligible; + + eligible = !vcpu->spin_loop.in_spin_loop || + vcpu->spin_loop.dy_eligible; + + if (vcpu->spin_loop.in_spin_loop) + kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible); + + return eligible; +#else + return true; +#endif +} + +/* + * Unlike kvm_arch_vcpu_runnable, this function is called outside + * a vcpu_load/vcpu_put pair. However, for most architectures + * kvm_arch_vcpu_runnable does not require vcpu_load. + */ +bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu) +{ + return kvm_arch_vcpu_runnable(vcpu); +} + +static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu) +{ + if (kvm_arch_dy_runnable(vcpu)) + return true; + +#ifdef CONFIG_KVM_ASYNC_PF + if (!list_empty_careful(&vcpu->async_pf.done)) + return true; +#endif + + return false; +} + +bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu) +{ + return false; +} + +void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) +{ + struct kvm *kvm = me->kvm; + struct kvm_vcpu *vcpu; + int last_boosted_vcpu = me->kvm->last_boosted_vcpu; + unsigned long i; + int yielded = 0; + int try = 3; + int pass; + + kvm_vcpu_set_in_spin_loop(me, true); + /* + * We boost the priority of a VCPU that is runnable but not + * currently running, because it got preempted by something + * else and called schedule in __vcpu_run. Hopefully that + * VCPU is holding the lock that we need and will release it. + * We approximate round-robin by starting at the last boosted VCPU. + */ + for (pass = 0; pass < 2 && !yielded && try; pass++) { + kvm_for_each_vcpu(i, vcpu, kvm) { + if (!pass && i <= last_boosted_vcpu) { + i = last_boosted_vcpu; + continue; + } else if (pass && i > last_boosted_vcpu) + break; + if (!READ_ONCE(vcpu->ready)) + continue; + if (vcpu == me) + continue; + if (kvm_vcpu_is_blocking(vcpu) && !vcpu_dy_runnable(vcpu)) + continue; + if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode && + !kvm_arch_dy_has_pending_interrupt(vcpu) && + !kvm_arch_vcpu_in_kernel(vcpu)) + continue; + if (!kvm_vcpu_eligible_for_directed_yield(vcpu)) + continue; + + yielded = kvm_vcpu_yield_to(vcpu); + if (yielded > 0) { + kvm->last_boosted_vcpu = i; + break; + } else if (yielded < 0) { + try--; + if (!try) + break; + } + } + } + kvm_vcpu_set_in_spin_loop(me, false); + + /* Ensure vcpu is not eligible during next spinloop */ + kvm_vcpu_set_dy_eligible(me, false); +} +EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin); + +static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff) +{ +#ifdef CONFIG_HAVE_KVM_DIRTY_RING + return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) && + (pgoff < KVM_DIRTY_LOG_PAGE_OFFSET + + kvm->dirty_ring_size / PAGE_SIZE); +#else + return false; +#endif +} + +static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf) +{ + struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data; + struct page *page; + + if (vmf->pgoff == 0) + page = virt_to_page(vcpu->run); +#ifdef CONFIG_X86 + else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET) + page = virt_to_page(vcpu->arch.pio_data); +#endif +#ifdef CONFIG_KVM_MMIO + else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET) + page = virt_to_page(vcpu->kvm->coalesced_mmio_ring); +#endif + else if (kvm_page_in_dirty_ring(vcpu->kvm, vmf->pgoff)) + page = kvm_dirty_ring_get_page( + &vcpu->dirty_ring, + vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET); + else + return kvm_arch_vcpu_fault(vcpu, vmf); + get_page(page); + vmf->page = page; + return 0; +} + +static const struct vm_operations_struct kvm_vcpu_vm_ops = { + .fault = kvm_vcpu_fault, +}; + +static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct kvm_vcpu *vcpu = file->private_data; + unsigned long pages = vma_pages(vma); + + if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) || + kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) && + ((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED))) + return -EINVAL; + + vma->vm_ops = &kvm_vcpu_vm_ops; + return 0; +} + +static int kvm_vcpu_release(struct inode *inode, struct file *filp) +{ + struct kvm_vcpu *vcpu = filp->private_data; + + kvm_put_kvm(vcpu->kvm); + return 0; +} + +static const struct file_operations kvm_vcpu_fops = { + .release = kvm_vcpu_release, + .unlocked_ioctl = kvm_vcpu_ioctl, + .mmap = kvm_vcpu_mmap, + .llseek = noop_llseek, + KVM_COMPAT(kvm_vcpu_compat_ioctl), +}; + +/* + * Allocates an inode for the vcpu. + */ +static int create_vcpu_fd(struct kvm_vcpu *vcpu) +{ + char name[8 + 1 + ITOA_MAX_LEN + 1]; + + snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id); + return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC); +} + +#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS +static int vcpu_get_pid(void *data, u64 *val) +{ + struct kvm_vcpu *vcpu = data; + + rcu_read_lock(); + *val = pid_nr(rcu_dereference(vcpu->pid)); + rcu_read_unlock(); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n"); + +static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) +{ + struct dentry *debugfs_dentry; + char dir_name[ITOA_MAX_LEN * 2]; + + if (!debugfs_initialized()) + return; + + snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id); + debugfs_dentry = debugfs_create_dir(dir_name, + vcpu->kvm->debugfs_dentry); + debugfs_create_file("pid", 0444, debugfs_dentry, vcpu, + &vcpu_get_pid_fops); + + kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry); +} +#endif + +/* + * Creates some virtual cpus. Good luck creating more than one. + */ +static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) +{ + int r; + struct kvm_vcpu *vcpu; + struct page *page; + + if (id >= KVM_MAX_VCPU_IDS) + return -EINVAL; + + mutex_lock(&kvm->lock); + if (kvm->created_vcpus >= kvm->max_vcpus) { + mutex_unlock(&kvm->lock); + return -EINVAL; + } + + r = kvm_arch_vcpu_precreate(kvm, id); + if (r) { + mutex_unlock(&kvm->lock); + return r; + } + + kvm->created_vcpus++; + mutex_unlock(&kvm->lock); + + vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT); + if (!vcpu) { + r = -ENOMEM; + goto vcpu_decrement; + } + + BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE); + page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + if (!page) { + r = -ENOMEM; + goto vcpu_free; + } + vcpu->run = page_address(page); + + kvm_vcpu_init(vcpu, kvm, id); + + r = kvm_arch_vcpu_create(vcpu); + if (r) + goto vcpu_free_run_page; + + if (kvm->dirty_ring_size) { + r = kvm_dirty_ring_alloc(&vcpu->dirty_ring, + id, kvm->dirty_ring_size); + if (r) + goto arch_vcpu_destroy; + } + + mutex_lock(&kvm->lock); + +#ifdef CONFIG_LOCKDEP + /* Ensure that lockdep knows vcpu->mutex is taken *inside* kvm->lock */ + mutex_lock(&vcpu->mutex); + mutex_unlock(&vcpu->mutex); +#endif + + if (kvm_get_vcpu_by_id(kvm, id)) { + r = -EEXIST; + goto unlock_vcpu_destroy; + } + + vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus); + r = xa_reserve(&kvm->vcpu_array, vcpu->vcpu_idx, GFP_KERNEL_ACCOUNT); + if (r) + goto unlock_vcpu_destroy; + + /* Now it's all set up, let userspace reach it */ + kvm_get_kvm(kvm); + r = create_vcpu_fd(vcpu); + if (r < 0) + goto kvm_put_xa_release; + + if (KVM_BUG_ON(xa_store(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, 0), kvm)) { + r = -EINVAL; + goto kvm_put_xa_release; + } + + /* + * Pairs with smp_rmb() in kvm_get_vcpu. Store the vcpu + * pointer before kvm->online_vcpu's incremented value. + */ + smp_wmb(); + atomic_inc(&kvm->online_vcpus); + + mutex_unlock(&kvm->lock); + kvm_arch_vcpu_postcreate(vcpu); + kvm_create_vcpu_debugfs(vcpu); + return r; + +kvm_put_xa_release: + kvm_put_kvm_no_destroy(kvm); + xa_release(&kvm->vcpu_array, vcpu->vcpu_idx); +unlock_vcpu_destroy: + mutex_unlock(&kvm->lock); + kvm_dirty_ring_free(&vcpu->dirty_ring); +arch_vcpu_destroy: + kvm_arch_vcpu_destroy(vcpu); +vcpu_free_run_page: + free_page((unsigned long)vcpu->run); +vcpu_free: + kmem_cache_free(kvm_vcpu_cache, vcpu); +vcpu_decrement: + mutex_lock(&kvm->lock); + kvm->created_vcpus--; + mutex_unlock(&kvm->lock); + return r; +} + +static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset) +{ + if (sigset) { + sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP)); + vcpu->sigset_active = 1; + vcpu->sigset = *sigset; + } else + vcpu->sigset_active = 0; + return 0; +} + +static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm_vcpu *vcpu = file->private_data; + + return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header, + &kvm_vcpu_stats_desc[0], &vcpu->stat, + sizeof(vcpu->stat), user_buffer, size, offset); +} + +static int kvm_vcpu_stats_release(struct inode *inode, struct file *file) +{ + struct kvm_vcpu *vcpu = file->private_data; + + kvm_put_kvm(vcpu->kvm); + return 0; +} + +static const struct file_operations kvm_vcpu_stats_fops = { + .read = kvm_vcpu_stats_read, + .release = kvm_vcpu_stats_release, + .llseek = noop_llseek, +}; + +static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu) +{ + int fd; + struct file *file; + char name[15 + ITOA_MAX_LEN + 1]; + + snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id); + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile(name, &kvm_vcpu_stats_fops, vcpu, O_RDONLY); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + + kvm_get_kvm(vcpu->kvm); + + file->f_mode |= FMODE_PREAD; + fd_install(fd, file); + + return fd; +} + +static long kvm_vcpu_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm_vcpu *vcpu = filp->private_data; + void __user *argp = (void __user *)arg; + int r; + struct kvm_fpu *fpu = NULL; + struct kvm_sregs *kvm_sregs = NULL; + + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead) + return -EIO; + + if (unlikely(_IOC_TYPE(ioctl) != KVMIO)) + return -EINVAL; + + /* + * Some architectures have vcpu ioctls that are asynchronous to vcpu + * execution; mutex_lock() would break them. + */ + r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg); + if (r != -ENOIOCTLCMD) + return r; + + if (mutex_lock_killable(&vcpu->mutex)) + return -EINTR; + switch (ioctl) { + case KVM_RUN: { + struct pid *oldpid; + r = -EINVAL; + if (arg) + goto out; + oldpid = rcu_access_pointer(vcpu->pid); + if (unlikely(oldpid != task_pid(current))) { + /* The thread running this VCPU changed. */ + struct pid *newpid; + + r = kvm_arch_vcpu_run_pid_change(vcpu); + if (r) + break; + + newpid = get_task_pid(current, PIDTYPE_PID); + rcu_assign_pointer(vcpu->pid, newpid); + if (oldpid) + synchronize_rcu(); + put_pid(oldpid); + } + r = kvm_arch_vcpu_ioctl_run(vcpu); + trace_kvm_userspace_exit(vcpu->run->exit_reason, r); + break; + } + case KVM_GET_REGS: { + struct kvm_regs *kvm_regs; + + r = -ENOMEM; + kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL_ACCOUNT); + if (!kvm_regs) + goto out; + r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs); + if (r) + goto out_free1; + r = -EFAULT; + if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs))) + goto out_free1; + r = 0; +out_free1: + kfree(kvm_regs); + break; + } + case KVM_SET_REGS: { + struct kvm_regs *kvm_regs; + + kvm_regs = memdup_user(argp, sizeof(*kvm_regs)); + if (IS_ERR(kvm_regs)) { + r = PTR_ERR(kvm_regs); + goto out; + } + r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs); + kfree(kvm_regs); + break; + } + case KVM_GET_SREGS: { + kvm_sregs = kzalloc(sizeof(struct kvm_sregs), + GFP_KERNEL_ACCOUNT); + r = -ENOMEM; + if (!kvm_sregs) + goto out; + r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs))) + goto out; + r = 0; + break; + } + case KVM_SET_SREGS: { + kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs)); + if (IS_ERR(kvm_sregs)) { + r = PTR_ERR(kvm_sregs); + kvm_sregs = NULL; + goto out; + } + r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs); + break; + } + case KVM_GET_MP_STATE: { + struct kvm_mp_state mp_state; + + r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, &mp_state, sizeof(mp_state))) + goto out; + r = 0; + break; + } + case KVM_SET_MP_STATE: { + struct kvm_mp_state mp_state; + + r = -EFAULT; + if (copy_from_user(&mp_state, argp, sizeof(mp_state))) + goto out; + r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state); + break; + } + case KVM_TRANSLATE: { + struct kvm_translation tr; + + r = -EFAULT; + if (copy_from_user(&tr, argp, sizeof(tr))) + goto out; + r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, &tr, sizeof(tr))) + goto out; + r = 0; + break; + } + case KVM_SET_GUEST_DEBUG: { + struct kvm_guest_debug dbg; + + r = -EFAULT; + if (copy_from_user(&dbg, argp, sizeof(dbg))) + goto out; + r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg); + break; + } + case KVM_SET_SIGNAL_MASK: { + struct kvm_signal_mask __user *sigmask_arg = argp; + struct kvm_signal_mask kvm_sigmask; + sigset_t sigset, *p; + + p = NULL; + if (argp) { + r = -EFAULT; + if (copy_from_user(&kvm_sigmask, argp, + sizeof(kvm_sigmask))) + goto out; + r = -EINVAL; + if (kvm_sigmask.len != sizeof(sigset)) + goto out; + r = -EFAULT; + if (copy_from_user(&sigset, sigmask_arg->sigset, + sizeof(sigset))) + goto out; + p = &sigset; + } + r = kvm_vcpu_ioctl_set_sigmask(vcpu, p); + break; + } + case KVM_GET_FPU: { + fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL_ACCOUNT); + r = -ENOMEM; + if (!fpu) + goto out; + r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu); + if (r) + goto out; + r = -EFAULT; + if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu))) + goto out; + r = 0; + break; + } + case KVM_SET_FPU: { + fpu = memdup_user(argp, sizeof(*fpu)); + if (IS_ERR(fpu)) { + r = PTR_ERR(fpu); + fpu = NULL; + goto out; + } + r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu); + break; + } + case KVM_GET_STATS_FD: { + r = kvm_vcpu_ioctl_get_stats_fd(vcpu); + break; + } + default: + r = kvm_arch_vcpu_ioctl(filp, ioctl, arg); + } +out: + mutex_unlock(&vcpu->mutex); + kfree(fpu); + kfree(kvm_sregs); + return r; +} + +#ifdef CONFIG_KVM_COMPAT +static long kvm_vcpu_compat_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm_vcpu *vcpu = filp->private_data; + void __user *argp = compat_ptr(arg); + int r; + + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead) + return -EIO; + + switch (ioctl) { + case KVM_SET_SIGNAL_MASK: { + struct kvm_signal_mask __user *sigmask_arg = argp; + struct kvm_signal_mask kvm_sigmask; + sigset_t sigset; + + if (argp) { + r = -EFAULT; + if (copy_from_user(&kvm_sigmask, argp, + sizeof(kvm_sigmask))) + goto out; + r = -EINVAL; + if (kvm_sigmask.len != sizeof(compat_sigset_t)) + goto out; + r = -EFAULT; + if (get_compat_sigset(&sigset, + (compat_sigset_t __user *)sigmask_arg->sigset)) + goto out; + r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset); + } else + r = kvm_vcpu_ioctl_set_sigmask(vcpu, NULL); + break; + } + default: + r = kvm_vcpu_ioctl(filp, ioctl, arg); + } + +out: + return r; +} +#endif + +static int kvm_device_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct kvm_device *dev = filp->private_data; + + if (dev->ops->mmap) + return dev->ops->mmap(dev, vma); + + return -ENODEV; +} + +static int kvm_device_ioctl_attr(struct kvm_device *dev, + int (*accessor)(struct kvm_device *dev, + struct kvm_device_attr *attr), + unsigned long arg) +{ + struct kvm_device_attr attr; + + if (!accessor) + return -EPERM; + + if (copy_from_user(&attr, (void __user *)arg, sizeof(attr))) + return -EFAULT; + + return accessor(dev, &attr); +} + +static long kvm_device_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) +{ + struct kvm_device *dev = filp->private_data; + + if (dev->kvm->mm != current->mm || dev->kvm->vm_dead) + return -EIO; + + switch (ioctl) { + case KVM_SET_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg); + case KVM_GET_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg); + case KVM_HAS_DEVICE_ATTR: + return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg); + default: + if (dev->ops->ioctl) + return dev->ops->ioctl(dev, ioctl, arg); + + return -ENOTTY; + } +} + +static int kvm_device_release(struct inode *inode, struct file *filp) +{ + struct kvm_device *dev = filp->private_data; + struct kvm *kvm = dev->kvm; + + if (dev->ops->release) { + mutex_lock(&kvm->lock); + list_del(&dev->vm_node); + dev->ops->release(dev); + mutex_unlock(&kvm->lock); + } + + kvm_put_kvm(kvm); + return 0; +} + +static const struct file_operations kvm_device_fops = { + .unlocked_ioctl = kvm_device_ioctl, + .release = kvm_device_release, + KVM_COMPAT(kvm_device_ioctl), + .mmap = kvm_device_mmap, +}; + +struct kvm_device *kvm_device_from_filp(struct file *filp) +{ + if (filp->f_op != &kvm_device_fops) + return NULL; + + return filp->private_data; +} + +static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = { +#ifdef CONFIG_KVM_MPIC + [KVM_DEV_TYPE_FSL_MPIC_20] = &kvm_mpic_ops, + [KVM_DEV_TYPE_FSL_MPIC_42] = &kvm_mpic_ops, +#endif +}; + +int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type) +{ + if (type >= ARRAY_SIZE(kvm_device_ops_table)) + return -ENOSPC; + + if (kvm_device_ops_table[type] != NULL) + return -EEXIST; + + kvm_device_ops_table[type] = ops; + return 0; +} + +void kvm_unregister_device_ops(u32 type) +{ + if (kvm_device_ops_table[type] != NULL) + kvm_device_ops_table[type] = NULL; +} + +static int kvm_ioctl_create_device(struct kvm *kvm, + struct kvm_create_device *cd) +{ + const struct kvm_device_ops *ops; + struct kvm_device *dev; + bool test = cd->flags & KVM_CREATE_DEVICE_TEST; + int type; + int ret; + + if (cd->type >= ARRAY_SIZE(kvm_device_ops_table)) + return -ENODEV; + + type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table)); + ops = kvm_device_ops_table[type]; + if (ops == NULL) + return -ENODEV; + + if (test) + return 0; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL_ACCOUNT); + if (!dev) + return -ENOMEM; + + dev->ops = ops; + dev->kvm = kvm; + + mutex_lock(&kvm->lock); + ret = ops->create(dev, type); + if (ret < 0) { + mutex_unlock(&kvm->lock); + kfree(dev); + return ret; + } + list_add(&dev->vm_node, &kvm->devices); + mutex_unlock(&kvm->lock); + + if (ops->init) + ops->init(dev); + + kvm_get_kvm(kvm); + ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC); + if (ret < 0) { + kvm_put_kvm_no_destroy(kvm); + mutex_lock(&kvm->lock); + list_del(&dev->vm_node); + if (ops->release) + ops->release(dev); + mutex_unlock(&kvm->lock); + if (ops->destroy) + ops->destroy(dev); + return ret; + } + + cd->fd = ret; + return 0; +} + +static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) +{ + switch (arg) { + case KVM_CAP_USER_MEMORY: + case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: + case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: + case KVM_CAP_INTERNAL_ERROR_DATA: +#ifdef CONFIG_HAVE_KVM_MSI + case KVM_CAP_SIGNAL_MSI: +#endif +#ifdef CONFIG_HAVE_KVM_IRQFD + case KVM_CAP_IRQFD: +#endif + case KVM_CAP_IOEVENTFD_ANY_LENGTH: + case KVM_CAP_CHECK_EXTENSION_VM: + case KVM_CAP_ENABLE_CAP_VM: + case KVM_CAP_HALT_POLL: + return 1; +#ifdef CONFIG_KVM_MMIO + case KVM_CAP_COALESCED_MMIO: + return KVM_COALESCED_MMIO_PAGE_OFFSET; + case KVM_CAP_COALESCED_PIO: + return 1; +#endif +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: + return KVM_DIRTY_LOG_MANUAL_CAPS; +#endif +#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING + case KVM_CAP_IRQ_ROUTING: + return KVM_MAX_IRQ_ROUTES; +#endif +#if KVM_ADDRESS_SPACE_NUM > 1 + case KVM_CAP_MULTI_ADDRESS_SPACE: + return KVM_ADDRESS_SPACE_NUM; +#endif + case KVM_CAP_NR_MEMSLOTS: + return KVM_USER_MEM_SLOTS; + case KVM_CAP_DIRTY_LOG_RING: +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO + return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); +#else + return 0; +#endif + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL + return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); +#else + return 0; +#endif +#ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: +#endif + case KVM_CAP_BINARY_STATS_FD: + case KVM_CAP_SYSTEM_EVENT_DATA: + return 1; + default: + break; + } + return kvm_vm_ioctl_check_extension(kvm, arg); +} + +static int kvm_vm_ioctl_enable_dirty_log_ring(struct kvm *kvm, u32 size) +{ + int r; + + if (!KVM_DIRTY_LOG_PAGE_OFFSET) + return -EINVAL; + + /* the size should be power of 2 */ + if (!size || (size & (size - 1))) + return -EINVAL; + + /* Should be bigger to keep the reserved entries, or a page */ + if (size < kvm_dirty_ring_get_rsvd_entries() * + sizeof(struct kvm_dirty_gfn) || size < PAGE_SIZE) + return -EINVAL; + + if (size > KVM_DIRTY_RING_MAX_ENTRIES * + sizeof(struct kvm_dirty_gfn)) + return -E2BIG; + + /* We only allow it to set once */ + if (kvm->dirty_ring_size) + return -EINVAL; + + mutex_lock(&kvm->lock); + + if (kvm->created_vcpus) { + /* We don't allow to change this value after vcpu created */ + r = -EINVAL; + } else { + kvm->dirty_ring_size = size; + r = 0; + } + + mutex_unlock(&kvm->lock); + return r; +} + +static int kvm_vm_ioctl_reset_dirty_pages(struct kvm *kvm) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + int cleared = 0; + + if (!kvm->dirty_ring_size) + return -EINVAL; + + mutex_lock(&kvm->slots_lock); + + kvm_for_each_vcpu(i, vcpu, kvm) + cleared += kvm_dirty_ring_reset(vcpu->kvm, &vcpu->dirty_ring); + + mutex_unlock(&kvm->slots_lock); + + if (cleared) + kvm_flush_remote_tlbs(kvm); + + return cleared; +} + +int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm, + struct kvm_enable_cap *cap) +{ + return -EINVAL; +} + +bool kvm_are_all_memslots_empty(struct kvm *kvm) +{ + int i; + + lockdep_assert_held(&kvm->slots_lock); + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + if (!kvm_memslots_empty(__kvm_memslots(kvm, i))) + return false; + } + + return true; +} +EXPORT_SYMBOL_GPL(kvm_are_all_memslots_empty); + +static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, + struct kvm_enable_cap *cap) +{ + switch (cap->cap) { +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: { + u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE; + + if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE) + allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS; + + if (cap->flags || (cap->args[0] & ~allowed_options)) + return -EINVAL; + kvm->manual_dirty_log_protect = cap->args[0]; + return 0; + } +#endif + case KVM_CAP_HALT_POLL: { + if (cap->flags || cap->args[0] != (unsigned int)cap->args[0]) + return -EINVAL; + + kvm->max_halt_poll_ns = cap->args[0]; + + /* + * Ensure kvm->override_halt_poll_ns does not become visible + * before kvm->max_halt_poll_ns. + * + * Pairs with the smp_rmb() in kvm_vcpu_max_halt_poll_ns(). + */ + smp_wmb(); + kvm->override_halt_poll_ns = true; + + return 0; + } + case KVM_CAP_DIRTY_LOG_RING: + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: + if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap)) + return -EINVAL; + + return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]); + case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: { + int r = -EINVAL; + + if (!IS_ENABLED(CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP) || + !kvm->dirty_ring_size || cap->flags) + return r; + + mutex_lock(&kvm->slots_lock); + + /* + * For simplicity, allow enabling ring+bitmap if and only if + * there are no memslots, e.g. to ensure all memslots allocate + * a bitmap after the capability is enabled. + */ + if (kvm_are_all_memslots_empty(kvm)) { + kvm->dirty_ring_with_bitmap = true; + r = 0; + } + + mutex_unlock(&kvm->slots_lock); + + return r; + } + default: + return kvm_vm_ioctl_enable_cap(kvm, cap); + } +} + +static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm *kvm = file->private_data; + + return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header, + &kvm_vm_stats_desc[0], &kvm->stat, + sizeof(kvm->stat), user_buffer, size, offset); +} + +static int kvm_vm_stats_release(struct inode *inode, struct file *file) +{ + struct kvm *kvm = file->private_data; + + kvm_put_kvm(kvm); + return 0; +} + +static const struct file_operations kvm_vm_stats_fops = { + .read = kvm_vm_stats_read, + .release = kvm_vm_stats_release, + .llseek = noop_llseek, +}; + +static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) +{ + int fd; + struct file *file; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile("kvm-vm-stats", + &kvm_vm_stats_fops, kvm, O_RDONLY); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + + kvm_get_kvm(kvm); + + file->f_mode |= FMODE_PREAD; + fd_install(fd, file); + + return fd; +} + +static long kvm_vm_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm *kvm = filp->private_data; + void __user *argp = (void __user *)arg; + int r; + + if (kvm->mm != current->mm || kvm->vm_dead) + return -EIO; + switch (ioctl) { + case KVM_CREATE_VCPU: + r = kvm_vm_ioctl_create_vcpu(kvm, arg); + break; + case KVM_ENABLE_CAP: { + struct kvm_enable_cap cap; + + r = -EFAULT; + if (copy_from_user(&cap, argp, sizeof(cap))) + goto out; + r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap); + break; + } + case KVM_SET_USER_MEMORY_REGION: { + struct kvm_userspace_memory_region kvm_userspace_mem; + + r = -EFAULT; + if (copy_from_user(&kvm_userspace_mem, argp, + sizeof(kvm_userspace_mem))) + goto out; + + r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem); + break; + } + case KVM_GET_DIRTY_LOG: { + struct kvm_dirty_log log; + + r = -EFAULT; + if (copy_from_user(&log, argp, sizeof(log))) + goto out; + r = kvm_vm_ioctl_get_dirty_log(kvm, &log); + break; + } +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CLEAR_DIRTY_LOG: { + struct kvm_clear_dirty_log log; + + r = -EFAULT; + if (copy_from_user(&log, argp, sizeof(log))) + goto out; + r = kvm_vm_ioctl_clear_dirty_log(kvm, &log); + break; + } +#endif +#ifdef CONFIG_KVM_MMIO + case KVM_REGISTER_COALESCED_MMIO: { + struct kvm_coalesced_mmio_zone zone; + + r = -EFAULT; + if (copy_from_user(&zone, argp, sizeof(zone))) + goto out; + r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone); + break; + } + case KVM_UNREGISTER_COALESCED_MMIO: { + struct kvm_coalesced_mmio_zone zone; + + r = -EFAULT; + if (copy_from_user(&zone, argp, sizeof(zone))) + goto out; + r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone); + break; + } +#endif + case KVM_IRQFD: { + struct kvm_irqfd data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof(data))) + goto out; + r = kvm_irqfd(kvm, &data); + break; + } + case KVM_IOEVENTFD: { + struct kvm_ioeventfd data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof(data))) + goto out; + r = kvm_ioeventfd(kvm, &data); + break; + } +#ifdef CONFIG_HAVE_KVM_MSI + case KVM_SIGNAL_MSI: { + struct kvm_msi msi; + + r = -EFAULT; + if (copy_from_user(&msi, argp, sizeof(msi))) + goto out; + r = kvm_send_userspace_msi(kvm, &msi); + break; + } +#endif +#ifdef __KVM_HAVE_IRQ_LINE + case KVM_IRQ_LINE_STATUS: + case KVM_IRQ_LINE: { + struct kvm_irq_level irq_event; + + r = -EFAULT; + if (copy_from_user(&irq_event, argp, sizeof(irq_event))) + goto out; + + r = kvm_vm_ioctl_irq_line(kvm, &irq_event, + ioctl == KVM_IRQ_LINE_STATUS); + if (r) + goto out; + + r = -EFAULT; + if (ioctl == KVM_IRQ_LINE_STATUS) { + if (copy_to_user(argp, &irq_event, sizeof(irq_event))) + goto out; + } + + r = 0; + break; + } +#endif +#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING + case KVM_SET_GSI_ROUTING: { + struct kvm_irq_routing routing; + struct kvm_irq_routing __user *urouting; + struct kvm_irq_routing_entry *entries = NULL; + + r = -EFAULT; + if (copy_from_user(&routing, argp, sizeof(routing))) + goto out; + r = -EINVAL; + if (!kvm_arch_can_set_irq_routing(kvm)) + goto out; + if (routing.nr > KVM_MAX_IRQ_ROUTES) + goto out; + if (routing.flags) + goto out; + if (routing.nr) { + urouting = argp; + entries = vmemdup_user(urouting->entries, + array_size(sizeof(*entries), + routing.nr)); + if (IS_ERR(entries)) { + r = PTR_ERR(entries); + goto out; + } + } + r = kvm_set_irq_routing(kvm, entries, routing.nr, + routing.flags); + kvfree(entries); + break; + } +#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */ + case KVM_CREATE_DEVICE: { + struct kvm_create_device cd; + + r = -EFAULT; + if (copy_from_user(&cd, argp, sizeof(cd))) + goto out; + + r = kvm_ioctl_create_device(kvm, &cd); + if (r) + goto out; + + r = -EFAULT; + if (copy_to_user(argp, &cd, sizeof(cd))) + goto out; + + r = 0; + break; + } + case KVM_CHECK_EXTENSION: + r = kvm_vm_ioctl_check_extension_generic(kvm, arg); + break; + case KVM_RESET_DIRTY_RINGS: + r = kvm_vm_ioctl_reset_dirty_pages(kvm); + break; + case KVM_GET_STATS_FD: + r = kvm_vm_ioctl_get_stats_fd(kvm); + break; + default: + r = kvm_arch_vm_ioctl(filp, ioctl, arg); + } +out: + return r; +} + +#ifdef CONFIG_KVM_COMPAT +struct compat_kvm_dirty_log { + __u32 slot; + __u32 padding1; + union { + compat_uptr_t dirty_bitmap; /* one bit per page */ + __u64 padding2; + }; +}; + +struct compat_kvm_clear_dirty_log { + __u32 slot; + __u32 num_pages; + __u64 first_page; + union { + compat_uptr_t dirty_bitmap; /* one bit per page */ + __u64 padding2; + }; +}; + +long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl, + unsigned long arg) +{ + return -ENOTTY; +} + +static long kvm_vm_compat_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + struct kvm *kvm = filp->private_data; + int r; + + if (kvm->mm != current->mm || kvm->vm_dead) + return -EIO; + + r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg); + if (r != -ENOTTY) + return r; + + switch (ioctl) { +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT + case KVM_CLEAR_DIRTY_LOG: { + struct compat_kvm_clear_dirty_log compat_log; + struct kvm_clear_dirty_log log; + + if (copy_from_user(&compat_log, (void __user *)arg, + sizeof(compat_log))) + return -EFAULT; + log.slot = compat_log.slot; + log.num_pages = compat_log.num_pages; + log.first_page = compat_log.first_page; + log.padding2 = compat_log.padding2; + log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap); + + r = kvm_vm_ioctl_clear_dirty_log(kvm, &log); + break; + } +#endif + case KVM_GET_DIRTY_LOG: { + struct compat_kvm_dirty_log compat_log; + struct kvm_dirty_log log; + + if (copy_from_user(&compat_log, (void __user *)arg, + sizeof(compat_log))) + return -EFAULT; + log.slot = compat_log.slot; + log.padding1 = compat_log.padding1; + log.padding2 = compat_log.padding2; + log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap); + + r = kvm_vm_ioctl_get_dirty_log(kvm, &log); + break; + } + default: + r = kvm_vm_ioctl(filp, ioctl, arg); + } + return r; +} +#endif + +static const struct file_operations kvm_vm_fops = { + .release = kvm_vm_release, + .unlocked_ioctl = kvm_vm_ioctl, + .llseek = noop_llseek, + KVM_COMPAT(kvm_vm_compat_ioctl), +}; + +bool file_is_kvm(struct file *file) +{ + return file && file->f_op == &kvm_vm_fops; +} +EXPORT_SYMBOL_GPL(file_is_kvm); + +static int kvm_dev_ioctl_create_vm(unsigned long type) +{ + char fdname[ITOA_MAX_LEN + 1]; + int r, fd; + struct kvm *kvm; + struct file *file; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + snprintf(fdname, sizeof(fdname), "%d", fd); + + kvm = kvm_create_vm(type, fdname); + if (IS_ERR(kvm)) { + r = PTR_ERR(kvm); + goto put_fd; + } + + file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR); + if (IS_ERR(file)) { + r = PTR_ERR(file); + goto put_kvm; + } + + /* + * Don't call kvm_put_kvm anymore at this point; file->f_op is + * already set, with ->release() being kvm_vm_release(). In error + * cases it will be called by the final fput(file) and will take + * care of doing kvm_put_kvm(kvm). + */ + kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm); + + fd_install(fd, file); + return fd; + +put_kvm: + kvm_put_kvm(kvm); +put_fd: + put_unused_fd(fd); + return r; +} + +static long kvm_dev_ioctl(struct file *filp, + unsigned int ioctl, unsigned long arg) +{ + int r = -EINVAL; + + switch (ioctl) { + case KVM_GET_API_VERSION: + if (arg) + goto out; + r = KVM_API_VERSION; + break; + case KVM_CREATE_VM: + r = kvm_dev_ioctl_create_vm(arg); + break; + case KVM_CHECK_EXTENSION: + r = kvm_vm_ioctl_check_extension_generic(NULL, arg); + break; + case KVM_GET_VCPU_MMAP_SIZE: + if (arg) + goto out; + r = PAGE_SIZE; /* struct kvm_run */ +#ifdef CONFIG_X86 + r += PAGE_SIZE; /* pio data page */ +#endif +#ifdef CONFIG_KVM_MMIO + r += PAGE_SIZE; /* coalesced mmio ring page */ +#endif + break; + case KVM_TRACE_ENABLE: + case KVM_TRACE_PAUSE: + case KVM_TRACE_DISABLE: + r = -EOPNOTSUPP; + break; + default: + return kvm_arch_dev_ioctl(filp, ioctl, arg); + } +out: + return r; +} + +static struct file_operations kvm_chardev_ops = { + .unlocked_ioctl = kvm_dev_ioctl, + .llseek = noop_llseek, + KVM_COMPAT(kvm_dev_ioctl), +}; + +static struct miscdevice kvm_dev = { + KVM_MINOR, + "kvm", + &kvm_chardev_ops, +}; + +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING +__visible bool kvm_rebooting; +EXPORT_SYMBOL_GPL(kvm_rebooting); + +static DEFINE_PER_CPU(bool, hardware_enabled); +static int kvm_usage_count; + +static int __hardware_enable_nolock(void) +{ + if (__this_cpu_read(hardware_enabled)) + return 0; + + if (kvm_arch_hardware_enable()) { + pr_info("kvm: enabling virtualization on CPU%d failed\n", + raw_smp_processor_id()); + return -EIO; + } + + __this_cpu_write(hardware_enabled, true); + return 0; +} + +static void hardware_enable_nolock(void *failed) +{ + if (__hardware_enable_nolock()) + atomic_inc(failed); +} + +static int kvm_online_cpu(unsigned int cpu) +{ + int ret = 0; + + /* + * Abort the CPU online process if hardware virtualization cannot + * be enabled. Otherwise running VMs would encounter unrecoverable + * errors when scheduled to this CPU. + */ + mutex_lock(&kvm_lock); + if (kvm_usage_count) + ret = __hardware_enable_nolock(); + mutex_unlock(&kvm_lock); + return ret; +} + +static void hardware_disable_nolock(void *junk) +{ + /* + * Note, hardware_disable_all_nolock() tells all online CPUs to disable + * hardware, not just CPUs that successfully enabled hardware! + */ + if (!__this_cpu_read(hardware_enabled)) + return; + + kvm_arch_hardware_disable(); + + __this_cpu_write(hardware_enabled, false); +} + +static int kvm_offline_cpu(unsigned int cpu) +{ + mutex_lock(&kvm_lock); + if (kvm_usage_count) + hardware_disable_nolock(NULL); + mutex_unlock(&kvm_lock); + return 0; +} + +static void hardware_disable_all_nolock(void) +{ + BUG_ON(!kvm_usage_count); + + kvm_usage_count--; + if (!kvm_usage_count) + on_each_cpu(hardware_disable_nolock, NULL, 1); +} + +static void hardware_disable_all(void) +{ + cpus_read_lock(); + mutex_lock(&kvm_lock); + hardware_disable_all_nolock(); + mutex_unlock(&kvm_lock); + cpus_read_unlock(); +} + +static int hardware_enable_all(void) +{ + atomic_t failed = ATOMIC_INIT(0); + int r; + + /* + * Do not enable hardware virtualization if the system is going down. + * If userspace initiated a forced reboot, e.g. reboot -f, then it's + * possible for an in-flight KVM_CREATE_VM to trigger hardware enabling + * after kvm_reboot() is called. Note, this relies on system_state + * being set _before_ kvm_reboot(), which is why KVM uses a syscore ops + * hook instead of registering a dedicated reboot notifier (the latter + * runs before system_state is updated). + */ + if (system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF || + system_state == SYSTEM_RESTART) + return -EBUSY; + + /* + * When onlining a CPU, cpu_online_mask is set before kvm_online_cpu() + * is called, and so on_each_cpu() between them includes the CPU that + * is being onlined. As a result, hardware_enable_nolock() may get + * invoked before kvm_online_cpu(), which also enables hardware if the + * usage count is non-zero. Disable CPU hotplug to avoid attempting to + * enable hardware multiple times. + */ + cpus_read_lock(); + mutex_lock(&kvm_lock); + + r = 0; + + kvm_usage_count++; + if (kvm_usage_count == 1) { + on_each_cpu(hardware_enable_nolock, &failed, 1); + + if (atomic_read(&failed)) { + hardware_disable_all_nolock(); + r = -EBUSY; + } + } + + mutex_unlock(&kvm_lock); + cpus_read_unlock(); + + return r; +} + +static void kvm_shutdown(void) +{ + /* + * Disable hardware virtualization and set kvm_rebooting to indicate + * that KVM has asynchronously disabled hardware virtualization, i.e. + * that relevant errors and exceptions aren't entirely unexpected. + * Some flavors of hardware virtualization need to be disabled before + * transferring control to firmware (to perform shutdown/reboot), e.g. + * on x86, virtualization can block INIT interrupts, which are used by + * firmware to pull APs back under firmware control. Note, this path + * is used for both shutdown and reboot scenarios, i.e. neither name is + * 100% comprehensive. + */ + pr_info("kvm: exiting hardware virtualization\n"); + kvm_rebooting = true; + on_each_cpu(hardware_disable_nolock, NULL, 1); +} + +static int kvm_suspend(void) +{ + /* + * Secondary CPUs and CPU hotplug are disabled across the suspend/resume + * callbacks, i.e. no need to acquire kvm_lock to ensure the usage count + * is stable. Assert that kvm_lock is not held to ensure the system + * isn't suspended while KVM is enabling hardware. Hardware enabling + * can be preempted, but the task cannot be frozen until it has dropped + * all locks (userspace tasks are frozen via a fake signal). + */ + lockdep_assert_not_held(&kvm_lock); + lockdep_assert_irqs_disabled(); + + if (kvm_usage_count) + hardware_disable_nolock(NULL); + return 0; +} + +static void kvm_resume(void) +{ + lockdep_assert_not_held(&kvm_lock); + lockdep_assert_irqs_disabled(); + + if (kvm_usage_count) + WARN_ON_ONCE(__hardware_enable_nolock()); +} + +static struct syscore_ops kvm_syscore_ops = { + .suspend = kvm_suspend, + .resume = kvm_resume, + .shutdown = kvm_shutdown, +}; +#else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ +static int hardware_enable_all(void) +{ + return 0; +} + +static void hardware_disable_all(void) +{ + +} +#endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ + +static void kvm_iodevice_destructor(struct kvm_io_device *dev) +{ + if (dev->ops->destructor) + dev->ops->destructor(dev); +} + +static void kvm_io_bus_destroy(struct kvm_io_bus *bus) +{ + int i; + + for (i = 0; i < bus->dev_count; i++) { + struct kvm_io_device *pos = bus->range[i].dev; + + kvm_iodevice_destructor(pos); + } + kfree(bus); +} + +static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1, + const struct kvm_io_range *r2) +{ + gpa_t addr1 = r1->addr; + gpa_t addr2 = r2->addr; + + if (addr1 < addr2) + return -1; + + /* If r2->len == 0, match the exact address. If r2->len != 0, + * accept any overlapping write. Any order is acceptable for + * overlapping ranges, because kvm_io_bus_get_first_dev ensures + * we process all of them. + */ + if (r2->len) { + addr1 += r1->len; + addr2 += r2->len; + } + + if (addr1 > addr2) + return 1; + + return 0; +} + +static int kvm_io_bus_sort_cmp(const void *p1, const void *p2) +{ + return kvm_io_bus_cmp(p1, p2); +} + +static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus, + gpa_t addr, int len) +{ + struct kvm_io_range *range, key; + int off; + + key = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + range = bsearch(&key, bus->range, bus->dev_count, + sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp); + if (range == NULL) + return -ENOENT; + + off = range - bus->range; + + while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0) + off--; + + return off; +} + +static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus, + struct kvm_io_range *range, const void *val) +{ + int idx; + + idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len); + if (idx < 0) + return -EOPNOTSUPP; + + while (idx < bus->dev_count && + kvm_io_bus_cmp(range, &bus->range[idx]) == 0) { + if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr, + range->len, val)) + return idx; + idx++; + } + + return -EOPNOTSUPP; +} + +/* kvm_io_bus_write - called under kvm->slots_lock */ +int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, + int len, const void *val) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + int r; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu); + if (!bus) + return -ENOMEM; + r = __kvm_io_bus_write(vcpu, bus, &range, val); + return r < 0 ? r : 0; +} +EXPORT_SYMBOL_GPL(kvm_io_bus_write); + +/* kvm_io_bus_write_cookie - called under kvm->slots_lock */ +int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, + gpa_t addr, int len, const void *val, long cookie) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu); + if (!bus) + return -ENOMEM; + + /* First try the device referenced by cookie. */ + if ((cookie >= 0) && (cookie < bus->dev_count) && + (kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0)) + if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len, + val)) + return cookie; + + /* + * cookie contained garbage; fall back to search and return the + * correct cookie value. + */ + return __kvm_io_bus_write(vcpu, bus, &range, val); +} + +static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus, + struct kvm_io_range *range, void *val) +{ + int idx; + + idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len); + if (idx < 0) + return -EOPNOTSUPP; + + while (idx < bus->dev_count && + kvm_io_bus_cmp(range, &bus->range[idx]) == 0) { + if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr, + range->len, val)) + return idx; + idx++; + } + + return -EOPNOTSUPP; +} + +/* kvm_io_bus_read - called under kvm->slots_lock */ +int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, + int len, void *val) +{ + struct kvm_io_bus *bus; + struct kvm_io_range range; + int r; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + }; + + bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu); + if (!bus) + return -ENOMEM; + r = __kvm_io_bus_read(vcpu, bus, &range, val); + return r < 0 ? r : 0; +} + +/* Caller must hold slots_lock. */ +int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, + int len, struct kvm_io_device *dev) +{ + int i; + struct kvm_io_bus *new_bus, *bus; + struct kvm_io_range range; + + bus = kvm_get_bus(kvm, bus_idx); + if (!bus) + return -ENOMEM; + + /* exclude ioeventfd which is limited by maximum fd */ + if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1) + return -ENOSPC; + + new_bus = kmalloc(struct_size(bus, range, bus->dev_count + 1), + GFP_KERNEL_ACCOUNT); + if (!new_bus) + return -ENOMEM; + + range = (struct kvm_io_range) { + .addr = addr, + .len = len, + .dev = dev, + }; + + for (i = 0; i < bus->dev_count; i++) + if (kvm_io_bus_cmp(&bus->range[i], &range) > 0) + break; + + memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range)); + new_bus->dev_count++; + new_bus->range[i] = range; + memcpy(new_bus->range + i + 1, bus->range + i, + (bus->dev_count - i) * sizeof(struct kvm_io_range)); + rcu_assign_pointer(kvm->buses[bus_idx], new_bus); + synchronize_srcu_expedited(&kvm->srcu); + kfree(bus); + + return 0; +} + +int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, + struct kvm_io_device *dev) +{ + int i; + struct kvm_io_bus *new_bus, *bus; + + lockdep_assert_held(&kvm->slots_lock); + + bus = kvm_get_bus(kvm, bus_idx); + if (!bus) + return 0; + + for (i = 0; i < bus->dev_count; i++) { + if (bus->range[i].dev == dev) { + break; + } + } + + if (i == bus->dev_count) + return 0; + + new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1), + GFP_KERNEL_ACCOUNT); + if (new_bus) { + memcpy(new_bus, bus, struct_size(bus, range, i)); + new_bus->dev_count--; + memcpy(new_bus->range + i, bus->range + i + 1, + flex_array_size(new_bus, range, new_bus->dev_count - i)); + } + + rcu_assign_pointer(kvm->buses[bus_idx], new_bus); + synchronize_srcu_expedited(&kvm->srcu); + + /* + * If NULL bus is installed, destroy the old bus, including all the + * attached devices. Otherwise, destroy the caller's device only. + */ + if (!new_bus) { + pr_err("kvm: failed to shrink bus, removing it completely\n"); + kvm_io_bus_destroy(bus); + return -ENOMEM; + } + + kvm_iodevice_destructor(dev); + kfree(bus); + return 0; +} + +struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx, + gpa_t addr) +{ + struct kvm_io_bus *bus; + int dev_idx, srcu_idx; + struct kvm_io_device *iodev = NULL; + + srcu_idx = srcu_read_lock(&kvm->srcu); + + bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu); + if (!bus) + goto out_unlock; + + dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1); + if (dev_idx < 0) + goto out_unlock; + + iodev = bus->range[dev_idx].dev; + +out_unlock: + srcu_read_unlock(&kvm->srcu, srcu_idx); + + return iodev; +} +EXPORT_SYMBOL_GPL(kvm_io_bus_get_dev); + +static int kvm_debugfs_open(struct inode *inode, struct file *file, + int (*get)(void *, u64 *), int (*set)(void *, u64), + const char *fmt) +{ + int ret; + struct kvm_stat_data *stat_data = inode->i_private; + + /* + * The debugfs files are a reference to the kvm struct which + * is still valid when kvm_destroy_vm is called. kvm_get_kvm_safe + * avoids the race between open and the removal of the debugfs directory. + */ + if (!kvm_get_kvm_safe(stat_data->kvm)) + return -ENOENT; + + ret = simple_attr_open(inode, file, get, + kvm_stats_debugfs_mode(stat_data->desc) & 0222 + ? set : NULL, fmt); + if (ret) + kvm_put_kvm(stat_data->kvm); + + return ret; +} + +static int kvm_debugfs_release(struct inode *inode, struct file *file) +{ + struct kvm_stat_data *stat_data = inode->i_private; + + simple_attr_release(inode, file); + kvm_put_kvm(stat_data->kvm); + + return 0; +} + +static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val) +{ + *val = *(u64 *)((void *)(&kvm->stat) + offset); + + return 0; +} + +static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset) +{ + *(u64 *)((void *)(&kvm->stat) + offset) = 0; + + return 0; +} + +static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + *val = 0; + + kvm_for_each_vcpu(i, vcpu, kvm) + *val += *(u64 *)((void *)(&vcpu->stat) + offset); + + return 0; +} + +static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset) +{ + unsigned long i; + struct kvm_vcpu *vcpu; + + kvm_for_each_vcpu(i, vcpu, kvm) + *(u64 *)((void *)(&vcpu->stat) + offset) = 0; + + return 0; +} + +static int kvm_stat_data_get(void *data, u64 *val) +{ + int r = -EFAULT; + struct kvm_stat_data *stat_data = data; + + switch (stat_data->kind) { + case KVM_STAT_VM: + r = kvm_get_stat_per_vm(stat_data->kvm, + stat_data->desc->desc.offset, val); + break; + case KVM_STAT_VCPU: + r = kvm_get_stat_per_vcpu(stat_data->kvm, + stat_data->desc->desc.offset, val); + break; + } + + return r; +} + +static int kvm_stat_data_clear(void *data, u64 val) +{ + int r = -EFAULT; + struct kvm_stat_data *stat_data = data; + + if (val) + return -EINVAL; + + switch (stat_data->kind) { + case KVM_STAT_VM: + r = kvm_clear_stat_per_vm(stat_data->kvm, + stat_data->desc->desc.offset); + break; + case KVM_STAT_VCPU: + r = kvm_clear_stat_per_vcpu(stat_data->kvm, + stat_data->desc->desc.offset); + break; + } + + return r; +} + +static int kvm_stat_data_open(struct inode *inode, struct file *file) +{ + __simple_attr_check_format("%llu\n", 0ull); + return kvm_debugfs_open(inode, file, kvm_stat_data_get, + kvm_stat_data_clear, "%llu\n"); +} + +static const struct file_operations stat_fops_per_vm = { + .owner = THIS_MODULE, + .open = kvm_stat_data_open, + .release = kvm_debugfs_release, + .read = simple_attr_read, + .write = simple_attr_write, + .llseek = no_llseek, +}; + +static int vm_stat_get(void *_offset, u64 *val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + u64 tmp_val; + + *val = 0; + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_get_stat_per_vm(kvm, offset, &tmp_val); + *val += tmp_val; + } + mutex_unlock(&kvm_lock); + return 0; +} + +static int vm_stat_clear(void *_offset, u64 val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + + if (val) + return -EINVAL; + + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_clear_stat_per_vm(kvm, offset); + } + mutex_unlock(&kvm_lock); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n"); +DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n"); + +static int vcpu_stat_get(void *_offset, u64 *val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + u64 tmp_val; + + *val = 0; + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_get_stat_per_vcpu(kvm, offset, &tmp_val); + *val += tmp_val; + } + mutex_unlock(&kvm_lock); + return 0; +} + +static int vcpu_stat_clear(void *_offset, u64 val) +{ + unsigned offset = (long)_offset; + struct kvm *kvm; + + if (val) + return -EINVAL; + + mutex_lock(&kvm_lock); + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm_clear_stat_per_vcpu(kvm, offset); + } + mutex_unlock(&kvm_lock); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear, + "%llu\n"); +DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n"); + +static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) +{ + struct kobj_uevent_env *env; + unsigned long long created, active; + + if (!kvm_dev.this_device || !kvm) + return; + + mutex_lock(&kvm_lock); + if (type == KVM_EVENT_CREATE_VM) { + kvm_createvm_count++; + kvm_active_vms++; + } else if (type == KVM_EVENT_DESTROY_VM) { + kvm_active_vms--; + } + created = kvm_createvm_count; + active = kvm_active_vms; + mutex_unlock(&kvm_lock); + + env = kzalloc(sizeof(*env), GFP_KERNEL_ACCOUNT); + if (!env) + return; + + add_uevent_var(env, "CREATED=%llu", created); + add_uevent_var(env, "COUNT=%llu", active); + + if (type == KVM_EVENT_CREATE_VM) { + add_uevent_var(env, "EVENT=create"); + kvm->userspace_pid = task_pid_nr(current); + } else if (type == KVM_EVENT_DESTROY_VM) { + add_uevent_var(env, "EVENT=destroy"); + } + add_uevent_var(env, "PID=%d", kvm->userspace_pid); + + if (!IS_ERR(kvm->debugfs_dentry)) { + char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT); + + if (p) { + tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX); + if (!IS_ERR(tmp)) + add_uevent_var(env, "STATS_PATH=%s", tmp); + kfree(p); + } + } + /* no need for checks, since we are adding at most only 5 keys */ + env->envp[env->envp_idx++] = NULL; + kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp); + kfree(env); +} + +static void kvm_init_debug(void) +{ + const struct file_operations *fops; + const struct _kvm_stats_desc *pdesc; + int i; + + kvm_debugfs_dir = debugfs_create_dir("kvm", NULL); + + for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) { + pdesc = &kvm_vm_stats_desc[i]; + if (kvm_stats_debugfs_mode(pdesc) & 0222) + fops = &vm_stat_fops; + else + fops = &vm_stat_readonly_fops; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm_debugfs_dir, + (void *)(long)pdesc->desc.offset, fops); + } + + for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) { + pdesc = &kvm_vcpu_stats_desc[i]; + if (kvm_stats_debugfs_mode(pdesc) & 0222) + fops = &vcpu_stat_fops; + else + fops = &vcpu_stat_readonly_fops; + debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc), + kvm_debugfs_dir, + (void *)(long)pdesc->desc.offset, fops); + } +} + +static inline +struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn) +{ + return container_of(pn, struct kvm_vcpu, preempt_notifier); +} + +static void kvm_sched_in(struct preempt_notifier *pn, int cpu) +{ + struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); + + WRITE_ONCE(vcpu->preempted, false); + WRITE_ONCE(vcpu->ready, false); + + __this_cpu_write(kvm_running_vcpu, vcpu); + kvm_arch_sched_in(vcpu, cpu); + kvm_arch_vcpu_load(vcpu, cpu); +} + +static void kvm_sched_out(struct preempt_notifier *pn, + struct task_struct *next) +{ + struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); + + if (current->on_rq) { + WRITE_ONCE(vcpu->preempted, true); + WRITE_ONCE(vcpu->ready, true); + } + kvm_arch_vcpu_put(vcpu); + __this_cpu_write(kvm_running_vcpu, NULL); +} + +/** + * kvm_get_running_vcpu - get the vcpu running on the current CPU. + * + * We can disable preemption locally around accessing the per-CPU variable, + * and use the resolved vcpu pointer after enabling preemption again, + * because even if the current thread is migrated to another CPU, reading + * the per-CPU value later will give us the same value as we update the + * per-CPU variable in the preempt notifier handlers. + */ +struct kvm_vcpu *kvm_get_running_vcpu(void) +{ + struct kvm_vcpu *vcpu; + + preempt_disable(); + vcpu = __this_cpu_read(kvm_running_vcpu); + preempt_enable(); + + return vcpu; +} +EXPORT_SYMBOL_GPL(kvm_get_running_vcpu); + +/** + * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus. + */ +struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void) +{ + return &kvm_running_vcpu; +} + +#ifdef CONFIG_GUEST_PERF_EVENTS +static unsigned int kvm_guest_state(void) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + unsigned int state; + + if (!kvm_arch_pmi_in_guest(vcpu)) + return 0; + + state = PERF_GUEST_ACTIVE; + if (!kvm_arch_vcpu_in_kernel(vcpu)) + state |= PERF_GUEST_USER; + + return state; +} + +static unsigned long kvm_guest_get_ip(void) +{ + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); + + /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */ + if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu))) + return 0; + + return kvm_arch_vcpu_get_ip(vcpu); +} + +static struct perf_guest_info_callbacks kvm_guest_cbs = { + .state = kvm_guest_state, + .get_ip = kvm_guest_get_ip, + .handle_intel_pt_intr = NULL, +}; + +void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void)) +{ + kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler; + perf_register_guest_info_callbacks(&kvm_guest_cbs); +} +void kvm_unregister_perf_callbacks(void) +{ + perf_unregister_guest_info_callbacks(&kvm_guest_cbs); +} +#endif + +int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) +{ + int r; + int cpu; + +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING + r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", + kvm_online_cpu, kvm_offline_cpu); + if (r) + return r; + + register_syscore_ops(&kvm_syscore_ops); +#endif + + /* A kmem cache lets us meet the alignment requirements of fx_save. */ + if (!vcpu_align) + vcpu_align = __alignof__(struct kvm_vcpu); + kvm_vcpu_cache = + kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align, + SLAB_ACCOUNT, + offsetof(struct kvm_vcpu, arch), + offsetofend(struct kvm_vcpu, stats_id) + - offsetof(struct kvm_vcpu, arch), + NULL); + if (!kvm_vcpu_cache) { + r = -ENOMEM; + goto err_vcpu_cache; + } + + for_each_possible_cpu(cpu) { + if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu), + GFP_KERNEL, cpu_to_node(cpu))) { + r = -ENOMEM; + goto err_cpu_kick_mask; + } + } + + r = kvm_irqfd_init(); + if (r) + goto err_irqfd; + + r = kvm_async_pf_init(); + if (r) + goto err_async_pf; + + kvm_chardev_ops.owner = module; + + kvm_preempt_ops.sched_in = kvm_sched_in; + kvm_preempt_ops.sched_out = kvm_sched_out; + + kvm_init_debug(); + + r = kvm_vfio_ops_init(); + if (WARN_ON_ONCE(r)) + goto err_vfio; + + /* + * Registration _must_ be the very last thing done, as this exposes + * /dev/kvm to userspace, i.e. all infrastructure must be setup! + */ + r = misc_register(&kvm_dev); + if (r) { + pr_err("kvm: misc device register failed\n"); + goto err_register; + } + + return 0; + +err_register: + kvm_vfio_ops_exit(); +err_vfio: + kvm_async_pf_deinit(); +err_async_pf: + kvm_irqfd_exit(); +err_irqfd: +err_cpu_kick_mask: + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); + kmem_cache_destroy(kvm_vcpu_cache); +err_vcpu_cache: +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING + unregister_syscore_ops(&kvm_syscore_ops); + cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE); +#endif + return r; +} +EXPORT_SYMBOL_GPL(kvm_init); + +void kvm_exit(void) +{ + int cpu; + + /* + * Note, unregistering /dev/kvm doesn't strictly need to come first, + * fops_get(), a.k.a. try_module_get(), prevents acquiring references + * to KVM while the module is being stopped. + */ + misc_deregister(&kvm_dev); + + debugfs_remove_recursive(kvm_debugfs_dir); + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); + kmem_cache_destroy(kvm_vcpu_cache); + kvm_vfio_ops_exit(); + kvm_async_pf_deinit(); +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING + unregister_syscore_ops(&kvm_syscore_ops); + cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE); +#endif + kvm_irqfd_exit(); +} +EXPORT_SYMBOL_GPL(kvm_exit); + +struct kvm_vm_worker_thread_context { + struct kvm *kvm; + struct task_struct *parent; + struct completion init_done; + kvm_vm_thread_fn_t thread_fn; + uintptr_t data; + int err; +}; + +static int kvm_vm_worker_thread(void *context) +{ + /* + * The init_context is allocated on the stack of the parent thread, so + * we have to locally copy anything that is needed beyond initialization + */ + struct kvm_vm_worker_thread_context *init_context = context; + struct task_struct *parent; + struct kvm *kvm = init_context->kvm; + kvm_vm_thread_fn_t thread_fn = init_context->thread_fn; + uintptr_t data = init_context->data; + int err; + + err = kthread_park(current); + /* kthread_park(current) is never supposed to return an error */ + WARN_ON(err != 0); + if (err) + goto init_complete; + + err = cgroup_attach_task_all(init_context->parent, current); + if (err) { + kvm_err("%s: cgroup_attach_task_all failed with err %d\n", + __func__, err); + goto init_complete; + } + + set_user_nice(current, task_nice(init_context->parent)); + +init_complete: + init_context->err = err; + complete(&init_context->init_done); + init_context = NULL; + + if (err) + goto out; + + /* Wait to be woken up by the spawner before proceeding. */ + kthread_parkme(); + + if (!kthread_should_stop()) + err = thread_fn(kvm, data); + +out: + /* + * Move kthread back to its original cgroup to prevent it lingering in + * the cgroup of the VM process, after the latter finishes its + * execution. + * + * kthread_stop() waits on the 'exited' completion condition which is + * set in exit_mm(), via mm_release(), in do_exit(). However, the + * kthread is removed from the cgroup in the cgroup_exit() which is + * called after the exit_mm(). This causes the kthread_stop() to return + * before the kthread actually quits the cgroup. + */ + rcu_read_lock(); + parent = rcu_dereference(current->real_parent); + get_task_struct(parent); + rcu_read_unlock(); + cgroup_attach_task_all(parent, current); + put_task_struct(parent); + + return err; +} + +int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn, + uintptr_t data, const char *name, + struct task_struct **thread_ptr) +{ + struct kvm_vm_worker_thread_context init_context = {}; + struct task_struct *thread; + + *thread_ptr = NULL; + init_context.kvm = kvm; + init_context.parent = current; + init_context.thread_fn = thread_fn; + init_context.data = data; + init_completion(&init_context.init_done); + + thread = kthread_run(kvm_vm_worker_thread, &init_context, + "%s-%d", name, task_pid_nr(current)); + if (IS_ERR(thread)) + return PTR_ERR(thread); + + /* kthread_run is never supposed to return NULL */ + WARN_ON(thread == NULL); + + wait_for_completion(&init_context.init_done); + + if (!init_context.err) + *thread_ptr = thread; + + return init_context.err; +} |