diff options
Diffstat (limited to 'arch/arm64/kvm/mmu.c')
| -rw-r--r-- | arch/arm64/kvm/mmu.c | 2158 |
1 files changed, 2158 insertions, 0 deletions
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c new file mode 100644 index 0000000000..482280fe22 --- /dev/null +++ b/arch/arm64/kvm/mmu.c @@ -0,0 +1,2158 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall <c.dall@virtualopensystems.com> + */ + +#include <linux/mman.h> +#include <linux/kvm_host.h> +#include <linux/io.h> +#include <linux/hugetlb.h> +#include <linux/sched/signal.h> +#include <trace/events/kvm.h> +#include <asm/pgalloc.h> +#include <asm/cacheflush.h> +#include <asm/kvm_arm.h> +#include <asm/kvm_mmu.h> +#include <asm/kvm_pgtable.h> +#include <asm/kvm_ras.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_emulate.h> +#include <asm/virt.h> + +#include "trace.h" + +static struct kvm_pgtable *hyp_pgtable; +static DEFINE_MUTEX(kvm_hyp_pgd_mutex); + +static unsigned long __ro_after_init hyp_idmap_start; +static unsigned long __ro_after_init hyp_idmap_end; +static phys_addr_t __ro_after_init hyp_idmap_vector; + +static unsigned long __ro_after_init io_map_base; + +static phys_addr_t __stage2_range_addr_end(phys_addr_t addr, phys_addr_t end, + phys_addr_t size) +{ + phys_addr_t boundary = ALIGN_DOWN(addr + size, size); + + return (boundary - 1 < end - 1) ? boundary : end; +} + +static phys_addr_t stage2_range_addr_end(phys_addr_t addr, phys_addr_t end) +{ + phys_addr_t size = kvm_granule_size(KVM_PGTABLE_MIN_BLOCK_LEVEL); + + return __stage2_range_addr_end(addr, end, size); +} + +/* + * Release kvm_mmu_lock periodically if the memory region is large. Otherwise, + * we may see kernel panics with CONFIG_DETECT_HUNG_TASK, + * CONFIG_LOCKUP_DETECTOR, CONFIG_LOCKDEP. Additionally, holding the lock too + * long will also starve other vCPUs. We have to also make sure that the page + * tables are not freed while we released the lock. + */ +static int stage2_apply_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, + phys_addr_t end, + int (*fn)(struct kvm_pgtable *, u64, u64), + bool resched) +{ + struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu); + int ret; + u64 next; + + do { + struct kvm_pgtable *pgt = mmu->pgt; + if (!pgt) + return -EINVAL; + + next = stage2_range_addr_end(addr, end); + ret = fn(pgt, addr, next - addr); + if (ret) + break; + + if (resched && next != end) + cond_resched_rwlock_write(&kvm->mmu_lock); + } while (addr = next, addr != end); + + return ret; +} + +#define stage2_apply_range_resched(mmu, addr, end, fn) \ + stage2_apply_range(mmu, addr, end, fn, true) + +/* + * Get the maximum number of page-tables pages needed to split a range + * of blocks into PAGE_SIZE PTEs. It assumes the range is already + * mapped at level 2, or at level 1 if allowed. + */ +static int kvm_mmu_split_nr_page_tables(u64 range) +{ + int n = 0; + + if (KVM_PGTABLE_MIN_BLOCK_LEVEL < 2) + n += DIV_ROUND_UP(range, PUD_SIZE); + n += DIV_ROUND_UP(range, PMD_SIZE); + return n; +} + +static bool need_split_memcache_topup_or_resched(struct kvm *kvm) +{ + struct kvm_mmu_memory_cache *cache; + u64 chunk_size, min; + + if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) + return true; + + chunk_size = kvm->arch.mmu.split_page_chunk_size; + min = kvm_mmu_split_nr_page_tables(chunk_size); + cache = &kvm->arch.mmu.split_page_cache; + return kvm_mmu_memory_cache_nr_free_objects(cache) < min; +} + +static int kvm_mmu_split_huge_pages(struct kvm *kvm, phys_addr_t addr, + phys_addr_t end) +{ + struct kvm_mmu_memory_cache *cache; + struct kvm_pgtable *pgt; + int ret, cache_capacity; + u64 next, chunk_size; + + lockdep_assert_held_write(&kvm->mmu_lock); + + chunk_size = kvm->arch.mmu.split_page_chunk_size; + cache_capacity = kvm_mmu_split_nr_page_tables(chunk_size); + + if (chunk_size == 0) + return 0; + + cache = &kvm->arch.mmu.split_page_cache; + + do { + if (need_split_memcache_topup_or_resched(kvm)) { + write_unlock(&kvm->mmu_lock); + cond_resched(); + /* Eager page splitting is best-effort. */ + ret = __kvm_mmu_topup_memory_cache(cache, + cache_capacity, + cache_capacity); + write_lock(&kvm->mmu_lock); + if (ret) + break; + } + + pgt = kvm->arch.mmu.pgt; + if (!pgt) + return -EINVAL; + + next = __stage2_range_addr_end(addr, end, chunk_size); + ret = kvm_pgtable_stage2_split(pgt, addr, next - addr, cache); + if (ret) + break; + } while (addr = next, addr != end); + + return ret; +} + +static bool memslot_is_logging(struct kvm_memory_slot *memslot) +{ + return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY); +} + +/** + * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8 + * @kvm: pointer to kvm structure. + * + * Interface to HYP function to flush all VM TLB entries + */ +int kvm_arch_flush_remote_tlbs(struct kvm *kvm) +{ + kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu); + return 0; +} + +int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, + gfn_t gfn, u64 nr_pages) +{ + kvm_tlb_flush_vmid_range(&kvm->arch.mmu, + gfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT); + return 0; +} + +static bool kvm_is_device_pfn(unsigned long pfn) +{ + return !pfn_is_map_memory(pfn); +} + +static void *stage2_memcache_zalloc_page(void *arg) +{ + struct kvm_mmu_memory_cache *mc = arg; + void *virt; + + /* Allocated with __GFP_ZERO, so no need to zero */ + virt = kvm_mmu_memory_cache_alloc(mc); + if (virt) + kvm_account_pgtable_pages(virt, 1); + return virt; +} + +static void *kvm_host_zalloc_pages_exact(size_t size) +{ + return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO); +} + +static void *kvm_s2_zalloc_pages_exact(size_t size) +{ + void *virt = kvm_host_zalloc_pages_exact(size); + + if (virt) + kvm_account_pgtable_pages(virt, (size >> PAGE_SHIFT)); + return virt; +} + +static void kvm_s2_free_pages_exact(void *virt, size_t size) +{ + kvm_account_pgtable_pages(virt, -(size >> PAGE_SHIFT)); + free_pages_exact(virt, size); +} + +static struct kvm_pgtable_mm_ops kvm_s2_mm_ops; + +static void stage2_free_unlinked_table_rcu_cb(struct rcu_head *head) +{ + struct page *page = container_of(head, struct page, rcu_head); + void *pgtable = page_to_virt(page); + u32 level = page_private(page); + + kvm_pgtable_stage2_free_unlinked(&kvm_s2_mm_ops, pgtable, level); +} + +static void stage2_free_unlinked_table(void *addr, u32 level) +{ + struct page *page = virt_to_page(addr); + + set_page_private(page, (unsigned long)level); + call_rcu(&page->rcu_head, stage2_free_unlinked_table_rcu_cb); +} + +static void kvm_host_get_page(void *addr) +{ + get_page(virt_to_page(addr)); +} + +static void kvm_host_put_page(void *addr) +{ + put_page(virt_to_page(addr)); +} + +static void kvm_s2_put_page(void *addr) +{ + struct page *p = virt_to_page(addr); + /* Dropping last refcount, the page will be freed */ + if (page_count(p) == 1) + kvm_account_pgtable_pages(addr, -1); + put_page(p); +} + +static int kvm_host_page_count(void *addr) +{ + return page_count(virt_to_page(addr)); +} + +static phys_addr_t kvm_host_pa(void *addr) +{ + return __pa(addr); +} + +static void *kvm_host_va(phys_addr_t phys) +{ + return __va(phys); +} + +static void clean_dcache_guest_page(void *va, size_t size) +{ + __clean_dcache_guest_page(va, size); +} + +static void invalidate_icache_guest_page(void *va, size_t size) +{ + __invalidate_icache_guest_page(va, size); +} + +/* + * Unmapping vs dcache management: + * + * If a guest maps certain memory pages as uncached, all writes will + * bypass the data cache and go directly to RAM. However, the CPUs + * can still speculate reads (not writes) and fill cache lines with + * data. + * + * Those cache lines will be *clean* cache lines though, so a + * clean+invalidate operation is equivalent to an invalidate + * operation, because no cache lines are marked dirty. + * + * Those clean cache lines could be filled prior to an uncached write + * by the guest, and the cache coherent IO subsystem would therefore + * end up writing old data to disk. + * + * This is why right after unmapping a page/section and invalidating + * the corresponding TLBs, we flush to make sure the IO subsystem will + * never hit in the cache. + * + * This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as + * we then fully enforce cacheability of RAM, no matter what the guest + * does. + */ +/** + * unmap_stage2_range -- Clear stage2 page table entries to unmap a range + * @mmu: The KVM stage-2 MMU pointer + * @start: The intermediate physical base address of the range to unmap + * @size: The size of the area to unmap + * @may_block: Whether or not we are permitted to block + * + * Clear a range of stage-2 mappings, lowering the various ref-counts. Must + * be called while holding mmu_lock (unless for freeing the stage2 pgd before + * destroying the VM), otherwise another faulting VCPU may come in and mess + * with things behind our backs. + */ +static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size, + bool may_block) +{ + struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu); + phys_addr_t end = start + size; + + lockdep_assert_held_write(&kvm->mmu_lock); + WARN_ON(size & ~PAGE_MASK); + WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap, + may_block)); +} + +static void unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size) +{ + __unmap_stage2_range(mmu, start, size, true); +} + +static void stage2_flush_memslot(struct kvm *kvm, + struct kvm_memory_slot *memslot) +{ + phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT; + phys_addr_t end = addr + PAGE_SIZE * memslot->npages; + + stage2_apply_range_resched(&kvm->arch.mmu, addr, end, kvm_pgtable_stage2_flush); +} + +/** + * stage2_flush_vm - Invalidate cache for pages mapped in stage 2 + * @kvm: The struct kvm pointer + * + * Go through the stage 2 page tables and invalidate any cache lines + * backing memory already mapped to the VM. + */ +static void stage2_flush_vm(struct kvm *kvm) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int idx, bkt; + + idx = srcu_read_lock(&kvm->srcu); + write_lock(&kvm->mmu_lock); + + slots = kvm_memslots(kvm); + kvm_for_each_memslot(memslot, bkt, slots) + stage2_flush_memslot(kvm, memslot); + + write_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); +} + +/** + * free_hyp_pgds - free Hyp-mode page tables + */ +void __init free_hyp_pgds(void) +{ + mutex_lock(&kvm_hyp_pgd_mutex); + if (hyp_pgtable) { + kvm_pgtable_hyp_destroy(hyp_pgtable); + kfree(hyp_pgtable); + hyp_pgtable = NULL; + } + mutex_unlock(&kvm_hyp_pgd_mutex); +} + +static bool kvm_host_owns_hyp_mappings(void) +{ + if (is_kernel_in_hyp_mode()) + return false; + + if (static_branch_likely(&kvm_protected_mode_initialized)) + return false; + + /* + * This can happen at boot time when __create_hyp_mappings() is called + * after the hyp protection has been enabled, but the static key has + * not been flipped yet. + */ + if (!hyp_pgtable && is_protected_kvm_enabled()) + return false; + + WARN_ON(!hyp_pgtable); + + return true; +} + +int __create_hyp_mappings(unsigned long start, unsigned long size, + unsigned long phys, enum kvm_pgtable_prot prot) +{ + int err; + + if (WARN_ON(!kvm_host_owns_hyp_mappings())) + return -EINVAL; + + mutex_lock(&kvm_hyp_pgd_mutex); + err = kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot); + mutex_unlock(&kvm_hyp_pgd_mutex); + + return err; +} + +static phys_addr_t kvm_kaddr_to_phys(void *kaddr) +{ + if (!is_vmalloc_addr(kaddr)) { + BUG_ON(!virt_addr_valid(kaddr)); + return __pa(kaddr); + } else { + return page_to_phys(vmalloc_to_page(kaddr)) + + offset_in_page(kaddr); + } +} + +struct hyp_shared_pfn { + u64 pfn; + int count; + struct rb_node node; +}; + +static DEFINE_MUTEX(hyp_shared_pfns_lock); +static struct rb_root hyp_shared_pfns = RB_ROOT; + +static struct hyp_shared_pfn *find_shared_pfn(u64 pfn, struct rb_node ***node, + struct rb_node **parent) +{ + struct hyp_shared_pfn *this; + + *node = &hyp_shared_pfns.rb_node; + *parent = NULL; + while (**node) { + this = container_of(**node, struct hyp_shared_pfn, node); + *parent = **node; + if (this->pfn < pfn) + *node = &((**node)->rb_left); + else if (this->pfn > pfn) + *node = &((**node)->rb_right); + else + return this; + } + + return NULL; +} + +static int share_pfn_hyp(u64 pfn) +{ + struct rb_node **node, *parent; + struct hyp_shared_pfn *this; + int ret = 0; + + mutex_lock(&hyp_shared_pfns_lock); + this = find_shared_pfn(pfn, &node, &parent); + if (this) { + this->count++; + goto unlock; + } + + this = kzalloc(sizeof(*this), GFP_KERNEL); + if (!this) { + ret = -ENOMEM; + goto unlock; + } + + this->pfn = pfn; + this->count = 1; + rb_link_node(&this->node, parent, node); + rb_insert_color(&this->node, &hyp_shared_pfns); + ret = kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn, 1); +unlock: + mutex_unlock(&hyp_shared_pfns_lock); + + return ret; +} + +static int unshare_pfn_hyp(u64 pfn) +{ + struct rb_node **node, *parent; + struct hyp_shared_pfn *this; + int ret = 0; + + mutex_lock(&hyp_shared_pfns_lock); + this = find_shared_pfn(pfn, &node, &parent); + if (WARN_ON(!this)) { + ret = -ENOENT; + goto unlock; + } + + this->count--; + if (this->count) + goto unlock; + + rb_erase(&this->node, &hyp_shared_pfns); + kfree(this); + ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn, 1); +unlock: + mutex_unlock(&hyp_shared_pfns_lock); + + return ret; +} + +int kvm_share_hyp(void *from, void *to) +{ + phys_addr_t start, end, cur; + u64 pfn; + int ret; + + if (is_kernel_in_hyp_mode()) + return 0; + + /* + * The share hcall maps things in the 'fixed-offset' region of the hyp + * VA space, so we can only share physically contiguous data-structures + * for now. + */ + if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to)) + return -EINVAL; + + if (kvm_host_owns_hyp_mappings()) + return create_hyp_mappings(from, to, PAGE_HYP); + + start = ALIGN_DOWN(__pa(from), PAGE_SIZE); + end = PAGE_ALIGN(__pa(to)); + for (cur = start; cur < end; cur += PAGE_SIZE) { + pfn = __phys_to_pfn(cur); + ret = share_pfn_hyp(pfn); + if (ret) + return ret; + } + + return 0; +} + +void kvm_unshare_hyp(void *from, void *to) +{ + phys_addr_t start, end, cur; + u64 pfn; + + if (is_kernel_in_hyp_mode() || kvm_host_owns_hyp_mappings() || !from) + return; + + start = ALIGN_DOWN(__pa(from), PAGE_SIZE); + end = PAGE_ALIGN(__pa(to)); + for (cur = start; cur < end; cur += PAGE_SIZE) { + pfn = __phys_to_pfn(cur); + WARN_ON(unshare_pfn_hyp(pfn)); + } +} + +/** + * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode + * @from: The virtual kernel start address of the range + * @to: The virtual kernel end address of the range (exclusive) + * @prot: The protection to be applied to this range + * + * The same virtual address as the kernel virtual address is also used + * in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying + * physical pages. + */ +int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot) +{ + phys_addr_t phys_addr; + unsigned long virt_addr; + unsigned long start = kern_hyp_va((unsigned long)from); + unsigned long end = kern_hyp_va((unsigned long)to); + + if (is_kernel_in_hyp_mode()) + return 0; + + if (!kvm_host_owns_hyp_mappings()) + return -EPERM; + + start = start & PAGE_MASK; + end = PAGE_ALIGN(end); + + for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) { + int err; + + phys_addr = kvm_kaddr_to_phys(from + virt_addr - start); + err = __create_hyp_mappings(virt_addr, PAGE_SIZE, phys_addr, + prot); + if (err) + return err; + } + + return 0; +} + +static int __hyp_alloc_private_va_range(unsigned long base) +{ + lockdep_assert_held(&kvm_hyp_pgd_mutex); + + if (!PAGE_ALIGNED(base)) + return -EINVAL; + + /* + * Verify that BIT(VA_BITS - 1) hasn't been flipped by + * allocating the new area, as it would indicate we've + * overflowed the idmap/IO address range. + */ + if ((base ^ io_map_base) & BIT(VA_BITS - 1)) + return -ENOMEM; + + io_map_base = base; + + return 0; +} + +/** + * hyp_alloc_private_va_range - Allocates a private VA range. + * @size: The size of the VA range to reserve. + * @haddr: The hypervisor virtual start address of the allocation. + * + * The private virtual address (VA) range is allocated below io_map_base + * and aligned based on the order of @size. + * + * Return: 0 on success or negative error code on failure. + */ +int hyp_alloc_private_va_range(size_t size, unsigned long *haddr) +{ + unsigned long base; + int ret = 0; + + mutex_lock(&kvm_hyp_pgd_mutex); + + /* + * This assumes that we have enough space below the idmap + * page to allocate our VAs. If not, the check in + * __hyp_alloc_private_va_range() will kick. A potential + * alternative would be to detect that overflow and switch + * to an allocation above the idmap. + * + * The allocated size is always a multiple of PAGE_SIZE. + */ + size = PAGE_ALIGN(size); + base = io_map_base - size; + ret = __hyp_alloc_private_va_range(base); + + mutex_unlock(&kvm_hyp_pgd_mutex); + + if (!ret) + *haddr = base; + + return ret; +} + +static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size, + unsigned long *haddr, + enum kvm_pgtable_prot prot) +{ + unsigned long addr; + int ret = 0; + + if (!kvm_host_owns_hyp_mappings()) { + addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping, + phys_addr, size, prot); + if (IS_ERR_VALUE(addr)) + return addr; + *haddr = addr; + + return 0; + } + + size = PAGE_ALIGN(size + offset_in_page(phys_addr)); + ret = hyp_alloc_private_va_range(size, &addr); + if (ret) + return ret; + + ret = __create_hyp_mappings(addr, size, phys_addr, prot); + if (ret) + return ret; + + *haddr = addr + offset_in_page(phys_addr); + return ret; +} + +int create_hyp_stack(phys_addr_t phys_addr, unsigned long *haddr) +{ + unsigned long base; + size_t size; + int ret; + + mutex_lock(&kvm_hyp_pgd_mutex); + /* + * Efficient stack verification using the PAGE_SHIFT bit implies + * an alignment of our allocation on the order of the size. + */ + size = PAGE_SIZE * 2; + base = ALIGN_DOWN(io_map_base - size, size); + + ret = __hyp_alloc_private_va_range(base); + + mutex_unlock(&kvm_hyp_pgd_mutex); + + if (ret) { + kvm_err("Cannot allocate hyp stack guard page\n"); + return ret; + } + + /* + * Since the stack grows downwards, map the stack to the page + * at the higher address and leave the lower guard page + * unbacked. + * + * Any valid stack address now has the PAGE_SHIFT bit as 1 + * and addresses corresponding to the guard page have the + * PAGE_SHIFT bit as 0 - this is used for overflow detection. + */ + ret = __create_hyp_mappings(base + PAGE_SIZE, PAGE_SIZE, phys_addr, + PAGE_HYP); + if (ret) + kvm_err("Cannot map hyp stack\n"); + + *haddr = base + size; + + return ret; +} + +/** + * create_hyp_io_mappings - Map IO into both kernel and HYP + * @phys_addr: The physical start address which gets mapped + * @size: Size of the region being mapped + * @kaddr: Kernel VA for this mapping + * @haddr: HYP VA for this mapping + */ +int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, + void __iomem **kaddr, + void __iomem **haddr) +{ + unsigned long addr; + int ret; + + if (is_protected_kvm_enabled()) + return -EPERM; + + *kaddr = ioremap(phys_addr, size); + if (!*kaddr) + return -ENOMEM; + + if (is_kernel_in_hyp_mode()) { + *haddr = *kaddr; + return 0; + } + + ret = __create_hyp_private_mapping(phys_addr, size, + &addr, PAGE_HYP_DEVICE); + if (ret) { + iounmap(*kaddr); + *kaddr = NULL; + *haddr = NULL; + return ret; + } + + *haddr = (void __iomem *)addr; + return 0; +} + +/** + * create_hyp_exec_mappings - Map an executable range into HYP + * @phys_addr: The physical start address which gets mapped + * @size: Size of the region being mapped + * @haddr: HYP VA for this mapping + */ +int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size, + void **haddr) +{ + unsigned long addr; + int ret; + + BUG_ON(is_kernel_in_hyp_mode()); + + ret = __create_hyp_private_mapping(phys_addr, size, + &addr, PAGE_HYP_EXEC); + if (ret) { + *haddr = NULL; + return ret; + } + + *haddr = (void *)addr; + return 0; +} + +static struct kvm_pgtable_mm_ops kvm_user_mm_ops = { + /* We shouldn't need any other callback to walk the PT */ + .phys_to_virt = kvm_host_va, +}; + +static int get_user_mapping_size(struct kvm *kvm, u64 addr) +{ + struct kvm_pgtable pgt = { + .pgd = (kvm_pteref_t)kvm->mm->pgd, + .ia_bits = vabits_actual, + .start_level = (KVM_PGTABLE_MAX_LEVELS - + CONFIG_PGTABLE_LEVELS), + .mm_ops = &kvm_user_mm_ops, + }; + unsigned long flags; + kvm_pte_t pte = 0; /* Keep GCC quiet... */ + u32 level = ~0; + int ret; + + /* + * Disable IRQs so that we hazard against a concurrent + * teardown of the userspace page tables (which relies on + * IPI-ing threads). + */ + local_irq_save(flags); + ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level); + local_irq_restore(flags); + + if (ret) + return ret; + + /* + * Not seeing an error, but not updating level? Something went + * deeply wrong... + */ + if (WARN_ON(level >= KVM_PGTABLE_MAX_LEVELS)) + return -EFAULT; + + /* Oops, the userspace PTs are gone... Replay the fault */ + if (!kvm_pte_valid(pte)) + return -EAGAIN; + + return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level)); +} + +static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = { + .zalloc_page = stage2_memcache_zalloc_page, + .zalloc_pages_exact = kvm_s2_zalloc_pages_exact, + .free_pages_exact = kvm_s2_free_pages_exact, + .free_unlinked_table = stage2_free_unlinked_table, + .get_page = kvm_host_get_page, + .put_page = kvm_s2_put_page, + .page_count = kvm_host_page_count, + .phys_to_virt = kvm_host_va, + .virt_to_phys = kvm_host_pa, + .dcache_clean_inval_poc = clean_dcache_guest_page, + .icache_inval_pou = invalidate_icache_guest_page, +}; + +/** + * kvm_init_stage2_mmu - Initialise a S2 MMU structure + * @kvm: The pointer to the KVM structure + * @mmu: The pointer to the s2 MMU structure + * @type: The machine type of the virtual machine + * + * Allocates only the stage-2 HW PGD level table(s). + * Note we don't need locking here as this is only called when the VM is + * created, which can only be done once. + */ +int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type) +{ + u32 kvm_ipa_limit = get_kvm_ipa_limit(); + int cpu, err; + struct kvm_pgtable *pgt; + u64 mmfr0, mmfr1; + u32 phys_shift; + + if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK) + return -EINVAL; + + phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); + if (is_protected_kvm_enabled()) { + phys_shift = kvm_ipa_limit; + } else if (phys_shift) { + if (phys_shift > kvm_ipa_limit || + phys_shift < ARM64_MIN_PARANGE_BITS) + return -EINVAL; + } else { + phys_shift = KVM_PHYS_SHIFT; + if (phys_shift > kvm_ipa_limit) { + pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n", + current->comm); + return -EINVAL; + } + } + + mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); + mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift); + + if (mmu->pgt != NULL) { + kvm_err("kvm_arch already initialized?\n"); + return -EINVAL; + } + + pgt = kzalloc(sizeof(*pgt), GFP_KERNEL_ACCOUNT); + if (!pgt) + return -ENOMEM; + + mmu->arch = &kvm->arch; + err = kvm_pgtable_stage2_init(pgt, mmu, &kvm_s2_mm_ops); + if (err) + goto out_free_pgtable; + + mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran)); + if (!mmu->last_vcpu_ran) { + err = -ENOMEM; + goto out_destroy_pgtable; + } + + for_each_possible_cpu(cpu) + *per_cpu_ptr(mmu->last_vcpu_ran, cpu) = -1; + + /* The eager page splitting is disabled by default */ + mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT; + mmu->split_page_cache.gfp_zero = __GFP_ZERO; + + mmu->pgt = pgt; + mmu->pgd_phys = __pa(pgt->pgd); + return 0; + +out_destroy_pgtable: + kvm_pgtable_stage2_destroy(pgt); +out_free_pgtable: + kfree(pgt); + return err; +} + +void kvm_uninit_stage2_mmu(struct kvm *kvm) +{ + kvm_free_stage2_pgd(&kvm->arch.mmu); + kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache); +} + +static void stage2_unmap_memslot(struct kvm *kvm, + struct kvm_memory_slot *memslot) +{ + hva_t hva = memslot->userspace_addr; + phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT; + phys_addr_t size = PAGE_SIZE * memslot->npages; + hva_t reg_end = hva + size; + + /* + * A memory region could potentially cover multiple VMAs, and any holes + * between them, so iterate over all of them to find out if we should + * unmap any of them. + * + * +--------------------------------------------+ + * +---------------+----------------+ +----------------+ + * | : VMA 1 | VMA 2 | | VMA 3 : | + * +---------------+----------------+ +----------------+ + * | memory region | + * +--------------------------------------------+ + */ + do { + struct vm_area_struct *vma; + hva_t vm_start, vm_end; + + vma = find_vma_intersection(current->mm, hva, reg_end); + if (!vma) + break; + + /* + * Take the intersection of this VMA with the memory region + */ + vm_start = max(hva, vma->vm_start); + vm_end = min(reg_end, vma->vm_end); + + if (!(vma->vm_flags & VM_PFNMAP)) { + gpa_t gpa = addr + (vm_start - memslot->userspace_addr); + unmap_stage2_range(&kvm->arch.mmu, gpa, vm_end - vm_start); + } + hva = vm_end; + } while (hva < reg_end); +} + +/** + * stage2_unmap_vm - Unmap Stage-2 RAM mappings + * @kvm: The struct kvm pointer + * + * Go through the memregions and unmap any regular RAM + * backing memory already mapped to the VM. + */ +void stage2_unmap_vm(struct kvm *kvm) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int idx, bkt; + + idx = srcu_read_lock(&kvm->srcu); + mmap_read_lock(current->mm); + write_lock(&kvm->mmu_lock); + + slots = kvm_memslots(kvm); + kvm_for_each_memslot(memslot, bkt, slots) + stage2_unmap_memslot(kvm, memslot); + + write_unlock(&kvm->mmu_lock); + mmap_read_unlock(current->mm); + srcu_read_unlock(&kvm->srcu, idx); +} + +void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu) +{ + struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu); + struct kvm_pgtable *pgt = NULL; + + write_lock(&kvm->mmu_lock); + pgt = mmu->pgt; + if (pgt) { + mmu->pgd_phys = 0; + mmu->pgt = NULL; + free_percpu(mmu->last_vcpu_ran); + } + write_unlock(&kvm->mmu_lock); + + if (pgt) { + kvm_pgtable_stage2_destroy(pgt); + kfree(pgt); + } +} + +static void hyp_mc_free_fn(void *addr, void *unused) +{ + free_page((unsigned long)addr); +} + +static void *hyp_mc_alloc_fn(void *unused) +{ + return (void *)__get_free_page(GFP_KERNEL_ACCOUNT); +} + +void free_hyp_memcache(struct kvm_hyp_memcache *mc) +{ + if (is_protected_kvm_enabled()) + __free_hyp_memcache(mc, hyp_mc_free_fn, + kvm_host_va, NULL); +} + +int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages) +{ + if (!is_protected_kvm_enabled()) + return 0; + + return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn, + kvm_host_pa, NULL); +} + +/** + * kvm_phys_addr_ioremap - map a device range to guest IPA + * + * @kvm: The KVM pointer + * @guest_ipa: The IPA at which to insert the mapping + * @pa: The physical address of the device + * @size: The size of the mapping + * @writable: Whether or not to create a writable mapping + */ +int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, + phys_addr_t pa, unsigned long size, bool writable) +{ + phys_addr_t addr; + int ret = 0; + struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO }; + struct kvm_pgtable *pgt = kvm->arch.mmu.pgt; + enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE | + KVM_PGTABLE_PROT_R | + (writable ? KVM_PGTABLE_PROT_W : 0); + + if (is_protected_kvm_enabled()) + return -EPERM; + + size += offset_in_page(guest_ipa); + guest_ipa &= PAGE_MASK; + + for (addr = guest_ipa; addr < guest_ipa + size; addr += PAGE_SIZE) { + ret = kvm_mmu_topup_memory_cache(&cache, + kvm_mmu_cache_min_pages(kvm)); + if (ret) + break; + + write_lock(&kvm->mmu_lock); + ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot, + &cache, 0); + write_unlock(&kvm->mmu_lock); + if (ret) + break; + + pa += PAGE_SIZE; + } + + kvm_mmu_free_memory_cache(&cache); + return ret; +} + +/** + * stage2_wp_range() - write protect stage2 memory region range + * @mmu: The KVM stage-2 MMU pointer + * @addr: Start address of range + * @end: End address of range + */ +static void stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end) +{ + stage2_apply_range_resched(mmu, addr, end, kvm_pgtable_stage2_wrprotect); +} + +/** + * kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot + * @kvm: The KVM pointer + * @slot: The memory slot to write protect + * + * Called to start logging dirty pages after memory region + * KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns + * all present PUD, PMD and PTEs are write protected in the memory region. + * Afterwards read of dirty page log can be called. + * + * Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired, + * serializing operations for VM memory regions. + */ +static void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot) +{ + struct kvm_memslots *slots = kvm_memslots(kvm); + struct kvm_memory_slot *memslot = id_to_memslot(slots, slot); + phys_addr_t start, end; + + if (WARN_ON_ONCE(!memslot)) + return; + + start = memslot->base_gfn << PAGE_SHIFT; + end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT; + + write_lock(&kvm->mmu_lock); + stage2_wp_range(&kvm->arch.mmu, start, end); + write_unlock(&kvm->mmu_lock); + kvm_flush_remote_tlbs_memslot(kvm, memslot); +} + +/** + * kvm_mmu_split_memory_region() - split the stage 2 blocks into PAGE_SIZE + * pages for memory slot + * @kvm: The KVM pointer + * @slot: The memory slot to split + * + * Acquires kvm->mmu_lock. Called with kvm->slots_lock mutex acquired, + * serializing operations for VM memory regions. + */ +static void kvm_mmu_split_memory_region(struct kvm *kvm, int slot) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + phys_addr_t start, end; + + lockdep_assert_held(&kvm->slots_lock); + + slots = kvm_memslots(kvm); + memslot = id_to_memslot(slots, slot); + + start = memslot->base_gfn << PAGE_SHIFT; + end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT; + + write_lock(&kvm->mmu_lock); + kvm_mmu_split_huge_pages(kvm, start, end); + write_unlock(&kvm->mmu_lock); +} + +/* + * kvm_arch_mmu_enable_log_dirty_pt_masked() - enable dirty logging for selected pages. + * @kvm: The KVM pointer + * @slot: The memory slot associated with mask + * @gfn_offset: The gfn offset in memory slot + * @mask: The mask of pages at offset 'gfn_offset' in this memory + * slot to enable dirty logging on + * + * Writes protect selected pages to enable dirty logging, and then + * splits them to PAGE_SIZE. Caller must acquire kvm->mmu_lock. + */ +void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, + struct kvm_memory_slot *slot, + gfn_t gfn_offset, unsigned long mask) +{ + phys_addr_t base_gfn = slot->base_gfn + gfn_offset; + phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT; + phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT; + + lockdep_assert_held_write(&kvm->mmu_lock); + + stage2_wp_range(&kvm->arch.mmu, start, end); + + /* + * Eager-splitting is done when manual-protect is set. We + * also check for initially-all-set because we can avoid + * eager-splitting if initially-all-set is false. + * Initially-all-set equal false implies that huge-pages were + * already split when enabling dirty logging: no need to do it + * again. + */ + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) + kvm_mmu_split_huge_pages(kvm, start, end); +} + +static void kvm_send_hwpoison_signal(unsigned long address, short lsb) +{ + send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, current); +} + +static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot, + unsigned long hva, + unsigned long map_size) +{ + gpa_t gpa_start; + hva_t uaddr_start, uaddr_end; + size_t size; + + /* The memslot and the VMA are guaranteed to be aligned to PAGE_SIZE */ + if (map_size == PAGE_SIZE) + return true; + + size = memslot->npages * PAGE_SIZE; + + gpa_start = memslot->base_gfn << PAGE_SHIFT; + + uaddr_start = memslot->userspace_addr; + uaddr_end = uaddr_start + size; + + /* + * Pages belonging to memslots that don't have the same alignment + * within a PMD/PUD for userspace and IPA cannot be mapped with stage-2 + * PMD/PUD entries, because we'll end up mapping the wrong pages. + * + * Consider a layout like the following: + * + * memslot->userspace_addr: + * +-----+--------------------+--------------------+---+ + * |abcde|fgh Stage-1 block | Stage-1 block tv|xyz| + * +-----+--------------------+--------------------+---+ + * + * memslot->base_gfn << PAGE_SHIFT: + * +---+--------------------+--------------------+-----+ + * |abc|def Stage-2 block | Stage-2 block |tvxyz| + * +---+--------------------+--------------------+-----+ + * + * If we create those stage-2 blocks, we'll end up with this incorrect + * mapping: + * d -> f + * e -> g + * f -> h + */ + if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1))) + return false; + + /* + * Next, let's make sure we're not trying to map anything not covered + * by the memslot. This means we have to prohibit block size mappings + * for the beginning and end of a non-block aligned and non-block sized + * memory slot (illustrated by the head and tail parts of the + * userspace view above containing pages 'abcde' and 'xyz', + * respectively). + * + * Note that it doesn't matter if we do the check using the + * userspace_addr or the base_gfn, as both are equally aligned (per + * the check above) and equally sized. + */ + return (hva & ~(map_size - 1)) >= uaddr_start && + (hva & ~(map_size - 1)) + map_size <= uaddr_end; +} + +/* + * Check if the given hva is backed by a transparent huge page (THP) and + * whether it can be mapped using block mapping in stage2. If so, adjust + * the stage2 PFN and IPA accordingly. Only PMD_SIZE THPs are currently + * supported. This will need to be updated to support other THP sizes. + * + * Returns the size of the mapping. + */ +static long +transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot, + unsigned long hva, kvm_pfn_t *pfnp, + phys_addr_t *ipap) +{ + kvm_pfn_t pfn = *pfnp; + + /* + * Make sure the adjustment is done only for THP pages. Also make + * sure that the HVA and IPA are sufficiently aligned and that the + * block map is contained within the memslot. + */ + if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) { + int sz = get_user_mapping_size(kvm, hva); + + if (sz < 0) + return sz; + + if (sz < PMD_SIZE) + return PAGE_SIZE; + + /* + * The address we faulted on is backed by a transparent huge + * page. However, because we map the compound huge page and + * not the individual tail page, we need to transfer the + * refcount to the head page. We have to be careful that the + * THP doesn't start to split while we are adjusting the + * refcounts. + * + * We are sure this doesn't happen, because mmu_invalidate_retry + * was successful and we are holding the mmu_lock, so if this + * THP is trying to split, it will be blocked in the mmu + * notifier before touching any of the pages, specifically + * before being able to call __split_huge_page_refcount(). + * + * We can therefore safely transfer the refcount from PG_tail + * to PG_head and switch the pfn from a tail page to the head + * page accordingly. + */ + *ipap &= PMD_MASK; + kvm_release_pfn_clean(pfn); + pfn &= ~(PTRS_PER_PMD - 1); + get_page(pfn_to_page(pfn)); + *pfnp = pfn; + + return PMD_SIZE; + } + + /* Use page mapping if we cannot use block mapping. */ + return PAGE_SIZE; +} + +static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva) +{ + unsigned long pa; + + if (is_vm_hugetlb_page(vma) && !(vma->vm_flags & VM_PFNMAP)) + return huge_page_shift(hstate_vma(vma)); + + if (!(vma->vm_flags & VM_PFNMAP)) + return PAGE_SHIFT; + + VM_BUG_ON(is_vm_hugetlb_page(vma)); + + pa = (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start); + +#ifndef __PAGETABLE_PMD_FOLDED + if ((hva & (PUD_SIZE - 1)) == (pa & (PUD_SIZE - 1)) && + ALIGN_DOWN(hva, PUD_SIZE) >= vma->vm_start && + ALIGN(hva, PUD_SIZE) <= vma->vm_end) + return PUD_SHIFT; +#endif + + if ((hva & (PMD_SIZE - 1)) == (pa & (PMD_SIZE - 1)) && + ALIGN_DOWN(hva, PMD_SIZE) >= vma->vm_start && + ALIGN(hva, PMD_SIZE) <= vma->vm_end) + return PMD_SHIFT; + + return PAGE_SHIFT; +} + +/* + * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be + * able to see the page's tags and therefore they must be initialised first. If + * PG_mte_tagged is set, tags have already been initialised. + * + * The race in the test/set of the PG_mte_tagged flag is handled by: + * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs + * racing to santise the same page + * - mmap_lock protects between a VM faulting a page in and the VMM performing + * an mprotect() to add VM_MTE + */ +static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, + unsigned long size) +{ + unsigned long i, nr_pages = size >> PAGE_SHIFT; + struct page *page = pfn_to_page(pfn); + + if (!kvm_has_mte(kvm)) + return; + + for (i = 0; i < nr_pages; i++, page++) { + if (try_page_mte_tagging(page)) { + mte_clear_page_tags(page_address(page)); + set_page_mte_tagged(page); + } + } +} + +static bool kvm_vma_mte_allowed(struct vm_area_struct *vma) +{ + return vma->vm_flags & VM_MTE_ALLOWED; +} + +static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + struct kvm_memory_slot *memslot, unsigned long hva, + unsigned long fault_status) +{ + int ret = 0; + bool write_fault, writable, force_pte = false; + bool exec_fault, mte_allowed; + bool device = false; + unsigned long mmu_seq; + struct kvm *kvm = vcpu->kvm; + struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; + struct vm_area_struct *vma; + short vma_shift; + gfn_t gfn; + kvm_pfn_t pfn; + bool logging_active = memslot_is_logging(memslot); + unsigned long fault_level = kvm_vcpu_trap_get_fault_level(vcpu); + long vma_pagesize, fault_granule; + enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; + struct kvm_pgtable *pgt; + + fault_granule = 1UL << ARM64_HW_PGTABLE_LEVEL_SHIFT(fault_level); + write_fault = kvm_is_write_fault(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); + VM_BUG_ON(write_fault && exec_fault); + + if (fault_status == ESR_ELx_FSC_PERM && !write_fault && !exec_fault) { + kvm_err("Unexpected L2 read permission error\n"); + return -EFAULT; + } + + /* + * Permission faults just need to update the existing leaf entry, + * and so normally don't require allocations from the memcache. The + * only exception to this is when dirty logging is enabled at runtime + * and a write fault needs to collapse a block entry into a table. + */ + if (fault_status != ESR_ELx_FSC_PERM || + (logging_active && write_fault)) { + ret = kvm_mmu_topup_memory_cache(memcache, + kvm_mmu_cache_min_pages(kvm)); + if (ret) + return ret; + } + + /* + * Let's check if we will get back a huge page backed by hugetlbfs, or + * get block mapping for device MMIO region. + */ + mmap_read_lock(current->mm); + vma = vma_lookup(current->mm, hva); + if (unlikely(!vma)) { + kvm_err("Failed to find VMA for hva 0x%lx\n", hva); + mmap_read_unlock(current->mm); + return -EFAULT; + } + + /* + * logging_active is guaranteed to never be true for VM_PFNMAP + * memslots. + */ + if (logging_active) { + force_pte = true; + vma_shift = PAGE_SHIFT; + } else { + vma_shift = get_vma_page_shift(vma, hva); + } + + switch (vma_shift) { +#ifndef __PAGETABLE_PMD_FOLDED + case PUD_SHIFT: + if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE)) + break; + fallthrough; +#endif + case CONT_PMD_SHIFT: + vma_shift = PMD_SHIFT; + fallthrough; + case PMD_SHIFT: + if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) + break; + fallthrough; + case CONT_PTE_SHIFT: + vma_shift = PAGE_SHIFT; + force_pte = true; + fallthrough; + case PAGE_SHIFT: + break; + default: + WARN_ONCE(1, "Unknown vma_shift %d", vma_shift); + } + + vma_pagesize = 1UL << vma_shift; + if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE) + fault_ipa &= ~(vma_pagesize - 1); + + gfn = fault_ipa >> PAGE_SHIFT; + mte_allowed = kvm_vma_mte_allowed(vma); + + /* Don't use the VMA after the unlock -- it may have vanished */ + vma = NULL; + + /* + * Read mmu_invalidate_seq so that KVM can detect if the results of + * vma_lookup() or __gfn_to_pfn_memslot() become stale prior to + * acquiring kvm->mmu_lock. + * + * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs + * with the smp_wmb() in kvm_mmu_invalidate_end(). + */ + mmu_seq = vcpu->kvm->mmu_invalidate_seq; + mmap_read_unlock(current->mm); + + pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL, + write_fault, &writable, NULL); + if (pfn == KVM_PFN_ERR_HWPOISON) { + kvm_send_hwpoison_signal(hva, vma_shift); + return 0; + } + if (is_error_noslot_pfn(pfn)) + return -EFAULT; + + if (kvm_is_device_pfn(pfn)) { + /* + * If the page was identified as device early by looking at + * the VMA flags, vma_pagesize is already representing the + * largest quantity we can map. If instead it was mapped + * via gfn_to_pfn_prot(), vma_pagesize is set to PAGE_SIZE + * and must not be upgraded. + * + * In both cases, we don't let transparent_hugepage_adjust() + * change things at the last minute. + */ + device = true; + } else if (logging_active && !write_fault) { + /* + * Only actually map the page as writable if this was a write + * fault. + */ + writable = false; + } + + if (exec_fault && device) + return -ENOEXEC; + + read_lock(&kvm->mmu_lock); + pgt = vcpu->arch.hw_mmu->pgt; + if (mmu_invalidate_retry(kvm, mmu_seq)) + goto out_unlock; + + /* + * If we are not forced to use page mapping, check if we are + * backed by a THP and thus use block mapping if possible. + */ + if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) { + if (fault_status == ESR_ELx_FSC_PERM && + fault_granule > PAGE_SIZE) + vma_pagesize = fault_granule; + else + vma_pagesize = transparent_hugepage_adjust(kvm, memslot, + hva, &pfn, + &fault_ipa); + + if (vma_pagesize < 0) { + ret = vma_pagesize; + goto out_unlock; + } + } + + if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) { + /* Check the VMM hasn't introduced a new disallowed VMA */ + if (mte_allowed) { + sanitise_mte_tags(kvm, pfn, vma_pagesize); + } else { + ret = -EFAULT; + goto out_unlock; + } + } + + if (writable) + prot |= KVM_PGTABLE_PROT_W; + + if (exec_fault) + prot |= KVM_PGTABLE_PROT_X; + + if (device) + prot |= KVM_PGTABLE_PROT_DEVICE; + else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) + prot |= KVM_PGTABLE_PROT_X; + + /* + * Under the premise of getting a FSC_PERM fault, we just need to relax + * permissions only if vma_pagesize equals fault_granule. Otherwise, + * kvm_pgtable_stage2_map() should be called to change block size. + */ + if (fault_status == ESR_ELx_FSC_PERM && vma_pagesize == fault_granule) + ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot); + else + ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize, + __pfn_to_phys(pfn), prot, + memcache, + KVM_PGTABLE_WALK_HANDLE_FAULT | + KVM_PGTABLE_WALK_SHARED); + + /* Mark the page dirty only if the fault is handled successfully */ + if (writable && !ret) { + kvm_set_pfn_dirty(pfn); + mark_page_dirty_in_slot(kvm, memslot, gfn); + } + +out_unlock: + read_unlock(&kvm->mmu_lock); + kvm_release_pfn_clean(pfn); + return ret != -EAGAIN ? ret : 0; +} + +/* Resolve the access fault by making the page young again. */ +static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) +{ + kvm_pte_t pte; + struct kvm_s2_mmu *mmu; + + trace_kvm_access_fault(fault_ipa); + + read_lock(&vcpu->kvm->mmu_lock); + mmu = vcpu->arch.hw_mmu; + pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa); + read_unlock(&vcpu->kvm->mmu_lock); + + if (kvm_pte_valid(pte)) + kvm_set_pfn_accessed(kvm_pte_to_pfn(pte)); +} + +/** + * kvm_handle_guest_abort - handles all 2nd stage aborts + * @vcpu: the VCPU pointer + * + * Any abort that gets to the host is almost guaranteed to be caused by a + * missing second stage translation table entry, which can mean that either the + * guest simply needs more memory and we must allocate an appropriate page or it + * can mean that the guest tried to access I/O memory, which is emulated by user + * space. The distinction is based on the IPA causing the fault and whether this + * memory region has been registered as standard RAM by user space. + */ +int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) +{ + unsigned long fault_status; + phys_addr_t fault_ipa; + struct kvm_memory_slot *memslot; + unsigned long hva; + bool is_iabt, write_fault, writable; + gfn_t gfn; + int ret, idx; + + fault_status = kvm_vcpu_trap_get_fault_type(vcpu); + + fault_ipa = kvm_vcpu_get_fault_ipa(vcpu); + is_iabt = kvm_vcpu_trap_is_iabt(vcpu); + + if (fault_status == ESR_ELx_FSC_FAULT) { + /* Beyond sanitised PARange (which is the IPA limit) */ + if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) { + kvm_inject_size_fault(vcpu); + return 1; + } + + /* Falls between the IPA range and the PARange? */ + if (fault_ipa >= BIT_ULL(vcpu->arch.hw_mmu->pgt->ia_bits)) { + fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0); + + if (is_iabt) + kvm_inject_pabt(vcpu, fault_ipa); + else + kvm_inject_dabt(vcpu, fault_ipa); + return 1; + } + } + + /* Synchronous External Abort? */ + if (kvm_vcpu_abt_issea(vcpu)) { + /* + * For RAS the host kernel may handle this abort. + * There is no need to pass the error into the guest. + */ + if (kvm_handle_guest_sea(fault_ipa, kvm_vcpu_get_esr(vcpu))) + kvm_inject_vabt(vcpu); + + return 1; + } + + trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu), + kvm_vcpu_get_hfar(vcpu), fault_ipa); + + /* Check the stage-2 fault is trans. fault or write fault */ + if (fault_status != ESR_ELx_FSC_FAULT && + fault_status != ESR_ELx_FSC_PERM && + fault_status != ESR_ELx_FSC_ACCESS) { + kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n", + kvm_vcpu_trap_get_class(vcpu), + (unsigned long)kvm_vcpu_trap_get_fault(vcpu), + (unsigned long)kvm_vcpu_get_esr(vcpu)); + return -EFAULT; + } + + idx = srcu_read_lock(&vcpu->kvm->srcu); + + gfn = fault_ipa >> PAGE_SHIFT; + memslot = gfn_to_memslot(vcpu->kvm, gfn); + hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable); + write_fault = kvm_is_write_fault(vcpu); + if (kvm_is_error_hva(hva) || (write_fault && !writable)) { + /* + * The guest has put either its instructions or its page-tables + * somewhere it shouldn't have. Userspace won't be able to do + * anything about this (there's no syndrome for a start), so + * re-inject the abort back into the guest. + */ + if (is_iabt) { + ret = -ENOEXEC; + goto out; + } + + if (kvm_vcpu_abt_iss1tw(vcpu)) { + kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); + ret = 1; + goto out_unlock; + } + + /* + * Check for a cache maintenance operation. Since we + * ended-up here, we know it is outside of any memory + * slot. But we can't find out if that is for a device, + * or if the guest is just being stupid. The only thing + * we know for sure is that this range cannot be cached. + * + * So let's assume that the guest is just being + * cautious, and skip the instruction. + */ + if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) { + kvm_incr_pc(vcpu); + ret = 1; + goto out_unlock; + } + + /* + * The IPA is reported as [MAX:12], so we need to + * complement it with the bottom 12 bits from the + * faulting VA. This is always 12 bits, irrespective + * of the page size. + */ + fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1); + ret = io_mem_abort(vcpu, fault_ipa); + goto out_unlock; + } + + /* Userspace should not be able to register out-of-bounds IPAs */ + VM_BUG_ON(fault_ipa >= kvm_phys_size(vcpu->kvm)); + + if (fault_status == ESR_ELx_FSC_ACCESS) { + handle_access_fault(vcpu, fault_ipa); + ret = 1; + goto out_unlock; + } + + ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status); + if (ret == 0) + ret = 1; +out: + if (ret == -ENOEXEC) { + kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu)); + ret = 1; + } +out_unlock: + srcu_read_unlock(&vcpu->kvm->srcu, idx); + return ret; +} + +bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +{ + if (!kvm->arch.mmu.pgt) + return false; + + __unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT, + (range->end - range->start) << PAGE_SHIFT, + range->may_block); + + return false; +} + +bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + kvm_pfn_t pfn = pte_pfn(range->arg.pte); + + if (!kvm->arch.mmu.pgt) + return false; + + WARN_ON(range->end - range->start != 1); + + /* + * If the page isn't tagged, defer to user_mem_abort() for sanitising + * the MTE tags. The S2 pte should have been unmapped by + * mmu_notifier_invalidate_range_end(). + */ + if (kvm_has_mte(kvm) && !page_mte_tagged(pfn_to_page(pfn))) + return false; + + /* + * We've moved a page around, probably through CoW, so let's treat + * it just like a translation fault and the map handler will clean + * the cache to the PoC. + * + * The MMU notifiers will have unmapped a huge PMD before calling + * ->change_pte() (which in turn calls kvm_set_spte_gfn()) and + * therefore we never need to clear out a huge PMD through this + * calling path and a memcache is not required. + */ + kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, range->start << PAGE_SHIFT, + PAGE_SIZE, __pfn_to_phys(pfn), + KVM_PGTABLE_PROT_R, NULL, 0); + + return false; +} + +bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + u64 size = (range->end - range->start) << PAGE_SHIFT; + + if (!kvm->arch.mmu.pgt) + return false; + + return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt, + range->start << PAGE_SHIFT, + size, true); +} + +bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + u64 size = (range->end - range->start) << PAGE_SHIFT; + + if (!kvm->arch.mmu.pgt) + return false; + + return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt, + range->start << PAGE_SHIFT, + size, false); +} + +phys_addr_t kvm_mmu_get_httbr(void) +{ + return __pa(hyp_pgtable->pgd); +} + +phys_addr_t kvm_get_idmap_vector(void) +{ + return hyp_idmap_vector; +} + +static int kvm_map_idmap_text(void) +{ + unsigned long size = hyp_idmap_end - hyp_idmap_start; + int err = __create_hyp_mappings(hyp_idmap_start, size, hyp_idmap_start, + PAGE_HYP_EXEC); + if (err) + kvm_err("Failed to idmap %lx-%lx\n", + hyp_idmap_start, hyp_idmap_end); + + return err; +} + +static void *kvm_hyp_zalloc_page(void *arg) +{ + return (void *)get_zeroed_page(GFP_KERNEL); +} + +static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = { + .zalloc_page = kvm_hyp_zalloc_page, + .get_page = kvm_host_get_page, + .put_page = kvm_host_put_page, + .phys_to_virt = kvm_host_va, + .virt_to_phys = kvm_host_pa, +}; + +int __init kvm_mmu_init(u32 *hyp_va_bits) +{ + int err; + u32 idmap_bits; + u32 kernel_bits; + + hyp_idmap_start = __pa_symbol(__hyp_idmap_text_start); + hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE); + hyp_idmap_end = __pa_symbol(__hyp_idmap_text_end); + hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE); + hyp_idmap_vector = __pa_symbol(__kvm_hyp_init); + + /* + * We rely on the linker script to ensure at build time that the HYP + * init code does not cross a page boundary. + */ + BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK); + + /* + * The ID map may be configured to use an extended virtual address + * range. This is only the case if system RAM is out of range for the + * currently configured page size and VA_BITS_MIN, in which case we will + * also need the extended virtual range for the HYP ID map, or we won't + * be able to enable the EL2 MMU. + * + * However, in some cases the ID map may be configured for fewer than + * the number of VA bits used by the regular kernel stage 1. This + * happens when VA_BITS=52 and the kernel image is placed in PA space + * below 48 bits. + * + * At EL2, there is only one TTBR register, and we can't switch between + * translation tables *and* update TCR_EL2.T0SZ at the same time. Bottom + * line: we need to use the extended range with *both* our translation + * tables. + * + * So use the maximum of the idmap VA bits and the regular kernel stage + * 1 VA bits to assure that the hypervisor can both ID map its code page + * and map any kernel memory. + */ + idmap_bits = 64 - ((idmap_t0sz & TCR_T0SZ_MASK) >> TCR_T0SZ_OFFSET); + kernel_bits = vabits_actual; + *hyp_va_bits = max(idmap_bits, kernel_bits); + + kvm_debug("Using %u-bit virtual addresses at EL2\n", *hyp_va_bits); + kvm_debug("IDMAP page: %lx\n", hyp_idmap_start); + kvm_debug("HYP VA range: %lx:%lx\n", + kern_hyp_va(PAGE_OFFSET), + kern_hyp_va((unsigned long)high_memory - 1)); + + if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) && + hyp_idmap_start < kern_hyp_va((unsigned long)high_memory - 1) && + hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) { + /* + * The idmap page is intersecting with the VA space, + * it is not safe to continue further. + */ + kvm_err("IDMAP intersecting with HYP VA, unable to continue\n"); + err = -EINVAL; + goto out; + } + + hyp_pgtable = kzalloc(sizeof(*hyp_pgtable), GFP_KERNEL); + if (!hyp_pgtable) { + kvm_err("Hyp mode page-table not allocated\n"); + err = -ENOMEM; + goto out; + } + + err = kvm_pgtable_hyp_init(hyp_pgtable, *hyp_va_bits, &kvm_hyp_mm_ops); + if (err) + goto out_free_pgtable; + + err = kvm_map_idmap_text(); + if (err) + goto out_destroy_pgtable; + + io_map_base = hyp_idmap_start; + return 0; + +out_destroy_pgtable: + kvm_pgtable_hyp_destroy(hyp_pgtable); +out_free_pgtable: + kfree(hyp_pgtable); + hyp_pgtable = NULL; +out: + return err; +} + +void kvm_arch_commit_memory_region(struct kvm *kvm, + struct kvm_memory_slot *old, + const struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + bool log_dirty_pages = new && new->flags & KVM_MEM_LOG_DIRTY_PAGES; + + /* + * At this point memslot has been committed and there is an + * allocated dirty_bitmap[], dirty pages will be tracked while the + * memory slot is write protected. + */ + if (log_dirty_pages) { + + if (change == KVM_MR_DELETE) + return; + + /* + * Huge and normal pages are write-protected and split + * on either of these two cases: + * + * 1. with initial-all-set: gradually with CLEAR ioctls, + */ + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) + return; + /* + * or + * 2. without initial-all-set: all in one shot when + * enabling dirty logging. + */ + kvm_mmu_wp_memory_region(kvm, new->id); + kvm_mmu_split_memory_region(kvm, new->id); + } else { + /* + * Free any leftovers from the eager page splitting cache. Do + * this when deleting, moving, disabling dirty logging, or + * creating the memslot (a nop). Doing it for deletes makes + * sure we don't leak memory, and there's no need to keep the + * cache around for any of the other cases. + */ + kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache); + } +} + +int kvm_arch_prepare_memory_region(struct kvm *kvm, + const struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + hva_t hva, reg_end; + int ret = 0; + + if (change != KVM_MR_CREATE && change != KVM_MR_MOVE && + change != KVM_MR_FLAGS_ONLY) + return 0; + + /* + * Prevent userspace from creating a memory region outside of the IPA + * space addressable by the KVM guest IPA space. + */ + if ((new->base_gfn + new->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT)) + return -EFAULT; + + hva = new->userspace_addr; + reg_end = hva + (new->npages << PAGE_SHIFT); + + mmap_read_lock(current->mm); + /* + * A memory region could potentially cover multiple VMAs, and any holes + * between them, so iterate over all of them. + * + * +--------------------------------------------+ + * +---------------+----------------+ +----------------+ + * | : VMA 1 | VMA 2 | | VMA 3 : | + * +---------------+----------------+ +----------------+ + * | memory region | + * +--------------------------------------------+ + */ + do { + struct vm_area_struct *vma; + + vma = find_vma_intersection(current->mm, hva, reg_end); + if (!vma) + break; + + if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) { + ret = -EINVAL; + break; + } + + if (vma->vm_flags & VM_PFNMAP) { + /* IO region dirty page logging not allowed */ + if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) { + ret = -EINVAL; + break; + } + } + hva = min(reg_end, vma->vm_end); + } while (hva < reg_end); + + mmap_read_unlock(current->mm); + return ret; +} + +void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ +} + +void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) +{ +} + +void kvm_arch_flush_shadow_all(struct kvm *kvm) +{ + kvm_uninit_stage2_mmu(kvm); +} + +void kvm_arch_flush_shadow_memslot(struct kvm *kvm, + struct kvm_memory_slot *slot) +{ + gpa_t gpa = slot->base_gfn << PAGE_SHIFT; + phys_addr_t size = slot->npages << PAGE_SHIFT; + + write_lock(&kvm->mmu_lock); + unmap_stage2_range(&kvm->arch.mmu, gpa, size); + write_unlock(&kvm->mmu_lock); +} + +/* + * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized). + * + * Main problems: + * - S/W ops are local to a CPU (not broadcast) + * - We have line migration behind our back (speculation) + * - System caches don't support S/W at all (damn!) + * + * In the face of the above, the best we can do is to try and convert + * S/W ops to VA ops. Because the guest is not allowed to infer the + * S/W to PA mapping, it can only use S/W to nuke the whole cache, + * which is a rather good thing for us. + * + * Also, it is only used when turning caches on/off ("The expected + * usage of the cache maintenance instructions that operate by set/way + * is associated with the cache maintenance instructions associated + * with the powerdown and powerup of caches, if this is required by + * the implementation."). + * + * We use the following policy: + * + * - If we trap a S/W operation, we enable VM trapping to detect + * caches being turned on/off, and do a full clean. + * + * - We flush the caches on both caches being turned on and off. + * + * - Once the caches are enabled, we stop trapping VM ops. + */ +void kvm_set_way_flush(struct kvm_vcpu *vcpu) +{ + unsigned long hcr = *vcpu_hcr(vcpu); + + /* + * If this is the first time we do a S/W operation + * (i.e. HCR_TVM not set) flush the whole memory, and set the + * VM trapping. + * + * Otherwise, rely on the VM trapping to wait for the MMU + + * Caches to be turned off. At that point, we'll be able to + * clean the caches again. + */ + if (!(hcr & HCR_TVM)) { + trace_kvm_set_way_flush(*vcpu_pc(vcpu), + vcpu_has_cache_enabled(vcpu)); + stage2_flush_vm(vcpu->kvm); + *vcpu_hcr(vcpu) = hcr | HCR_TVM; + } +} + +void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled) +{ + bool now_enabled = vcpu_has_cache_enabled(vcpu); + + /* + * If switching the MMU+caches on, need to invalidate the caches. + * If switching it off, need to clean the caches. + * Clean + invalidate does the trick always. + */ + if (now_enabled != was_enabled) + stage2_flush_vm(vcpu->kvm); + + /* Caches are now on, stop trapping VM ops (until a S/W op) */ + if (now_enabled) + *vcpu_hcr(vcpu) &= ~HCR_TVM; + + trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled); +} |