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-rw-r--r--arch/x86/kernel/kvm.c1054
1 files changed, 1054 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
new file mode 100644
index 000000000..fe9babe94
--- /dev/null
+++ b/arch/x86/kernel/kvm.c
@@ -0,0 +1,1054 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * KVM paravirt_ops implementation
+ *
+ * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright IBM Corporation, 2007
+ * Authors: Anthony Liguori <aliguori@us.ibm.com>
+ */
+
+#define pr_fmt(fmt) "kvm-guest: " fmt
+
+#include <linux/context_tracking.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/kvm_para.h>
+#include <linux/cpu.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/hardirq.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/hash.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/kprobes.h>
+#include <linux/nmi.h>
+#include <linux/swait.h>
+#include <linux/syscore_ops.h>
+#include <asm/timer.h>
+#include <asm/cpu.h>
+#include <asm/traps.h>
+#include <asm/desc.h>
+#include <asm/tlbflush.h>
+#include <asm/apic.h>
+#include <asm/apicdef.h>
+#include <asm/hypervisor.h>
+#include <asm/tlb.h>
+#include <asm/cpuidle_haltpoll.h>
+#include <asm/ptrace.h>
+#include <asm/reboot.h>
+#include <asm/svm.h>
+
+DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
+
+static int kvmapf = 1;
+
+static int __init parse_no_kvmapf(char *arg)
+{
+ kvmapf = 0;
+ return 0;
+}
+
+early_param("no-kvmapf", parse_no_kvmapf);
+
+static int steal_acc = 1;
+static int __init parse_no_stealacc(char *arg)
+{
+ steal_acc = 0;
+ return 0;
+}
+
+early_param("no-steal-acc", parse_no_stealacc);
+
+static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
+DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible;
+static int has_steal_clock = 0;
+
+static int has_guest_poll = 0;
+/*
+ * No need for any "IO delay" on KVM
+ */
+static void kvm_io_delay(void)
+{
+}
+
+#define KVM_TASK_SLEEP_HASHBITS 8
+#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
+
+struct kvm_task_sleep_node {
+ struct hlist_node link;
+ struct swait_queue_head wq;
+ u32 token;
+ int cpu;
+};
+
+static struct kvm_task_sleep_head {
+ raw_spinlock_t lock;
+ struct hlist_head list;
+} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
+
+static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
+ u32 token)
+{
+ struct hlist_node *p;
+
+ hlist_for_each(p, &b->list) {
+ struct kvm_task_sleep_node *n =
+ hlist_entry(p, typeof(*n), link);
+ if (n->token == token)
+ return n;
+ }
+
+ return NULL;
+}
+
+static bool kvm_async_pf_queue_task(u32 token, struct kvm_task_sleep_node *n)
+{
+ u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
+ struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
+ struct kvm_task_sleep_node *e;
+
+ raw_spin_lock(&b->lock);
+ e = _find_apf_task(b, token);
+ if (e) {
+ /* dummy entry exist -> wake up was delivered ahead of PF */
+ hlist_del(&e->link);
+ raw_spin_unlock(&b->lock);
+ kfree(e);
+ return false;
+ }
+
+ n->token = token;
+ n->cpu = smp_processor_id();
+ init_swait_queue_head(&n->wq);
+ hlist_add_head(&n->link, &b->list);
+ raw_spin_unlock(&b->lock);
+ return true;
+}
+
+/*
+ * kvm_async_pf_task_wait_schedule - Wait for pagefault to be handled
+ * @token: Token to identify the sleep node entry
+ *
+ * Invoked from the async pagefault handling code or from the VM exit page
+ * fault handler. In both cases RCU is watching.
+ */
+void kvm_async_pf_task_wait_schedule(u32 token)
+{
+ struct kvm_task_sleep_node n;
+ DECLARE_SWAITQUEUE(wait);
+
+ lockdep_assert_irqs_disabled();
+
+ if (!kvm_async_pf_queue_task(token, &n))
+ return;
+
+ for (;;) {
+ prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
+ if (hlist_unhashed(&n.link))
+ break;
+
+ local_irq_enable();
+ schedule();
+ local_irq_disable();
+ }
+ finish_swait(&n.wq, &wait);
+}
+EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait_schedule);
+
+static void apf_task_wake_one(struct kvm_task_sleep_node *n)
+{
+ hlist_del_init(&n->link);
+ if (swq_has_sleeper(&n->wq))
+ swake_up_one(&n->wq);
+}
+
+static void apf_task_wake_all(void)
+{
+ int i;
+
+ for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
+ struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
+ struct kvm_task_sleep_node *n;
+ struct hlist_node *p, *next;
+
+ raw_spin_lock(&b->lock);
+ hlist_for_each_safe(p, next, &b->list) {
+ n = hlist_entry(p, typeof(*n), link);
+ if (n->cpu == smp_processor_id())
+ apf_task_wake_one(n);
+ }
+ raw_spin_unlock(&b->lock);
+ }
+}
+
+void kvm_async_pf_task_wake(u32 token)
+{
+ u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
+ struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
+ struct kvm_task_sleep_node *n, *dummy = NULL;
+
+ if (token == ~0) {
+ apf_task_wake_all();
+ return;
+ }
+
+again:
+ raw_spin_lock(&b->lock);
+ n = _find_apf_task(b, token);
+ if (!n) {
+ /*
+ * Async #PF not yet handled, add a dummy entry for the token.
+ * Allocating the token must be down outside of the raw lock
+ * as the allocator is preemptible on PREEMPT_RT kernels.
+ */
+ if (!dummy) {
+ raw_spin_unlock(&b->lock);
+ dummy = kzalloc(sizeof(*dummy), GFP_ATOMIC);
+
+ /*
+ * Continue looping on allocation failure, eventually
+ * the async #PF will be handled and allocating a new
+ * node will be unnecessary.
+ */
+ if (!dummy)
+ cpu_relax();
+
+ /*
+ * Recheck for async #PF completion before enqueueing
+ * the dummy token to avoid duplicate list entries.
+ */
+ goto again;
+ }
+ dummy->token = token;
+ dummy->cpu = smp_processor_id();
+ init_swait_queue_head(&dummy->wq);
+ hlist_add_head(&dummy->link, &b->list);
+ dummy = NULL;
+ } else {
+ apf_task_wake_one(n);
+ }
+ raw_spin_unlock(&b->lock);
+
+ /* A dummy token might be allocated and ultimately not used. */
+ if (dummy)
+ kfree(dummy);
+}
+EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
+
+noinstr u32 kvm_read_and_reset_apf_flags(void)
+{
+ u32 flags = 0;
+
+ if (__this_cpu_read(apf_reason.enabled)) {
+ flags = __this_cpu_read(apf_reason.flags);
+ __this_cpu_write(apf_reason.flags, 0);
+ }
+
+ return flags;
+}
+EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
+
+noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
+{
+ u32 flags = kvm_read_and_reset_apf_flags();
+ irqentry_state_t state;
+
+ if (!flags)
+ return false;
+
+ state = irqentry_enter(regs);
+ instrumentation_begin();
+
+ /*
+ * If the host managed to inject an async #PF into an interrupt
+ * disabled region, then die hard as this is not going to end well
+ * and the host side is seriously broken.
+ */
+ if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
+ panic("Host injected async #PF in interrupt disabled region\n");
+
+ if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
+ if (unlikely(!(user_mode(regs))))
+ panic("Host injected async #PF in kernel mode\n");
+ /* Page is swapped out by the host. */
+ kvm_async_pf_task_wait_schedule(token);
+ } else {
+ WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
+ }
+
+ instrumentation_end();
+ irqentry_exit(regs, state);
+ return true;
+}
+
+DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+ u32 token;
+
+ ack_APIC_irq();
+
+ inc_irq_stat(irq_hv_callback_count);
+
+ if (__this_cpu_read(apf_reason.enabled)) {
+ token = __this_cpu_read(apf_reason.token);
+ kvm_async_pf_task_wake(token);
+ __this_cpu_write(apf_reason.token, 0);
+ wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
+ }
+
+ set_irq_regs(old_regs);
+}
+
+static void __init paravirt_ops_setup(void)
+{
+ pv_info.name = "KVM";
+
+ if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
+ pv_ops.cpu.io_delay = kvm_io_delay;
+
+#ifdef CONFIG_X86_IO_APIC
+ no_timer_check = 1;
+#endif
+}
+
+static void kvm_register_steal_time(void)
+{
+ int cpu = smp_processor_id();
+ struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
+
+ if (!has_steal_clock)
+ return;
+
+ wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
+ pr_info("stealtime: cpu %d, msr %llx\n", cpu,
+ (unsigned long long) slow_virt_to_phys(st));
+}
+
+static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
+
+static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
+{
+ /**
+ * This relies on __test_and_clear_bit to modify the memory
+ * in a way that is atomic with respect to the local CPU.
+ * The hypervisor only accesses this memory from the local CPU so
+ * there's no need for lock or memory barriers.
+ * An optimization barrier is implied in apic write.
+ */
+ if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
+ return;
+ apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK);
+}
+
+static void kvm_guest_cpu_init(void)
+{
+ if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
+ u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
+
+ WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));
+
+ pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
+ pa |= KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
+
+ if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
+ pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
+
+ wrmsrl(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
+
+ wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
+ __this_cpu_write(apf_reason.enabled, 1);
+ pr_info("KVM setup async PF for cpu %d\n", smp_processor_id());
+ }
+
+ if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
+ unsigned long pa;
+
+ /* Size alignment is implied but just to make it explicit. */
+ BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
+ __this_cpu_write(kvm_apic_eoi, 0);
+ pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
+ | KVM_MSR_ENABLED;
+ wrmsrl(MSR_KVM_PV_EOI_EN, pa);
+ }
+
+ if (has_steal_clock)
+ kvm_register_steal_time();
+}
+
+static void kvm_pv_disable_apf(void)
+{
+ if (!__this_cpu_read(apf_reason.enabled))
+ return;
+
+ wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
+ __this_cpu_write(apf_reason.enabled, 0);
+
+ pr_info("Unregister pv shared memory for cpu %d\n", smp_processor_id());
+}
+
+static void kvm_disable_steal_time(void)
+{
+ if (!has_steal_clock)
+ return;
+
+ wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
+}
+
+static void kvm_pv_guest_cpu_reboot(void *unused)
+{
+ /*
+ * We disable PV EOI before we load a new kernel by kexec,
+ * since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
+ * New kernel can re-enable when it boots.
+ */
+ if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+ wrmsrl(MSR_KVM_PV_EOI_EN, 0);
+ kvm_pv_disable_apf();
+ kvm_disable_steal_time();
+}
+
+static int kvm_pv_reboot_notify(struct notifier_block *nb,
+ unsigned long code, void *unused)
+{
+ if (code == SYS_RESTART)
+ on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kvm_pv_reboot_nb = {
+ .notifier_call = kvm_pv_reboot_notify,
+};
+
+static u64 kvm_steal_clock(int cpu)
+{
+ u64 steal;
+ struct kvm_steal_time *src;
+ int version;
+
+ src = &per_cpu(steal_time, cpu);
+ do {
+ version = src->version;
+ virt_rmb();
+ steal = src->steal;
+ virt_rmb();
+ } while ((version & 1) || (version != src->version));
+
+ return steal;
+}
+
+static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
+{
+ early_set_memory_decrypted((unsigned long) ptr, size);
+}
+
+/*
+ * Iterate through all possible CPUs and map the memory region pointed
+ * by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
+ *
+ * Note: we iterate through all possible CPUs to ensure that CPUs
+ * hotplugged will have their per-cpu variable already mapped as
+ * decrypted.
+ */
+static void __init sev_map_percpu_data(void)
+{
+ int cpu;
+
+ if (!sev_active())
+ return;
+
+ for_each_possible_cpu(cpu) {
+ __set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
+ __set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
+ __set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
+ }
+}
+
+static bool pv_tlb_flush_supported(void)
+{
+ return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+ !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+ kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask);
+
+static void kvm_guest_cpu_offline(bool shutdown)
+{
+ kvm_disable_steal_time();
+ if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+ wrmsrl(MSR_KVM_PV_EOI_EN, 0);
+ kvm_pv_disable_apf();
+ if (!shutdown)
+ apf_task_wake_all();
+ kvmclock_disable();
+}
+
+static int kvm_cpu_online(unsigned int cpu)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ kvm_guest_cpu_init();
+ local_irq_restore(flags);
+ return 0;
+}
+
+#ifdef CONFIG_SMP
+
+static bool pv_ipi_supported(void)
+{
+ return kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI);
+}
+
+static bool pv_sched_yield_supported(void)
+{
+ return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
+ !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+ kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
+}
+
+#define KVM_IPI_CLUSTER_SIZE (2 * BITS_PER_LONG)
+
+static void __send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ unsigned long flags;
+ int cpu, apic_id, icr;
+ int min = 0, max = 0;
+#ifdef CONFIG_X86_64
+ __uint128_t ipi_bitmap = 0;
+#else
+ u64 ipi_bitmap = 0;
+#endif
+ long ret;
+
+ if (cpumask_empty(mask))
+ return;
+
+ local_irq_save(flags);
+
+ switch (vector) {
+ default:
+ icr = APIC_DM_FIXED | vector;
+ break;
+ case NMI_VECTOR:
+ icr = APIC_DM_NMI;
+ break;
+ }
+
+ for_each_cpu(cpu, mask) {
+ apic_id = per_cpu(x86_cpu_to_apicid, cpu);
+ if (!ipi_bitmap) {
+ min = max = apic_id;
+ } else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
+ ipi_bitmap <<= min - apic_id;
+ min = apic_id;
+ } else if (apic_id > min && apic_id < min + KVM_IPI_CLUSTER_SIZE) {
+ max = apic_id < max ? max : apic_id;
+ } else {
+ ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+ (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+ WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
+ ret);
+ min = max = apic_id;
+ ipi_bitmap = 0;
+ }
+ __set_bit(apic_id - min, (unsigned long *)&ipi_bitmap);
+ }
+
+ if (ipi_bitmap) {
+ ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+ (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+ WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
+ ret);
+ }
+
+ local_irq_restore(flags);
+}
+
+static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ __send_ipi_mask(mask, vector);
+}
+
+static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+ unsigned int this_cpu = smp_processor_id();
+ struct cpumask *new_mask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
+ const struct cpumask *local_mask;
+
+ cpumask_copy(new_mask, mask);
+ cpumask_clear_cpu(this_cpu, new_mask);
+ local_mask = new_mask;
+ __send_ipi_mask(local_mask, vector);
+}
+
+/*
+ * Set the IPI entry points
+ */
+static void kvm_setup_pv_ipi(void)
+{
+ apic->send_IPI_mask = kvm_send_ipi_mask;
+ apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+ pr_info("setup PV IPIs\n");
+}
+
+static void kvm_smp_send_call_func_ipi(const struct cpumask *mask)
+{
+ int cpu;
+
+ native_send_call_func_ipi(mask);
+
+ /* Make sure other vCPUs get a chance to run if they need to. */
+ for_each_cpu(cpu, mask) {
+ if (vcpu_is_preempted(cpu)) {
+ kvm_hypercall1(KVM_HC_SCHED_YIELD, per_cpu(x86_cpu_to_apicid, cpu));
+ break;
+ }
+ }
+}
+
+static void __init kvm_smp_prepare_boot_cpu(void)
+{
+ /*
+ * Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
+ * shares the guest physical address with the hypervisor.
+ */
+ sev_map_percpu_data();
+
+ kvm_guest_cpu_init();
+ native_smp_prepare_boot_cpu();
+ kvm_spinlock_init();
+}
+
+static int kvm_cpu_down_prepare(unsigned int cpu)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ kvm_guest_cpu_offline(false);
+ local_irq_restore(flags);
+ return 0;
+}
+
+#endif
+
+static int kvm_suspend(void)
+{
+ u64 val = 0;
+
+ kvm_guest_cpu_offline(false);
+
+#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
+ if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
+ rdmsrl(MSR_KVM_POLL_CONTROL, val);
+ has_guest_poll = !(val & 1);
+#endif
+ return 0;
+}
+
+static void kvm_resume(void)
+{
+ kvm_cpu_online(raw_smp_processor_id());
+
+#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
+ if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL) && has_guest_poll)
+ wrmsrl(MSR_KVM_POLL_CONTROL, 0);
+#endif
+}
+
+static struct syscore_ops kvm_syscore_ops = {
+ .suspend = kvm_suspend,
+ .resume = kvm_resume,
+};
+
+/*
+ * After a PV feature is registered, the host will keep writing to the
+ * registered memory location. If the guest happens to shutdown, this memory
+ * won't be valid. In cases like kexec, in which you install a new kernel, this
+ * means a random memory location will be kept being written.
+ */
+#ifdef CONFIG_KEXEC_CORE
+static void kvm_crash_shutdown(struct pt_regs *regs)
+{
+ kvm_guest_cpu_offline(true);
+ native_machine_crash_shutdown(regs);
+}
+#endif
+
+static void kvm_flush_tlb_others(const struct cpumask *cpumask,
+ const struct flush_tlb_info *info)
+{
+ u8 state;
+ int cpu;
+ struct kvm_steal_time *src;
+ struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
+
+ cpumask_copy(flushmask, cpumask);
+ /*
+ * We have to call flush only on online vCPUs. And
+ * queue flush_on_enter for pre-empted vCPUs
+ */
+ for_each_cpu(cpu, flushmask) {
+ src = &per_cpu(steal_time, cpu);
+ state = READ_ONCE(src->preempted);
+ if ((state & KVM_VCPU_PREEMPTED)) {
+ if (try_cmpxchg(&src->preempted, &state,
+ state | KVM_VCPU_FLUSH_TLB))
+ __cpumask_clear_cpu(cpu, flushmask);
+ }
+ }
+
+ native_flush_tlb_others(flushmask, info);
+}
+
+static void __init kvm_guest_init(void)
+{
+ int i;
+
+ paravirt_ops_setup();
+ register_reboot_notifier(&kvm_pv_reboot_nb);
+ for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
+ raw_spin_lock_init(&async_pf_sleepers[i].lock);
+
+ if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+ has_steal_clock = 1;
+ pv_ops.time.steal_clock = kvm_steal_clock;
+ }
+
+ if (pv_tlb_flush_supported()) {
+ pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
+ pv_ops.mmu.tlb_remove_table = tlb_remove_table;
+ pr_info("KVM setup pv remote TLB flush\n");
+ }
+
+ if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+ apic_set_eoi_write(kvm_guest_apic_eoi_write);
+
+ if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
+ static_branch_enable(&kvm_async_pf_enabled);
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
+ }
+
+#ifdef CONFIG_SMP
+ smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
+ if (pv_sched_yield_supported()) {
+ smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi;
+ pr_info("setup PV sched yield\n");
+ }
+ if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
+ kvm_cpu_online, kvm_cpu_down_prepare) < 0)
+ pr_err("failed to install cpu hotplug callbacks\n");
+#else
+ sev_map_percpu_data();
+ kvm_guest_cpu_init();
+#endif
+
+#ifdef CONFIG_KEXEC_CORE
+ machine_ops.crash_shutdown = kvm_crash_shutdown;
+#endif
+
+ register_syscore_ops(&kvm_syscore_ops);
+
+ /*
+ * Hard lockup detection is enabled by default. Disable it, as guests
+ * can get false positives too easily, for example if the host is
+ * overcommitted.
+ */
+ hardlockup_detector_disable();
+}
+
+static noinline uint32_t __kvm_cpuid_base(void)
+{
+ if (boot_cpu_data.cpuid_level < 0)
+ return 0; /* So we don't blow up on old processors */
+
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+ return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
+
+ return 0;
+}
+
+static inline uint32_t kvm_cpuid_base(void)
+{
+ static int kvm_cpuid_base = -1;
+
+ if (kvm_cpuid_base == -1)
+ kvm_cpuid_base = __kvm_cpuid_base();
+
+ return kvm_cpuid_base;
+}
+
+bool kvm_para_available(void)
+{
+ return kvm_cpuid_base() != 0;
+}
+EXPORT_SYMBOL_GPL(kvm_para_available);
+
+unsigned int kvm_arch_para_features(void)
+{
+ return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
+}
+
+unsigned int kvm_arch_para_hints(void)
+{
+ return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_para_hints);
+
+static uint32_t __init kvm_detect(void)
+{
+ return kvm_cpuid_base();
+}
+
+static void __init kvm_apic_init(void)
+{
+#if defined(CONFIG_SMP)
+ if (pv_ipi_supported())
+ kvm_setup_pv_ipi();
+#endif
+}
+
+static void __init kvm_init_platform(void)
+{
+ kvmclock_init();
+ x86_platform.apic_post_init = kvm_apic_init;
+}
+
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
+{
+ /* RAX and CPL are already in the GHCB */
+ ghcb_set_rbx(ghcb, regs->bx);
+ ghcb_set_rcx(ghcb, regs->cx);
+ ghcb_set_rdx(ghcb, regs->dx);
+ ghcb_set_rsi(ghcb, regs->si);
+}
+
+static bool kvm_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
+{
+ /* No checking of the return state needed */
+ return true;
+}
+#endif
+
+const __initconst struct hypervisor_x86 x86_hyper_kvm = {
+ .name = "KVM",
+ .detect = kvm_detect,
+ .type = X86_HYPER_KVM,
+ .init.guest_late_init = kvm_guest_init,
+ .init.x2apic_available = kvm_para_available,
+ .init.init_platform = kvm_init_platform,
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+ .runtime.sev_es_hcall_prepare = kvm_sev_es_hcall_prepare,
+ .runtime.sev_es_hcall_finish = kvm_sev_es_hcall_finish,
+#endif
+};
+
+static __init int activate_jump_labels(void)
+{
+ if (has_steal_clock) {
+ static_key_slow_inc(&paravirt_steal_enabled);
+ if (steal_acc)
+ static_key_slow_inc(&paravirt_steal_rq_enabled);
+ }
+
+ return 0;
+}
+arch_initcall(activate_jump_labels);
+
+static __init int kvm_alloc_cpumask(void)
+{
+ int cpu;
+ bool alloc = false;
+
+ if (!kvm_para_available() || nopv)
+ return 0;
+
+ if (pv_tlb_flush_supported())
+ alloc = true;
+
+#if defined(CONFIG_SMP)
+ if (pv_ipi_supported())
+ alloc = true;
+#endif
+
+ if (alloc)
+ for_each_possible_cpu(cpu) {
+ zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu),
+ GFP_KERNEL, cpu_to_node(cpu));
+ }
+
+ return 0;
+}
+arch_initcall(kvm_alloc_cpumask);
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+
+/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
+static void kvm_kick_cpu(int cpu)
+{
+ int apicid;
+ unsigned long flags = 0;
+
+ apicid = per_cpu(x86_cpu_to_apicid, cpu);
+ kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
+}
+
+#include <asm/qspinlock.h>
+
+static void kvm_wait(u8 *ptr, u8 val)
+{
+ unsigned long flags;
+
+ if (in_nmi())
+ return;
+
+ local_irq_save(flags);
+
+ if (READ_ONCE(*ptr) != val)
+ goto out;
+
+ /*
+ * halt until it's our turn and kicked. Note that we do safe halt
+ * for irq enabled case to avoid hang when lock info is overwritten
+ * in irq spinlock slowpath and no spurious interrupt occur to save us.
+ */
+ if (arch_irqs_disabled_flags(flags))
+ halt();
+ else
+ safe_halt();
+
+out:
+ local_irq_restore(flags);
+}
+
+#ifdef CONFIG_X86_32
+__visible bool __kvm_vcpu_is_preempted(long cpu)
+{
+ struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
+
+ return !!(src->preempted & KVM_VCPU_PREEMPTED);
+}
+PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
+
+#else
+
+#include <asm/asm-offsets.h>
+
+extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
+
+/*
+ * Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
+ * restoring to/from the stack.
+ */
+asm(
+".pushsection .text;"
+".global __raw_callee_save___kvm_vcpu_is_preempted;"
+".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
+"__raw_callee_save___kvm_vcpu_is_preempted:"
+"movq __per_cpu_offset(,%rdi,8), %rax;"
+"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
+"setne %al;"
+ASM_RET
+".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;"
+".popsection");
+
+#endif
+
+/*
+ * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
+ */
+void __init kvm_spinlock_init(void)
+{
+ /*
+ * In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an
+ * advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is
+ * preferred over native qspinlock when vCPU is preempted.
+ */
+ if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {
+ pr_info("PV spinlocks disabled, no host support\n");
+ return;
+ }
+
+ /*
+ * Disable PV spinlocks and use native qspinlock when dedicated pCPUs
+ * are available.
+ */
+ if (kvm_para_has_hint(KVM_HINTS_REALTIME)) {
+ pr_info("PV spinlocks disabled with KVM_HINTS_REALTIME hints\n");
+ goto out;
+ }
+
+ if (num_possible_cpus() == 1) {
+ pr_info("PV spinlocks disabled, single CPU\n");
+ goto out;
+ }
+
+ if (nopvspin) {
+ pr_info("PV spinlocks disabled, forced by \"nopvspin\" parameter\n");
+ goto out;
+ }
+
+ pr_info("PV spinlocks enabled\n");
+
+ __pv_init_lock_hash();
+ pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
+ pv_ops.lock.queued_spin_unlock =
+ PV_CALLEE_SAVE(__pv_queued_spin_unlock);
+ pv_ops.lock.wait = kvm_wait;
+ pv_ops.lock.kick = kvm_kick_cpu;
+
+ if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+ pv_ops.lock.vcpu_is_preempted =
+ PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
+ }
+ /*
+ * When PV spinlock is enabled which is preferred over
+ * virt_spin_lock(), virt_spin_lock_key's value is meaningless.
+ * Just disable it anyway.
+ */
+out:
+ static_branch_disable(&virt_spin_lock_key);
+}
+
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
+
+static void kvm_disable_host_haltpoll(void *i)
+{
+ wrmsrl(MSR_KVM_POLL_CONTROL, 0);
+}
+
+static void kvm_enable_host_haltpoll(void *i)
+{
+ wrmsrl(MSR_KVM_POLL_CONTROL, 1);
+}
+
+void arch_haltpoll_enable(unsigned int cpu)
+{
+ if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
+ pr_err_once("host does not support poll control\n");
+ pr_err_once("host upgrade recommended\n");
+ return;
+ }
+
+ /* Enable guest halt poll disables host halt poll */
+ smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
+
+void arch_haltpoll_disable(unsigned int cpu)
+{
+ if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
+ return;
+
+ /* Disable guest halt poll enables host halt poll */
+ smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 10:45:19 +0000