@@ -377,6 +377,7 @@ struct kvm_vcpu_arch {
u32 __user *apf_data;
u64 apf_msr_val;
+ u32 async_pf_id;
};
struct kvm_mem_alias {
@@ -539,6 +540,10 @@ struct kvm_x86_ops {
const struct trace_print_flags *exit_reasons_str;
};
+struct kvm_arch_async_pf {
+ u32 token;
+};
+
extern struct kvm_x86_ops *kvm_x86_ops;
int kvm_mmu_module_init(void);
@@ -817,4 +822,12 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
void kvm_define_shared_msr(unsigned index, u32 msr);
void kvm_set_shared_msr(unsigned index, u64 val);
+struct kvm_async_pf;
+
+void kvm_arch_inject_async_page_not_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work);
+void kvm_arch_inject_async_page_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work);
+bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu);
#endif /* _ASM_X86_KVM_HOST_H */
+
@@ -28,6 +28,8 @@ config KVM
select HAVE_KVM_IRQCHIP
select HAVE_KVM_EVENTFD
select KVM_APIC_ARCHITECTURE
+ select KVM_ASYNC_PF
+ select SLOW_WORK
select USER_RETURN_NOTIFIER
---help---
Support hosting fully virtualized guest machines using hardware
@@ -19,6 +19,7 @@
#include "mmu.h"
#include "kvm_cache_regs.h"
+#include "x86.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@@ -29,6 +30,8 @@
#include <linux/swap.h>
#include <linux/hugetlb.h>
#include <linux/compiler.h>
+#include <trace/events/kvm.h>
+#undef TRACE_INCLUDE_FILE
#include <asm/page.h>
#include <asm/cmpxchg.h>
@@ -2189,6 +2192,21 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
error_code & PFERR_WRITE_MASK, gfn);
}
+int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
+{
+ struct kvm_arch_async_pf arch;
+ arch.token = (vcpu->arch.async_pf_id++ << 12) | vcpu->vcpu_id;
+ return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
+}
+
+static bool can_do_async_pf(struct kvm_vcpu *vcpu)
+{
+ if (!vcpu->arch.apf_data || kvm_event_needs_reinjection(vcpu))
+ return false;
+
+ return !!kvm_x86_ops->get_cpl(vcpu);
+}
+
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
u32 error_code)
{
@@ -2211,7 +2229,23 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
- pfn = gfn_to_pfn(vcpu->kvm, gfn);
+
+ if (can_do_async_pf(vcpu)) {
+ r = gfn_to_pfn_async(vcpu->kvm, gfn, &pfn);
+ trace_kvm_try_async_get_page(r, pfn);
+ } else {
+do_sync:
+ r = 1;
+ pfn = gfn_to_pfn(vcpu->kvm, gfn);
+ }
+
+ if (!r) {
+ if (!kvm_arch_setup_async_pf(vcpu, gpa, gfn))
+ goto do_sync;
+ return 0;
+ }
+
+ /* mmio */
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return 1;
@@ -419,7 +419,21 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
- pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
+
+ if (can_do_async_pf(vcpu)) {
+ r = gfn_to_pfn_async(vcpu->kvm, walker.gfn, &pfn);
+ trace_kvm_try_async_get_page(r, pfn);
+ } else {
+do_sync:
+ r = 1;
+ pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
+ }
+
+ if (!r) {
+ if (!kvm_arch_setup_async_pf(vcpu, addr, walker.gfn))
+ goto do_sync;
+ return 0;
+ }
/* mmio */
if (is_error_pfn(pfn)) {
@@ -3898,6 +3898,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
}
}
+ kvm_check_async_pf_completion(vcpu);
+
preempt_disable();
kvm_x86_ops->prepare_guest_switch(vcpu);
@@ -5151,8 +5153,10 @@ static void kvm_free_vcpus(struct kvm *kvm)
/*
* Unpin any mmu pages first.
*/
- kvm_for_each_vcpu(i, vcpu, kvm)
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ kvm_clear_async_pf_completion_queue(vcpu);
kvm_unload_vcpu_mmu(vcpu);
+ }
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_arch_vcpu_free(vcpu);
@@ -5251,10 +5255,11 @@ void kvm_arch_flush_shadow(struct kvm *kvm)
int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
return vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE
+ || !list_empty_careful(&vcpu->async_pf_done)
|| vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED
- || vcpu->arch.nmi_pending ||
- (kvm_arch_interrupt_allowed(vcpu) &&
- kvm_cpu_has_interrupt(vcpu));
+ || vcpu->arch.nmi_pending
+ || (kvm_arch_interrupt_allowed(vcpu) &&
+ kvm_cpu_has_interrupt(vcpu));
}
void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
@@ -5301,6 +5306,30 @@ void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
}
EXPORT_SYMBOL_GPL(kvm_set_rflags);
+void kvm_arch_inject_async_page_not_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ put_user(KVM_PV_REASON_PAGE_NOT_PRESENT, vcpu->arch.apf_data);
+ kvm_inject_page_fault(vcpu, work->arch.token, 0);
+ trace_kvm_send_async_pf(work->arch.token, work->gva,
+ KVM_PV_REASON_PAGE_NOT_PRESENT);
+}
+
+void kvm_arch_inject_async_page_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ put_user(KVM_PV_REASON_PAGE_READY, vcpu->arch.apf_data);
+ kvm_inject_page_fault(vcpu, work->arch.token, 0);
+ trace_kvm_send_async_pf(work->arch.token, work->gva,
+ KVM_PV_REASON_PAGE_READY);
+}
+
+bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)
+{
+ return !kvm_event_needs_reinjection(vcpu) &&
+ kvm_x86_ops->interrupt_allowed(vcpu);
+}
+
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
@@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <linux/preempt.h>
#include <linux/msi.h>
+#include <linux/slow-work.h>
#include <asm/signal.h>
#include <linux/kvm.h>
@@ -72,6 +73,25 @@ void __kvm_io_bus_unregister_dev(struct kvm_io_bus *bus,
void kvm_io_bus_unregister_dev(struct kvm *kvm, struct kvm_io_bus *bus,
struct kvm_io_device *dev);
+#ifdef CONFIG_KVM_ASYNC_PF
+struct kvm_async_pf {
+ struct slow_work work;
+ struct list_head link;
+ struct kvm_vcpu *vcpu;
+ struct mm_struct *mm;
+ gva_t gva;
+ unsigned long addr;
+ struct kvm_arch_async_pf arch;
+ struct page *page;
+ atomic_t used;
+};
+
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);
+void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu);
+int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+ struct kvm_arch_async_pf *arch);
+#endif
+
struct kvm_vcpu {
struct kvm *kvm;
#ifdef CONFIG_PREEMPT_NOTIFIERS
@@ -99,6 +119,12 @@ struct kvm_vcpu {
gpa_t mmio_phys_addr;
#endif
+#ifdef CONFIG_KVM_ASYNC_PF
+ struct list_head async_pf_done;
+ spinlock_t async_pf_lock;
+ struct kvm_async_pf *async_pf_work;
+#endif
+
struct kvm_vcpu_arch arch;
};
@@ -263,6 +289,7 @@ void kvm_release_page_dirty(struct page *page);
void kvm_set_page_dirty(struct page *page);
void kvm_set_page_accessed(struct page *page);
+int gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, pfn_t *pfn);
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
void kvm_release_pfn_dirty(pfn_t);
void kvm_release_pfn_clean(pfn_t pfn);
@@ -145,6 +145,66 @@ TRACE_EVENT(kvm_mmio,
__entry->len, __entry->gpa, __entry->val)
);
+#ifdef CONFIG_KVM_ASYNC_PF
+TRACE_EVENT(
+ kvm_try_async_get_page,
+ TP_PROTO(bool r, u64 pfn),
+ TP_ARGS(r, pfn),
+
+ TP_STRUCT__entry(
+ __field(__u64, pfn)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = r ? pfn : (u64)-1;
+ ),
+
+ TP_printk("pfn %#llx", __entry->pfn)
+);
+
+TRACE_EVENT(
+ kvm_send_async_pf,
+ TP_PROTO(u64 token, u64 gva, u64 reason),
+ TP_ARGS(token, gva, reason),
+
+ TP_STRUCT__entry(
+ __field(__u64, token)
+ __field(__u64, gva)
+ __field(bool, np)
+ ),
+
+ TP_fast_assign(
+ __entry->token = token;
+ __entry->gva = gva;
+ __entry->np = (reason == KVM_PV_REASON_PAGE_NOT_PRESENT);
+ ),
+
+ TP_printk("token %#llx gva %#llx %s", __entry->token, __entry->gva,
+ __entry->np ? "not present" : "ready")
+);
+
+TRACE_EVENT(
+ kvm_async_pf_completed,
+ TP_PROTO(unsigned long address, struct page *page, u64 gva),
+ TP_ARGS(address, page, gva),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, address)
+ __field(struct page*, page)
+ __field(u64, gva)
+ ),
+
+ TP_fast_assign(
+ __entry->address = address;
+ __entry->page = page;
+ __entry->gva = gva;
+ ),
+
+ TP_printk("gva %#llx address %#lx pfn %lx", __entry->gva,
+ __entry->address, page_to_pfn(__entry->page))
+);
+#endif
+
#endif /* _TRACE_KVM_MAIN_H */
/* This part must be outside protection */
@@ -12,3 +12,6 @@ config HAVE_KVM_EVENTFD
config KVM_APIC_ARCHITECTURE
bool
+
+config KVM_ASYNC_PF
+ bool
@@ -76,6 +76,10 @@ static atomic_t hardware_enable_failed;
struct kmem_cache *kvm_vcpu_cache;
EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
+#ifdef CONFIG_KVM_ASYNC_PF
+static struct kmem_cache *async_pf_cache;
+#endif
+
static __read_mostly struct preempt_ops kvm_preempt_ops;
struct dentry *kvm_debugfs_dir;
@@ -176,6 +180,10 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
init_waitqueue_head(&vcpu->wq);
+#ifdef CONFIG_KVM_ASYNC_PF
+ INIT_LIST_HEAD(&vcpu->async_pf_done);
+ spin_lock_init(&vcpu->async_pf_lock);
+#endif
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page) {
@@ -822,6 +830,52 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
+int gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, pfn_t *pfn)
+{
+ struct page *page[1];
+ unsigned long addr;
+ int npages = 0;
+
+ *pfn = bad_pfn;
+
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr)) {
+ get_page(bad_page);
+ return 1;
+ }
+
+#ifdef CONFIG_X86
+ npages = __get_user_pages_fast(addr, 1, 1, page);
+
+#endif
+ if (unlikely(npages != 1)) {
+ down_read(¤t->mm->mmap_sem);
+ npages = get_user_pages_noio(current, current->mm, addr, 1, 1,
+ 0, page, NULL);
+ up_read(¤t->mm->mmap_sem);
+ }
+
+ if (unlikely(npages != 1)) {
+ struct vm_area_struct *vma;
+
+ down_read(¤t->mm->mmap_sem);
+ vma = find_vma(current->mm, addr);
+
+ if (vma == NULL || addr < vma->vm_start ||
+ !(vma->vm_flags & VM_PFNMAP)) {
+ up_read(¤t->mm->mmap_sem);
+ return 0; /* do async fault in */
+ }
+
+ *pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ up_read(¤t->mm->mmap_sem);
+ BUG_ON(!kvm_is_mmio_pfn(*pfn));
+ } else
+ *pfn = page_to_pfn(page[0]);
+
+ return 1;
+}
+
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
{
struct page *page[1];
@@ -1076,6 +1130,151 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
}
}
+#ifdef CONFIG_KVM_ASYNC_PF
+static void async_pf_work_free(struct kvm_async_pf *apf)
+{
+ if (atomic_dec_and_test(&apf->used))
+ kmem_cache_free(async_pf_cache, apf);
+}
+
+static int async_pf_get_ref(struct slow_work *work)
+{
+ struct kvm_async_pf *apf =
+ container_of(work, struct kvm_async_pf, work);
+
+ atomic_inc(&apf->used);
+ return 0;
+}
+
+static void async_pf_put_ref(struct slow_work *work)
+{
+ struct kvm_async_pf *apf =
+ container_of(work, struct kvm_async_pf, work);
+
+ kvm_put_kvm(apf->vcpu->kvm);
+ async_pf_work_free(apf);
+}
+
+static void async_pf_execute(struct slow_work *work)
+{
+ struct page *page;
+ struct kvm_async_pf *apf =
+ container_of(work, struct kvm_async_pf, work);
+ wait_queue_head_t *q = &apf->vcpu->wq;
+
+ might_sleep();
+
+ down_read(&apf->mm->mmap_sem);
+ get_user_pages(current, apf->mm, apf->addr, 1, 1, 0, &page, NULL);
+ up_read(&apf->mm->mmap_sem);
+
+ spin_lock(&apf->vcpu->async_pf_lock);
+ list_add_tail(&apf->link, &apf->vcpu->async_pf_done);
+ apf->page = page;
+ spin_unlock(&apf->vcpu->async_pf_lock);
+
+ trace_kvm_async_pf_completed(apf->addr, apf->page, apf->gva);
+
+ if (waitqueue_active(q))
+ wake_up_interruptible(q);
+
+ mmdrop(apf->mm);
+}
+
+struct slow_work_ops async_pf_ops = {
+ .get_ref = async_pf_get_ref,
+ .put_ref = async_pf_put_ref,
+ .execute = async_pf_execute
+};
+
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
+{
+ while (!list_empty(&vcpu->async_pf_done)) {
+ struct kvm_async_pf *work =
+ list_entry(vcpu->async_pf_done.next,
+ typeof(*work), link);
+ list_del(&work->link);
+ put_page(work->page);
+ kmem_cache_free(async_pf_cache, work);
+ }
+}
+
+void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
+{
+ struct kvm_async_pf *work = vcpu->async_pf_work;
+
+ if (work) {
+ vcpu->async_pf_work = NULL;
+ if (work->page == NULL) {
+ kvm_arch_inject_async_page_not_present(vcpu, work);
+ return;
+ } else {
+ spin_lock(&vcpu->async_pf_lock);
+ list_del(&work->link);
+ spin_unlock(&vcpu->async_pf_lock);
+ put_page(work->page);
+ async_pf_work_free(work);
+ }
+ }
+
+ if (list_empty_careful(&vcpu->async_pf_done) ||
+ !kvm_arch_can_inject_async_page_present(vcpu))
+ return;
+
+ spin_lock(&vcpu->async_pf_lock);
+ work = list_first_entry(&vcpu->async_pf_done, typeof(*work), link);
+ list_del(&work->link);
+ spin_unlock(&vcpu->async_pf_lock);
+
+ kvm_arch_inject_async_page_present(vcpu, work);
+
+ put_page(work->page);
+ async_pf_work_free(work);
+}
+
+int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+ struct kvm_arch_async_pf *arch)
+{
+ struct kvm_async_pf *work;
+
+ /* setup slow work */
+
+ /* do alloc atomic since if we are going to sleep anyway we
+ may as well sleep faulting in page */
+ work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
+ if (!work)
+ return 0;
+
+ atomic_set(&work->used, 1);
+ work->page = NULL;
+ work->vcpu = vcpu;
+ work->gva = gva;
+ work->addr = gfn_to_hva(vcpu->kvm, gfn);
+ work->arch = *arch;
+ work->mm = current->mm;
+ atomic_inc(&work->mm->mm_count);
+ kvm_get_kvm(work->vcpu->kvm);
+
+ /* this can't really happen otherwise gfn_to_pfn_async
+ would succeed */
+ if (unlikely(kvm_is_error_hva(work->addr)))
+ goto retry_sync;
+
+ slow_work_init(&work->work, &async_pf_ops);
+ if (slow_work_enqueue(&work->work) != 0)
+ goto retry_sync;
+
+ vcpu->async_pf_work = work;
+ return 1;
+retry_sync:
+ kvm_put_kvm(work->vcpu->kvm);
+ mmdrop(work->mm);
+ kmem_cache_free(async_pf_cache, work);
+ return 0;
+}
+
+#endif
+
/*
* The vCPU has executed a HLT instruction with in-kernel mode enabled.
*/
@@ -2104,6 +2303,19 @@ int kvm_init(void *opaque, unsigned int vcpu_size,
goto out_free_5;
}
+#ifdef CONFIG_KVM_ASYNC_PF
+ async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
+
+ if (!async_pf_cache) {
+ r = -ENOMEM;
+ goto out_free_6;
+ }
+
+ r = slow_work_register_user();
+ if (r)
+ goto out_free;
+#endif
+
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
@@ -2111,7 +2323,7 @@ int kvm_init(void *opaque, unsigned int vcpu_size,
r = misc_register(&kvm_dev);
if (r) {
printk(KERN_ERR "kvm: misc device register failed\n");
- goto out_free;
+ goto out_unreg;
}
kvm_preempt_ops.sched_in = kvm_sched_in;
@@ -2121,7 +2333,13 @@ int kvm_init(void *opaque, unsigned int vcpu_size,
return 0;
+out_unreg:
+#ifdef CONFIG_KVM_ASYNC_PF
+ slow_work_unregister_user();
out_free:
+ kmem_cache_destroy(async_pf_cache);
+out_free_6:
+#endif
kmem_cache_destroy(kvm_vcpu_cache);
out_free_5:
sysdev_unregister(&kvm_sysdev);
@@ -2150,6 +2368,11 @@ void kvm_exit(void)
kvm_exit_debug();
misc_deregister(&kvm_dev);
kmem_cache_destroy(kvm_vcpu_cache);
+#ifdef CONFIG_KVM_ASYNC_PF
+ if (async_pf_cache)
+ kmem_cache_destroy(async_pf_cache);
+ slow_work_unregister_user();
+#endif
sysdev_unregister(&kvm_sysdev);
sysdev_class_unregister(&kvm_sysdev_class);
unregister_reboot_notifier(&kvm_reboot_notifier);