@@ -83,6 +83,8 @@
#define KVM_NR_FIXED_MTRR_REGION 88
#define KVM_NR_VAR_MTRR 8
+#define ASYNC_PF_PER_VCPU 64
+
extern spinlock_t kvm_lock;
extern struct list_head vm_list;
@@ -412,6 +414,10 @@ struct kvm_vcpu_arch {
u64 hv_vapic;
cpumask_var_t wbinvd_dirty_mask;
+
+ struct {
+ gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
+ } apf;
};
struct kvm_arch {
@@ -585,7 +591,12 @@ struct kvm_x86_ops {
const struct trace_print_flags *exit_reasons_str;
};
+struct kvm_arch_async_pf {
+ gfn_t gfn;
+};
+
extern struct kvm_x86_ops *kvm_x86_ops;
+extern struct kvm_async_pf *kvm_double_apf;
int kvm_mmu_module_init(void);
void kvm_mmu_module_exit(void);
@@ -823,4 +834,10 @@ void kvm_set_shared_msr(unsigned index, u64 val, u64 mask);
bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip);
+void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work);
+void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work);
+extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);
+
#endif /* _ASM_X86_KVM_HOST_H */
@@ -28,6 +28,7 @@ config KVM
select HAVE_KVM_IRQCHIP
select HAVE_KVM_EVENTFD
select KVM_APIC_ARCHITECTURE
+ select KVM_ASYNC_PF
select USER_RETURN_NOTIFIER
select KVM_MMIO
---help---
@@ -9,6 +9,7 @@ kvm-y += $(addprefix ../../../virt/kvm/, kvm_main.o ioapic.o \
coalesced_mmio.o irq_comm.o eventfd.o \
assigned-dev.o)
kvm-$(CONFIG_IOMMU_API) += $(addprefix ../../../virt/kvm/, iommu.o)
+kvm-$(CONFIG_KVM_ASYNC_PF) += $(addprefix ../../../virt/kvm/, async_pf.o)
kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \
i8254.o timer.o
@@ -18,9 +18,11 @@
*
*/
+#include "irq.h"
#include "mmu.h"
#include "x86.h"
#include "kvm_cache_regs.h"
+#include "x86.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@@ -2575,6 +2577,49 @@ 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.gfn = gfn;
+
+ return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
+}
+
+static bool can_do_async_pf(struct kvm_vcpu *vcpu)
+{
+ if (unlikely(!irqchip_in_kernel(vcpu->kvm) ||
+ kvm_event_needs_reinjection(vcpu)))
+ return false;
+
+ return kvm_x86_ops->interrupt_allowed(vcpu);
+}
+
+static bool try_async_pf(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva,
+ pfn_t *pfn)
+{
+ bool async;
+
+ *pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async);
+
+ if (!async)
+ return false; /* *pfn has correct page already */
+
+ put_page(pfn_to_page(*pfn));
+
+ if (can_do_async_pf(vcpu)) {
+ trace_kvm_try_async_get_page(async, *pfn);
+ if (kvm_find_async_pf_gfn(vcpu, gfn)) {
+ vcpu->async_pf.work = kvm_double_apf;
+ return true;
+ } else if (kvm_arch_setup_async_pf(vcpu, gva, gfn))
+ return true;
+ }
+
+ *pfn = gfn_to_pfn(vcpu->kvm, gfn);
+
+ return false;
+}
+
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
u32 error_code)
{
@@ -2597,7 +2642,11 @@ 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 (try_async_pf(vcpu, gfn, gpa, &pfn))
+ return 0;
+
+ /* mmio */
if (is_error_pfn(pfn))
return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
spin_lock(&vcpu->kvm->mmu_lock);
@@ -573,7 +573,9 @@ 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 (try_async_pf(vcpu, walker.gfn, addr, &pfn))
+ return 0;
/* mmio */
if (is_error_pfn(pfn))
@@ -43,6 +43,7 @@
#include <linux/slab.h>
#include <linux/perf_event.h>
#include <linux/uaccess.h>
+#include <linux/hash.h>
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
@@ -116,6 +117,7 @@ struct kvm_shared_msrs {
static struct kvm_shared_msrs_global __read_mostly shared_msrs_global;
static DEFINE_PER_CPU(struct kvm_shared_msrs, shared_msrs);
+struct kvm_async_pf *kvm_double_apf;
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "pf_fixed", VCPU_STAT(pf_fixed) },
@@ -4635,6 +4637,12 @@ int kvm_arch_init(void *opaque)
goto out;
}
+ kvm_double_apf = kzalloc(sizeof(struct kvm_async_pf), GFP_KERNEL);
+ if (!kvm_double_apf) {
+ r = -ENOMEM;
+ goto out;
+ }
+
r = kvm_mmu_module_init();
if (r)
goto out;
@@ -4657,6 +4665,7 @@ int kvm_arch_init(void *opaque)
return 0;
out:
+ kfree(kvm_double_apf);
return r;
}
@@ -4669,6 +4678,7 @@ void kvm_arch_exit(void)
CPUFREQ_TRANSITION_NOTIFIER);
unregister_hotcpu_notifier(&kvmclock_cpu_notifier_block);
kvm_x86_ops = NULL;
+ kfree(kvm_double_apf);
kvm_mmu_module_exit();
}
@@ -5112,6 +5122,13 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (unlikely(r))
goto out;
+ kvm_check_async_pf_completion(vcpu);
+ if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) {
+ /* Page is swapped out. Do synthetic halt */
+ r = 1;
+ goto out;
+ }
+
if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
inject_pending_event(vcpu);
@@ -5781,6 +5798,9 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
kvm_make_request(KVM_REQ_EVENT, vcpu);
+ kvm_clear_async_pf_completion_queue(vcpu);
+ memset(vcpu->arch.apf.gfns, 0xff, sizeof vcpu->arch.apf.gfns);
+
return kvm_x86_ops->vcpu_reset(vcpu);
}
@@ -5869,6 +5889,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask, GFP_KERNEL))
goto fail_free_mce_banks;
+ memset(vcpu->arch.apf.gfns, 0xff, sizeof vcpu->arch.apf.gfns);
+
return 0;
fail_free_mce_banks:
kfree(vcpu->arch.mce_banks);
@@ -5927,8 +5949,10 @@ 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);
@@ -6040,6 +6064,7 @@ 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) &&
@@ -6098,6 +6123,88 @@ void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
}
EXPORT_SYMBOL_GPL(kvm_set_rflags);
+static inline u32 kvm_async_pf_hash_fn(gfn_t gfn)
+{
+ return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU));
+}
+
+static inline u32 kvm_async_pf_next_probe(u32 key)
+{
+ return (key + 1) & (roundup_pow_of_two(ASYNC_PF_PER_VCPU) - 1);
+}
+
+static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ u32 key = kvm_async_pf_hash_fn(gfn);
+
+ while (vcpu->arch.apf.gfns[key] != -1)
+ key = kvm_async_pf_next_probe(key);
+
+ vcpu->arch.apf.gfns[key] = gfn;
+}
+
+static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ int i;
+ u32 key = kvm_async_pf_hash_fn(gfn);
+
+ for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) &&
+ (vcpu->arch.apf.gfns[key] != gfn ||
+ vcpu->arch.apf.gfns[key] == -1); i++)
+ key = kvm_async_pf_next_probe(key);
+
+ return key;
+}
+
+bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ return vcpu->arch.apf.gfns[kvm_async_pf_gfn_slot(vcpu, gfn)] == gfn;
+}
+
+static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ u32 i, j, k;
+
+ i = j = kvm_async_pf_gfn_slot(vcpu, gfn);
+ while (true) {
+ vcpu->arch.apf.gfns[i] = -1;
+ do {
+ j = kvm_async_pf_next_probe(j);
+ if (vcpu->arch.apf.gfns[j] == -1)
+ return;
+ k = kvm_async_pf_hash_fn(vcpu->arch.apf.gfns[j]);
+ /*
+ * k lies cyclically in ]i,j]
+ * | i.k.j |
+ * |....j i.k.| or |.k..j i...|
+ */
+ } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j));
+ vcpu->arch.apf.gfns[i] = vcpu->arch.apf.gfns[j];
+ i = j;
+ }
+}
+
+void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+
+ if (work == kvm_double_apf)
+ trace_kvm_async_pf_doublefault(kvm_rip_read(vcpu));
+ else {
+ trace_kvm_async_pf_not_present(work->gva);
+
+ kvm_add_async_pf_gfn(vcpu, work->arch.gfn);
+ }
+}
+
+void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ trace_kvm_async_pf_ready(work->gva);
+ kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
+}
+
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
@@ -74,6 +74,26 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx,
int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
struct kvm_io_device *dev);
+#ifdef CONFIG_KVM_ASYNC_PF
+struct kvm_async_pf {
+ struct work_struct work;
+ struct list_head link;
+ struct list_head queue;
+ struct kvm_vcpu *vcpu;
+ struct mm_struct *mm;
+ gva_t gva;
+ unsigned long addr;
+ struct kvm_arch_async_pf arch;
+ struct page *page;
+};
+
+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);
+int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu);
+#endif
+
struct kvm_vcpu {
struct kvm *kvm;
#ifdef CONFIG_PREEMPT_NOTIFIERS
@@ -104,6 +124,16 @@ struct kvm_vcpu {
gpa_t mmio_phys_addr;
#endif
+#ifdef CONFIG_KVM_ASYNC_PF
+ struct {
+ u32 queued;
+ struct list_head queue;
+ struct list_head done;
+ spinlock_t lock;
+ struct kvm_async_pf *work;
+ } async_pf;
+#endif
+
struct kvm_vcpu_arch arch;
};
@@ -302,6 +332,7 @@ void kvm_set_page_accessed(struct page *page);
pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr);
pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn);
+pfn_t gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, bool *async);
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn);
@@ -185,6 +185,94 @@ TRACE_EVENT(kvm_age_page,
__entry->referenced ? "YOUNG" : "OLD")
);
+#ifdef CONFIG_KVM_ASYNC_PF
+TRACE_EVENT(
+ kvm_try_async_get_page,
+ TP_PROTO(bool async, u64 pfn),
+ TP_ARGS(async, pfn),
+
+ TP_STRUCT__entry(
+ __field(__u64, pfn)
+ ),
+
+ TP_fast_assign(
+ __entry->pfn = (!async) ? pfn : (u64)-1;
+ ),
+
+ TP_printk("pfn %#llx", __entry->pfn)
+);
+
+TRACE_EVENT(
+ kvm_async_pf_not_present,
+ TP_PROTO(u64 gva),
+ TP_ARGS(gva),
+
+ TP_STRUCT__entry(
+ __field(__u64, gva)
+ ),
+
+ TP_fast_assign(
+ __entry->gva = gva;
+ ),
+
+ TP_printk("gva %#llx not present", __entry->gva)
+);
+
+TRACE_EVENT(
+ kvm_async_pf_ready,
+ TP_PROTO(u64 gva),
+ TP_ARGS(gva),
+
+ TP_STRUCT__entry(
+ __field(__u64, gva)
+ ),
+
+ TP_fast_assign(
+ __entry->gva = gva;
+ ),
+
+ TP_printk("gva %#llx ready", __entry->gva)
+);
+
+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))
+);
+
+TRACE_EVENT(
+ kvm_async_pf_doublefault,
+ TP_PROTO(unsigned long rip),
+ TP_ARGS(rip),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, rip)
+ ),
+
+ TP_fast_assign(
+ __entry->rip = rip;
+ ),
+
+ TP_printk("rip = %#lx", __entry->rip)
+);
+
+#endif
+
#endif /* _TRACE_KVM_MAIN_H */
/* This part must be outside protection */
@@ -15,3 +15,6 @@ config KVM_APIC_ARCHITECTURE
config KVM_MMIO
bool
+
+config KVM_ASYNC_PF
+ bool
new file mode 100644
@@ -0,0 +1,220 @@
+/*
+ * kvm asynchromous fault support
+ *
+ * Copyright 2010 Red Hat, Inc.
+ *
+ * Author:
+ * Gleb Natapov <gleb@redhat.com>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/kvm_host.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mmu_context.h>
+
+#include "async_pf.h"
+#include <trace/events/kvm.h>
+
+static struct kmem_cache *async_pf_cache;
+
+int kvm_async_pf_init(void)
+{
+ async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
+
+ if (!async_pf_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void kvm_async_pf_deinit(void)
+{
+ if (async_pf_cache)
+ kmem_cache_destroy(async_pf_cache);
+ async_pf_cache = NULL;
+}
+
+void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
+{
+ INIT_LIST_HEAD(&vcpu->async_pf.done);
+ INIT_LIST_HEAD(&vcpu->async_pf.queue);
+ spin_lock_init(&vcpu->async_pf.lock);
+}
+
+static void async_pf_execute(struct work_struct *work)
+{
+ struct page *page;
+ struct kvm_async_pf *apf =
+ container_of(work, struct kvm_async_pf, work);
+ struct mm_struct *mm = apf->mm;
+ struct kvm_vcpu *vcpu = apf->vcpu;
+ unsigned long addr = apf->addr;
+ gva_t gva = apf->gva;
+
+ might_sleep();
+
+ use_mm(mm);
+ down_read(&mm->mmap_sem);
+ get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
+ up_read(&mm->mmap_sem);
+ unuse_mm(mm);
+
+ spin_lock(&vcpu->async_pf.lock);
+ list_add_tail(&apf->link, &vcpu->async_pf.done);
+ apf->page = page;
+ spin_unlock(&vcpu->async_pf.lock);
+
+ /*
+ * apf may be freed by kvm_check_async_pf_completion() after
+ * this point
+ */
+
+ trace_kvm_async_pf_completed(addr, page, gva);
+
+ if (waitqueue_active(&vcpu->wq))
+ wake_up_interruptible(&vcpu->wq);
+
+ mmdrop(mm);
+ kvm_put_kvm(vcpu->kvm);
+}
+
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
+{
+ /* cancel outstanding work queue item */
+ while (!list_empty(&vcpu->async_pf.queue)) {
+ struct kvm_async_pf *work =
+ list_entry(vcpu->async_pf.queue.next,
+ typeof(*work), queue);
+ cancel_work_sync(&work->work);
+ list_del(&work->queue);
+ if (!work->page) /* work was canceled */
+ kmem_cache_free(async_pf_cache, work);
+ }
+
+ spin_lock(&vcpu->async_pf.lock);
+ 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);
+ }
+ spin_unlock(&vcpu->async_pf.lock);
+
+ vcpu->async_pf.queued = 0;
+ vcpu->async_pf.work = NULL;
+}
+
+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_async_page_not_present(vcpu, work);
+ return;
+ } else {
+ /* page was swapped in before vcpu entry */
+ spin_lock(&vcpu->async_pf.lock);
+ list_del(&work->link);
+ spin_unlock(&vcpu->async_pf.lock);
+ goto free;
+ }
+ }
+
+ if (list_empty_careful(&vcpu->async_pf.done))
+ 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_async_page_present(vcpu, work);
+
+free:
+ list_del(&work->queue);
+ vcpu->async_pf.queued--;
+ put_page(work->page);
+ kmem_cache_free(async_pf_cache, 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;
+
+ if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
+ return 0;
+
+ /* setup delayed work */
+
+ /* do alloc nowait since if we are going to sleep anyway we
+ may as well sleep faulting in page */
+ work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
+ if (!work)
+ return 0;
+
+ 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;
+
+ INIT_WORK(&work->work, async_pf_execute);
+ if (!schedule_work(&work->work))
+ goto retry_sync;
+
+ vcpu->async_pf.work = work;
+ list_add_tail(&work->queue, &vcpu->async_pf.queue);
+ vcpu->async_pf.queued++;
+ return 1;
+retry_sync:
+ kvm_put_kvm(work->vcpu->kvm);
+ mmdrop(work->mm);
+ kmem_cache_free(async_pf_cache, work);
+ return 0;
+}
+
+int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
+{
+ struct kvm_async_pf *work;
+
+ if (!list_empty(&vcpu->async_pf.done))
+ return 0;
+
+ work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
+ if (!work)
+ return -ENOMEM;
+
+ work->page = bad_page;
+ get_page(bad_page);
+ INIT_LIST_HEAD(&work->queue); /* for list_del to work */
+
+ list_add_tail(&work->link, &vcpu->async_pf.done);
+ vcpu->async_pf.queued++;
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,36 @@
+/*
+ * kvm asynchromous fault support
+ *
+ * Copyright 2010 Red Hat, Inc.
+ *
+ * Author:
+ * Gleb Natapov <gleb@redhat.com>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __KVM_ASYNC_PF_H__
+#define __KVM_ASYNC_PF_H__
+
+#ifdef CONFIG_KVM_ASYNC_PF
+int kvm_async_pf_init(void);
+void kvm_async_pf_deinit(void);
+void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu);
+#else
+#define kvm_async_pf_init() (0)
+#define kvm_async_pf_deinit() do{}while(0)
+#define kvm_async_pf_vcpu_init(C) do{}while(0)
+#endif
+
+#endif
@@ -55,6 +55,7 @@
#include <asm-generic/bitops/le.h>
#include "coalesced_mmio.h"
+#include "async_pf.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
@@ -186,6 +187,7 @@ 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);
+ kvm_async_pf_vcpu_init(vcpu);
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page) {
@@ -948,17 +950,29 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
-static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
+static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,
+ bool *async)
{
struct page *page[1];
- int npages;
+ int npages = 0;
pfn_t pfn;
- if (atomic)
+ /* we can do it either atomically or asynchronously, not both */
+ BUG_ON(atomic && async);
+
+ if (atomic || async)
npages = __get_user_pages_fast(addr, 1, 1, page);
- else {
+
+ if (unlikely(npages != 1) && !atomic) {
might_sleep();
- npages = get_user_pages_fast(addr, 1, 1, page);
+
+ if (async) {
+ 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);
+ } else
+ npages = get_user_pages_fast(addr, 1, 1, page);
}
if (unlikely(npages != 1)) {
@@ -978,6 +992,9 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
if (vma == NULL || addr < vma->vm_start ||
!(vma->vm_flags & VM_PFNMAP)) {
+ if (async && !(vma->vm_flags & VM_PFNMAP) &&
+ (vma->vm_flags & VM_WRITE))
+ *async = true;
up_read(¤t->mm->mmap_sem);
return_fault_page:
get_page(fault_page);
@@ -995,32 +1012,41 @@ return_fault_page:
pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr)
{
- return hva_to_pfn(kvm, addr, true);
+ return hva_to_pfn(kvm, addr, true, NULL);
}
EXPORT_SYMBOL_GPL(hva_to_pfn_atomic);
-static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic)
+static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic, bool *async)
{
unsigned long addr;
+ if (async)
+ *async = false;
+
addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr)) {
get_page(bad_page);
return page_to_pfn(bad_page);
}
- return hva_to_pfn(kvm, addr, atomic);
+ return hva_to_pfn(kvm, addr, atomic, async);
}
pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn)
{
- return __gfn_to_pfn(kvm, gfn, true);
+ return __gfn_to_pfn(kvm, gfn, true, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic);
+pfn_t gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, bool *async)
+{
+ return __gfn_to_pfn(kvm, gfn, false, async);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_async);
+
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
{
- return __gfn_to_pfn(kvm, gfn, false);
+ return __gfn_to_pfn(kvm, gfn, false, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn);
@@ -1028,7 +1054,7 @@ pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn)
{
unsigned long addr = gfn_to_hva_memslot(slot, gfn);
- return hva_to_pfn(kvm, addr, false);
+ return hva_to_pfn(kvm, addr, false, NULL);
}
int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
@@ -2335,6 +2361,10 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
goto out_free_5;
}
+ r = kvm_async_pf_init();
+ if (r)
+ goto out_free;
+
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
@@ -2342,7 +2372,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
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;
@@ -2352,6 +2382,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
return 0;
+out_unreg:
+ kvm_async_pf_deinit();
out_free:
kmem_cache_destroy(kvm_vcpu_cache);
out_free_5:
@@ -2384,6 +2416,7 @@ void kvm_exit(void)
kvm_exit_debug();
misc_deregister(&kvm_dev);
kmem_cache_destroy(kvm_vcpu_cache);
+ kvm_async_pf_deinit();
sysdev_unregister(&kvm_sysdev);
sysdev_class_unregister(&kvm_sysdev_class);
unregister_reboot_notifier(&kvm_reboot_notifier);