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-rw-r--r--arch/x86/include/asm/kvm_host.h18
-rw-r--r--arch/x86/kvm/Kconfig1
-rw-r--r--arch/x86/kvm/Makefile1
-rw-r--r--arch/x86/kvm/mmu.c52
-rw-r--r--arch/x86/kvm/paging_tmpl.h4
-rw-r--r--arch/x86/kvm/x86.c112
6 files changed, 183 insertions, 5 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f702f82aa1e..b5f4c1a36d6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -83,11 +83,14 @@
#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;
struct kvm_vcpu;
struct kvm;
+struct kvm_async_pf;
enum kvm_reg {
VCPU_REGS_RAX = 0,
@@ -412,6 +415,11 @@ struct kvm_vcpu_arch {
u64 hv_vapic;
cpumask_var_t wbinvd_dirty_mask;
+
+ struct {
+ bool halted;
+ gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
+ } apf;
};
struct kvm_arch {
@@ -585,6 +593,10 @@ 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;
int kvm_mmu_module_init(void);
@@ -799,4 +811,10 @@ 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 */
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index ddc131ff438..50f63648ce1 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -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---
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 31a7035c4bd..c53bf19b1da 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -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
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index fbb04aee830..4ab04de5a76 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -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>
@@ -2587,6 +2589,50 @@ 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)) {
+ trace_kvm_async_pf_doublefault(gva, gfn);
+ kvm_make_request(KVM_REQ_APF_HALT, vcpu);
+ 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)
{
@@ -2609,7 +2655,11 @@ 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);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index cd7a833a3b5..c45376dd041 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -568,7 +568,9 @@ 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))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c05d4770129..3cd4d091c2f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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
@@ -155,6 +156,13 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
u64 __read_mostly host_xcr0;
+static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
+{
+ int i;
+ for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU); i++)
+ vcpu->arch.apf.gfns[i] = ~0;
+}
+
static void kvm_on_user_return(struct user_return_notifier *urn)
{
unsigned slot;
@@ -5115,6 +5123,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
vcpu->fpu_active = 0;
kvm_x86_ops->fpu_deactivate(vcpu);
}
+ if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
+ /* Page is swapped out. Do synthetic halt */
+ vcpu->arch.apf.halted = true;
+ r = 1;
+ goto out;
+ }
}
r = kvm_mmu_reload(vcpu);
@@ -5243,7 +5257,8 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
r = 1;
while (r > 0) {
- if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
+ if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
+ !vcpu->arch.apf.halted)
r = vcpu_enter_guest(vcpu);
else {
srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
@@ -5256,6 +5271,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
vcpu->arch.mp_state =
KVM_MP_STATE_RUNNABLE;
case KVM_MP_STATE_RUNNABLE:
+ vcpu->arch.apf.halted = false;
break;
case KVM_MP_STATE_SIPI_RECEIVED:
default:
@@ -5277,6 +5293,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
vcpu->run->exit_reason = KVM_EXIT_INTR;
++vcpu->stat.request_irq_exits;
}
+
+ kvm_check_async_pf_completion(vcpu);
+
if (signal_pending(current)) {
r = -EINTR;
vcpu->run->exit_reason = KVM_EXIT_INTR;
@@ -5792,6 +5811,10 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
kvm_make_request(KVM_REQ_EVENT, vcpu);
+ kvm_clear_async_pf_completion_queue(vcpu);
+ kvm_async_pf_hash_reset(vcpu);
+ vcpu->arch.apf.halted = false;
+
return kvm_x86_ops->vcpu_reset(vcpu);
}
@@ -5880,6 +5903,8 @@ 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;
+ kvm_async_pf_hash_reset(vcpu);
+
return 0;
fail_free_mce_banks:
kfree(vcpu->arch.mce_banks);
@@ -5938,8 +5963,10 @@ 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);
@@ -6050,7 +6077,9 @@ 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
+ return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
+ !vcpu->arch.apf.halted)
+ || !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) &&
@@ -6109,6 +6138,83 @@ 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] != ~0)
+ 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] == ~0); 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] = ~0;
+ do {
+ j = kvm_async_pf_next_probe(j);
+ if (vcpu->arch.apf.gfns[j] == ~0)
+ 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)
+{
+ trace_kvm_async_pf_not_present(work->gva);
+
+ kvm_make_request(KVM_REQ_APF_HALT, vcpu);
+ 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);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-24 14:05:49 +0000