[Devel] [PATCH 2/6] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
Denis Plotnikov
dplotnikov at virtuozzo.com
Wed Sep 20 17:31:01 MSK 2017
From: Wanpeng Li <wanpeng.li at hotmail.com>
This patch adds the L1 guest async page fault #PF vmexit handler, such
by L1 similar to ordinary async page fault.
Cc: Paolo Bonzini <pbonzini at redhat.com>
Cc: Radim Krčmář <rkrcmar at redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li at hotmail.com>
[Passed insn parameters to kvm_mmu_page_fault().]
Signed-off-by: Radim Krčmář <rkrcmar at redhat.com>
(cherry picked from commit 1261bfa326f5e903166498628a1894edce0caabc)
fix #PSBM-56498
Signed-off-by: Denis Plotnikov <dplotnikov at virtuozzo.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/mmu.c | 33 +++++++++++++++++++++++++++++++++
arch/x86/kvm/mmu.h | 3 +++
arch/x86/kvm/svm.c | 36 ++++++------------------------------
arch/x86/kvm/vmx.c | 15 ++++++++-------
5 files changed, 51 insertions(+), 37 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 004aff6..36561f25 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -593,6 +593,7 @@ struct kvm_vcpu_arch {
u64 msr_val;
u32 id;
bool send_user_only;
+ u32 host_apf_reason;
} apf;
/* OSVW MSRs (AMD only) */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 6fdc4ef..83584eb 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -42,6 +42,7 @@
#include <asm/io.h>
#include <asm/vmx.h>
#include <asm/kvm_page_track.h>
+#include "trace.h"
/*
* When setting this variable to true it enables Two-Dimensional-Paging
@@ -3517,6 +3518,38 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
return false;
}
+int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
+ u64 fault_address, char *insn, int insn_len,
+ bool need_unprotect)
+{
+ int r = 1;
+
+ switch (vcpu->arch.apf.host_apf_reason) {
+ default:
+ trace_kvm_page_fault(fault_address, error_code);
+
+ if (need_unprotect && kvm_event_needs_reinjection(vcpu))
+ kvm_mmu_unprotect_page_virt(vcpu, fault_address);
+ r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
+ insn_len);
+ break;
+ case KVM_PV_REASON_PAGE_NOT_PRESENT:
+ vcpu->arch.apf.host_apf_reason = 0;
+ local_irq_disable();
+ kvm_async_pf_task_wait(fault_address);
+ local_irq_enable();
+ break;
+ case KVM_PV_REASON_PAGE_READY:
+ vcpu->arch.apf.host_apf_reason = 0;
+ local_irq_disable();
+ kvm_async_pf_task_wake(fault_address);
+ local_irq_enable();
+ break;
+ }
+ return r;
+}
+EXPORT_SYMBOL_GPL(kvm_handle_page_fault);
+
static bool
check_hugepage_cache_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int level)
{
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 58fe98a..bfadd00 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -74,6 +74,9 @@ enum {
int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct);
void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu);
void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly);
+int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
+ u64 fault_address, char *insn, int insn_len,
+ bool need_unprotect);
static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)
{
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 89689b0..05e224a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -173,7 +173,6 @@ struct vcpu_svm {
unsigned int3_injected;
unsigned long int3_rip;
- u32 apf_reason;
/* cached guest cpuid flags for faster access */
bool nrips_enabled : 1;
@@ -1902,34 +1901,11 @@ static void svm_set_dr7(struct kvm_vcpu *vcpu, unsigned long value)
static int pf_interception(struct vcpu_svm *svm)
{
u64 fault_address = svm->vmcb->control.exit_info_2;
- u32 error_code;
- int r = 1;
+ u64 error_code = svm->vmcb->control.exit_info_1;
- switch (svm->apf_reason) {
- default:
- error_code = svm->vmcb->control.exit_info_1;
-
- trace_kvm_page_fault(fault_address, error_code);
- if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu))
- kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address);
- r = kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code,
+ return kvm_handle_page_fault(&svm->vcpu, error_code, fault_address,
svm->vmcb->control.insn_bytes,
- svm->vmcb->control.insn_len);
- break;
- case KVM_PV_REASON_PAGE_NOT_PRESENT:
- svm->apf_reason = 0;
- local_irq_disable();
- kvm_async_pf_task_wait(fault_address);
- local_irq_enable();
- break;
- case KVM_PV_REASON_PAGE_READY:
- svm->apf_reason = 0;
- local_irq_disable();
- kvm_async_pf_task_wake(fault_address);
- local_irq_enable();
- break;
- }
- return r;
+ svm->vmcb->control.insn_len, !npt_enabled);
}
static int db_interception(struct vcpu_svm *svm)
@@ -2397,7 +2373,7 @@ static int nested_svm_exit_special(struct vcpu_svm *svm)
break;
case SVM_EXIT_EXCP_BASE + PF_VECTOR:
/* When we're shadowing, trap PFs, but not async PF */
- if (!npt_enabled && svm->apf_reason == 0)
+ if (!npt_enabled && svm->vcpu.arch.apf.host_apf_reason == 0)
return NESTED_EXIT_HOST;
break;
case SVM_EXIT_EXCP_BASE + NM_VECTOR:
@@ -2443,7 +2419,7 @@ static int nested_svm_intercept(struct vcpu_svm *svm)
vmexit = NESTED_EXIT_DONE;
/* async page fault always cause vmexit */
else if ((exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) &&
- svm->apf_reason != 0)
+ svm->vcpu.arch.apf.host_apf_reason != 0)
vmexit = NESTED_EXIT_DONE;
break;
}
@@ -4504,7 +4480,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
/* if exit due to PF check for async PF */
if (svm->vmcb->control.exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR)
- svm->apf_reason = kvm_read_and_reset_pf_reason();
+ svm->vcpu.arch.apf.host_apf_reason = kvm_read_and_reset_pf_reason();
if (npt_enabled) {
vcpu->arch.regs_avail &= ~(1 << VCPU_EXREG_PDPTR);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b52ba18..b2c01f8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5277,14 +5277,11 @@ static int handle_exception(struct kvm_vcpu *vcpu)
}
if (is_page_fault(intr_info)) {
- /* EPT won't cause page fault directly */
- BUG_ON(enable_ept);
cr2 = vmcs_readl(EXIT_QUALIFICATION);
- trace_kvm_page_fault(cr2, error_code);
-
- if (kvm_event_needs_reinjection(vcpu))
- kvm_mmu_unprotect_page_virt(vcpu, cr2);
- return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0);
+ /* EPT won't cause page fault directly */
+ WARN_ON_ONCE(!vcpu->arch.apf.host_apf_reason && enable_ept);
+ return kvm_handle_page_fault(vcpu, error_code, cr2, NULL, 0,
+ true);
}
ex_no = intr_info & INTR_INFO_VECTOR_MASK;
@@ -8312,6 +8309,10 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
vmx->exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
exit_intr_info = vmx->exit_intr_info;
+ /* if exit due to PF check for async PF */
+ if (is_page_fault(exit_intr_info))
+ vmx->vcpu.arch.apf.host_apf_reason = kvm_read_and_reset_pf_reason();
+
/* Handle machine checks before interrupts are enabled */
if (is_machine_check(exit_intr_info))
kvm_machine_check();
--
2.7.4
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