[Devel] [PATCH 3/6] KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf
Denis Plotnikov
dplotnikov at virtuozzo.com
Wed Sep 20 17:31:02 MSK 2017
From: Wanpeng Li <wanpeng.li at hotmail.com>
Add an nested_apf field to vcpu->arch.exception to identify an async page
fault, and constructs the expected vm-exit information fields. Force a
nested VM exit from nested_vmx_check_exception() if the injected #PF is
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>
Signed-off-by: Radim Krčmář <rkrcmar at redhat.com>
(cherry picked from commit adfe20fb48785dd73af3bf91407196eb5403c8cf)
fix #PSBM-56498
Signed-off-by: Denis Plotnikov <dplotnikov at virtuozzo.com>
---
arch/x86/include/asm/kvm_emulate.h | 1 +
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/svm.c | 16 ++++++++++------
arch/x86/kvm/vmx.c | 17 ++++++++++++++---
arch/x86/kvm/x86.c | 9 ++++++++-
5 files changed, 35 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 19d14ac..ad1689b 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -23,6 +23,7 @@ struct x86_exception {
u16 error_code;
bool nested_page_fault;
u64 address; /* cr2 or nested page fault gpa */
+ u8 async_page_fault;
};
/*
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 36561f25..ac1a7c1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -495,6 +495,7 @@ struct kvm_vcpu_arch {
bool reinject;
u8 nr;
u32 error_code;
+ u8 nested_apf;
} exception;
struct kvm_queued_interrupt {
@@ -594,6 +595,7 @@ struct kvm_vcpu_arch {
u32 id;
bool send_user_only;
u32 host_apf_reason;
+ unsigned long nested_apf_token;
} apf;
/* OSVW MSRs (AMD only) */
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 05e224a..67939a0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2215,15 +2215,19 @@ static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
if (!is_guest_mode(&svm->vcpu))
return 0;
+ vmexit = nested_svm_intercept(svm);
+ if (vmexit != NESTED_EXIT_DONE)
+ return 0;
+
svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + nr;
svm->vmcb->control.exit_code_hi = 0;
svm->vmcb->control.exit_info_1 = error_code;
- svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;
-
- vmexit = nested_svm_intercept(svm);
- if (vmexit == NESTED_EXIT_DONE)
- svm->nested.exit_required = true;
+ if (svm->vcpu.arch.exception.nested_apf)
+ svm->vmcb->control.exit_info_2 = svm->vcpu.arch.apf.nested_apf_token;
+ else
+ svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;
+ svm->nested.exit_required = true;
return vmexit;
}
@@ -2419,7 +2423,7 @@ 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->vcpu.arch.apf.host_apf_reason != 0)
+ svm->vcpu.arch.exception.nested_apf != 0)
vmexit = NESTED_EXIT_DONE;
break;
}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b2c01f8..2c14d1b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2281,13 +2281,24 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
* KVM wants to inject page-faults which it got to the guest. This function
* checks whether in a nested guest, we need to inject them to L1 or L2.
*/
-static int nested_vmx_check_exception(struct kvm_vcpu *vcpu, unsigned nr)
+static int nested_vmx_check_exception(struct kvm_vcpu *vcpu)
{
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+ unsigned int nr = vcpu->arch.exception.nr;
- if (!(vmcs12->exception_bitmap & (1u << nr)))
+ if (!((vmcs12->exception_bitmap & (1u << nr)) ||
+ (nr == PF_VECTOR && vcpu->arch.exception.nested_apf)))
return 0;
+ if (vcpu->arch.exception.nested_apf) {
+ vmcs_write32(VM_EXIT_INTR_ERROR_CODE, vcpu->arch.exception.error_code);
+ nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
+ PF_VECTOR | INTR_TYPE_HARD_EXCEPTION |
+ INTR_INFO_DELIVER_CODE_MASK | INTR_INFO_VALID_MASK,
+ vcpu->arch.apf.nested_apf_token);
+ return 1;
+ }
+
nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
vmcs_read32(VM_EXIT_INTR_INFO),
vmcs_readl(EXIT_QUALIFICATION));
@@ -2302,7 +2313,7 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
u32 intr_info = nr | INTR_INFO_VALID_MASK;
if (!reinject && is_guest_mode(vcpu) &&
- nested_vmx_check_exception(vcpu, nr))
+ nested_vmx_check_exception(vcpu))
return;
if (has_error_code) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 01522ec..66cbb9f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -444,7 +444,12 @@ EXPORT_SYMBOL_GPL(kvm_complete_insn_gp);
void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)
{
++vcpu->stat.pf_guest;
- vcpu->arch.cr2 = fault->address;
+ vcpu->arch.exception.nested_apf =
+ is_guest_mode(vcpu) && fault->async_page_fault;
+ if (vcpu->arch.exception.nested_apf)
+ vcpu->arch.apf.nested_apf_token = fault->address;
+ else
+ vcpu->arch.cr2 = fault->address;
kvm_queue_exception_e(vcpu, PF_VECTOR, fault->error_code);
}
EXPORT_SYMBOL_GPL(kvm_inject_page_fault);
@@ -8419,6 +8424,7 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
fault.error_code = 0;
fault.nested_page_fault = false;
fault.address = work->arch.token;
+ fault.async_page_fault = true;
kvm_inject_page_fault(vcpu, &fault);
}
}
@@ -8441,6 +8447,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
fault.error_code = 0;
fault.nested_page_fault = false;
fault.address = work->arch.token;
+ fault.async_page_fault = true;
kvm_inject_page_fault(vcpu, &fault);
}
vcpu->arch.apf.halted = false;
--
2.7.4
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