Commit adfe20fb authored by Wanpeng Li's avatar Wanpeng Li Committed by Radim Krčmář
Browse files

KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf 



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@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent 1261bfa3

arch/x86/include/asm/kvm_emulate.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};



/*

arch/x86/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -550,6 +550,7 @@ struct kvm_vcpu_arch { 
		bool reinject;

		u8 nr;

		u32 error_code;

		u8 nested_apf;

	} exception;



	struct kvm_queued_interrupt {
@@ -651,6 +652,7 @@ struct kvm_vcpu_arch { 
		u32 id;

		bool send_user_only;

		u32 host_apf_reason;

		unsigned long nested_apf_token;

	} apf;



	/* OSVW MSRs (AMD only) */

arch/x86/kvm/svm.c

+10 −6
Original line number Diff line number Diff line
@@ -2423,15 +2423,19 @@ 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;

	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;



	vmexit = nested_svm_intercept(svm);

	if (vmexit == NESTED_EXIT_DONE)

	svm->nested.exit_required = true;



	return vmexit;

}
@@ -2653,7 +2657,7 @@ static int nested_svm_intercept(struct vcpu_svm *svm) 
		}

		/* 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;

	}

arch/x86/kvm/vmx.c

+14 −3
Original line number Diff line number Diff line
@@ -2422,13 +2422,24 @@ 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));
@@ -2445,7 +2456,7 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu) 
	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) {

arch/x86/kvm/x86.c

+8 −1
Original line number Diff line number Diff line
@@ -450,6 +450,11 @@ 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.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);

}
@@ -8582,6 +8587,7 @@ 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);

	}

}
@@ -8604,6 +8610,7 @@ 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;

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