From: Paolo Bonzini <pbonzini@redhat.com>

Date: Fri, 11 Aug 2017 18:36:43 +0200

Subject: KVM: SVM: limit kvm_handle_page_fault to #PF handling

Patch-mainline: v4.15-rc1

Git-commit: d0006530576f1c7a49b2010eac7afdcb5a3613ae

References: bsc#1077761

It has always annoyed me a bit how SVM_EXIT_NPF is handled by

pf_interception.  This is also the only reason behind the

under-documented need_unprotect argument to kvm_handle_page_fault.

Let NPF go straight to kvm_mmu_page_fault, just like VMX

does in handle_ept_violation and handle_ept_misconfig.

Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Acked-by: Alexander Graf <agraf@suse.de>

---

 arch/x86/kvm/mmu.c |    5 ++---

 arch/x86/kvm/mmu.h |    3 +--

 arch/x86/kvm/svm.c |   15 +++++++++++++--

 arch/x86/kvm/vmx.c |    3 +--

 4 files changed, 17 insertions(+), 9 deletions(-)

--- a/arch/x86/kvm/mmu.c

+++ b/arch/x86/kvm/mmu.c

@@ -3820,8 +3820,7 @@

 }

 int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,

-				u64 fault_address, char *insn, int insn_len,

-				bool need_unprotect)

+				u64 fault_address, char *insn, int insn_len)

 {

 	int r = 1;

@@ -3829,7 +3828,7 @@

 	default:

 		trace_kvm_page_fault(fault_address, error_code);

-		if (need_unprotect && kvm_event_needs_reinjection(vcpu))

+		if (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);

--- a/arch/x86/kvm/mmu.h

+++ b/arch/x86/kvm/mmu.h

@@ -65,8 +65,7 @@

 			     bool accessed_dirty);

 bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu);

 int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,

-				u64 fault_address, char *insn, int insn_len,

-				bool need_unprotect);

+				u64 fault_address, char *insn, int insn_len);

 static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)

 {

--- a/arch/x86/kvm/svm.c

+++ b/arch/x86/kvm/svm.c

@@ -2140,7 +2140,18 @@

 	return kvm_handle_page_fault(&svm->vcpu, error_code, fault_address,

 			svm->vmcb->control.insn_bytes,

-			svm->vmcb->control.insn_len, !npt_enabled);

+			svm->vmcb->control.insn_len);

+}

+

+static int npf_interception(struct vcpu_svm *svm)

+{

+	u64 fault_address = svm->vmcb->control.exit_info_2;

+	u64 error_code = svm->vmcb->control.exit_info_1;

+

+	trace_kvm_page_fault(fault_address, error_code);

+	return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code,

+			svm->vmcb->control.insn_bytes,

+			svm->vmcb->control.insn_len);

 }

 static int db_interception(struct vcpu_svm *svm)

@@ -4127,7 +4138,7 @@

 	[SVM_EXIT_MONITOR]			= monitor_interception,

 	[SVM_EXIT_MWAIT]			= mwait_interception,

 	[SVM_EXIT_XSETBV]			= xsetbv_interception,

-	[SVM_EXIT_NPF]				= pf_interception,

+	[SVM_EXIT_NPF]				= npf_interception,

 	[SVM_EXIT_RSM]                          = emulate_on_interception,

 	[SVM_EXIT_AVIC_INCOMPLETE_IPI]		= avic_incomplete_ipi_interception,

 	[SVM_EXIT_AVIC_UNACCELERATED_ACCESS]	= avic_unaccelerated_access_interception,

--- a/arch/x86/kvm/vmx.c

+++ b/arch/x86/kvm/vmx.c

@@ -5881,8 +5881,7 @@

 		cr2 = vmcs_readl(EXIT_QUALIFICATION);

 		/* 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);

+		return kvm_handle_page_fault(vcpu, error_code, cr2, NULL, 0);

 	}

 	ex_no = intr_info & INTR_INFO_VECTOR_MASK;