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Commit d0006530 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: SVM: limit kvm_handle_page_fault to #PF handling 



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: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1cf53587

arch/x86/kvm/mmu.c

+2 −3
Original line number Diff line number Diff line
@@ -3820,8 +3820,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, 
}



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 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, 
	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);

arch/x86/kvm/mmu.h

+1 −2
Original line number Diff line number Diff line
@@ -65,8 +65,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, 
			     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)

{

arch/x86/kvm/svm.c

+13 −2
Original line number Diff line number Diff line
@@ -2141,7 +2141,18 @@ static int pf_interception(struct vcpu_svm *svm) 


	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)
@@ -4128,7 +4139,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = { 
	[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,

arch/x86/kvm/vmx.c

+1 −2
Original line number Diff line number Diff line
@@ -5894,8 +5894,7 @@ static int handle_exception(struct kvm_vcpu *vcpu) 
		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;