Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ef54bcfe authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: skip writeback on injection of nested exception 



If a nested page fault happens during emulation, we will inject a vmexit,
not a page fault.  However because writeback happens after the injection,
we will write ctxt->eip from L2 into the L1 EIP.  We do not write back
if an instruction caused an interception vmexit---do the same for page
faults.

Suggested-by: default avatarGleb Natapov <gleb@kernel.org>
Reviewed-by: default avatarGleb Natapov <gleb@kernel.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5e352519

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -893,7 +893,6 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); 
int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,

			    gfn_t gfn, void *data, int offset, int len,

			    u32 access);

void kvm_propagate_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault);

bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);



static inline int __kvm_irq_line_state(unsigned long *irq_state,

arch/x86/kvm/x86.c

+10 −5
Original line number Diff line number Diff line
@@ -408,12 +408,14 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) 
}

EXPORT_SYMBOL_GPL(kvm_inject_page_fault);



void kvm_propagate_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)

static bool kvm_propagate_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault)

{

	if (mmu_is_nested(vcpu) && !fault->nested_page_fault)

		vcpu->arch.nested_mmu.inject_page_fault(vcpu, fault);

	else

		vcpu->arch.mmu.inject_page_fault(vcpu, fault);



	return fault->nested_page_fault;

}



void kvm_inject_nmi(struct kvm_vcpu *vcpu)
@@ -4929,16 +4931,18 @@ static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask) 
	}

}



static void inject_emulated_exception(struct kvm_vcpu *vcpu)

static bool inject_emulated_exception(struct kvm_vcpu *vcpu)

{

	struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;

	if (ctxt->exception.vector == PF_VECTOR)

		kvm_propagate_fault(vcpu, &ctxt->exception);

	else if (ctxt->exception.error_code_valid)

		return kvm_propagate_fault(vcpu, &ctxt->exception);



	if (ctxt->exception.error_code_valid)

		kvm_queue_exception_e(vcpu, ctxt->exception.vector,

				      ctxt->exception.error_code);

	else

		kvm_queue_exception(vcpu, ctxt->exception.vector);

	return false;

}



static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
@@ -5300,8 +5304,9 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, 
	}



	if (ctxt->have_exception) {

		inject_emulated_exception(vcpu);

		r = EMULATE_DONE;

		if (inject_emulated_exception(vcpu))

			return r;

	} else if (vcpu->arch.pio.count) {

		if (!vcpu->arch.pio.in) {

			/* FIXME: return into emulator if single-stepping.  */