Commit d647eb63 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: svm: add nrips module parameter 



Allow testing code for old processors that lack the next RIP save
feature, by disabling usage of the next_rip field.

Nested hypervisors however get the feature unconditionally.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c550505b

arch/x86/kvm/svm.c

+12 −3
Original line number Diff line number Diff line
@@ -367,6 +367,10 @@ static int avic; 
module_param(avic, int, S_IRUGO);

#endif



/* enable/disable Next RIP Save */

static int nrips = true;

module_param(nrips, int, 0444);



/* enable/disable Virtual VMLOAD VMSAVE */

static int vls = true;

module_param(vls, int, 0444);
@@ -773,7 +777,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu) 
{

	struct vcpu_svm *svm = to_svm(vcpu);



	if (svm->vmcb->control.next_rip != 0) {

	if (nrips && svm->vmcb->control.next_rip != 0) {

		WARN_ON_ONCE(!static_cpu_has(X86_FEATURE_NRIPS));

		svm->next_rip = svm->vmcb->control.next_rip;

	}
@@ -810,7 +814,7 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu) 


	kvm_deliver_exception_payload(&svm->vcpu);



	if (nr == BP_VECTOR && !static_cpu_has(X86_FEATURE_NRIPS)) {

	if (nr == BP_VECTOR && !nrips) {

		unsigned long rip, old_rip = kvm_rip_read(&svm->vcpu);



		/*
@@ -1367,6 +1371,11 @@ static __init int svm_hardware_setup(void) 
	} else

		kvm_disable_tdp();



	if (nrips) {

		if (!boot_cpu_has(X86_FEATURE_NRIPS))

			nrips = false;

	}



	if (avic) {

		if (!npt_enabled ||

		    !boot_cpu_has(X86_FEATURE_AVIC) ||
@@ -3938,7 +3947,7 @@ static int rdpmc_interception(struct vcpu_svm *svm) 
{

	int err;



	if (!static_cpu_has(X86_FEATURE_NRIPS))

	if (!nrips)

		return emulate_on_interception(svm);



	err = kvm_rdpmc(&svm->vcpu);