diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-06-20 14:13:33 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-03 16:14:38 +0200 |
| commit | d647eb63e67156fae44d2b467b1f314fc676de7a (patch) | |
| tree | bfafb564b7683a9b3955c05d9b54d3a941510369 /arch/x86/kvm/svm.c | |
| parent | c550505b57832936aebb5eb376375bc258f8a807 (diff) | |
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: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 5db50c19d1c7..5270711e787f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -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); |