Message ID | 20220822170659.2527086-4-pbonzini@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | KVM: x86: never write to memory from kvm_vcpu_check_block | expand |
On Mon, Aug 22, 2022 at 10:08 AM Paolo Bonzini <pbonzini@redhat.com> wrote: > > From: Sean Christopherson <seanjc@google.com> > > Set KVM_REQ_EVENT when MTF becomes pending to ensure that KVM will run > through inject_pending_event() and thus vmx_check_nested_events() prior > to re-entering the guest. > > MTF currently works by virtue of KVM's hack that calls > kvm_check_nested_events() from kvm_vcpu_running(), but that hack will > be removed in the near future. Until that call is removed, the patch > introduces no functional change. > > Fixes: 5ef8acbdd687 ("KVM: nVMX: Emulate MTF when performing instruction emulation") > Cc: stable@vger.kernel.org > Signed-off-by: Sean Christopherson <seanjc@google.com> > Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- What happens if live migration occurs before the KVM_REQ_EVENT is processed?
On 8/22/22 19:52, Jim Mattson wrote: > On Mon, Aug 22, 2022 at 10:08 AM Paolo Bonzini <pbonzini@redhat.com> wrote: >> >> From: Sean Christopherson <seanjc@google.com> >> >> Set KVM_REQ_EVENT when MTF becomes pending to ensure that KVM will run >> through inject_pending_event() and thus vmx_check_nested_events() prior >> to re-entering the guest. >> >> MTF currently works by virtue of KVM's hack that calls >> kvm_check_nested_events() from kvm_vcpu_running(), but that hack will >> be removed in the near future. Until that call is removed, the patch >> introduces no functional change. >> >> Fixes: 5ef8acbdd687 ("KVM: nVMX: Emulate MTF when performing instruction emulation") >> Cc: stable@vger.kernel.org >> Signed-off-by: Sean Christopherson <seanjc@google.com> >> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> --- > What happens if live migration occurs before the KVM_REQ_EVENT is processed? Good point, this must be squashed in: diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index ab135f9ef52f..a703b71d675d 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -6481,6 +6481,8 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, if (ret) goto error_guest_mode; + if (vmx->nested.mtf_pending) + kvm_make_request(KVM_REQ_EVENT, vcpu); return 0; error_guest_mode: so that the other side restores the request. Paolo
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index c9b49a09e6b5..d22e67ac1e69 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1659,10 +1659,12 @@ static void vmx_update_emulated_instruction(struct kvm_vcpu *vcpu) */ if (nested_cpu_has_mtf(vmcs12) && (!vcpu->arch.exception.pending || - vcpu->arch.exception.nr == DB_VECTOR)) + vcpu->arch.exception.nr == DB_VECTOR)) { vmx->nested.mtf_pending = true; - else + kvm_make_request(KVM_REQ_EVENT, vcpu); + } else { vmx->nested.mtf_pending = false; + } } static int vmx_skip_emulated_instruction(struct kvm_vcpu *vcpu)