On Thu, 2021-04-01 at 19:05 +0200, Paolo Bonzini wrote:
> On 01/04/21 16:38, Maxim Levitsky wrote:
> > Injected interrupts/nmi should not block a pending exception,
> > but rather be either lost if nested hypervisor doesn't
> > intercept the pending exception (as in stock x86), or be delivered
> > in exitintinfo/IDT_VECTORING_INFO field, as a part of a VMexit
> > that corresponds to the pending exception.
> >
> > The only reason for an exception to be blocked is when nested run
> > is pending (and that can't really happen currently
> > but still worth checking for).
> >
> > Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
>
> This patch would be an almost separate bugfix, right? I am going to
> queue this, but a confirmation would be helpful.
Yes, this patch doesn't depend on anything else.
Thanks!
Best regards,
Maxim Levitsky
>
> Paolo
>
> > ---
> > arch/x86/kvm/svm/nested.c | 8 +++++++-
> > arch/x86/kvm/vmx/nested.c | 10 ++++++++--
> > 2 files changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> > index 8523f60adb92..34a37b2bd486 100644
> > --- a/arch/x86/kvm/svm/nested.c
> > +++ b/arch/x86/kvm/svm/nested.c
> > @@ -1062,7 +1062,13 @@ static int svm_check_nested_events(struct kvm_vcpu
> > *vcpu)
> > }
> >
> > if (vcpu->arch.exception.pending) {
> > - if (block_nested_events)
> > + /*
> > + * Only a pending nested run can block a pending exception.
> > + * Otherwise an injected NMI/interrupt should either be
> > + * lost or delivered to the nested hypervisor in the EXITINTINFO
> > + * vmcb field, while delivering the pending exception.
> > + */
> > + if (svm->nested.nested_run_pending)
> > return -EBUSY;
> > if (!nested_exit_on_exception(svm))
> > return 0;
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index fd334e4aa6db..c3ba842fc07f 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -3806,9 +3806,15 @@ static int vmx_check_nested_events(struct kvm_vcpu
> > *vcpu)
> >
> > /*
> > * Process any exceptions that are not debug traps before MTF.
> > + *
> > + * Note that only a pending nested run can block a pending exception.
> > + * Otherwise an injected NMI/interrupt should either be
> > + * lost or delivered to the nested hypervisor in the IDT_VECTORING_INFO,
> > + * while delivering the pending exception.
> > */
> > +
> > if (vcpu->arch.exception.pending && !vmx_pending_dbg_trap(vcpu)) {
> > - if (block_nested_events)
> > + if (vmx->nested.nested_run_pending)
> > return -EBUSY;
> > if (!nested_vmx_check_exception(vcpu, &exit_qual))
> > goto no_vmexit;
> > @@ -3825,7 +3831,7 @@ static int vmx_check_nested_events(struct kvm_vcpu
> > *vcpu)
> > }
> >
> > if (vcpu->arch.exception.pending) {
> > - if (block_nested_events)
> > + if (vmx->nested.nested_run_pending)
> > return -EBUSY;
> > if (!nested_vmx_check_exception(vcpu, &exit_qual))
> > goto no_vmexit;
> >
