| Message ID | 20210727170620.1643969-1-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] KVM: x86: accept userspace interrupt only if no event is injected | expand |
On Tue, Jul 27, 2021, Paolo Bonzini wrote: > Once an exception has been injected, any side effects related to > the exception (such as setting CR2 or DR6) have been taked place. > Therefore, once KVM sets the VM-entry interruption information > field or the AMD EVENTINJ field, the next VM-entry must deliver that > exception. > > Pending interrupts are processed after injected exceptions, so > in theory it would not be a problem to use KVM_INTERRUPT when > an injected exception is present. However, DOSEMU is using > run->ready_for_interrupt_injection to detect interrupt windows > and then using KVM_SET_SREGS/KVM_SET_REGS to inject the > interrupt manually. For this to work, the interrupt window > must be delayed after the completion of the previous event > injection. > > Cc: stable@vger.kernel.org > Reported-by: Stas Sergeev <stsp2@yandex.ru> > Tested-by: Stas Sergeev <stsp2@yandex.ru> > Fixes: 71cc849b7093 ("KVM: x86: Fix split-irqchip vs interrupt injection window request") > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > (cherry picked from commit 043264d97e9ab74cc9661c8b1f9c00c8ce24cad9) ? I can't find 043264d97e9ab74cc9661c8b1f9c00c8ce24cad9 anywhere. > --- > arch/x86/kvm/x86.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 4116567f3d44..5e921f1e00db 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4358,8 +4358,18 @@ static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) > > static int kvm_vcpu_ready_for_interrupt_injection(struct kvm_vcpu *vcpu) > { > + /* > + * Do not cause an interrupt window exit if an exception > + * is pending or an event needs reinjection; userspace > + * might want to inject the interrupt manually using KVM_SET_REGS > + * or KVM_SET_SREGS. For that to work, we must be at an > + * instruction boundary and with no events half-injected. > + */ > return kvm_arch_interrupt_allowed(vcpu) && > - kvm_cpu_accept_dm_intr(vcpu); > + kvm_cpu_accept_dm_intr(vcpu) && Opportunistically align this indentation? > + !kvm_event_needs_reinjection(vcpu) Missing &&, apparently the mysterious cherry-pick didn't go so well :-) > + !vcpu->arch.exception.pending; > + > } > > static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, > -- > 2.27.0 >
On 27/07/21 22:58, Sean Christopherson wrote: >> --- >> arch/x86/kvm/x86.c | 12 +++++++++++- >> 1 file changed, 11 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 4116567f3d44..5e921f1e00db 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -4358,8 +4358,18 @@ static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) >> >> static int kvm_vcpu_ready_for_interrupt_injection(struct kvm_vcpu *vcpu) >> { >> + /* >> + * Do not cause an interrupt window exit if an exception >> + * is pending or an event needs reinjection; userspace >> + * might want to inject the interrupt manually using KVM_SET_REGS >> + * or KVM_SET_SREGS. For that to work, we must be at an >> + * instruction boundary and with no events half-injected. >> + */ >> return kvm_arch_interrupt_allowed(vcpu) && >> - kvm_cpu_accept_dm_intr(vcpu); >> + kvm_cpu_accept_dm_intr(vcpu) && > > Opportunistically align this indentation? Yep, good idea. >> + !kvm_event_needs_reinjection(vcpu) > > Missing &&, apparently the mysterious cherry-pick didn't go so well :-) Well, yeah. The only way I can excuse myself, is by not being the kind of person that yells for such stupid things... Paolo
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4116567f3d44..5e921f1e00db 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4358,8 +4358,18 @@ static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) static int kvm_vcpu_ready_for_interrupt_injection(struct kvm_vcpu *vcpu) { + /* + * Do not cause an interrupt window exit if an exception + * is pending or an event needs reinjection; userspace + * might want to inject the interrupt manually using KVM_SET_REGS + * or KVM_SET_SREGS. For that to work, we must be at an + * instruction boundary and with no events half-injected. + */ return kvm_arch_interrupt_allowed(vcpu) && - kvm_cpu_accept_dm_intr(vcpu); + kvm_cpu_accept_dm_intr(vcpu) && + !kvm_event_needs_reinjection(vcpu) + !vcpu->arch.exception.pending; + } static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,