| Message ID | 20210714213846.854837-1-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: x86: accept userspace interrupt only if no event is injected | expand |
15.07.2021 00:38, Paolo Bonzini пишет: > Once an exception has been injected, any side effects related to > the exception (such as setting CR2 or DR6) have been taked "taken"? Probably a typo. > 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, DOSBox dosemu2 to be precise. > 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> > --- > arch/x86/kvm/x86.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index fe3aaf195292..7fbab29b3569 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4342,6 +4342,9 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu, > > static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) > { > + if (kvm_event_needs_reinjection(vcpu)) > + return false; > + kvm_event_needs_reinjection() seems to miss exception.pending check. Don't we need it too? Also perhaps a comment would be good to have to avoid it from disappearing again, as obviously kvm devs tend to overlook the possibility of injecting interrupts by hands.
On 16/07/21 09:27, stsp wrote: >> + if (kvm_event_needs_reinjection(vcpu)) >> + return false; >> + > > kvm_event_needs_reinjection() seems > to miss exception.pending check. > Don't we need it too? Yes, good point. Paolo
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fe3aaf195292..7fbab29b3569 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4342,6 +4342,9 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu, static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) { + if (kvm_event_needs_reinjection(vcpu)) + return false; + /* * We can accept userspace's request for interrupt injection * as long as we have a place to store the interrupt number.