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, DOSBox 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; + /* * We can accept userspace's request for interrupt injection * as long as we have a place to store the interrupt number.
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.
linux-stable-mirror@lists.linaro.org
-
Paolo Bonzini -
stsp