kvm: x86: Add exception payload fields to kvm_vcpu_events
The per-VM capability KVM_CAP_EXCEPTION_PAYLOAD (to be introduced in a
later commit) adds the following fields to struct kvm_vcpu_events:
exception_has_payload, exception_payload, and exception.pending.
With this capability set, all of the details of vcpu->arch.exception,
including the payload for a pending exception, are reported to
userspace in response to KVM_GET_VCPU_EVENTS.
With this capability clear, the original ABI is preserved, and the
exception.injected field is set for either pending or injected
exceptions.
When userspace calls KVM_SET_VCPU_EVENTS with
KVM_CAP_EXCEPTION_PAYLOAD clear, exception.injected is no longer
translated to exception.pending. KVM_SET_VCPU_EVENTS can now only
establish a pending exception when KVM_CAP_EXCEPTION_PAYLOAD is set.
Reported-by: Jim Mattson <jmattson@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 532b660..2ef7065 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3373,19 +3373,33 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
struct kvm_vcpu_events *events)
{
process_nmi(vcpu);
+
/*
- * FIXME: pass injected and pending separately. This is only
- * needed for nested virtualization, whose state cannot be
- * migrated yet. For now we can combine them.
+ * The API doesn't provide the instruction length for software
+ * exceptions, so don't report them. As long as the guest RIP
+ * isn't advanced, we should expect to encounter the exception
+ * again.
*/
- events->exception.injected =
- (vcpu->arch.exception.pending ||
- vcpu->arch.exception.injected) &&
- !kvm_exception_is_soft(vcpu->arch.exception.nr);
+ if (kvm_exception_is_soft(vcpu->arch.exception.nr)) {
+ events->exception.injected = 0;
+ events->exception.pending = 0;
+ } else {
+ events->exception.injected = vcpu->arch.exception.injected;
+ events->exception.pending = vcpu->arch.exception.pending;
+ /*
+ * For ABI compatibility, deliberately conflate
+ * pending and injected exceptions when
+ * KVM_CAP_EXCEPTION_PAYLOAD isn't enabled.
+ */
+ if (!vcpu->kvm->arch.exception_payload_enabled)
+ events->exception.injected |=
+ vcpu->arch.exception.pending;
+ }
events->exception.nr = vcpu->arch.exception.nr;
events->exception.has_error_code = vcpu->arch.exception.has_error_code;
- events->exception.pad = 0;
events->exception.error_code = vcpu->arch.exception.error_code;
+ events->exception_has_payload = vcpu->arch.exception.has_payload;
+ events->exception_payload = vcpu->arch.exception.payload;
events->interrupt.injected =
vcpu->arch.interrupt.injected && !vcpu->arch.interrupt.soft;
@@ -3409,6 +3423,9 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
events->flags = (KVM_VCPUEVENT_VALID_NMI_PENDING
| KVM_VCPUEVENT_VALID_SHADOW
| KVM_VCPUEVENT_VALID_SMM);
+ if (vcpu->kvm->arch.exception_payload_enabled)
+ events->flags |= KVM_VCPUEVENT_VALID_PAYLOAD;
+
memset(&events->reserved, 0, sizeof(events->reserved));
}
@@ -3420,12 +3437,24 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
if (events->flags & ~(KVM_VCPUEVENT_VALID_NMI_PENDING
| KVM_VCPUEVENT_VALID_SIPI_VECTOR
| KVM_VCPUEVENT_VALID_SHADOW
- | KVM_VCPUEVENT_VALID_SMM))
+ | KVM_VCPUEVENT_VALID_SMM
+ | KVM_VCPUEVENT_VALID_PAYLOAD))
return -EINVAL;
- if (events->exception.injected &&
- (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR ||
- is_guest_mode(vcpu)))
+ if (events->flags & KVM_VCPUEVENT_VALID_PAYLOAD) {
+ if (!vcpu->kvm->arch.exception_payload_enabled)
+ return -EINVAL;
+ if (events->exception.pending)
+ events->exception.injected = 0;
+ else
+ events->exception_has_payload = 0;
+ } else {
+ events->exception.pending = 0;
+ events->exception_has_payload = 0;
+ }
+
+ if ((events->exception.injected || events->exception.pending) &&
+ (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR))
return -EINVAL;
/* INITs are latched while in SMM */
@@ -3435,13 +3464,13 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
return -EINVAL;
process_nmi(vcpu);
- vcpu->arch.exception.injected = false;
- vcpu->arch.exception.pending = events->exception.injected;
+ vcpu->arch.exception.injected = events->exception.injected;
+ vcpu->arch.exception.pending = events->exception.pending;
vcpu->arch.exception.nr = events->exception.nr;
vcpu->arch.exception.has_error_code = events->exception.has_error_code;
vcpu->arch.exception.error_code = events->exception.error_code;
- vcpu->arch.exception.has_payload = false;
- vcpu->arch.exception.payload = 0;
+ vcpu->arch.exception.has_payload = events->exception_has_payload;
+ vcpu->arch.exception.payload = events->exception_payload;
vcpu->arch.interrupt.injected = events->interrupt.injected;
vcpu->arch.interrupt.nr = events->interrupt.nr;