KVM: Fix simultaneous NMIs
If simultaneous NMIs happen, we're supposed to queue the second
and next (collapsing them), but currently we sometimes collapse
the second into the first.
Fix by using a counter for pending NMIs instead of a bool; since
the counter limit depends on whether the processor is currently
in an NMI handler, which can only be checked in vcpu context
(via the NMI mask), we add a new KVM_REQ_NMI to request recalculation
of the counter.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6ab4241..ab62711 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -413,8 +413,9 @@
u32 tsc_catchup_mult;
s8 tsc_catchup_shift;
- bool nmi_pending;
- bool nmi_injected;
+ atomic_t nmi_queued; /* unprocessed asynchronous NMIs */
+ unsigned nmi_pending; /* NMI queued after currently running handler */
+ bool nmi_injected; /* Trying to inject an NMI this entry */
struct mtrr_state_type mtrr_state;
u32 pat;