[10/13] KVM: x86: WARN on injected+pending exception even in nested case
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Message ID 20200423022550.15113-11-sean.j.christopherson@intel.com
State New
Headers show
Series
  • KVM: x86: Event fixes and cleanup
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Commit Message

Sean Christopherson April 23, 2020, 2:25 a.m. UTC
WARN if a pending exception is coincident with an injected exception
before calling check_nested_events() so that the WARN will fire even if
inject_pending_event() bails early because check_nested_events() detects
the conflict.  Bailing early isn't problematic (quite the opposite), but
suppressing the WARN is undesirable as it could mask a bug elsewhere in
KVM.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/x86.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Jim Mattson April 28, 2020, 10:05 p.m. UTC | #1
On Wed, Apr 22, 2020 at 7:26 PM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> WARN if a pending exception is coincident with an injected exception
> before calling check_nested_events() so that the WARN will fire even if
> inject_pending_event() bails early because check_nested_events() detects
> the conflict.  Bailing early isn't problematic (quite the opposite), but
> suppressing the WARN is undesirable as it could mask a bug elsewhere in
> KVM.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

Patch
diff mbox series

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6af873b7e0ae..7c49a7dc601f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7693,6 +7693,9 @@  static int inject_pending_event(struct kvm_vcpu *vcpu)
 			kvm_x86_ops.set_irq(vcpu);
 	}
 
+	WARN_ON_ONCE(vcpu->arch.exception.injected &&
+		     vcpu->arch.exception.pending);
+
 	/*
 	 * Call check_nested_events() even if we reinjected a previous event
 	 * in order for caller to determine if it should require immediate-exit
@@ -7711,7 +7714,6 @@  static int inject_pending_event(struct kvm_vcpu *vcpu)
 					vcpu->arch.exception.has_error_code,
 					vcpu->arch.exception.error_code);
 
-		WARN_ON_ONCE(vcpu->arch.exception.injected);
 		vcpu->arch.exception.pending = false;
 		vcpu->arch.exception.injected = true;