[PATCH 15/21] KVM: x86: Use kvm_queue_exception_e() to queue #DF

Sean Christopherson
2022-03-11T03:29:54Z

Queue #DF by recursing on kvm_multiple_exception() by way of
kvm_queue_exception_e() instead of open coding the behavior. This will
allow KVM to Just Work when a future commit moves exception interception
checks (for L2 => L1) into kvm_multiple_exception().

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/x86.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 74843767383c..d6fbff896263 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -669,25 +669,22 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
}
class1 = exception_class(prev_nr);
class2 = exception_class(nr);
- if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
- || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
+ if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY) ||
+ (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
/*
- * Generate double fault per SDM Table 5-5. Set
- * exception.pending = true so that the double fault
- * can trigger a nested vmexit.
+ * Synthesize #DF. Clear the previously injected or pending
+ * exception so as not to incorrectly trigger shutdown.
*/
- vcpu->arch.exception.pending = true;
vcpu->arch.exception.injected = false;
- vcpu->arch.exception.has_error_code = true;
- vcpu->arch.exception.vector = DF_VECTOR;
- vcpu->arch.exception.error_code = 0;
- vcpu->arch.exception.has_payload = false;
- vcpu->arch.exception.payload = 0;
- } else
+ vcpu->arch.exception.pending = false;
+
+ kvm_queue_exception_e(vcpu, DF_VECTOR, 0);
+ } else {
/* replace previous exception with a new one in a hope
that instruction re-execution will regenerate lost
exception */
goto queue;
+ }
}

void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
--
2.35.1.723.g4982287a31-goog