When async pagefault is resolved vCPU may be executing L2 guest.
In order to allow L1 take better scheduling decisions in such cases,
make L2 exit to L1 on a fake external interupt, without actually
injecting it (unless L2 has other reasons to vmexit).
This patch does that for x86/AMD.
Signed-off-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
---
Note 1: I didn't have a chance to test this; I'll do when I get access to an
AMD machine and let you know if anything goes wrong
Note 2: I mostly modelled this patch after the one for vmx but is looks not
very appealing for svm. I'd appreciate being pointed at a better location
where to stick the fake external interrupt vmexit.
arch/x86/kvm/svm.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8ca1eca..1f6ae15 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3723,6 +3723,15 @@ static int mwait_interception(struct vcpu_svm *svm)
return nop_interception(svm);
}
+static int svm_check_nested_events(struct kvm_vcpu *vcpu, bool external_intr)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (kvm_async_pf_has_ready(vcpu))
+ nested_svm_intr(svm);
+ return 0;
+}
+
enum avic_ipi_failure_cause {
AVIC_IPI_FAILURE_INVALID_INT_TYPE,
AVIC_IPI_FAILURE_TARGET_NOT_RUNNING,
@@ -5406,6 +5415,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.check_intercept = svm_check_intercept,
.handle_external_intr = svm_handle_external_intr,
+ .check_nested_events = svm_check_nested_events,
.sched_in = svm_sched_in,
--
2.9.3
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