Handle pml in nested vmx

[Wincy Van <fanwenyi0529@xxxxxxxxx>]

I find that L2 can't boot in the kvm queue branch.
L0 KVM will inject a nested vmx exit reason 62 (EXIT_REASON_PML_FULL)
to L1, if L1 can't handle this exit reason, it will report a hardware error.

According to my test, both RHEL 6.x (kernel 2.6.32) and VirtualBox for Windows
will be affected by this bug.

Here is my workaround:

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 379087a..72784ac 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8135,6 +8135,8 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
                 * the XSS exit bitmap in vmcs12.
                 */
                return nested_cpu_has2(vmcs12, SECONDARY_EXEC_XSAVES);
+       case EXIT_REASON_PML_FULL:
+               return false;
        case EXIT_REASON_PREEMPTION_TIMER:
                return false;
        default:


If this patch applied, the bug seems to be fixed, but I can't ensure
that L0's pml is
working properly in this scene.

Is this patch doing the right thing (without implement nested pml)?

Thanks,
Wincy