Re: [PATCH 0/6] KVM: x86: KVM_SET_SREGS.CR4 bug fixes and cleanup

From: Sean Christopherson
Date: Thu Oct 08 2020 - 13:59:55 EST


On Thu, Oct 08, 2020 at 07:00:13PM +0300, stsp wrote:
> 07.10.2020 04:44, Sean Christopherson пишет:
> >Two bug fixes to handle KVM_SET_SREGS without a preceding KVM_SET_CPUID2.
> Hi Sean & KVM devs.
>
> I tested the patches, and wherever I
> set VMXE in CR4, I now get
> KVM: KVM_SET_SREGS: Invalid argument
> Before the patch I was able (with many
> problems, but still) to set VMXE sometimes.
>
> So its a NAK so far, waiting for an update. :)

IIRC, you said you were going to test on AMD? Assuming that's correct, -EINVAL
is the expected behavior. KVM was essentially lying before; it never actually
set CR4.VMXE in hardware, it just didn't properply detect the error and so VMXE
was set in KVM's shadow of the guest's CR4.