Re: [PATCH v6 06/13] KVM: nVMX: optimize prepare_vmcs02{,_full} for Enlightened VMCS case

[Vitaly Kuznetsov]

Paolo Bonzini <pbonzini@xxxxxxxxxx> writes:

> On 17/10/2018 19:08, Jim Mattson wrote:
>> I believe that ESXi reads GUEST_CS_AR_BYTES on every VM-exit to
>> determine code size.
>
> Which makes me wonder, maybe we should add GUEST_SS_AR_BYTES which is
> where the CPL lives.  But then your tests from last year didn't find it.
>

Hyper-V does read GUEST_SS_AR_BYTES. Way less frequent than
GUEST_CS_AR_BYTES but still.

Based on that my suggestion would be to shadow GUEST_SS_AR_BYTES, keep
GUEST_SS_AR_BYTES and unshadow the rest (GUEST_ES_BASE,
GUEST_CS_SELECTOR, GUEST_CS_LIMIT, GUEST_CS_BASE). I can do this as a
separate patch as I see this series is already in kvm/queue.

-- 
Vitaly