Re: [PATCH] kvm: VMX: do not use vm-exit instruction length for fast MMIO

[David Hildenbrand <david@redhat.com>]

On 18.08.2017 14:35, Paolo Bonzini wrote:
> On 18/08/2017 13:57, David Hildenbrand wrote:
>> What about a hack:
>>
>> 1. clear instruction length when entering
>> 2. check if instruction length is set when trying to forward the RIP
>> 2a. if set, use it
>> 2b. if not set, compute it
> 
> It's undefined, so we don't know that the instruction length remains
> zero (also, on older processors and possibly some nested setups the
> field is read-only).

Oh I see, too bad :(

> 
> Testing the hypervisor bit is the first line of action.
> 
> Paolo


-- 

Thanks,

David