Re: [PATCH v2 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE

Tao Xu
2019-05-29T02:27:40Z

On 29/05/2019 09:28, Paolo Bonzini wrote:
> On 24/05/19 09:56, Tao Xu wrote:
>> As the latest Intel 64 and IA-32 Architectures Software Developer's
>> Manual, UMWAIT and TPAUSE instructions cause a VM exit if the
>> “RDTSC exiting” and “enable user wait and pause” VM-execution controls
>> are both 1.
>>
>> This patch is to handle the vm-exit for UMWAIT and TPAUSE as invalid_op.
>
> KVM never enables RDTSC exiting, so this is not necessary.
>
> Paolo
>
OK, but should we just drop this patch?
Or add the VMX_EXIT_REASONS bits of UMWAIT and TPAUSE and handle like
XSAVES/XRSTORS:
"kvm_skip_emulated_instruction(vcpu);"
"WARN(1, "this should never happen\n");"

Looking forward to your reply.

Tao