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

From: Tao Xu
Date: Tue May 28 2019 - 22:31:00 EST


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
âRDTSC exitingâ and âenable user wait and pauseâ 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