Re: [kvm-unit-tests PATCH 7/7] x86: VMX: Add tests for nested "load IA32_PERF_GLOBAL_CTRL"

[Oliver Upton <oupton@google.com>]

On Thu, Aug 29, 2019 at 10:33:48AM -0700, Jim Mattson wrote:
> On Wed, Aug 28, 2019 at 4:41 PM Oliver Upton <oupton@google.com> wrote:
> >
> > Tests to verify that KVM performs the correct checks on Host/Guest state
> > at VM-entry, as described in SDM 26.3.1.1 "Checks on Guest Control
> > Registers, Debug Registers, and MSRs" and SDM 26.2.2 "Checks on Host
> > Control Registers and MSRs".
> >
> > Test that KVM does the following:
> >
> >     If the "load IA32_PERF_GLOBAL_CTRL" VM-entry control is 1, the
> >     reserved bits of the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the
> >     GUEST_IA32_PERF_GLOBAL_CTRL VMCS field. Otherwise, the VM-entry
> >     should fail with an exit reason of "VM-entry failure due to invalid
> >     guest state" (33).
> >
> >     If the "load IA32_PERF_GLOBAL_CTRL" VM-exit control is 1, the
> >     reserved bits of the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the
> >     HOST_IA32_PERF_GLOBAL_CTRL VMCS field. Otherwise, the VM-entry
> >     should fail with a VM-instruction error of "VM entry with invalid
> >     host-state field(s)" (8).
> 
> Could you add a simple functionality test as well? That is, after a
> successful nested VM-entry, the L2 guest should be able to observe the
> GUEST_IA32_PERF_GLOBAL_CTRL value when it reads the
> IA32_PERF_GLOBAL_CTRL MSR, and after a subsequent nested VM-exit, the
> L1 guest should be able to observe the HOST_IA32_PERF_GLOBAL_CTRL
> value when it reads the IA32_PERF_GLOBAL_CTRL MSR.

Definitely should. I think I can just add it as an additional check to
the common test code for host and guest tests, since we already have the
guest brought up and configured correctly anyway.

I have a couple style nits to correct in this patch as well. I'll add
this to the v2 I'm going to send out for the series.