Re: [PATCH 0/3] KVM: x86: Clean up RESET "emulation"

Sean Christopherson
2021-09-17T17:35:04Z

On Fri, Sep 17, 2021, Paolo Bonzini wrote:
> On Wed, Sep 15, 2021 at 1:08 AM Sean Christopherson <seanjc@google.com> wrote:
> > Add dedicated helpers to emulate RESET instead of having the relevant code
> > scattered through vcpu_create() and vcpu_reset(). Paolo, I think this is
> > what you meant by "have init_vmcb/svm_vcpu_reset look more like the VMX
> > code"[*].
> >
> > [*] https://lore.kernel.org/all/c3563870-62c3-897d-3148-e48bb755310c@redhat.com/
>
> That assumes that I remember what I meant :)

Ha! That's why I write changelogs with --verbose :-)

> but I do like it so yes, that was it. Especially the fact that init_vmcb now
> has a single caller. I would further consider moving save area initialization
> to *_vcpu_reset, and keeping the control fields in init_vmcb/vmcs. That would
> make it easier to relate the two functions to separate parts of the manuals.

I like the idea, but I think I'd prefer to tackle that at the same time as generic
support for handling MSRs at RESET/INIT. E.g. instead of manually writing
vmcs.GUEST_SYSENTER_* at RESET, provide infrastruture to automagically run through
all emulated/virtualized at RESET and/or INIT as appropriate to initialize the
guest value.