Re: [PATCH v11 14/16] KVM: x86/vmx: Flip Arch LBREn bit on guest state change

[Yang, Weijiang]

On 5/17/2022 5:01 PM, Paolo Bonzini wrote:
> On 5/17/22 10:56, Yang, Weijiang wrote:
> > > I added more things to ease migration handling in SMM because: 1) qemu
> > > checks LBREn before transfer Arch LBR MSRs.
> I think it should always transfer them instead?  There's time to post a
> fixup patch.
OK, I'll send a fix patch.
> > > 2) Perf event is created when
> > > LBREn is being set.  Two things are not certain: 1) IA32_LBR_CTL doesn't have
> > > corresponding slot in SMRAM,not sure if we need to rely on it to transfer the MSR.
> > > I chose 0x7f10 as the offset(CET takes 0x7f08) for storage, need you double check if
> > > it's free or used.
> 0x7f10 sounds good.
>
> > Hi, Paolo,
> >
> > I found there're some rebase conflicts between this series and your kvm
> > queue branch due to PEBS patches, I can re-post a new version based on
> > your queue branch if necessary.
> Yes, please.
Sure, I'll post  v12 soon.
> > Waiting for your comments on this patch...
> I already commented that using bit 63 is not good, didn't I?
Clear :-D, thanks!
> Paolo