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

[Paolo Bonzini]

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.

> > 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.

> Waiting for your comments on this patch...

I already commented that using bit 63 is not good, didn't I?

Paolo