Re: [PATCH v4 09/26] KVM: Do processor compatibility check on resume

[Isaku Yamahata]

On Fri, Sep 09, 2022 at 10:15:16AM +0800,
Chao Gao <chao.gao@xxxxxxxxx> wrote:

> On Thu, Sep 08, 2022 at 04:25:25PM -0700, isaku.yamahata@xxxxxxxxx wrote:
> >From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> >
> >So far the processor compatibility check is not done on resume. It should
> >be done.  The resume is called for resuming from S3/S4.  CPUs can be
> >replaced or the kernel can resume from S4 on a different machine.  So
> 
> Are they valid cases handled by other kernel components? Trying to
> handle them in KVM only doesn't help as kernel is likely to fail
> somewhere else.

I guess no.  Actually without the compatibility check, kvm_resume() tries to
enable it by calling hardware_enable_nolock().  The real effect on error case of
this patch is to print out (potentially) more helpful message gracefully by
check_processor_compatibility instead of error message of haredware_enable.
-- 
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>