Re: [PATCH v5 0/2] MTE support for KVM guest

[Haibo Xu]

On Wed, 16 Dec 2020 at 18:23, Steven Price <steven.price@arm.com> wrote:
>
> On 16/12/2020 07:31, Haibo Xu wrote:
> [...]
> > Hi Steve,
>
> Hi Haibo
>
> > I have finished verifying the POC on a FVP setup, and the MTE test case can
> > be migrated from one VM to another successfully. Since the test case is very
> > simple which just maps one page with MTE enabled and does some memory
> > access, so I can't say it's OK for other cases.
>
> That's great progress.
>
> >
> > BTW, I noticed that you have sent out patch set v6 which mentions that 
> > mapping
> > all the guest memory with PROT_MTE was not feasible. So what's the plan for 
> > the
> > next step? Will new KVM APIs which can facilitate the tag store and recover 
> > be
> > available?
>
> I'm currently rebasing on top of the KASAN MTE patch series. My plan for
> now is to switch back to not requiring the VMM to supply PROT_MTE (so
> KVM 'upgrades' the pages as necessary) and I'll add an RFC patch on the
> end of the series to add an KVM API for doing bulk read/write of tags.
> That way the VMM can map guest memory without PROT_MTE (so device 'DMA'
> accesses will be unchecked), and use the new API for migration.
>

Great! Will have a try with the new API in my POC!

> Thanks,
>
> Steve