[PATCH v12 54/84] KVM: arm64: Mark "struct page" pfns accessed/dirty before dropping mmu_lock

Marc Zyngier maz at kernel.org
Tue Aug 6 01:55:22 PDT 2024


On Tue, 06 Aug 2024 00:26:54 +0100,
Oliver Upton <oliver.upton at linux.dev> wrote:
> 
> On Mon, Aug 05, 2024 at 11:26:03PM +0000, Oliver Upton wrote:
> > [+cc Fuad]
> 
> Take 2!
> 
> > Fuad, you mentioned in commit 9c30fc615daa ("KVM: arm64: Move setting
> > the page as dirty out of the critical section") that restructuring
> > around the MMU lock was helpful for reuse (presumably for pKVM), but I
> > lack the context there.
> > 
> > On Fri, Jul 26, 2024 at 04:52:03PM -0700, Sean Christopherson wrote:
> > > Mark pages/folios accessed+dirty prior to dropping mmu_lock, as marking a
> > > page/folio dirty after it has been written back can make some filesystems
> > > unhappy (backing KVM guests will such filesystem files is uncommon, and
> > 
> > typo: s/will/with/
> > 
> > > the race is minuscule, hence the lack of complaints).  See the link below
> > > for details.

Should we consider reverting 9c30fc615daa then?

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.



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