# Re: \[PATCH v10 5/9\] KVM: Use gfn instead of hva for mmu\_notifier\_retry

- From: Isaku Yamahata \<hidden\>
- Date: 2022-12-07 06:34:18 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2022/12/239762
- Thread: https://ratatoskr.run/kvm/2022/12/239625/t.md

```text
On Tue, Dec 06, 2022 at 07:56:23PM +0800,
Chao Peng [ref] wrote:

> > > -       if (unlikely(kvm->mmu_invalidate_in_progress) &&
> > > -           hva >= kvm->mmu_invalidate_range_start &&
> > > -           hva < kvm->mmu_invalidate_range_end)
> > > -               return 1;
> > > +       if (unlikely(kvm->mmu_invalidate_in_progress)) {
> > > +               /*
> > > +                * Dropping mmu_lock after bumping mmu_invalidate_in_progress
> > > +                * but before updating the range is a KVM bug.
> > > +                */
> > > +               if (WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA ||
> > > +                                kvm->mmu_invalidate_range_end == INVALID_GPA))
> > 
> > INVALID_GPA is an x86-specific define in
> > arch/x86/include/asm/kvm_host.h, so this doesn't build on other
> > architectures. The obvious fix is to move it to
> > include/linux/kvm_host.h.
> 
> Hmm, INVALID_GPA is defined as ZERO for x86, not 100% confident this is
> correct choice for other architectures, but after search it has not been
> used for other architectures, so should be safe to make it common.

INVALID_GPA is defined as all bit 1.  Please notice "~" (tilde).

#define INVALID_GPA (~(gpa_t)0)
-- 
Isaku Yamahata [ref]
```