Re: [PATCH v10 5/9] KVM: Use gfn instead of hva for mmu_notifier_retry

Isaku Yamahata
2022-12-07T06:34:17Z

On Tue, Dec 06, 2022 at 07:56:23PM +0800,
Chao Peng <chao.p.peng@linux.intel.com> 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 <isaku.yamahata@gmail.com>