On Fri, May 31, 2024 at 12:11:33PM -0700, Oliver Upton wrote:
On Wed, May 29, 2024 at 06:05:09PM +0000, James Houghton wrote:
[...]
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 9e2bbee77491..eabb07c66a07 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1319,10 +1319,8 @@ static int stage2_age_walker(const struct kvm_pgtable_visit_ctx *ctx, data->young = true; /*
* stage2_age_walker() is always called while holding the MMU lock for* write, so this will always succeed. Nonetheless, this deliberately* follows the race detection pattern of the other stage-2 walkers in* case the locking mechanics of the MMU notifiers is ever changed.
* This walk may not be exclusive; the PTE is permitted to change* from under us.It is probably worth mentioning that if there was a race to update the PTE then the GFN is most likely young, so failing to clear AF probably isn't even consequential.
Oh, and the WARN_ON() in kvm_pgtable_stage2_test_clear_young() is bogus now. Maybe demote it to:
r = kvm_pgtable_walk(...); WARN_ON_ONCE(r && r != -EAGAIN);