Re: [PATCH 07/17] KVM: pfncache: Add guest-mode pinning (GUEST_USES_PFN successor)

[David Woodhouse]

On Sun, 2026-09-20 at 21:53 +0000, sashiko-bot@xxxxxxxxxx wrote:
> [Severity: Critical]
> Does the early skip condition in this loop fail to check for
> GPC_GUEST_USING?

No. GPC_GUEST_USING can only be set while GPC_VALID is, and whoever
clears GPC_VALID is responsible for kicking any vCPU that was using it
(and waiting). The vCPU can't re-enter guest mode without servicing
that kicked request, so can't re-pin without a full refresh.

> [Severity: Critical]
> does this zeroing of the state in kvm_gpc_deactivate() hide the
> GPC_GUEST_USING pin from concurrent invalidators?

It kicks any vCPU just like the normal invalidate path.

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