Re: [PATCH 4/3] KVM: x86/xen: Make runstate cache gpcs share a lock

From: David Woodhouse
Date: Tue Jan 31 2023 - 11:58:56 EST


(resending from non-broken system)

On Mon, 2023-01-30 at 14:25 +0900, David Stevens wrote:
> From: David Stevens <stevensd@xxxxxxxxxxxx>
>
> Simplify locking in the case where the guest's runstate_info is split
> across two pages by sharing a single lock for the two gpcs.
>
> Signed-off-by: David Stevens <stevensd@xxxxxxxxxxxx>
> ---
> I tested this patch with xen_shinfo_test as suggested, and it still
> passes. I agree that it makes sense to do this as a seperate patch. For
> the bot reported issue, looks like I forgot to build with lockdep
> enabled. I'll fix the issue with that patch in the next revision of the
> series, so that there aren't any commits which don't build.

Ack. Running actual Xen guests also works (but it's the xen_shinfo_test
which is going to exercise cross-page runstate and is most
interesting).

Tested-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Reviewed-By: David Woodhouse <dwmw@xxxxxxxxxxxx>


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