Re: [PATCH] KVM: arm64: vgic-debug: Don't put unmarked LPIs

Marc Zyngier
2024-08-17T10:25:45Z

On Sat, 17 Aug 2024 11:15:41 +0100,
Zenghui Yu <yuzenghui@huawei.com> wrote:
>
> If there were LPIs being mapped behind our back (i.e., between .start() and
> .stop()), we would put them at iter_unmark_lpis() without checking if they
> were actually *marked*, which is obviously not good.
>
> Switch to use the xa_for_each_marked() iterator to fix it.
>
> Fixes: 85d3ccc8b75b ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator")
> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
> ---
> arch/arm64/kvm/vgic/vgic-debug.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/vgic/vgic-debug.c b/arch/arm64/kvm/vgic/vgic-debug.c
> index bc74d06398ef..e1397ab2072a 100644
> --- a/arch/arm64/kvm/vgic/vgic-debug.c
> +++ b/arch/arm64/kvm/vgic/vgic-debug.c
> @@ -85,7 +85,7 @@ static void iter_unmark_lpis(struct kvm *kvm)
> struct vgic_irq *irq;
> unsigned long intid;
>
> - xa_for_each(&dist->lpi_xa, intid, irq) {
> + xa_for_each_marked(&dist->lpi_xa, intid, irq, LPI_XA_MARK_DEBUG_ITER) {
> xa_clear_mark(&dist->lpi_xa, intid, LPI_XA_MARK_DEBUG_ITER);
> vgic_put_irq(kvm, irq);
> }

Ouch. Nicely caught. I think this deserves a

Cc: stable@vger.kernel.org # v6.10

With that,

Reviewed-by: Marc Zyngier <maz@kernel.org>

Thanks,

M.

--
Without deviation from the norm, progress is not possible.