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Re: [PATCH] xen/arm: gic-v3: Preserve ARE_NS when disabling the distributor
- To: "Orzel, Michal" <michal.orzel@xxxxxxx>, Mykola Kvach <xakep.amatop@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- From: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
- Date: Mon, 25 May 2026 14:34:07 +0200
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- Cc: Luca Fancellu <luca.fancellu@xxxxxxx>, Mykola Kvach <mykola_kvach@xxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Mon, 25 May 2026 12:34:19 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 5/25/26 12:18 PM, Orzel, Michal wrote:
On 19-May-26 16:31, Mykola Kvach wrote:
From: Mykola Kvach <mykola_kvach@xxxxxxxx>
gicv3_dist_init() disables the distributor before reprogramming the
global interrupt state. It used to do this by writing 0 to GICD_CTLR.
On a system where firmware has already enabled Non-secure affinity
routing, a zero write clears the Non-secure view's GICD_CTLR.ARE_NS bit.
Arm IHI 0069H.b, section 2.3.3 ("Changing affinity routing enables"),
states that changing GICD_CTLR.ARE_NS from 1 to 0 is UNPREDICTABLE. The
GICD_CTLR register description in section 12.9.4 carries the same rule
for the ARE_NS field.
Preserve ARE_NS while clearing the group enable bits. If firmware left
ARE_NS clear, the value written is still 0, preserving the existing
initialization flow.
Fixes: bc183a0235e0 ("xen/arm: Add support for GIC v3")
Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
@Oleksii, can we ask for a release ack here?
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
Thanks.
~ Oleksii
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