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([2a01:e0a:f0e:9070:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49996109652sm166024305e9.4.2026.08.17.02.40.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Aug 2026 02:40:16 -0700 (PDT) Message-ID: <99991405-f05d-48c9-9f5f-42871d0714cc@redhat.com> Date: Mon, 17 Aug 2026 11:40:15 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] KVM: arm64: vgic-its: Reword the comment on a collection-less ITE Content-Language: en-US To: Fuad Tabba , Marc Zyngier , Oliver Upton Cc: Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Will Deacon , Sascha Bischoff , Sebastian Ene , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260817092705.1112634-1-fuad.tabba@linux.dev> From: Eric Auger In-Reply-To: <20260817092705.1112634-1-fuad.tabba@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/17/26 11:27 AM, Fuad Tabba wrote: > The comment above the NULL collection check in vgic_its_save_ite() > names only MAPC with V=0, which is UNPREDICTABLE. The route that > requires the check is clearing GITS_BASER.Valid on a disabled > ITS, a legitimate operation that orphans every ITE at once. Name both > routes. > > No functional change intended. > > Suggested-by: Eric Auger > Link: https://lore.kernel.org/all/0ce5e496-a067-48fd-80d2-94fe9981d505@redhat.com/ > Signed-off-by: Fuad Tabba Reviewed-by: Eric Auger Eric > --- > > Notes: > Based on kvmarm/next, since the comment this reworks was added by > c6c156d931c3 ("KVM: arm64: vgic-its: Don't dereference a NULL collection > on ITT save") and is not in a release yet. > > arch/arm64/kvm/vgic/vgic-its.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c > index f6538b1976f9b..26c665e0a2386 100644 > --- a/arch/arm64/kvm/vgic/vgic-its.c > +++ b/arch/arm64/kvm/vgic/vgic-its.c > @@ -2112,9 +2112,9 @@ static int vgic_its_save_ite(struct vgic_its *its, struct its_device *dev, > u64 val; > > /* > - * MAPC with V=0 keeps the ITEs mapped but drops their collection, > - * and with it the ICID. Save a zeroed entry, which the restore path > - * reads back as invalid. > + * MAPC with V=0 and clearing GITS_BASER.Valid both keep the > + * ITEs mapped while dropping their collection, and with it the ICID. > + * Save a zeroed entry, which the restore path reads back as invalid. > */ > if (!ite->collection) > return vgic_its_write_entry_lock(its, gpa, 0ULL, ite); > > base-commit: 57e7cf13ac26bf1a3dba6cfa601f7b2481811575