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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1761135565; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=D7kgzKTYZ8ou97BveS1sALexRkahzseuftgDs0yDqws=; b=Y2qETNp5bqClgDjqUHyZedK7joUG0uBCsVKQGCiP2Q4RbhYULWFw8M8DIXMEZaRrxxNrUy AkhXmDjVe133x/6dFI4LgqFq5Y4dThkCWKjEZYg2NKT4S0kM04U2b6ZZZh0TTwF7WBdtaM Vi+C0ncYtkAZjW3+UeNSa9AbDLdSD6U= X-MC-Unique: z7F5lkEpNC2wGwz9Ajqrgw-1 X-Mimecast-MFC-AGG-ID: z7F5lkEpNC2wGwz9Ajqrgw_1761135562 From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: qemu-devel@nongnu.org Cc: Alex Williamson , John Levon , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Alex Williamson Subject: [PULL 12/12] vfio: only check region info cache for initial regions Date: Wed, 22 Oct 2025 14:18:46 +0200 Message-ID: <20251022121846.874152-13-clg@redhat.com> In-Reply-To: <20251022121846.874152-1-clg@redhat.com> References: <20251022121846.874152-1-clg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1761135710872154100 From: John Levon It is semantically valid for a VFIO device to increase the number of regions after initialization. In this case, we'd attempt to check for cached region info past the size of the ->reginfo array. Check for the region index and skip the cache in these cases. This also works around some VGPU use cases which appear to be a bug, where VFIO_DEVICE_QUERY_GFX_PLANE returns a region index beyond the reported ->num_regions. Fixes: 95cdb024 ("vfio: add region info cache") Signed-off-by: John Levon Reviewed-by: C=C3=A9dric Le Goater Reviewed-by: Alex Williamson Link: https://lore.kernel.org/qemu-devel/20251014151227.2298892-3-john.levo= n@nutanix.com Signed-off-by: C=C3=A9dric Le Goater --- hw/vfio/device.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/hw/vfio/device.c b/hw/vfio/device.c index 52079f4cf5bda7c1d9e6e3791a6c340a0e3f57ba..8b63e765acbacdccc5365d000e2= aa9bd49ae9701 100644 --- a/hw/vfio/device.c +++ b/hw/vfio/device.c @@ -205,10 +205,19 @@ int vfio_device_get_region_info(VFIODevice *vbasedev,= int index, int fd =3D -1; int ret; =20 - /* check cache */ - if (vbasedev->reginfo[index] !=3D NULL) { - *info =3D vbasedev->reginfo[index]; - return 0; + /* + * We only set up the region info cache for the initial number of regi= ons. + * + * Since a VFIO device may later increase the number of regions then u= se + * such regions with an index past ->num_initial_regions, don't attemp= t to + * use the info cache in those cases. + */ + if (index < vbasedev->num_initial_regions) { + /* check cache */ + if (vbasedev->reginfo[index] !=3D NULL) { + *info =3D vbasedev->reginfo[index]; + return 0; + } } =20 *info =3D g_malloc0(argsz); @@ -236,10 +245,12 @@ retry: goto retry; } =20 - /* fill cache */ - vbasedev->reginfo[index] =3D *info; - if (vbasedev->region_fds !=3D NULL) { - vbasedev->region_fds[index] =3D fd; + if (index < vbasedev->num_initial_regions) { + /* fill cache */ + vbasedev->reginfo[index] =3D *info; + if (vbasedev->region_fds !=3D NULL) { + vbasedev->region_fds[index] =3D fd; + } } =20 return 0; --=20 2.51.0