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Tue, 14 Jul 2026 23:22:12 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav05.fra02v.mail.ibm.com (Postfix) with SMTP; Tue, 14 Jul 2026 23:22:12 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id 437E11626C4; Wed, 15 Jul 2026 01:22:12 +0200 (CEST) From: Eric Farman To: linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Rosato , Halil Pasic , Christian Borntraeger , Eric Farman , stable@vger.kernel.org Subject: [PATCH v1 6/6] s390/vfio_ccw: lock I/O resources alongside I/O regions Date: Wed, 15 Jul 2026 01:22:08 +0200 Message-ID: <20260714232208.1683788-7-farman@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260714232208.1683788-1-farman@linux.ibm.com> References: <20260714232208.1683788-1-farman@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzE0MDI0MCBTYWx0ZWRfX3T2hzZ5ZuHRS fa5ul8XyJISItb3qHjmBrVku8xkxX3rJi+131B/udsYUaF7bctX0ISVIf/VP822rEG8mYmoOfR3 WkJV2nNdmAg9/PXlZ+ptB3mCF5L6HoE= X-Proofpoint-GUID: -aIfqjlLJgtxEpBs-PbIy1JAf2pymKLe X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzE0MDI0MCBTYWx0ZWRfX60mjDU47PK4V LkiD/F+kGtgOGQV5gzz3h4vmLNx3akyzbw09KYXTv4PdzddEbUa2WA8ztBk4mPv7vtrzQIG0Pkw XLrzVk23N30CXFZ6lWeREBW0twhrce/AQBMh3EllrCIJrYpERfDKAEH6JNvRJkBc7PQhswxR3uj BMeEnjcnrIvDFSg/iO0VIwKIvLVJnGe/9vkeFUmQYQEp54E82oIOmHs6OsZUuDAO5i/3D3ladCL TW1be0qwdiOeHjk1cn5gKcU/1LXClNKk8W6knV/rRQhnzB+RCWuwhaDGJbryi70DgwjU8o0tZDg Z8TFzIgJ5mRypA9Tzs03fFvLGOwGX7YnW88etc9jDLIVSeoi/gOdPy6dkgcxIObezm3pRXY9dL5 XBnH3buWwNrBj7AXitKJpg5TKv/cDobr12w8ShLbB0g+qTrQ0j0/CsTumiNDopzxHORQ+oOacH7 M6m6vW/EUacX9QyP1Lg== X-Proofpoint-ORIG-GUID: -aIfqjlLJgtxEpBs-PbIy1JAf2pymKLe X-Authority-Analysis: v=2.4 cv=PvajqQM3 c=1 sm=1 tr=0 ts=6a56c4ab cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=KyaCFF8TlgOd3ial2BYA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-14_05,2026-07-14_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 bulkscore=0 impostorscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607140240 The memory regions shared with userspace for vfio-ccw operations are correctly accessed under a lock, but there are a handful of related structures that are associated with the same lifespan of a given SSCH (and thus the written-to memory region). Some of these cases are done asynchronously from the guest (e.g., hot-unplug of a device or channel path event), and so should be protected in some similar way. Since a subchannel can only have one I/O active at a time, redefine the I/O mutex from protecting the region, to all the resources associated with the I/O. Fixes: 4f76617378ee ("vfio-ccw: protect the I/O region") Cc: stable@vger.kernel.org Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_chp.c | 2 +- drivers/s390/cio/vfio_ccw_drv.c | 2 ++ drivers/s390/cio/vfio_ccw_fsm.c | 5 +++++ drivers/s390/cio/vfio_ccw_private.h | 2 +- 4 files changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_= chp.c index 38c176cf6295..872620a9488d 100644 --- a/drivers/s390/cio/vfio_ccw_chp.c +++ b/drivers/s390/cio/vfio_ccw_chp.c @@ -90,13 +90,13 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_c= cw_private *private, if (pos + count > sizeof(*region)) return -EINVAL; =20 + mutex_lock(&private->io_mutex); crw =3D list_first_entry_or_null(&private->crw, struct vfio_ccw_crw, next); =20 if (crw) list_del(&crw->next); =20 - mutex_lock(&private->io_mutex); region =3D private->region[i].data; =20 if (crw) diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_= drv.c index 1a095085bc72..385af7daca3b 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -292,7 +292,9 @@ static void vfio_ccw_queue_crw(struct vfio_ccw_privat= e *private, crw->crw.erc =3D erc; crw->crw.rsid =3D rsid; =20 + mutex_lock(&private->io_mutex); list_add_tail(&crw->next, &private->crw); + mutex_unlock(&private->io_mutex); queue_work(vfio_ccw_work_q, &private->crw_work); } =20 diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_= fsm.c index 4d7988ea47ef..96f23da88a39 100644 --- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -171,7 +171,9 @@ static void fsm_notoper(struct vfio_ccw_private *priv= ate, private->state =3D VFIO_CCW_STATE_NOT_OPER; =20 /* This is usually handled during CLOSE event */ + mutex_lock(&private->io_mutex); cp_free(&private->cp); + mutex_unlock(&private->io_mutex); } =20 /* @@ -410,7 +412,10 @@ static void fsm_close(struct vfio_ccw_private *priva= te, =20 private->state =3D VFIO_CCW_STATE_STANDBY; spin_unlock_irq(&sch->lock); + + mutex_lock(&private->io_mutex); cp_free(&private->cp); + mutex_unlock(&private->io_mutex); return; =20 err_unlock: diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_= ccw_private.h index 0501d4bbcdbd..8f3792fdd31b 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -88,7 +88,7 @@ struct vfio_ccw_parent { * @state: internal state of the device * @completion: synchronization helper of the I/O completion * @io_region: MMIO region to input/output I/O arguments/results - * @io_mutex: protect against concurrent update of I/O regions + * @io_mutex: protect against concurrent update of I/O resources * @region: additional regions for other subchannel operations * @cmd_region: MMIO region for asynchronous I/O commands other than STA= RT * @schib_region: MMIO region for SCHIB information --=20 2.53.0