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Mon, 14 Sep 2026 12:17:16 +0000 (GMT) Received: from osiris (unknown [9.111.83.12]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Mon, 14 Sep 2026 12:17:16 +0000 (GMT) Date: Mon, 14 Sep 2026 14:17:15 +0200 From: Heiko Carstens To: Vineeth Vijayan Cc: wbezenah@linux.ibm.com, cohuck@redhat.com, pasic@linux.ibm.com, farman@linux.ibm.com, mjrosato@linux.ibm.com, oberpar@linux.ibm.com, linux-s390@vger.kernel.org Subject: Re: [PATCH 0/3] s390/cio: Harden pmcw/schib handling for dnv=0 Message-ID: <20260914121715.39845Ba0-hca@linux.ibm.com> References: <20260910093205.3357827-1-vneethv@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260910093205.3357827-1-vneethv@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTE0MDE3MSBTYWx0ZWRfX5Vd9Y8rPbDZZ iUgYQD7PUaFkbAdeem8bBImxEofhjBiO3cZ33cFtPUyQ1vNpZPMXO14lamq1RVc+I2EPMWVMCXp S+yVLbiT2NU3XXk3T1IZNRi6nuDD97i2zmdIn+UQt0CxOH4dMG8oUVXxbRaA8OdKELelxO3hghr 7TaaKDMWFsBRtKeIVFmLnGAY7rLnzF0zOIGDRPZst7+KgLFOKW3tl7ez2swla7ZxoXvRXliRhnQ 5nYKEMb6cCL38oBy4ntN4RazRLLpfoRDNrmQoHE/ePBSK/c5L6eY+OOC+HIzxMAOsdw/vEAM/+c dXoTVnhor5ctC68+8vaI9R0DADn4K9SIoX2bcBSE9wiZnfwgiJlihLn3SqxZ6TzD/A1iaEUmwXs 7pGwEXyRg0nyX9zPdmnURCRSfRNdN6SXlfCCSY1RBDHaer6SX5mZga60bXQNgZfXqfVxoROX11f Fny4XBIsC20eCDMx4aQ== X-Proofpoint-GUID: Omv19irjmql1phXwwOB7AqR6cZRqJDus X-Authority-Analysis: v=2.4 cv=DobDa2/+ c=1 sm=1 tr=0 ts=6aa7e5d1 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=8nJEP1OIZ-IA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=Dd6p6baFu_z_ejji7pMA:9 a=PRpDppDLrCsA:10 a=3ZKOabzyN94A:10 a=wPNLvfGTeEIA:10 X-Proofpoint-ORIG-GUID: Omv19irjmql1phXwwOB7AqR6cZRqJDus X-Proofpoint-Spam-Info: AW1haW4tMjYwOTE0MDE3MSBTYWx0ZWRfX36kYuD6ZKNI+ Z3sWnrVv1/GgntfZIGQVpo5WVJQXHECdTIQQKjZ0E/uelnT9GZy6LOQG1pu/KhRYjWK6wDRBVHy aOjfEgd0Blqv1QoQSTXrcJXe4aD1ask= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-14_03,2026-09-13_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 malwarescore=0 priorityscore=1501 suspectscore=0 impostorscore=0 spamscore=0 clxscore=1011 adultscore=0 bulkscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609140171 On Thu, Sep 10, 2026 at 11:32:00AM +0200, Vineeth Vijayan wrote: > For I/O subchannels, pmcw.dnv must be validated before relying on any > other PMCW or SCHIB fields. > Two issues exist today: > - Some I/O entry points check pmcw.ena without first verifying that > pmcw.dnv is set. > - cio_update_schib() updates the cached SCHIB before validating > pmcw.dnv, allowing an stsch result with dnv=0 to leave stale or > undefined data in sch->schib. >   > This can trigger spurious, non-fatal error messages in the guest kernel > log when a virtio device is being detached. >   > Fix this by validating pmcw.dnv before updating the cached SCHIB. Also > clear the cached SCHIB when stsch succeeds but returns dnv=0, ensuring > that stale state is not retained. >   > Additionally, add pmcw.dnv checks before pmcw.ena checks in I/O entry > points and return -ENODEV when no device is present. Guard remaining > direct accesses to cached PMCW fields, such as chpid[] and pam, to > ensure they are only evaluated when the SCHIB contents are valid. >   > This was reported and discussed at: >   > Link: https://lore.kernel.org/linux-s390/20260612155407.199218-1-wbezenah@linux.ibm.com/  > > Vineeth Vijayan (3): > s390/cio: Fix cio_update_schib() to not cache invalid schib > s390/cio: Check pmcw.dnv before pmcw.ena in I/O entry points > s390/cio: Guard PMCW field accesses with dnv check > > drivers/s390/cio/chp.c | 3 +++ > drivers/s390/cio/cio.c | 11 +++++++---- > drivers/s390/cio/device.c | 9 +++++---- > drivers/s390/cio/device_fsm.c | 3 +++ > drivers/s390/cio/device_ops.c | 21 +++++++++++++++++++++ > drivers/s390/cio/vfio_ccw_fsm.c | 2 +- > 6 files changed, 40 insertions(+), 9 deletions(-) What is supposed to happen with this series? Since none of the s390 maintainers were on to/cc I assume this is not supposed to go upstream and can be ignored?