From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4692C3D1AA2; Mon, 27 Jul 2026 19:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785181431; cv=none; b=aiE0E1+oz6H0hGJ8x8PA1xlmCQvvAUkC3b+0rRlifO7Xhbx+0SZ77wg645FQMbYLcsKAlHRR2skKuUUWqb0/Thay6bPCN4ZlwCvFpPaSAL2Uljvs4eOSnyQIyeB+OHMnm8kBmCrsCEWB/x0rIxyuWyzirGJSErUxRxD44hnAlN4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785181431; c=relaxed/simple; bh=ffnFhA3AiJ7Sh3cLiZNAA/z2Kg29Ywleux3RohIl54s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=utyPJwaV4WWnLQ1NHErhmg2RJkH0zUn2ULmT+VvmOmF3CdpF/TJiBG32aL+Sw+AWZ0RY08nsHJKe3SWRnXkTIlOT75bCitHwpU0STk+06MkmdcwNz0Z4ohb72qn5h+p7yubPMBTd6ZKKZeV+l/QSPIqpdHs8aCpqhmj42NEqgeg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=EGgmH9FT; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="EGgmH9FT" Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 66RIHagI2956896; Mon, 27 Jul 2026 19:43:49 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=I0KD+AE540ojdAz1S +BJRaOgj90Bwnu0DWJgE6VcGm0=; b=EGgmH9FTDbE/7AqD7SbW3+MM88ZcpCVEW XXOe/QHukjyxmQHbF7m+DjIdyk8WD4an+apL1RuzRUf4eFAcjPfIFtVrsUVaLUsv IcHBWHO8Kjh+IX8LaUhD8Tw1lGJRNTWHBMBpUX0+9nihTGBiHr+HviHTomm/tXjO wH5NRoZ0Q5Kca4qKBsvVH70onMIQeK2zkJAAxzCFCrnKv63EGlqV2e+j+kf6Lr21 TkH9kai5gElYnrR95LnNqaC47c/3D1IGOURQ+MSn+/korBwIBxCTJiPsiiZy2UXL YmdDpUFhf/S/VQalNlsIZSOEQs7VOwtj4ZBhgdKeEQPFJbkmrsFNw== Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fmuw79sx3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Jul 2026 19:43:49 +0000 (GMT) Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 66RJfJuj020964; Mon, 27 Jul 2026 19:43:48 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fna5xxghe-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Jul 2026 19:43:48 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 66RJhiA442205456 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 Jul 2026 19:43:44 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 39606200F4; Mon, 27 Jul 2026 19:22:37 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 12780200F1; Mon, 27 Jul 2026 19:22:37 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav05.fra02v.mail.ibm.com (Postfix) with SMTP; Mon, 27 Jul 2026 19:22:37 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id C9BAE162834; Mon, 27 Jul 2026 21:22:36 +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, Farhan Ali Subject: [PATCH v7 10/10] s390/vfio_ccw: implement a crw lock Date: Mon, 27 Jul 2026 21:22:30 +0200 Message-ID: <20260727192230.2715207-11-farman@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260727192230.2715207-1-farman@linux.ibm.com> References: <20260727192230.2715207-1-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-GUID: Me3m5IgpeDRkBqpSIpqrArg6zZtvwYFF X-Proofpoint-ORIG-GUID: Me3m5IgpeDRkBqpSIpqrArg6zZtvwYFF X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI3MDE3NyBTYWx0ZWRfX3khiTVrn8WbQ qqmf7np4iRAo9Tdrn/2azTtvy3a1V/2rlxmWZ0SVpjxe9li6Aaf8o8F7vEhwR9bp8Oy/lJ4N1mn TEBxmm3CZysZMKhyQqK9mDF1/YWux1uHLpgpqqb3ePBMWshn87FWDoi3F4tXRmu+wRKGreC+diP Q+LDGejpc5k8zD11VrrYWALZJCQn8ss9T92OWmj5kYNOa7cLqmlYpr33MCUJQ3HbC/ETNswVNrM ZE6yR+mTBw/xTrzjIfT0GaXASI+EzCIkgmykL52jKmN3Le8sg/ay5QZ/BkucZXwiUgkWFCh0WX7 Cm5OE9ALUTro6hJjHs16DktI3pNx1YNrttmNU0qlWyqaMX5jf6OwBa6wluc+Pg5fk0JK728vpln xi6A++VtMb+Lzer8C7pHHy1YJUGZPLM1eF3EfTpRzgdOcXNaD282lRqrX9jG4CYdj3iemHxnHva Uh8NhHwsAt50Zc6ikLg== X-Authority-Analysis: v=2.4 cv=SKFykuvH c=1 sm=1 tr=0 ts=6a67b4f5 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=huIa1HNm52ewcn7HQvQA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI3MDE3NyBTYWx0ZWRfX1jUtvKhDerMa San0TC3Fwl1n1zbPtVdhlraByaU0p+Cbs2yLRQvJjoiLTbe+pCs9lSawbfQoSG+tKHjwTzDQhv1 xwpVb2ex6Cyk8yC0okuJYk5y+HsUz7k= 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=2026-07-27_05,2026-07-27_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 phishscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607270177 Unlike the channel_program struct, which covers synchronous I/O submissions and asynchronous interrupts, the CRW region relies exclusively on asynchronous events coming from hardware. Implement a lock to manage the list of those payloads, to ensure they are read cohesively. Fixes: 3f02cb2fd9d2 ("vfio-ccw: Wire up the CRW irq and CRW region") Cc: stable@vger.kernel.org Cc: Farhan Ali Reviewed-by: Matthew Rosato Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_chp.c | 26 ++++++++++++++++---------- drivers/s390/cio/vfio_ccw_drv.c | 6 ++++++ drivers/s390/cio/vfio_ccw_ops.c | 4 ++++ drivers/s390/cio/vfio_ccw_private.h | 4 ++++ 4 files changed, 30 insertions(+), 10 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_= chp.c index 9269b54f5cfd..7708eb4d6de0 100644 --- a/drivers/s390/cio/vfio_ccw_chp.c +++ b/drivers/s390/cio/vfio_ccw_chp.c @@ -93,18 +93,13 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_c= cw_private *private, loff_t pos =3D *ppos & VFIO_CCW_OFFSET_MASK; struct ccw_crw_region *region; struct vfio_ccw_crw *crw; + unsigned long flags; int ret; =20 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); - - if (crw) - list_del(&crw->next); - if (i >=3D private->num_regions) { ret =3D -EINVAL; goto out; @@ -113,6 +108,16 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio_= ccw_private *private, i =3D array_index_nospec(i, private->num_regions); region =3D private->region[i].data; =20 + spin_lock_irqsave(&private->crw_lock, flags); + crw =3D list_first_entry_or_null(&private->crw, + struct vfio_ccw_crw, next); + + if (crw) + list_del(&crw->next); + + /* Drop CRW lock while copying to userspace */ + spin_unlock_irqrestore(&private->crw_lock, flags); + if (crw) memcpy(®ion->crw, &crw->crw, sizeof(region->crw)); =20 @@ -122,15 +127,16 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio= _ccw_private *private, ret =3D count; =20 region->crw =3D 0; - -out: - mutex_unlock(&private->io_mutex); - kfree(crw); =20 /* Notify the guest if more CRWs are on our queue */ + spin_lock_irqsave(&private->crw_lock, flags); if (!list_empty(&private->crw) && private->crw_trigger) eventfd_signal(private->crw_trigger); + spin_unlock_irqrestore(&private->crw_lock, flags); + +out: + mutex_unlock(&private->io_mutex); =20 return ret; } diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_= drv.c index 757ff5b2556e..ab6b518cc353 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -118,11 +118,14 @@ void vfio_ccw_sch_io_todo(struct work_struct *work) void vfio_ccw_crw_todo(struct work_struct *work) { struct vfio_ccw_private *private; + unsigned long flags; =20 private =3D container_of(work, struct vfio_ccw_private, crw_work); =20 + spin_lock_irqsave(&private->crw_lock, flags); if (!list_empty(&private->crw) && private->crw_trigger) eventfd_signal(private->crw_trigger); + spin_unlock_irqrestore(&private->crw_lock, flags); } =20 void vfio_ccw_notoper_todo(struct work_struct *work) @@ -286,6 +289,7 @@ static void vfio_ccw_queue_crw(struct vfio_ccw_privat= e *private, unsigned int rsid) { struct vfio_ccw_crw *crw; + unsigned long flags; =20 /* * If unable to allocate a CRW, just drop the event and @@ -303,7 +307,9 @@ static void vfio_ccw_queue_crw(struct vfio_ccw_privat= e *private, crw->crw.erc =3D erc; crw->crw.rsid =3D rsid; =20 + spin_lock_irqsave(&private->crw_lock, flags); list_add_tail(&crw->next, &private->crw); + spin_unlock_irqrestore(&private->crw_lock, flags); queue_work(vfio_ccw_work_q, &private->crw_work); } =20 diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_= ops.c index 8ec6b175d991..9cbb277b83fb 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -55,6 +55,7 @@ static int vfio_ccw_mdev_init_dev(struct vfio_device *v= dev) INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); INIT_WORK(&private->crw_work, vfio_ccw_crw_todo); INIT_WORK(&private->notoper_work, vfio_ccw_notoper_todo); + spin_lock_init(&private->crw_lock); =20 private->cp.guest_cp =3D kzalloc_objs(struct ccw1, CCWCHAIN_LEN_MAX); if (!private->cp.guest_cp) @@ -131,11 +132,14 @@ static void vfio_ccw_mdev_release_dev(struct vfio_d= evice *vdev) struct vfio_ccw_private *private =3D container_of(vdev, struct vfio_ccw_private, vdev); struct vfio_ccw_crw *crw, *temp; + unsigned long flags; =20 + spin_lock_irqsave(&private->crw_lock, flags); list_for_each_entry_safe(crw, temp, &private->crw, next) { list_del(&crw->next); kfree(crw); } + spin_unlock_irqrestore(&private->crw_lock, flags); =20 /* Should be empty, but just in case */ cancel_work_sync(&private->io_work); diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_= ccw_private.h index 739121116ab6..3bd0171d38d0 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -98,6 +98,8 @@ struct vfio_ccw_parent { * @cp: channel program for the current I/O operation * @irb: irb info received from interrupt * @scsw: scsw info + * @crw_lock: serialization of CRW list information + * @crw: list of Channel Report Word elements * @io_trigger: eventfd ctx for signaling userspace I/O results * @crw_trigger: eventfd ctx for signaling userspace CRW information * @req_trigger: eventfd ctx for signaling userspace to return device @@ -120,6 +122,8 @@ struct vfio_ccw_private { struct channel_program cp; struct irb irb; union scsw scsw; + + spinlock_t crw_lock; struct list_head crw; =20 struct eventfd_ctx *io_trigger; --=20 2.53.0