From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 0DB833BED44; Mon, 20 Jul 2026 20:19:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784578780; cv=none; b=VUMhbkrJy8wCA6nhiA85Vmy/mJRTuaWrbZRRuqYAwe6jaK6ptNy79K2P6y4aYMHuOwW8qilnA4BIq9egVxLleZiC0OhnLgPfcTj65d7TyH5uhEOLB32RsJcEtdvWLz6S71xiEHFS1CTA0FRP9UgeG1kM3RQbrazGe4kL36JmcVQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784578780; c=relaxed/simple; bh=8VSyzjuUzleU0iRGjJve6wH14nf3NIylq6KFDRi7Pts=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qsgLYwPGfNNWVcOQh1wpyHvXzjtF1jMk+CjyNP3eAilWX86nI6rz+/NFfrQqfaijT3CKQpfAuyY5bTiccxtXo8+fBfoHULidXkHF9RmTi2iwB5+LntbBvLBeUZVIxdn0m2OXKG6bhvNrx1A2hqbTlDtHUre7TeFP55p2tmwdHKE= 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=WgXRw2yU; arc=none smtp.client-ip=148.163.158.5 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="WgXRw2yU" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 66KJfpBS3048287; Mon, 20 Jul 2026 20:19:38 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=v2JqUU5j29LMneLiB CEz5Bg4k1E+Q/v1XQ6xgPRubTM=; b=WgXRw2yUKH+f++NDvWWjRxnFYrf989QsS Zn5HeHsScfs5wBfK7coAJn2ElJFppH6BrdmyA0JJE6K/vnTOz30UR3ZF5rF/Ugkx YqFE7jzABGSHINjc/xQ1cHiWBT0DUecgVjt8eVl2yWophAETLhdaMnV9lvWb0c8h d2kaQxWPCOwGRlyXJYqJrLcrUNHa8IPeeHEmdqD+sGcRhwAvoYM6IIRoQR63yN57 iTXKURAMOPSjpaHHUkqRkaI2P5whh3jKgrMy1OwYRpOLJRIxlzc87RY0fuYhvGe7 52IJbbxb4md9pQWNWc/0DBnbNUyN1WaBTY8zZPdprvcec88Gicpfw== Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fg77k12b9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 20 Jul 2026 20:19:37 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 66KKJafR015412; Mon, 20 Jul 2026 20:19:36 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fgp1g7175-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 20 Jul 2026 20:19:36 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 66KKJXPL24248604 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 20 Jul 2026 20:19:33 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2DF362004B; Mon, 20 Jul 2026 20:19:33 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 09BCC20040; Mon, 20 Jul 2026 20:19:33 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with SMTP; Mon, 20 Jul 2026 20:19:32 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id C474B1627A8; Mon, 20 Jul 2026 22:19:32 +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 Subject: [PATCH v2 7/7] s390/vfio_ccw: implement a crw lock Date: Mon, 20 Jul 2026 22:19:31 +0200 Message-ID: <20260720201931.976660-8-farman@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260720201931.976660-1-farman@linux.ibm.com> References: <20260720201931.976660-1-farman@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=HJXz0Itv c=1 sm=1 tr=0 ts=6a5e82d9 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=nxvipetsQlNpnt3QvtcA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIwMDIyMCBTYWx0ZWRfX+bRrksT/Gcla UBqEFuEr/t6W2Y9778rbwLVIUUbEWryxZnzv1XBHaFgihFBLLIknAuv2JkjvhhYdZAopswL99S9 E09toGvc50GFASqXu8LcnYXCau5ZKVmoYHghzmror3241pPExkQw44Kd/8rjZR3IVCEhpVhiVrM Zu5sp0OtYuSGmi9524P8zTraDFI8UCItKCyz8g/uXwWEtTcwnk4ULWjEsWYns7HLtLtVX3xq5cQ ZT9HimG6GBngM7Pq7PU5lGmUAHUX8OZfBLC/cv1/YE7BT6nzhsReE+bs2h7AGCPgAvPgox6KPyB 75Bn13Sg//+g00jZaEQAsqUtx7EjcNP+S+ADSSMctaHwVSyGqaKWWiOQbEOvoxYVeaDlQ8pGotm NRWsjLgdvJR4MNuoNU+OHER6QCb9J8R7W70/r4gvBkaWzjgQUPs3FVPKPDvFiGha5gvknPZuhil mH7WhclihoOyO3oD0Rg== X-Proofpoint-ORIG-GUID: 8yBwNuoYJE_re-G1nK3Pd-cXXWI5w_Xr X-Proofpoint-Spam-Info: AW1haW4tMjYwNzIwMDIyMCBTYWx0ZWRfXxD5UKkBFkWWR MSR4Oiy8h3PVJkKWvvod5E02kLAr7aFBmxBLNywRb/BOOh/tB5pT8cVzil2YBjiB/3zUhWlNV1P r9jzryqccKeYUBeQa0vNJBe1mFWRuHc= X-Proofpoint-GUID: 8yBwNuoYJE_re-G1nK3Pd-cXXWI5w_Xr 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=2026-07-20_05,2026-07-20_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 malwarescore=0 impostorscore=0 clxscore=1015 phishscore=0 spamscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607200220 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. Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_chp.c | 15 ++++++++++----- drivers/s390/cio/vfio_ccw_drv.c | 4 ++++ drivers/s390/cio/vfio_ccw_ops.c | 3 +++ drivers/s390/cio/vfio_ccw_private.h | 2 ++ 4 files changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_chp.c b/drivers/s390/cio/vfio_ccw_= chp.c index 38c176cf6295..bbc445efd67f 100644 --- a/drivers/s390/cio/vfio_ccw_chp.c +++ b/drivers/s390/cio/vfio_ccw_chp.c @@ -90,14 +90,18 @@ 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); + region =3D private->region[i].data; + + spin_lock(&private->crw_lock); 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; + /* Drop CRW lock while copying to userspace */ + spin_unlock(&private->crw_lock); =20 if (crw) memcpy(®ion->crw, &crw->crw, sizeof(region->crw)); @@ -108,14 +112,15 @@ static ssize_t vfio_ccw_crw_region_read(struct vfio= _ccw_private *private, ret =3D count; =20 region->crw =3D 0; - - mutex_unlock(&private->io_mutex); - kfree(crw); =20 /* Notify the guest if more CRWs are on our queue */ + spin_lock(&private->crw_lock); if (!list_empty(&private->crw) && private->crw_trigger) eventfd_signal(private->crw_trigger); + spin_unlock(&private->crw_lock); + + 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 bfb68de6e52c..12edccb62cbf 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -125,8 +125,10 @@ void vfio_ccw_crw_todo(struct work_struct *work) =20 private =3D container_of(work, struct vfio_ccw_private, crw_work); =20 + spin_lock(&private->crw_lock); if (!list_empty(&private->crw) && private->crw_trigger) eventfd_signal(private->crw_trigger); + spin_unlock(&private->crw_lock); } =20 /* @@ -296,7 +298,9 @@ 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(&private->crw_lock); list_add_tail(&crw->next, &private->crw); + spin_unlock(&private->crw_lock); 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 d2475b3158cf..b3699ffd2f1d 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -60,6 +60,7 @@ 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); spin_lock_init(&private->cp_lock); + spin_lock_init(&private->crw_lock); =20 private->cp.guest_cp =3D kzalloc_objs(struct ccw1, CCWCHAIN_LEN_MAX); if (!private->cp.guest_cp) @@ -137,10 +138,12 @@ static void vfio_ccw_mdev_release_dev(struct vfio_d= evice *vdev) container_of(vdev, struct vfio_ccw_private, vdev); struct vfio_ccw_crw *crw, *temp; =20 + spin_lock(&private->crw_lock); list_for_each_entry_safe(crw, temp, &private->crw, next) { list_del(&crw->next); kfree(crw); } + spin_unlock(&private->crw_lock); =20 kmem_cache_free(vfio_ccw_crw_region, private->crw_region); kmem_cache_free(vfio_ccw_schib_region, private->schib_region); diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_= ccw_private.h index 061b594fde36..4a43609d6422 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -120,6 +120,8 @@ struct vfio_ccw_private { =20 struct irb irb; union scsw scsw; + + spinlock_t crw_lock; struct list_head crw; =20 struct eventfd_ctx *io_trigger; --=20 2.53.0