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 2EAD7408635; Fri, 12 Jun 2026 18:10:59 +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=1781287862; cv=none; b=qaWuhbsa/qdX4a5SlqSbqDjtUnw0SpUFP5zxgxaJS84WyLVIL9XNmZW2b5uCKymnoDmruL1ig2hL1tqgFJGJ9GvIzhWaW1WsdNdCR12Ct3Niwhq6732NYnjEjpzEKpo8lmE9XGBqIoEbly9tMEHjk/Gagu0mKMESXuUV1HYDHZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781287862; c=relaxed/simple; bh=X7JoI+UTOag6Fvenxb27uYoaUdR1ZVKZkca26MhzwJg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JheINsRJaueFiIznJ8ZgiLGF2YVgJh8vslGFNleEABfDEvsOz2nBKcfKnmi4srxAo1OpBMxGJPB/gZeXw4EMGTKu4sppQrO2n+fU26GpQtMo0FUo91ax0k+FUk5QHwiVpXndVYKQI+f4UkmJNqudaI7IEnH0K4Ky2mu47QnR404= 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=aa4Sr2KR; 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="aa4Sr2KR" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 65CFCEbO1742531; Fri, 12 Jun 2026 18:10:57 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=7gM9eIB7jVJSrqa/i GDI7rSFFyVZ2GXsY/V4LWEaiNw=; b=aa4Sr2KRPHjD91yXVMKi4Hv6E8Bh/6PtO kY2Dx56Nug93ZgCf3Cc6RNg+UKLvi6rT/675KArw+kYLN9vNBcVGIg74bEJeLw/j nZCKbmUEAd/cAmNRccIxv/K1Hi0V1D5xeB3Q1dqPyF0xi0pvXZBy2q+1UW8XdFPB NNCS5L44iMHkyTdtqMcmQlIXIOez9sxmabr5Hhi3XyloPLLXlBDyXC8P3jNA7Pys rLbIxT6WM9aqvnL/Ex1cnEOsw4valZgMmNV/X6K37VkbCVmwSOcy1mDe2AwEm4vz 4GvyPLxdL31/Tfgvtqeo2t8d4LWuwypZjDOvSZ/oWuUdc7wGY868g== Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4eqe8bswdk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 12 Jun 2026 18:10:57 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 65CI4dnm016406; Fri, 12 Jun 2026 18:10:56 GMT Received: from smtprelay06.dal12v.mail.ibm.com ([172.16.1.8]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4eqe09s2j2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 12 Jun 2026 18:10:56 +0000 (GMT) Received: from smtpav04.dal12v.mail.ibm.com (smtpav04.dal12v.mail.ibm.com [10.241.53.103]) by smtprelay06.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 65CIAsOF28705426 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 12 Jun 2026 18:10:54 GMT Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 559F85805E; Fri, 12 Jun 2026 18:10:54 +0000 (GMT) Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 427595805A; Fri, 12 Jun 2026 18:10:53 +0000 (GMT) Received: from Mac.ibm.com (unknown [9.61.255.20]) by smtpav04.dal12v.mail.ibm.com (Postfix) with ESMTP; Fri, 12 Jun 2026 18:10:53 +0000 (GMT) From: Omar Elghoul To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: oelghoul@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, schnelle@linux.ibm.com, mjrosato@linux.ibm.com, alifm@linux.ibm.com, farman@linux.ibm.com, gbayer@linux.ibm.com, alex@shazbot.org Subject: [PATCH v4 3/4] vfio-pci/zdev: Add VFIO FMB device features Date: Fri, 12 Jun 2026 14:10:47 -0400 Message-ID: <20260612181048.91548-4-oelghoul@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260612181048.91548-1-oelghoul@linux.ibm.com> References: <20260612181048.91548-1-oelghoul@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: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=Xfa5Co55 c=1 sm=1 tr=0 ts=6a2c4bb1 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=o7ZLYlnJ96k-dGTR9YsA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjEyMDE2OSBTYWx0ZWRfX8m758jtOcptt r8eXxp16RTiqokRJFzHj3X3tdXgIrX45zRDvqa08Chd/Ddi4IYVgGiPwWxNt0M804XiX0SIrYV6 0MDE8DnJepEjZZbqstWXXTASAH+Oub3WqgMWqn4149f2IyxHuOmPzE1hnRHRVgyS2UjyS3O/geI oyZtiFaPH5EiW+qgQGBGyWKXL1DMqM+vyYdNHZOp+JaXbwnJOtVLHJt0pxdJSMiusRAaunNyi8b w8yuXlV/d/ohOLKV69QO4hwaCZzbq3Guh5QboRKQjIUpomEQyuG5AgM024qsU9JnX1BemvN+D89 i2gYcz+n+EqgsTB6Z69gEkI366SjgdK/UIM4qXbgCkcxqZrUqOnlWgkcqSqMHy1AyTzHWU2VLqn QaD1W2UWw1lZ+fihrq5S/Supe5RO5IdQnAyJ0UW0db0agxmrm7upj1En0X40D44UHeC6JSJzJbe ssVnFK8WIfHON/YQ1xQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwNjEyMDE2OSBTYWx0ZWRfX80ihRQcuU1rj HEfcozQkmBc7exzB1iHE66APL4KyTMXLfsm1800VAtXjAfRCZHu32rzW8Wj+fK6fnAZDQMLNX2p QsiD1+i3j/pUyI660d5qBRuW5okvHWI= X-Proofpoint-ORIG-GUID: g9HyAMrEZ0Ws53mKqkBjPxRKL_cLdxTA X-Proofpoint-GUID: g9HyAMrEZ0Ws53mKqkBjPxRKL_cLdxTA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-12_02,2026-06-12_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 suspectscore=0 clxscore=1015 phishscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606040000 definitions=main-2606120169 Introduce new VFIO features for zPCI devices to provide FMB passthrough to userspace. Allow the user to enable or disable the FMB using the SET-only feature VFIO_DEVICE_FEATURE_ZPCI_FMB_ENABLE. Likewise allow the user to read the latest FMB using the GET-only feature VFIO_DEVICE_FEATURE_ZPCI_FMB_READ in the case where the FMB is enabled. Additionally, when initializing the FMB kmem_cache, allow copy to userspace within the FMB's structure range. Signed-off-by: Omar Elghoul --- arch/s390/pci/pci.c | 8 ++++- drivers/vfio/pci/vfio_pci_core.c | 4 +++ drivers/vfio/pci/vfio_pci_priv.h | 18 +++++++++++ drivers/vfio/pci/vfio_pci_zdev.c | 55 ++++++++++++++++++++++++++++++++ include/uapi/linux/vfio.h | 29 +++++++++++++++++ 5 files changed, 113 insertions(+), 1 deletion(-) diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 21d3fccac789..104a924f8e4b 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -1134,8 +1134,14 @@ static int zpci_mem_init(void) BUILD_BUG_ON((CONFIG_ILLEGAL_POINTER_VALUE + 0x10000 > ZPCI_IOMAP_ADDR_BASE) && (CONFIG_ILLEGAL_POINTER_VALUE <= ZPCI_IOMAP_ADDR_MAX)); + struct kmem_cache_args fmb_cache_args = { + .align = __alignof__(struct zpci_fmb), + .useroffset = 0, + .usersize = sizeof(struct zpci_fmb) + }; + zdev_fmb_cache = kmem_cache_create("PCI_FMB_cache", sizeof(struct zpci_fmb), - __alignof__(struct zpci_fmb), 0, NULL); + &fmb_cache_args, 0); if (!zdev_fmb_cache) goto error_fmb; diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 050e7542952e..44e8e5526eae 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1569,6 +1569,10 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, return vfio_pci_core_feature_token(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_DMA_BUF: return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz); + case VFIO_DEVICE_FEATURE_ZPCI_FMB_ENABLE: + return vfio_pci_zdev_feature_fmb_enable(vdev, flags, arg, argsz); + case VFIO_DEVICE_FEATURE_ZPCI_FMB_READ: + return vfio_pci_zdev_feature_fmb_read(vdev, flags, arg, argsz); default: return -ENOTTY; } diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h index fca9d0dfac90..b7db064a6a95 100644 --- a/drivers/vfio/pci/vfio_pci_priv.h +++ b/drivers/vfio/pci/vfio_pci_priv.h @@ -93,6 +93,10 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev, struct vfio_info_cap *caps); int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev); void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev); +int vfio_pci_zdev_feature_fmb_enable(struct vfio_pci_core_device *vdev, u32 flags, + void __user *arg, size_t argsz); +int vfio_pci_zdev_feature_fmb_read(struct vfio_pci_core_device *vdev, u32 flags, + void __user *arg, size_t argsz); #else static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev, struct vfio_info_cap *caps) @@ -107,6 +111,20 @@ static inline int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev) static inline void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev) {} + +static inline int vfio_pci_zdev_feature_fmb_enable(struct vfio_pci_core_device *vdev, + u32 flags, void __user *arg, + size_t argsz) +{ + return -ENOTTY; +} + +static inline int vfio_pci_zdev_feature_fmb_read(struct vfio_pci_core_device *vdev, + u32 flags, void __user *arg, + size_t argsz) +{ + return -ENOTTY; +} #endif static inline bool vfio_pci_is_vga(struct pci_dev *pdev) diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c index 0990fdb146b7..ad1bcaf52ff2 100644 --- a/drivers/vfio/pci/vfio_pci_zdev.c +++ b/drivers/vfio/pci/vfio_pci_zdev.c @@ -167,3 +167,58 @@ void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev) if (zpci_kvm_hook.kvm_unregister) zpci_kvm_hook.kvm_unregister(zdev); } + +int vfio_pci_zdev_feature_fmb_enable(struct vfio_pci_core_device *vdev, u32 flags, + void __user *arg, size_t argsz) +{ + struct zpci_dev *zdev; + struct vfio_device_feature_zpci_fmb_enable fmb_enable; + int ret; + + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, sizeof(fmb_enable)); + if (ret != 1) + return ret; + + zdev = to_zpci(vdev->pdev); + if (!zdev) + return -ENODEV; + + if (copy_from_user(&fmb_enable, arg, sizeof(fmb_enable))) + return -EFAULT; + + guard(mutex)(&zdev->fmb_lock); + + if (fmb_enable.enabled) + return zpci_fmb_enable_device(zdev); + return zpci_fmb_disable_device(zdev); +} + +int vfio_pci_zdev_feature_fmb_read(struct vfio_pci_core_device *vdev, u32 flags, + void __user *arg, size_t argsz) +{ + struct zpci_dev *zdev; + struct vfio_device_feature_zpci_fmb_read fmb_read; + int ret; + + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET, sizeof(fmb_read)); + if (ret != 1) + return ret; + + zdev = to_zpci(vdev->pdev); + if (!zdev) + return -ENODEV; + + guard(mutex)(&zdev->fmb_lock); + + if (!zdev->fmb) + return -ENOMSG; + if (copy_from_user(&fmb_read, arg, sizeof(fmb_read))) + return -EFAULT; + if (!fmb_read.data) + return -EINVAL; + + if (copy_to_user((struct zpci_fmb __user *) fmb_read.data, zdev->fmb, zdev->fmb_length)) + return -EFAULT; + + return 0; +} diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 5de618a3a5ee..97e0f857fe4f 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1534,6 +1534,35 @@ struct vfio_device_feature_dma_buf { */ #define VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2 12 +/** + * Upon VFIO_DEVICE_FEATURE_SET, enable or disable FMB for the VFIO zPCI device. + * + * enabled is treated as a bool, so any non-zero value evaluates to true. This + * feature fails on attempt to double enable/disable. + * + * Returns: 0 on success, -1 and errno set appropriately on error. + */ +#define VFIO_DEVICE_FEATURE_ZPCI_FMB_ENABLE 13 + +struct vfio_device_feature_zpci_fmb_enable { + __u8 enabled; +}; + +/** + * Upon VFIO_DEVICE_FEATURE_GET, provide FMB passthrough for VFIO zPCI devices. + * + * The user-provided buffer must be at least fmb_length large, where fmb_length + * is reported in VFIO_DEVICE_INFO_CAP_ZPCI_BASE. + * + * Returns: 0 on success, -1 and errno set appropriately on error. errno==ENOMSG + * when the FMB is not enabled. + */ +#define VFIO_DEVICE_FEATURE_ZPCI_FMB_READ 14 + +struct vfio_device_feature_zpci_fmb_read { + __aligned_u64 data; +}; + /* -------- API for Type1 VFIO IOMMU -------- */ /** -- 2.54.0