From nobody Mon Feb 9 07:05:26 2026 Delivered-To: importer@patchew.org Received-SPF: temperror (zoho.com: Error in retrieving data from DNS) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=temperror (zoho.com: Error in retrieving data from DNS) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=intel.com ARC-Seal: i=1; a=rsa-sha256; t=1555663319; cv=none; d=zoho.com; s=zohoarc; b=ROR05kRtPFbGuE0ia1iHCI4UZWx8zBcxTR9WB7v99HCy4Tg85Egt3+TeyzOz/DsJ9oiwgsWNGo+mFNNDKJDqLHiF1p1OELDK/ffcHKDQT0kZqnBqjKUrmek71bQc1r28N9OpqPAY2LZOEwbBRtTi8omFnDRqgoS7guL4UxLC6uk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1555663319; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=CWdWBaKsM8UK0vRvK92dM2f6OzGa1ddE4i5fv0ivKMU=; b=fggLS9PD19Fon5E+q71jNgznqmnKyUE+3bwEs0/wztnJfPsz9Rn01k7G1oIlX69ykFByaUePlwskaJzhhrNi5pS4CKv4eooWHJNxbsNuT420ZkhVcUrJj+eXOGtkuy6QsFrPA18qo3xmvbKAdMJAXYIM7e/IfdxDjc39d3nSuk4= ARC-Authentication-Results: i=1; mx.zoho.com; spf=temperror (zoho.com: Error in retrieving data from DNS) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1555663319444959.7545388550506; Fri, 19 Apr 2019 01:41:59 -0700 (PDT) Received: from localhost ([127.0.0.1]:53405 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hHP5Y-0004cS-8g for importer@patchew.org; Fri, 19 Apr 2019 04:41:40 -0400 Received: from eggs.gnu.org ([209.51.188.92]:34198) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hHP4h-0004Go-Vr for qemu-devel@nongnu.org; Fri, 19 Apr 2019 04:40:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hHP4g-00046T-3g for qemu-devel@nongnu.org; Fri, 19 Apr 2019 04:40:47 -0400 Received: from mga06.intel.com ([134.134.136.31]:32085) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hHP4e-00045W-FK for qemu-devel@nongnu.org; Fri, 19 Apr 2019 04:40:44 -0400 Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Apr 2019 01:40:43 -0700 Received: from joy-optiplex-7040.sh.intel.com ([10.239.13.9]) by fmsmga005.fm.intel.com with ESMTP; 19 Apr 2019 01:40:38 -0700 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,368,1549958400"; d="scan'208";a="338990668" From: Yan Zhao To: intel-gvt-dev@lists.freedesktop.org Date: Fri, 19 Apr 2019 04:35:04 -0400 Message-Id: <20190419083505.19654-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190419083258.19580-1-yan.y.zhao@intel.com> References: <20190419083258.19580-1-yan.y.zhao@intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.31 Subject: [Qemu-devel] [PATCH 1/2] vfio/mdev: add version field as mandatory attribute for mdev device X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cjia@nvidia.com, kvm@vger.kernel.org, aik@ozlabs.ru, Zhengxiao.zx@alibaba-inc.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, kwankhede@nvidia.com, eauger@redhat.com, yi.l.liu@intel.com, eskultet@redhat.com, ziye.yang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, libvir-list@redhat.com, arei.gonglei@huawei.com, felipe@nutanix.com, Ken.Xue@amd.com, kevin.tian@intel.com, Yan Zhao , dgilbert@redhat.com, zhenyuw@linux.intel.com, alex.williamson@redhat.com, changpeng.liu@intel.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, zhi.a.wang@intel.com, jonathan.davies@nutanix.com, shaopeng.he@intel.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" device version attribute in mdev sysfs is used by user space software (e.g. libvirt) to query device compatibility for live migration of VFIO mdev devices. This attribute is mandatory if a mdev device supports live migration. It consists of two parts: common part and vendor proprietary part. common part: 32 bit. lower 16 bits is vendor id and higher 16 bits identifies device type. e.g., for pci device, it is "pci vendor id" | (VFIO_DEVICE_FLAGS_PCI << 16). vendor proprietary part: this part is varied in length. vendor driver can specify any string to identify a device. When reading this attribute, it should show device version string of the device of type . If a device does not support live migration, it should return errno. When writing a string to this attribute, it returns errno for incompatibility or returns written string length in compatibility case. If a device does not support live migration, it always returns errno. For user space software to use: 1. Before starting live migration, user space software first reads source side mdev device's version. e.g. "#cat \ /sys/bus/pci/devices/0000\:00\:02.0/5ac1fb20-2bbf-4842-bb7e-36c58c3be9cd/md= ev_type/version" 00028086-193b-i915-GVTg_V5_4 2. Then, user space software writes the source side returned version string to device version attribute in target side, and checks the return value. If a negative errno is returned in the target side, then mdev devices in source and target sides are not compatible; If a positive number is returned and it equals to the length of written string, then the two mdev devices in source and target side are compatible. e.g. (a) compatibility case "# echo 00028086-193b-i915-GVTg_V5_4 > /sys/bus/pci/devices/0000\:00\:02.0/882cc4da-dede-11e7-9180-078a62063ab1/md= ev_type/version" (b) incompatibility case "#echo 00028086-193b-i915-GVTg_V5_1 > /sys/bus/pci/devices/0000\:00\:02.0/882cc4da-dede-11e7-9180-078a62063ab1/md= ev_type/version" -bash: echo: write error: Invalid argument 3. if two mdev devices are compatible, user space software can start live migration, and vice versa. Note: if a mdev device does not support live migration, it either does not provide a version attribute, or always returns errno when its version attribute is read/written. Cc: Alex Williamson Cc: Erik Skultety Cc: "Dr. David Alan Gilbert" Cc: Cornelia Huck Cc: "Tian, Kevin" Cc: Zhenyu Wang Cc: "Wang, Zhi A" Cc: Neo Jia Cc: Kirti Wankhede Signed-off-by: Yan Zhao --- Documentation/vfio-mediated-device.txt | 36 ++++++++++++++++++++++++++ samples/vfio-mdev/mbochs.c | 17 ++++++++++++ samples/vfio-mdev/mdpy.c | 16 ++++++++++++ samples/vfio-mdev/mtty.c | 16 ++++++++++++ 4 files changed, 85 insertions(+) diff --git a/Documentation/vfio-mediated-device.txt b/Documentation/vfio-me= diated-device.txt index c3f69bcaf96e..bc28471c0667 100644 --- a/Documentation/vfio-mediated-device.txt +++ b/Documentation/vfio-mediated-device.txt @@ -202,6 +202,7 @@ Directories and files under the sysfs for Each Physical= Device | | |--- available_instances | | |--- device_api | | |--- description + | | |--- version | | |--- [devices] | |--- [] | | |--- create @@ -209,6 +210,7 @@ Directories and files under the sysfs for Each Physical= Device | | |--- available_instances | | |--- device_api | | |--- description + | | |--- version | | |--- [devices] | |--- [] | |--- create @@ -216,6 +218,7 @@ Directories and files under the sysfs for Each Physical= Device | |--- available_instances | |--- device_api | |--- description + | |--- version | |--- [devices] =20 * [mdev_supported_types] @@ -225,6 +228,8 @@ Directories and files under the sysfs for Each Physical= Device [], device_api, and available_instances are mandatory attributes that should be provided by vendor driver. =20 + version is a mandatory attribute if a mdev device supports live migratio= n. + * [] =20 The [] name is created by adding the device driver string as a = prefix @@ -246,6 +251,35 @@ Directories and files under the sysfs for Each Physica= l Device This attribute should show the number of devices of type that = can be created. =20 +* version + + This attribute is rw. It is used to check whether two devices are compat= ible + for live migration. If this attribute is missing, then the corresponding= mdev + device is regarded as not supporting live migration. + + It consists of two parts: common part and vendor proprietary part. + common part: 32 bit. lower 16 bits is vendor id and higher 16 bits ident= ifies + device type. e.g., for pci device, it is + "pci vendor id" | (VFIO_DEVICE_FLAGS_PCI << 16). + vendor proprietary part: this part is varied in length. vendor driver can + specify any string to identify a device. + + When reading this attribute, it should show device version string of the= device + of type . If a device does not support live migration, it should + return errno. + When writing a string to this attribute, it returns errno for incompatib= ility + or returns written string length in compatibility case. If a device does= not + support live migration, it always returns errno. + + for example. + # cat \ + /sys/bus/pci/devices/0000\:00\:02.0/mdev_supported_types/i915-GVTg_V5_2/v= ersion + 00028086-193b-i915-GVTg_V5_2 + + #echo 00028086-193b-i915-GVTg_V5_2 > \ + /sys/bus/pci/devices/0000\:00\:02.0/mdev_supported_types/i915-GVTg_V5_4/v= ersion + -bash: echo: write error: Invalid argument + * [device] =20 This directory contains links to the devices of type that have= been @@ -327,12 +361,14 @@ card. | | |-- available_instances | | |-- create | | |-- device_api + | | |-- version | | |-- devices | | `-- name | `-- mtty-2 | |-- available_instances | |-- create | |-- device_api + | |-- version | |-- devices | `-- name |-- mtty_dev diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index b038aa9f5a70..2f5ba96b91a2 100644 --- a/samples/vfio-mdev/mbochs.c +++ b/samples/vfio-mdev/mbochs.c @@ -1391,11 +1391,28 @@ static ssize_t device_api_show(struct kobject *kobj= , struct device *dev, } MDEV_TYPE_ATTR_RO(device_api); =20 +static ssize_t version_show(struct kobject *kobj, struct device *dev, + char *buf) +{ + /* do not support live migration */ + return -EINVAL; +} + +static ssize_t version_store(struct kobject *kobj, struct device *dev, + const char *buf, size_t count) +{ + /* do not support live migration */ + return -EINVAL; +} + +static MDEV_TYPE_ATTR_RW(version); + static struct attribute *mdev_types_attrs[] =3D { &mdev_type_attr_name.attr, &mdev_type_attr_description.attr, &mdev_type_attr_device_api.attr, &mdev_type_attr_available_instances.attr, + &mdev_type_attr_version.attr, NULL, }; =20 diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index cc86bf6566e4..ff15fdfc7d46 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -695,11 +695,27 @@ static ssize_t device_api_show(struct kobject *kobj, = struct device *dev, } MDEV_TYPE_ATTR_RO(device_api); =20 +static ssize_t version_show(struct kobject *kobj, struct device *dev, + char *buf) +{ + /* do not support live migration */ + return -EINVAL; +} + +static ssize_t version_store(struct kobject *kobj, struct device *dev, + const char *buf, size_t count) +{ + /* do not support live migration */ + return -EINVAL; +} +static MDEV_TYPE_ATTR_RW(version); + static struct attribute *mdev_types_attrs[] =3D { &mdev_type_attr_name.attr, &mdev_type_attr_description.attr, &mdev_type_attr_device_api.attr, &mdev_type_attr_available_instances.attr, + &mdev_type_attr_version.attr, NULL, }; =20 diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index 1c77c370c92f..4ae3aad3474d 100644 --- a/samples/vfio-mdev/mtty.c +++ b/samples/vfio-mdev/mtty.c @@ -1390,10 +1390,26 @@ static ssize_t device_api_show(struct kobject *kobj= , struct device *dev, =20 MDEV_TYPE_ATTR_RO(device_api); =20 +static ssize_t version_show(struct kobject *kobj, struct device *dev, + char *buf) +{ + /* do not support live migration */ + return -EINVAL; +} + +static ssize_t version_store(struct kobject *kobj, struct device *dev, + const char *buf, size_t count) +{ + /* do not support live migration */ + return -EINVAL; +} + +static MDEV_TYPE_ATTR_RW(version); static struct attribute *mdev_types_attrs[] =3D { &mdev_type_attr_name.attr, &mdev_type_attr_device_api.attr, &mdev_type_attr_available_instances.attr, + &mdev_type_attr_version.attr, NULL, }; =20 --=20 2.17.1