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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id a5-20020a0cb345000000b006588bd29c7esm1814713qvf.28.2023.09.27.05.22.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 27 Sep 2023 05:22:49 -0700 (PDT) Message-ID: Date: Wed, 27 Sep 2023 14:22:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device Content-Language: en-US To: "Duan, Zhenzhong" , "qemu-devel@nongnu.org" Cc: "alex.williamson@redhat.com" , "clg@redhat.com" , "jgg@nvidia.com" , "nicolinc@nvidia.com" , "Martins, Joao" , "peterx@redhat.com" , "jasowang@redhat.com" , "Tian, Kevin" , "Liu, Yi L" , "Sun, Yi Y" , "Peng, Chao P" References: <20230926113255.1177834-1-zhenzhong.duan@intel.com> <20230926113255.1177834-7-zhenzhong.duan@intel.com> From: Eric Auger In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.473, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: eric.auger@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 9/27/23 12:07, Duan, Zhenzhong wrote: > Hi Eric, > >> -----Original Message----- >> From: Eric Auger >> Sent: Wednesday, September 27, 2023 5:02 PM >> Subject: Re: [PATCH v2 06/12] vfio/pci: Introduce vfio_[attach/detach]_device >> >> Hi Zhenzhong, >> >> On 9/26/23 13:32, Zhenzhong Duan wrote: >>> From: Eric Auger >>> >>> We want the VFIO devices to be able to use two different >>> IOMMU backends, the legacy VFIO one and the new iommufd one. >>> >>> Introduce vfio_[attach/detach]_device which aim at hiding the >>> underlying IOMMU backend (IOCTLs, datatypes, ...). >>> >>> Once vfio_attach_device completes, the device is attached >>> to a security context and its fd can be used. Conversely >>> When vfio_detach_device completes, the device has been >>> detached from the security context. >>> >>> At the moment only the implementation based on the legacy >>> container/group exists. Let's use it from the vfio-pci device. >>> Subsequent patches will handle other devices. >>> >>> Signed-off-by: Eric Auger >>> Signed-off-by: Yi Liu >>> Signed-off-by: Zhenzhong Duan >>> --- >>> include/hw/vfio/vfio-common.h | 3 ++ >>> hw/vfio/common.c | 68 +++++++++++++++++++++++++++++++++++ >>> hw/vfio/pci.c | 50 +++----------------------- >>> hw/vfio/trace-events | 2 +- >>> 4 files changed, 77 insertions(+), 46 deletions(-) >>> >>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h >>> index c4e7c3b4a7..12fbfbc37d 100644 >>> --- a/include/hw/vfio/vfio-common.h >>> +++ b/include/hw/vfio/vfio-common.h >>> @@ -225,6 +225,9 @@ void vfio_put_group(VFIOGroup *group); >>> struct vfio_device_info *vfio_get_device_info(int fd); >>> int vfio_get_device(VFIOGroup *group, const char *name, >>> VFIODevice *vbasedev, Error **errp); >>> +int vfio_attach_device(char *name, VFIODevice *vbasedev, >>> + AddressSpace *as, Error **errp); >>> +void vfio_detach_device(VFIODevice *vbasedev); >>> >>> int vfio_kvm_device_add_fd(int fd, Error **errp); >>> int vfio_kvm_device_del_fd(int fd, Error **errp); >>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >>> index 959b1362bb..7f3798b152 100644 >>> --- a/hw/vfio/common.c >>> +++ b/hw/vfio/common.c >>> @@ -2611,3 +2611,71 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op) >>> } >>> return vfio_eeh_container_op(container, op); >>> } >>> + >>> +static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp) >>> +{ >>> + char *tmp, group_path[PATH_MAX], *group_name; >>> + int ret, groupid; >>> + ssize_t len; >>> + >>> + tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev); >>> + len = readlink(tmp, group_path, sizeof(group_path)); >>> + g_free(tmp); >>> + >>> + if (len <= 0 || len >= sizeof(group_path)) { >>> + ret = len < 0 ? -errno : -ENAMETOOLONG; >>> + error_setg_errno(errp, -ret, "no iommu_group found"); >>> + return ret; >>> + } >>> + >>> + group_path[len] = 0; >>> + >>> + group_name = basename(group_path); >>> + if (sscanf(group_name, "%d", &groupid) != 1) { >>> + error_setg_errno(errp, errno, "failed to read %s", group_path); >>> + return -errno; >>> + } >>> + return groupid; >>> +} >>> + >>> +int vfio_attach_device(char *name, VFIODevice *vbasedev, >>> + AddressSpace *as, Error **errp) >>> +{ >>> + int groupid = vfio_device_groupid(vbasedev, errp); >>> + VFIODevice *vbasedev_iter; >>> + VFIOGroup *group; >>> + int ret; >>> + >>> + if (groupid < 0) { >>> + return groupid; >>> + } >>> + >>> + trace_vfio_attach_device(vbasedev->name, groupid); >>> + >>> + group = vfio_get_group(groupid, as, errp); >>> + if (!group) { >>> + return -ENOENT; >>> + } >>> + >>> + QLIST_FOREACH(vbasedev_iter, &group->device_list, next) { >>> + if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) { >>> + error_setg(errp, "device is already attached"); >>> + vfio_put_group(group); >>> + return -EBUSY; >>> + } >>> + } >>> + ret = vfio_get_device(group, name, vbasedev, errp); >>> + if (ret) { >>> + vfio_put_group(group); >>> + } >>> + >>> + return ret; >>> +} >>> + >>> +void vfio_detach_device(VFIODevice *vbasedev) >>> +{ >>> + VFIOGroup *group = vbasedev->group; >>> + >>> + vfio_put_base_device(vbasedev); >>> + vfio_put_group(group); >>> +} >>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c >>> index 3b2ca3c24c..fe56789893 100644 >>> --- a/hw/vfio/pci.c >>> +++ b/hw/vfio/pci.c >>> @@ -2828,10 +2828,10 @@ static void vfio_populate_device(VFIOPCIDevice >> *vdev, Error **errp) >>> static void vfio_put_device(VFIOPCIDevice *vdev) >>> { >>> + vfio_detach_device(&vdev->vbasedev); >>> + >>> g_free(vdev->vbasedev.name); >>> g_free(vdev->msix); >>> - >>> - vfio_put_base_device(&vdev->vbasedev); >>> } >>> >>> static void vfio_err_notifier_handler(void *opaque) >>> @@ -2978,13 +2978,9 @@ static void vfio_realize(PCIDevice *pdev, Error >> **errp) >>> { >>> VFIOPCIDevice *vdev = VFIO_PCI(pdev); >>> VFIODevice *vbasedev = &vdev->vbasedev; >>> - VFIODevice *vbasedev_iter; >>> - VFIOGroup *group; >>> - char *tmp, *subsys, group_path[PATH_MAX], *group_name; >>> + char *tmp, *subsys; >>> Error *err = NULL; >>> - ssize_t len; >>> struct stat st; >>> - int groupid; >>> int i, ret; >>> bool is_mdev; >>> char uuid[UUID_FMT_LEN]; >>> @@ -3015,39 +3011,6 @@ static void vfio_realize(PCIDevice *pdev, Error >> **errp) >>> vbasedev->type = VFIO_DEVICE_TYPE_PCI; >>> vbasedev->dev = DEVICE(vdev); >>> >>> - tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev); >>> - len = readlink(tmp, group_path, sizeof(group_path)); >>> - g_free(tmp); >>> - >>> - if (len <= 0 || len >= sizeof(group_path)) { >>> - error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG, >>> - "no iommu_group found"); >>> - goto error; >>> - } >>> - >>> - group_path[len] = 0; >>> - >>> - group_name = basename(group_path); >>> - if (sscanf(group_name, "%d", &groupid) != 1) { >>> - error_setg_errno(errp, errno, "failed to read %s", group_path); >>> - goto error; >>> - } >>> - >>> - trace_vfio_realize(vbasedev->name, groupid); >>> - >>> - group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), >> errp); >>> - if (!group) { >>> - goto error; >>> - } >>> - >>> - QLIST_FOREACH(vbasedev_iter, &group->device_list, next) { >>> - if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) { >>> - error_setg(errp, "device is already attached"); >>> - vfio_put_group(group); >>> - goto error; >>> - } >>> - } >>> - >>> /* >>> * Mediated devices *might* operate compatibly with discarding of RAM, but >>> * we cannot know for certain, it depends on whether the mdev vendor >> driver >>> @@ -3065,7 +3028,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) >>> if (vbasedev->ram_block_discard_allowed && !is_mdev) { >>> error_setg(errp, "x-balloon-allowed only potentially compatible " >>> "with mdev devices"); >>> - vfio_put_group(group); >>> goto error; >>> } >>> >>> @@ -3076,10 +3038,10 @@ static void vfio_realize(PCIDevice *pdev, Error >> **errp) >>> name = g_strdup(vbasedev->name); >>> } >>> >>> - ret = vfio_get_device(group, name, vbasedev, errp); >>> + ret = vfio_attach_device(name, vbasedev, >>> + pci_device_iommu_address_space(pdev), errp); >>> g_free(name); >>> if (ret) { >>> - vfio_put_group(group); >> independently on this patch, I think in case of error we leak >> vbasedev->name. Please have a look and if confirmed you can send a >> separate patch. > In case of error, vbasedev->name is freed in vfio_put_device(). called in vfio_instance_finalize only. See comment below > >> Also I think if any subsequent action fail we shoudl properly detach the >> detach the device so introduce an extra error goto label, my bad sorry. > vfio_detach_device is called in vfio_instance_finalize(), this is just to follow > the old code, group and container resource allocated in vfio_realize() are > freed in vfio_instance_finalize(). > > I agree this is strange, but I guess there may be some reason I'm unclear. Yeah but if vfio_realize does fail, I am not sure the vfio_instance_finalize gets called Eric > > Thanks > Zhenzhong >