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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-427a5ef44b4sm138278325e9.42.2024.07.16.10.32.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Jul 2024 10:32:56 -0700 (PDT) Message-ID: Date: Tue, 16 Jul 2024 19:32:54 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 05/12] vfio/iommufd: Introduce auto domain creation Content-Language: en-US To: Joao Martins , qemu-devel@nongnu.org Cc: Yi Liu , Zhenzhong Duan , Alex Williamson , Cedric Le Goater , Jason Gunthorpe , Avihai Horon References: <20240712114704.8708-1-joao.m.martins@oracle.com> <20240712114704.8708-6-joao.m.martins@oracle.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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=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 7/16/24 18:44, Joao Martins wrote: > On 16/07/2024 17:04, Eric Auger wrote: >> Hi Joao, >> >> On 7/12/24 13:46, Joao Martins wrote: >>> There's generally two modes of operation for IOMMUFD: >>> >>> * The simple user API which intends to perform relatively simple things >>> with IOMMUs e.g. DPDK. It generally creates an IOAS and attach to VFIO >> It generally creates? can you explicit what is "it" >> > 'It' here refers to the process/API-user OK > >> I am confused by this automatic terminology again (not your fault). the doc says: >> " >> >> * >> >> Automatic domain - refers to an iommu domain created automatically >> when attaching a device to an IOAS object. This is compatible to the >> semantics of VFIO type1. >> >> * >> >> Manual domain - refers to an iommu domain designated by the user as >> the target pagetable to be attached to by a device. Though currently >> there are no uAPIs to directly create such domain, the datastructure >> and algorithms are ready for handling that use case. >> >> " >> >> >> in 1) the device is attached to the ioas id (using the auto domain if I am not wrong) >> Here you attach to an hwpt id. Isn't it a manual domain? >> > Correct. > > The 'auto domains' generally refers to the kernel-equivalent own automatic > attaching to a new pagetable. > > Here I call 'auto domains' in the userspace version too because we are doing the > exact same but from userspace, using the manual API in IOMMUFD. OK > >>> and mainly performs IOAS_MAP and UNMAP. >>> >>> * The native IOMMUFD API where you have fine grained control of the >>> IOMMU domain and model it accordingly. This is where most new feature >>> are being steered to. >>> >>> For dirty tracking 2) is required, as it needs to ensure that >>> the stage-2/parent IOMMU domain will only attach devices >>> that support dirty tracking (so far it is all homogeneous in x86, likely >>> not the case for smmuv3). Such invariant on dirty tracking provides a >>> useful guarantee to VMMs that will refuse incompatible device >>> attachments for IOMMU domains. >>> >>> Dirty tracking insurance is enforced via HWPT_ALLOC, which is >>> responsible for creating an IOMMU domain. This is contrast to the >>> 'simple API' where the IOMMU domain is created by IOMMUFD automatically >>> when it attaches to VFIO (usually referred as autodomains) but it has >>> the needed handling for mdevs. >>> >>> To support dirty tracking with the advanced IOMMUFD API, it needs >>> similar logic, where IOMMU domains are created and devices attached to >>> compatible domains. Essentially mimmicing kernel >>> iommufd_device_auto_get_domain(). With mdevs given there's no IOMMU domain >>> it falls back to IOAS attach. >>> >>> The auto domain logic allows different IOMMU domains to be created when >>> DMA dirty tracking is not desired (and VF can provide it), and others where >>> it is. Here is not used in this way here given how VFIODevice migration >> Here is not used in this way here ? >> > I meant, 'Here it is not used in this way given (...)' OK > >>> state is initialized after the device attachment. But such mixed mode of >>> IOMMU dirty tracking + device dirty tracking is an improvement that can >>> be added on. Keep the 'all of nothing' of type1 approach that we have >>> been using so far between container vs device dirty tracking. >>> >>> Signed-off-by: Joao Martins >>> --- >>> include/hw/vfio/vfio-common.h | 9 ++++ >>> include/sysemu/iommufd.h | 5 +++ >>> backends/iommufd.c | 30 +++++++++++++ >>> hw/vfio/iommufd.c | 82 +++++++++++++++++++++++++++++++++++ >>> backends/trace-events | 1 + >>> 5 files changed, 127 insertions(+) >>> >>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h >>> index 7419466bca92..2dd468ce3c02 100644 >>> --- a/include/hw/vfio/vfio-common.h >>> +++ b/include/hw/vfio/vfio-common.h >>> @@ -95,10 +95,17 @@ typedef struct VFIOHostDMAWindow { >>> >>> typedef struct IOMMUFDBackend IOMMUFDBackend; >>> >>> +typedef struct VFIOIOASHwpt { >>> + uint32_t hwpt_id; >>> + QLIST_HEAD(, VFIODevice) device_list; >>> + QLIST_ENTRY(VFIOIOASHwpt) next; >>> +} VFIOIOASHwpt; >>> + >>> typedef struct VFIOIOMMUFDContainer { >>> VFIOContainerBase bcontainer; >>> IOMMUFDBackend *be; >>> uint32_t ioas_id; >>> + QLIST_HEAD(, VFIOIOASHwpt) hwpt_list; >>> } VFIOIOMMUFDContainer; >>> >>> OBJECT_DECLARE_SIMPLE_TYPE(VFIOIOMMUFDContainer, VFIO_IOMMU_IOMMUFD); >>> @@ -135,6 +142,8 @@ typedef struct VFIODevice { >>> HostIOMMUDevice *hiod; >>> int devid; >>> IOMMUFDBackend *iommufd; >>> + VFIOIOASHwpt *hwpt; >>> + QLIST_ENTRY(VFIODevice) hwpt_next; >>> } VFIODevice; >>> >>> struct VFIODeviceOps { >>> diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h >>> index 57d502a1c79a..e917e7591d05 100644 >>> --- a/include/sysemu/iommufd.h >>> +++ b/include/sysemu/iommufd.h >>> @@ -50,6 +50,11 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id, >>> bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid, >>> uint32_t *type, void *data, uint32_t len, >>> uint64_t *caps, Error **errp); >>> +bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id, >>> + uint32_t pt_id, uint32_t flags, >>> + uint32_t data_type, uint32_t data_len, >>> + void *data_ptr, uint32_t *out_hwpt, >>> + Error **errp); >>> >>> #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd" >>> #endif >>> diff --git a/backends/iommufd.c b/backends/iommufd.c >>> index 2b3d51af26d2..5d3dfa917415 100644 >>> --- a/backends/iommufd.c >>> +++ b/backends/iommufd.c >>> @@ -208,6 +208,36 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id, >>> return ret; >>> } >>> >>> +bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id, >>> + uint32_t pt_id, uint32_t flags, >>> + uint32_t data_type, uint32_t data_len, >>> + void *data_ptr, uint32_t *out_hwpt, >>> + Error **errp) >>> +{ >>> + int ret, fd = be->fd; >>> + struct iommu_hwpt_alloc alloc_hwpt = { >>> + .size = sizeof(struct iommu_hwpt_alloc), >>> + .flags = flags, >>> + .dev_id = dev_id, >>> + .pt_id = pt_id, >>> + .data_type = data_type, >>> + .data_len = data_len, >>> + .data_uptr = (uint64_t)data_ptr, >>> + }; >>> + >>> + ret = ioctl(fd, IOMMU_HWPT_ALLOC, &alloc_hwpt); >>> + trace_iommufd_backend_alloc_hwpt(fd, dev_id, pt_id, flags, data_type, >>> + data_len, (uint64_t)data_ptr, >>> + alloc_hwpt.out_hwpt_id, ret); >>> + if (ret) { >>> + error_setg_errno(errp, errno, "Failed to allocate hwpt"); >>> + return false; >>> + } >>> + >>> + *out_hwpt = alloc_hwpt.out_hwpt_id; >>> + return true; >>> +} >>> + >>> bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid, >>> uint32_t *type, void *data, uint32_t len, >>> uint64_t *caps, Error **errp) >>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c >>> index 077dea8f1b64..325c7598d5a1 100644 >>> --- a/hw/vfio/iommufd.c >>> +++ b/hw/vfio/iommufd.c >>> @@ -212,10 +212,86 @@ static bool iommufd_cdev_detach_ioas_hwpt(VFIODevice *vbasedev, Error **errp) >>> return true; >>> } >>> >>> +static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev, >>> + VFIOIOMMUFDContainer *container, >>> + Error **errp) >>> +{ >>> + IOMMUFDBackend *iommufd = vbasedev->iommufd; >>> + uint32_t flags = 0; >>> + VFIOIOASHwpt *hwpt; >>> + uint32_t hwpt_id; >>> + int ret; >>> + >>> + /* Try to find a domain */ >>> + QLIST_FOREACH(hwpt, &container->hwpt_list, next) { >>> + ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id, errp); >>> + if (ret) { >>> + /* -EINVAL means the domain is incompatible with the device. */ >>> + if (ret == -EINVAL) { >>> + /* >>> + * It is an expected failure and it just means we will try >>> + * another domain, or create one if no existing compatible >>> + * domain is found. Hence why the error is discarded below. >>> + */ >>> + error_free(*errp); >>> + *errp = NULL; >>> + continue; >>> + } >>> + >>> + return false; >>> + } else { >>> + vbasedev->hwpt = hwpt; >>> + QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); >>> + return true; >>> + } >>> + } >>> + >>> + if (!iommufd_backend_alloc_hwpt(iommufd, vbasedev->devid, >>> + container->ioas_id, flags, >>> + IOMMU_HWPT_DATA_NONE, 0, NULL, >>> + &hwpt_id, errp)) { >>> + return false; >>> + } >>> + >>> + hwpt = g_malloc0(sizeof(*hwpt)); >>> + hwpt->hwpt_id = hwpt_id; >>> + QLIST_INIT(&hwpt->device_list); >>> + >>> + ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id, errp); >>> + if (ret) { >>> + iommufd_backend_free_id(container->be, hwpt->hwpt_id); >>> + g_free(hwpt); >>> + return false; >>> + } >>> + >>> + vbasedev->hwpt = hwpt; >>> + QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); >>> + QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next); >>> + return true; >>> +} >>> + >>> +static void iommufd_cdev_autodomains_put(VFIODevice *vbasedev, >>> + VFIOIOMMUFDContainer *container) >>> +{ >>> + VFIOIOASHwpt *hwpt = vbasedev->hwpt; >>> + >>> + QLIST_REMOVE(vbasedev, hwpt_next); >> don't you want to reset vbasedev->hwpt = NULL too? >> > Yeap, Thanks for catching that > >>> + if (QLIST_EMPTY(&hwpt->device_list)) { >>> + QLIST_REMOVE(hwpt, next); >>> + iommufd_backend_free_id(container->be, hwpt->hwpt_id); >>> + g_free(hwpt); >>> + } >>> +} >>> + >>> static bool iommufd_cdev_attach_container(VFIODevice *vbasedev, >>> VFIOIOMMUFDContainer *container, >>> Error **errp) >>> { >>> + /* mdevs aren't physical devices and will fail with auto domains */ >>> + if (!vbasedev->mdev) { >>> + return iommufd_cdev_autodomains_get(vbasedev, container, errp); >>> + } >>> + >>> return !iommufd_cdev_attach_ioas_hwpt(vbasedev, container->ioas_id, errp); >>> } >>> >>> @@ -224,6 +300,11 @@ static void iommufd_cdev_detach_container(VFIODevice *vbasedev, >>> { >>> Error *err = NULL; >>> >>> + if (vbasedev->hwpt) { >>> + iommufd_cdev_autodomains_put(vbasedev, container); >>> + return; >> Where do we detach the device from the hwpt? >> > In iommufd_backend_free_id() for auto domains Hum I see iommufd_backend_free_id frees the object. I guess the detach then is done on kernel side... Eric > >> Thanks >> >> Eric >>> + } >>> + >>> if (!iommufd_cdev_detach_ioas_hwpt(vbasedev, &err)) { >>> error_report_err(err); >>> } >>> @@ -354,6 +435,7 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev, >>> container = VFIO_IOMMU_IOMMUFD(object_new(TYPE_VFIO_IOMMU_IOMMUFD)); >>> container->be = vbasedev->iommufd; >>> container->ioas_id = ioas_id; >>> + QLIST_INIT(&container->hwpt_list); >>> >>> bcontainer = &container->bcontainer; >>> vfio_address_space_insert(space, bcontainer); >>> diff --git a/backends/trace-events b/backends/trace-events >>> index 211e6f374adc..4d8ac02fe7d6 100644 >>> --- a/backends/trace-events >>> +++ b/backends/trace-events >>> @@ -14,4 +14,5 @@ iommufd_backend_map_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size >>> iommufd_backend_unmap_dma_non_exist(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, int ret) " Unmap nonexistent mapping: iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" (%d)" >>> iommufd_backend_unmap_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, int ret) " iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" (%d)" >>> iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas) " iommufd=%d ioas=%d" >>> +iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, uint32_t flags, uint32_t hwpt_type, uint32_t len, uint64_t data_ptr, uint32_t out_hwpt_id, int ret) " iommufd=%d dev_id=%u pt_id=%u flags=0x%x hwpt_type=%u len=%u data_ptr=0x%"PRIx64" out_hwpt=%u (%d)" >>> iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d (%d)"