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([2a01:e0a:280:24f0:9db0:474c:ff43:9f5c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4266f74462esm25222095e9.48.2024.07.08.23.50.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 08 Jul 2024 23:50:37 -0700 (PDT) Message-ID: <6b5f84b5-134c-4507-84aa-5086f20f6eaa@redhat.com> Date: Tue, 9 Jul 2024 08:50:36 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 04/10] vfio/iommufd: Introduce auto domain creation To: Joao Martins , qemu-devel@nongnu.org Cc: Yi Liu , Eric Auger , Zhenzhong Duan , Alex Williamson , Jason Gunthorpe , Avihai Horon References: <20240708143420.16953-1-joao.m.martins@oracle.com> <20240708143420.16953-5-joao.m.martins@oracle.com> Content-Language: en-US, fr From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= In-Reply-To: <20240708143420.16953-5-joao.m.martins@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.142, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 7/8/24 4:34 PM, 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 > 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(). If this fails (i.e. mdevs) it falls back > to IOAS attach (which again is always the case for mdevs). > > 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 > 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' 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 | 4 ++ > backends/iommufd.c | 29 +++++++++++ > hw/vfio/iommufd.c | 91 +++++++++++++++++++++++++++++++++++ > backends/trace-events | 1 + > 5 files changed, 134 insertions(+) > > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h > index e8ddf92bb185..82c5a4aaa61e 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); > @@ -134,6 +141,8 @@ 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..35a8cec9780f 100644 > --- a/include/sysemu/iommufd.h > +++ b/include/sysemu/iommufd.h > @@ -50,6 +50,10 @@ 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); > +int 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); > > #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd" > #endif > diff --git a/backends/iommufd.c b/backends/iommufd.c > index 2b3d51af26d2..f5f73eaf4a1a 100644 > --- a/backends/iommufd.c > +++ b/backends/iommufd.c > @@ -208,6 +208,35 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id, > return ret; > } > > +int 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) > +{ > + 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) { > + ret = -errno; > + error_report("IOMMU_HWPT_ALLOC failed: %m"); Please add an 'Error **errp' parameter. > + } else { > + *out_hwpt = alloc_hwpt.out_hwpt_id; > + } > + return ret; > +} > + > 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 5a5993b17c2e..2ca9a32cc7b6 100644 > --- a/hw/vfio/iommufd.c > +++ b/hw/vfio/iommufd.c > @@ -212,10 +212,95 @@ 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, NULL); > + if (ret) { > + /* -EINVAL means the domain is incompatible with the device. */ > + if (ret == -EINVAL) { > + continue; > + } We should propagate an error in the false case. > + return false; > + } else { > + vbasedev->hwpt = hwpt; > + QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); > + return true; > + } > + } > + > + ret = iommufd_backend_alloc_hwpt(iommufd, > + vbasedev->devid, > + container->ioas_id, flags, > + IOMMU_HWPT_DATA_NONE, 0, NULL, &hwpt_id); > + if (ret) { > + /* > + * When there's no domains allocated we can still attempt a hardware > + * pagetable allocation for an mdev, which ends up returning -ENOENT > + * This is benign and meant to fallback into IOAS attach, hence don't > + * set errp. > + */ same here. > + 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); > + 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) > { > + if (iommufd_cdev_autodomains_get(vbasedev, container, errp)) { > + return true; > + } > + > + /* > + * iommufd_cdev_autodomains_get() may have an expected failure (-ENOENT) > + * for mdevs as they aren't real physical devices. @errp is only set > + * when real failures happened i.e. failing to attach to a newly created > + * hardware pagetable. These are fatal and should fail the attachment. > + */ > + if (*errp) { > + return false; > + } > + > return !iommufd_cdev_attach_ioas_hwpt(vbasedev, container->ioas_id, errp); > } > > @@ -224,6 +309,11 @@ static void iommufd_cdev_detach_container(VFIODevice *vbasedev, > { > Error *err = NULL; > > + if (vbasedev->hwpt) { > + iommufd_cdev_autodomains_put(vbasedev, container); > + return; > + } > + > if (!iommufd_cdev_detach_ioas_hwpt(vbasedev, &err)) { > error_report_err(err); > } > @@ -354,6 +444,7 @@ 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)"