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Fri, 25 Sep 2020 13:49:06 +0000 (UTC) Received: from laptop.redhat.com (ovpn-113-81.ams2.redhat.com [10.36.113.81]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30E975D9DC; Fri, 25 Sep 2020 13:49:01 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, stefanha@redhat.com, fam@euphon.net, philmd@redhat.com, alex.williamson@redhat.com Subject: [RFC 1/3] util/vfio-helpers: Collect IOVA reserved regions Date: Fri, 25 Sep 2020 15:48:43 +0200 Message-Id: <20200925134845.21053-2-eric.auger@redhat.com> In-Reply-To: <20200925134845.21053-1-eric.auger@redhat.com> References: <20200925134845.21053-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eric.auger@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/25 02:48:20 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.199, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lvivier@redhat.com, kwolf@redhat.com, cohuck@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The IOVA allocator currently ignores host reserved regions. As a result some chosen IOVAs may collide with some of them, resulting in VFIO MAP_DMA errors later on. This happens on ARM where the MSI reserved window quickly is encountered: [0x8000000, 0x8100000]. since 5.4 kernel, VFIO returns the usable IOVA regions. So let's enumerate them in the prospect to avoid them, later on. Signed-off-by: Eric Auger --- util/vfio-helpers.c | 75 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 73 insertions(+), 2 deletions(-) diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c index 583bdfb36f..8e91beba95 100644 --- a/util/vfio-helpers.c +++ b/util/vfio-helpers.c @@ -40,6 +40,11 @@ typedef struct { uint64_t iova; } IOVAMapping; +struct IOVARange { + uint64_t start; + uint64_t end; +}; + struct QEMUVFIOState { QemuMutex lock; @@ -49,6 +54,8 @@ struct QEMUVFIOState { int device; RAMBlockNotifier ram_notifier; struct vfio_region_info config_region_info, bar_region_info[6]; + struct IOVARange *usable_iova_ranges; + uint8_t nb_iova_ranges; /* These fields are protected by @lock */ /* VFIO's IO virtual address space is managed by splitting into a few @@ -236,6 +243,36 @@ static int qemu_vfio_pci_write_config(QEMUVFIOState *s, void *buf, int size, int return ret == size ? 0 : -errno; } +static void collect_usable_iova_ranges(QEMUVFIOState *s, void *first_cap) +{ + struct vfio_iommu_type1_info_cap_iova_range *cap_iova_range; + struct vfio_info_cap_header *cap = first_cap; + void *offset = first_cap; + int i; + + while (cap->id != VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE) { + if (cap->next) { + return; + } + offset += cap->next; + cap = (struct vfio_info_cap_header *)cap; + } + + cap_iova_range = (struct vfio_iommu_type1_info_cap_iova_range *)cap; + + s->nb_iova_ranges = cap_iova_range->nr_iovas; + if (s->nb_iova_ranges > 1) { + s->usable_iova_ranges = + g_realloc(s->usable_iova_ranges, + s->nb_iova_ranges * sizeof(struct IOVARange)); + } + + for (i = 0; i < s->nb_iova_ranges; i++) { + s->usable_iova_ranges[i].start = cap_iova_range->iova_ranges[i].start; + s->usable_iova_ranges[i].end = cap_iova_range->iova_ranges[i].end; + } +} + static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device, Error **errp) { @@ -243,10 +280,13 @@ static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device, int i; uint16_t pci_cmd; struct vfio_group_status group_status = { .argsz = sizeof(group_status) }; - struct vfio_iommu_type1_info iommu_info = { .argsz = sizeof(iommu_info) }; + struct vfio_iommu_type1_info *iommu_info = NULL; + size_t iommu_info_size = sizeof(*iommu_info); struct vfio_device_info device_info = { .argsz = sizeof(device_info) }; char *group_file = NULL; + s->usable_iova_ranges = NULL; + /* Create a new container */ s->container = open("/dev/vfio/vfio", O_RDWR); @@ -310,13 +350,38 @@ static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device, goto fail; } + iommu_info = g_malloc0(iommu_info_size); + iommu_info->argsz = iommu_info_size; + /* Get additional IOMMU info */ - if (ioctl(s->container, VFIO_IOMMU_GET_INFO, &iommu_info)) { + if (ioctl(s->container, VFIO_IOMMU_GET_INFO, iommu_info)) { error_setg_errno(errp, errno, "Failed to get IOMMU info"); ret = -errno; goto fail; } + /* + * if the kernel does not report usable IOVA regions, choose + * the legacy [QEMU_VFIO_IOVA_MIN, QEMU_VFIO_IOVA_MAX -1] region + */ + s->nb_iova_ranges = 1; + s->usable_iova_ranges = g_new0(struct IOVARange, 1); + s->usable_iova_ranges[0].start = QEMU_VFIO_IOVA_MIN; + s->usable_iova_ranges[0].end = QEMU_VFIO_IOVA_MAX - 1; + + if (iommu_info->argsz > iommu_info_size) { + void *first_cap; + + iommu_info_size = iommu_info->argsz; + iommu_info = g_realloc(iommu_info, iommu_info_size); + if (ioctl(s->container, VFIO_IOMMU_GET_INFO, iommu_info)) { + ret = -errno; + goto fail; + } + first_cap = (void *)iommu_info + iommu_info->cap_offset; + collect_usable_iova_ranges(s, first_cap); + } + s->device = ioctl(s->group, VFIO_GROUP_GET_DEVICE_FD, device); if (s->device < 0) { @@ -365,8 +430,12 @@ static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device, if (ret) { goto fail; } + g_free(iommu_info); return 0; fail: + g_free(s->usable_iova_ranges); + s->nb_iova_ranges = 0; + g_free(iommu_info); close(s->group); fail_container: close(s->container); @@ -716,6 +785,8 @@ void qemu_vfio_close(QEMUVFIOState *s) qemu_vfio_undo_mapping(s, &s->mappings[i], NULL); } ram_block_notifier_remove(&s->ram_notifier); + g_free(s->usable_iova_ranges); + s->nb_iova_ranges = 0; qemu_vfio_reset(s); close(s->device); close(s->group);