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bh=bOpLCl232BV1cFhR67SrTPAGiW78Gwt9UKIEAZc/kEI=; b=LfOv4JZV//to2xJWLBBYC/RPt8++TNdFYwUZ8DWE3nJYrd3ARKHN0sHooWQAO2M1n60o6H FR0ZcFp4VpBynwcI9FLvdYP7ycrcP+TzkvfvnryONa/lLQhrG1TlMu1ih5F2yR+n3of0u9 suioLFfRk5BNzwFXaqIyuOOTYpuqgpU= X-MC-Unique: sZ2w6PzuN4u-EoQzHRny-A-1 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: [PATCH v2 1/2] util/vfio-helpers: Collect IOVA reserved regions Date: Tue, 29 Sep 2020 10:55:49 +0200 Message-Id: <20200929085550.30926-2-eric.auger@redhat.com> In-Reply-To: <20200929085550.30926-1-eric.auger@redhat.com> References: <20200929085550.30926-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" 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 --- v1 -> v2: - fix the loop on caps - set s->usable_iova_ranges=3DNULL to avoid double free --- util/vfio-helpers.c | 72 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 70 insertions(+), 2 deletions(-) diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c index 583bdfb36f..ba0ee6e21c 100644 --- a/util/vfio-helpers.c +++ b/util/vfio-helpers.c @@ -40,6 +40,11 @@ typedef struct { uint64_t iova; } IOVAMapping; =20 +struct IOVARange { + uint64_t start; + uint64_t end; +}; + struct QEMUVFIOState { QemuMutex lock; =20 @@ -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; =20 /* These fields are protected by @lock */ /* VFIO's IO virtual address space is managed by splitting into a few @@ -236,6 +243,35 @@ static int qemu_vfio_pci_write_config(QEMUVFIOState *s= , void *buf, int size, int return ret =3D=3D size ? 0 : -errno; } =20 +static void collect_usable_iova_ranges(QEMUVFIOState *s, void *buf) +{ + struct vfio_iommu_type1_info *info =3D (struct vfio_iommu_type1_info *= )buf; + struct vfio_info_cap_header *cap =3D (void *)buf + info->cap_offset; + struct vfio_iommu_type1_info_cap_iova_range *cap_iova_range; + int i; + + while (cap->id !=3D VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE) { + if (!cap->next) { + return; + } + cap =3D (struct vfio_info_cap_header *)(buf + cap->next); + } + + cap_iova_range =3D (struct vfio_iommu_type1_info_cap_iova_range *)cap; + + s->nb_iova_ranges =3D cap_iova_range->nr_iovas; + if (s->nb_iova_ranges > 1) { + s->usable_iova_ranges =3D + g_realloc(s->usable_iova_ranges, + s->nb_iova_ranges * sizeof(struct IOVARange)); + } + + for (i =3D 0; i < s->nb_iova_ranges; i++) { + s->usable_iova_ranges[i].start =3D cap_iova_range->iova_ranges[i].= start; + s->usable_iova_ranges[i].end =3D cap_iova_range->iova_ranges[i].en= d; + } +} + static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device, Error **errp) { @@ -243,10 +279,13 @@ static int qemu_vfio_init_pci(QEMUVFIOState *s, const= char *device, int i; uint16_t pci_cmd; struct vfio_group_status group_status =3D { .argsz =3D sizeof(group_st= atus) }; - struct vfio_iommu_type1_info iommu_info =3D { .argsz =3D sizeof(iommu_= info) }; + struct vfio_iommu_type1_info *iommu_info =3D NULL; + size_t iommu_info_size =3D sizeof(*iommu_info); struct vfio_device_info device_info =3D { .argsz =3D sizeof(device_inf= o) }; char *group_file =3D NULL; =20 + s->usable_iova_ranges =3D NULL; + /* Create a new container */ s->container =3D open("/dev/vfio/vfio", O_RDWR); =20 @@ -310,13 +349,35 @@ static int qemu_vfio_init_pci(QEMUVFIOState *s, const= char *device, goto fail; } =20 + iommu_info =3D g_malloc0(iommu_info_size); + iommu_info->argsz =3D 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 =3D -errno; goto fail; } =20 + /* + * 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 =3D 1; + s->usable_iova_ranges =3D g_new0(struct IOVARange, 1); + s->usable_iova_ranges[0].start =3D QEMU_VFIO_IOVA_MIN; + s->usable_iova_ranges[0].end =3D QEMU_VFIO_IOVA_MAX - 1; + + if (iommu_info->argsz > iommu_info_size) { + iommu_info_size =3D iommu_info->argsz; + iommu_info =3D g_realloc(iommu_info, iommu_info_size); + if (ioctl(s->container, VFIO_IOMMU_GET_INFO, iommu_info)) { + ret =3D -errno; + goto fail; + } + collect_usable_iova_ranges(s, iommu_info); + } + s->device =3D ioctl(s->group, VFIO_GROUP_GET_DEVICE_FD, device); =20 if (s->device < 0) { @@ -365,8 +426,13 @@ 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->usable_iova_ranges =3D NULL; + s->nb_iova_ranges =3D 0; + g_free(iommu_info); close(s->group); fail_container: close(s->container); @@ -716,6 +782,8 @@ 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 =3D 0; qemu_vfio_reset(s); close(s->device); close(s->group); --=20 2.21.3