On 19/02/2024 08:58, Avihai Horon wrote: > Hi Joao, > > On 12/02/2024 15:56, Joao Martins wrote: >> External email: Use caution opening links or attachments >> >> >> 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. >> >> For dirty tracking such property is enabled/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) >> >> 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. >> >> Signed-off-by: Joao Martins <joao.m.mart...@oracle.com> >> --- >> Right now the only alternative to a userspace autodomains implementation >> is to mimmicing all the flags being added to HWPT_ALLOC but into VFIO >> IOAS attach. So opted for autodomains userspace approach to avoid the >> duplication of hwpt-alloc flags vs attach-ioas flags. I lack mdev real >> drivers atm, so testing with those is still TBD. >> >> Opinions, comments, welcome! >> --- >> backends/iommufd.c | 29 +++++++++++++ >> backends/trace-events | 1 + >> hw/vfio/iommufd.c | 78 +++++++++++++++++++++++++++++++++++ >> include/hw/vfio/vfio-common.h | 9 ++++ >> include/sysemu/iommufd.h | 4 ++ >> 5 files changed, 121 insertions(+) >> >> diff --git a/backends/iommufd.c b/backends/iommufd.c >> index 8486894f1b3f..2970135af4b9 100644 >> --- a/backends/iommufd.c >> +++ b/backends/iommufd.c >> @@ -211,6 +211,35 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, >> uint32_t ioas_id, >> return ret; >> } >> >> +int iommufd_backend_alloc_hwpt(int iommufd, 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; >> + 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, >> + .__reserved = 0, >> + }; >> + >> + ret = ioctl(iommufd, IOMMU_HWPT_ALLOC, &alloc_hwpt); >> + trace_iommufd_backend_alloc_hwpt(iommufd, dev_id, pt_id, flags, >> data_type, >> + data_len, (uint64_t)data_ptr, >> + alloc_hwpt.out_hwpt_id, ret); >> + if (ret) { >> + error_report("IOMMU_HWPT_ALLOC failed: %m"); >> + } else { >> + *out_hwpt = alloc_hwpt.out_hwpt_id; >> + } >> + return !ret ? 0 : -errno; >> +} >> + >> static const TypeInfo iommufd_backend_info = { >> .name = TYPE_IOMMUFD_BACKEND, >> .parent = TYPE_OBJECT, >> diff --git a/backends/trace-events b/backends/trace-events >> index d45c6e31a67e..f83a276a4253 100644 >> --- a/backends/trace-events >> +++ b/backends/trace-events >> @@ -13,5 +13,6 @@ iommu_backend_set_fd(int fd) "pre-opened /dev/iommu fd=%d" >> iommufd_backend_map_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t >> size, void *vaddr, bool readonly, int ret) " iommufd=%d ioas=%d >> iova=0x%"PRIx64" size=0x%"PRIx64" addr=%p readonly=%d (%d)" >> 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_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_alloc_ioas(int iommufd, uint32_t ioas, int ret) " >> iommufd=%d >> ioas=%d (%d)" >> iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d >> id=%d (%d)" >> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c >> index 7d39d7a5fa51..ca7ec45e725c 100644 >> --- a/hw/vfio/iommufd.c >> +++ b/hw/vfio/iommufd.c >> @@ -219,10 +219,82 @@ static int iommufd_cdev_detach_ioas_hwpt(VFIODevice >> *vbasedev, Error **errp) >> return ret; >> } >> >> +static int iommufd_cdev_autodomains_get(VFIODevice *vbasedev, >> + VFIOIOMMUFDContainer *container, >> + Error **errp) >> +{ >> + int iommufd = vbasedev->iommufd_dev.iommufd->fd; >> + VFIOIOASHwpt *hwpt; >> + Error *err = NULL; >> + int ret = -EINVAL; > > The -EINVAL initialization is not necessary. > /me nods
>> + uint32_t hwpt_id; >> + >> + /* Try to find a domain */ >> + QLIST_FOREACH(hwpt, &container->hwpt_list, next) { >> + ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id, &err); >> + if (ret) { >> + /* -EINVAL means the domain is incompatible with the device. */ >> + if (ret == -EINVAL) { > > On error iommufd_cdev_attach_ioas_hwpt() returns -1 and not -errno, so I guess > we need to change it. > /me facepalm yes indeed >> + continue; >> + } >> + return ret; >> + } else { >> + vbasedev->hwpt = hwpt; >> + QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); >> + return 0; >> + } >> + } >> + >> + ret = iommufd_backend_alloc_hwpt(iommufd, >> + vbasedev->iommufd_dev.devid, >> + container->ioas_id, 0, 0, 0, > > Should we explicitly pass IOMMU_HWPT_DATA_NONE instead of 0? > That's better yes. >> + NULL, &hwpt_id); >> + if (ret) { >> + error_append_hint(&err, >> + "Failed to allocate HWPT for device %s. Fallback to IOAS >> attach\n", >> + vbasedev->name); >> + warn_report_err(err); >> + return ret; >> + } >> + >> + 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, &err); >> + if (ret) { >> + iommufd_backend_free_id(container->be, hwpt->hwpt_id); >> + g_free(hwpt); >> + return ret; >> + } >> + >> + vbasedev->hwpt = hwpt; >> + QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); >> + QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next); >> + return 0; > > I think we need to improve error handling in this function. > There are various places where err is not freed/reported, not NULL-ed before > re-used, or used in error_append_hint() although it can be NULL. > If there are places where Error can be ignored, we can pass NULL instead of > &err. > Plus, errp parameter passed to this function is never used. > Let me fix all those for the non-RFC v3. >> +} >> + >> +static void iommufd_cdev_autodomains_put(VFIODevice *vbasedev, >> + VFIOIOMMUFDContainer *container) >> +{ >> + VFIOIOASHwpt *hwpt = vbasedev->hwpt; >> + >> + QLIST_REMOVE(vbasedev, hwpt_next); >> + QLIST_REMOVE(hwpt, next); > > Shouldn't QLIST_REMOVE(hwpt, next) be moved inside the if? > yes >> + if (QLIST_EMPTY(&hwpt->device_list)) { >> + iommufd_backend_free_id(container->be, hwpt->hwpt_id); >> + g_free(hwpt); >> + } >> +} >> + >> static int iommufd_cdev_attach_container(VFIODevice *vbasedev, >> VFIOIOMMUFDContainer *container, >> Error **errp) >> { >> + if (!iommufd_cdev_autodomains_get(vbasedev, container, errp)) { >> + return 0; >> + } > > If errp is used in iommufd_cdev_autodomains_get() eventually, we need to make > sure it doens't contain an Error object before using it again below. > yes