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"
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?
> 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 ?
> 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 <joao.m.mart...@oracle.com>
> ---
> 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?
> + 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?
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)"
