>-----Original Message-----
>From: Joao Martins <joao.m.mart...@oracle.com>
>Subject: Re: [PATCH v4 05/12] vfio/iommufd: Introduce auto domain
>creation
>
>On 16/07/2024 17:44, Joao Martins wrote:
>> On 16/07/2024 17:04, Eric Auger wrote:
>>> 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"
>>>
>> 'It' here refers to the process/API-user
>>
>>> 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?
>>>
>>
>> Correct.
>>
>> The 'auto domains' generally refers to the kernel-equivalent own
>automatic
>> attaching to a new pagetable.
>>
>> Here I call 'auto domains' in the userspace version too because we are
>doing the
>> exact same but from userspace, using the manual API in IOMMUFD.
>>
>>>> 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 ?
>>>
>>
>> I meant, 'Here it is not used in this way given (...)'
>>
>>>> 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?
>>>
>> Yeap, Thanks for catching that
>>
>>>
>>>> + 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?
>>>
>> In iommufd_backend_free_id() for auto domains
>>
>
>to clarify here I meant *userspace* auto domains
>
>*kernel* auto domains (mdev) goes via DETACH_IOMMUFD_PT
If the device is still attached to the hwpt, will iommufd_backend_free_id()
succeed?
Have you tried the hot unplug?
Thanks
Zhenzhong
>
>>> 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)"
>>>
>>
