On 7/16/24 18:44, 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
OK
>
>> 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.
OK
>
>>> 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 (...)'
OK
>
>>> 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
Hum I see iommufd_backend_free_id frees the object. I guess the detach
then is done on kernel side...
Eric
>
>> 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)"
