Re: [PATCH v4 09/12] vfio/iommufd: Implement VFIOIOMMUClass::set_dirty_tracking support

[Joao Martins <joao.m.martins@oracle.com>]

On 17/07/2024 13:36, Eric Auger wrote:
> 
> 
> On 7/12/24 13:47, Joao Martins wrote:
>> ioctl(iommufd, IOMMU_HWPT_SET_DIRTY_TRACKING, arg) is the UAPI that
>> enables or disables dirty page tracking. It is used if the hwpt
>> has been created with dirty tracking supported domain (stored in
>> hwpt::flags) and it is called on the whole list of iommu domains
>> it is are tracking. On failure it rolls it back.
> 
> it is are tracking ?

*it is*

> also please clearly state what is "it"
>

sure

>>
>> The checking of hwpt::flags is introduced here as a second user
> ?? -> introduce iommufd_hwpt_dirty_tracking() helper to avoid code dup?

Right I am doing that already. Not sure what the problem is with this sentence?

Or you meant to use yours as it's simpler/easier to understand.

>> and thus consolidate such check into a helper function
>> iommufd_hwpt_dirty_tracking().
>>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>>  include/sysemu/iommufd.h |  3 +++
>>  backends/iommufd.c       | 23 +++++++++++++++++++++++
>>  hw/vfio/iommufd.c        | 39 ++++++++++++++++++++++++++++++++++++++-
>>  backends/trace-events    |  1 +
>>  4 files changed, 65 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
>> index e917e7591d05..7416d9219703 100644
>> --- a/include/sysemu/iommufd.h
>> +++ b/include/sysemu/iommufd.h
>> @@ -55,6 +55,9 @@ bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id,
>>                                  uint32_t data_type, uint32_t data_len,
>>                                  void *data_ptr, uint32_t *out_hwpt,
>>                                  Error **errp);
>> +bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t hwpt_id,
>> +                                        bool start, Error **errp);
>>  
>>  #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
>> +
> spurious line change

ok

>>  #endif
>> diff --git a/backends/iommufd.c b/backends/iommufd.c
>> index 41a9dec3b2c5..239f0976e0ad 100644
>> --- a/backends/iommufd.c
>> +++ b/backends/iommufd.c
>> @@ -239,6 +239,29 @@ bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id,
>>      return true;
>>  }
>>  
>> +bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be,
>> +                                        uint32_t hwpt_id, bool start,
>> +                                        Error **errp)
>> +{
>> +    int ret;
>> +    struct iommu_hwpt_set_dirty_tracking set_dirty = {
>> +            .size = sizeof(set_dirty),
>> +            .hwpt_id = hwpt_id,
>> +            .flags = !start ? 0 : IOMMU_HWPT_DIRTY_TRACKING_ENABLE,
>> +    };
>> +
>> +    ret = ioctl(be->fd, IOMMU_HWPT_SET_DIRTY_TRACKING, &set_dirty);
>> +    trace_iommufd_backend_set_dirty(be->fd, hwpt_id, start, ret ? errno : 0);
>> +    if (ret) {
>> +        error_setg_errno(errp, errno,
>> +                         "IOMMU_HWPT_SET_DIRTY_TRACKING(hwpt_id %u) failed",
>> +                         hwpt_id);
>> +        return false;
>> +    }
>> +
>> +    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 edc8f97d8f3d..da678315faeb 100644
>> --- a/hw/vfio/iommufd.c
>> +++ b/hw/vfio/iommufd.c
>> @@ -110,6 +110,42 @@ static void iommufd_cdev_unbind_and_disconnect(VFIODevice *vbasedev)
>>      iommufd_backend_disconnect(vbasedev->iommufd);
>>  }
>>  
>> +static bool iommufd_hwpt_dirty_tracking(VFIOIOASHwpt *hwpt)
>> +{
>> +    return hwpt->hwpt_flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
>> +}
>> +
>> +static int iommufd_set_dirty_page_tracking(const VFIOContainerBase *bcontainer,
>> +                                           bool start, Error **errp)
>> +{
>> +    const VFIOIOMMUFDContainer *container =
>> +        container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);
>> +    VFIOIOASHwpt *hwpt;
>> +
>> +    QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
>> +        if (!iommufd_hwpt_dirty_tracking(hwpt)) {
>> +            continue;
>> +        }
>> +
>> +        if (!iommufd_backend_set_dirty_tracking(container->be,
>> +                                                hwpt->hwpt_id, start, errp)) {
>> +            goto err;
>> +        }
>> +    }
>> +
>> +    return 0;
>> +
>> +err:
>> +    QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
>> +        if (!iommufd_hwpt_dirty_tracking(hwpt)) {
>> +            continue;
>> +        }
>> +        iommufd_backend_set_dirty_tracking(container->be,
>> +                                           hwpt->hwpt_id, !start, NULL);
>> +    }
>> +    return -EINVAL;
>> +}
>> +
>>  static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
>>  {
>>      ERRP_GUARD();
>> @@ -278,7 +314,7 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
>>      QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next);
>>      QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next);
>>      container->bcontainer.dirty_pages_supported |=
>> -                              (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING);
>> +                              iommufd_hwpt_dirty_tracking(hwpt);
>>      return true;
>>  }
>>  
>> @@ -717,6 +753,7 @@ static void vfio_iommu_iommufd_class_init(ObjectClass *klass, void *data)
>>      vioc->attach_device = iommufd_cdev_attach;
>>      vioc->detach_device = iommufd_cdev_detach;
>>      vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
>> +    vioc->set_dirty_page_tracking = iommufd_set_dirty_page_tracking;
>>  };
>>  
>>  static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>> diff --git a/backends/trace-events b/backends/trace-events
>> index 4d8ac02fe7d6..28aca3b859d4 100644
>> --- a/backends/trace-events
>> +++ b/backends/trace-events
>> @@ -16,3 +16,4 @@ iommufd_backend_unmap_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t si
>>  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)"
>> +iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int ret) " iommufd=%d hwpt=%u enable=%d (%d)"
>