Re: [PATCH 1/5] vfio/iommufd: Save host iommu capabilities in VFIODevice.caps

[Eric Auger <eric.auger@redhat.com>]

On 4/11/25 12:17 PM, Zhenzhong Duan wrote:
> The saved caps copy can be used to check dirty tracking capability.
>
> The capabilities is gotten through IOMMUFD interface, so define a
> new structure HostIOMMUDeviceIOMMUFDCaps which contains vendor
> caps raw data in "include/system/iommufd.h".
>
> This is a prepare work for moving .realize() after .attach_device().
>
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Suggested-by: Eric Auger <eric.auger@redhat.com>
> Suggested-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  include/hw/vfio/vfio-device.h |  1 +
>  include/system/iommufd.h      | 22 ++++++++++++++++++++++
>  hw/vfio/iommufd.c             | 10 +++++++++-
>  3 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
> index 66797b4c92..09a7af891a 100644
> --- a/include/hw/vfio/vfio-device.h
> +++ b/include/hw/vfio/vfio-device.h
> @@ -77,6 +77,7 @@ typedef struct VFIODevice {
>      bool dirty_tracking; /* Protected by BQL */
>      bool iommu_dirty_tracking;
>      HostIOMMUDevice *hiod;
> +    HostIOMMUDeviceIOMMUFDCaps caps;
>      int devid;
>      IOMMUFDBackend *iommufd;
>      VFIOIOASHwpt *hwpt;
> diff --git a/include/system/iommufd.h b/include/system/iommufd.h
> index cbab75bfbf..0f337585c9 100644
> --- a/include/system/iommufd.h
> +++ b/include/system/iommufd.h
> @@ -18,6 +18,9 @@
>  #include "exec/hwaddr.h"
>  #include "exec/cpu-common.h"
>  #include "system/host_iommu_device.h"
> +#ifdef CONFIG_LINUX
> +#include <linux/iommufd.h>
> +#endif
>  
>  #define TYPE_IOMMUFD_BACKEND "iommufd"
>  OBJECT_DECLARE_TYPE(IOMMUFDBackend, IOMMUFDBackendClass, IOMMUFD_BACKEND)
> @@ -63,4 +66,23 @@ bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
>                                        Error **errp);
>  
>  #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
> +
> +typedef union VendorCaps {
> +    struct iommu_hw_info_vtd vtd;
> +    struct iommu_hw_info_arm_smmuv3 smmuv3;
> +} VendorCaps;
> +
> +/**
> + * struct HostIOMMUDeviceIOMMUFDCaps - Define host IOMMU device capabilities.
> + *
> + * @type: host platform IOMMU type.
> + *
> + * @hw_caps: host platform IOMMU capabilities (e.g. on IOMMUFD this represents
> + *           the @out_capabilities value returned from IOMMU_GET_HW_INFO ioctl)
> + */
> +typedef struct HostIOMMUDeviceIOMMUFDCaps {
> +    uint32_t type;
> +    uint64_t hw_caps;
> +    VendorCaps vendor_caps;
> +} HostIOMMUDeviceIOMMUFDCaps;
Why can't we extend the existing HostIOMMUDeviceCaps in host_iommu_device.h?

Eric
>  #endif
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index 48db105422..530cde6740 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -324,7 +324,7 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
>       * vfio_migration_realize() may decide to use VF dirty tracking
>       * instead.
>       */
> -    if (vbasedev->hiod->caps.hw_caps & IOMMU_HW_CAP_DIRTY_TRACKING) {
> +    if (vbasedev->caps.hw_caps & IOMMU_HW_CAP_DIRTY_TRACKING) {
>          flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
>      }
>  
> @@ -475,6 +475,7 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
>      int ret, devfd;
>      uint32_t ioas_id;
>      Error *err = NULL;
> +    HostIOMMUDeviceIOMMUFDCaps *caps = &vbasedev->caps;
>      const VFIOIOMMUClass *iommufd_vioc =
>          VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_IOMMUFD));
>  
> @@ -505,6 +506,13 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
>          goto err_alloc_ioas;
>      }
>  
> +    if (!iommufd_backend_get_device_info(vbasedev->iommufd, vbasedev->devid,
> +                                         &caps->type, &caps->vendor_caps,
> +                                         sizeof(VendorCaps), &caps->hw_caps,
> +                                         errp)) {
> +        goto err_alloc_ioas;
> +    }
> +
>      /* try to attach to an existing container in this space */
>      QLIST_FOREACH(bcontainer, &space->containers, next) {
>          container = container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);