Re: [PATCH v6 09/19] vfio/iommufd: Implement HostIOMMUDeviceClass::realize() handler

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

Hi Zhenzhong,
On 6/3/24 08:10, Zhenzhong Duan wrote:
> It calls iommufd_backend_get_device_info() to get host IOMMU
> related information and translate it into HostIOMMUDeviceCaps
> for query with .get_cap().
>
> Introduce macro VTD_MGAW_FROM_CAP to get MGAW which equals to
> (aw_bits - 1).
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  include/hw/i386/intel_iommu.h |  1 +
>  hw/vfio/iommufd.c             | 37 +++++++++++++++++++++++++++++++++++
>  2 files changed, 38 insertions(+)
>
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 7fa0a695c8..7d694b0813 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -47,6 +47,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(IntelIOMMUState, INTEL_IOMMU_DEVICE)
>  #define VTD_HOST_AW_48BIT           48
>  #define VTD_HOST_ADDRESS_WIDTH      VTD_HOST_AW_39BIT
>  #define VTD_HAW_MASK(aw)            ((1ULL << (aw)) - 1)
> +#define VTD_MGAW_FROM_CAP(cap)      ((cap >> 16) & 0x3fULL)
>  
>  #define DMAR_REPORT_F_INTR          (1)
>  
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index e4a507d55c..9d2e95e20e 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -25,6 +25,7 @@
>  #include "qemu/cutils.h"
>  #include "qemu/chardev_open.h"
>  #include "pci.h"
> +#include "hw/i386/intel_iommu_internal.h"
>  
>  static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
>                              ram_addr_t size, void *vaddr, bool readonly)
> @@ -619,6 +620,41 @@ static void vfio_iommu_iommufd_class_init(ObjectClass *klass, void *data)
>      vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
>  };
>  
> +static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
> +                                      Error **errp)
> +{
> +    VFIODevice *vdev = opaque;
I think it would make sense to store vdev in hiod. This would allow to
postpone some computations in the HostIOMMUDevice ops instead of doing
everything in the realize.
For instance to retrieve the usable iova_ranges I will need to access
the base container in the associated ops.

Thanks

Eric
> +    HostIOMMUDeviceCaps *caps = &hiod->caps;
> +    enum iommu_hw_info_type type;
> +    union {
> +        struct iommu_hw_info_vtd vtd;
> +    } data;
> +
> +    if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid,
> +                                         &type, &data, sizeof(data), errp)) {
> +        return false;
> +    }
> +
> +    caps->type = type;
> +
> +    switch (type) {
> +    case IOMMU_HW_INFO_TYPE_INTEL_VTD:
> +        caps->aw_bits = VTD_MGAW_FROM_CAP(data.vtd.cap_reg) + 1;
> +        break;
> +    case IOMMU_HW_INFO_TYPE_NONE:
> +        break;
> +    }
> +
> +    return true;
> +}
> +
> +static void hiod_iommufd_vfio_class_init(ObjectClass *oc, void *data)
> +{
> +    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_CLASS(oc);
> +
> +    hiodc->realize = hiod_iommufd_vfio_realize;
> +};
> +
>  static const TypeInfo types[] = {
>      {
>          .name = TYPE_VFIO_IOMMU_IOMMUFD,
> @@ -627,6 +663,7 @@ static const TypeInfo types[] = {
>      }, {
>          .name = TYPE_HOST_IOMMU_DEVICE_IOMMUFD_VFIO,
>          .parent = TYPE_HOST_IOMMU_DEVICE_IOMMUFD,
> +        .class_init = hiod_iommufd_vfio_class_init,
>      }
>  };
>