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

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

On 6/6/24 11:26, Eric Auger wrote:
> 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.

this would need to be opaque since the agent device can be either
VFIODevice or VDPA object though

Eric
> 
> 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,
>>      }
>>  };
>>  
>