Re: [PATCH v4 06/12] vfio/{iommufd,container}: Remove caps::aw_bits

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

On 16/07/2024 18:40, Eric Auger wrote:
> Hi Joao,
> 
> On 7/12/24 13:46, Joao Martins wrote:
>> In preparation to moving HostIOMMUDevice realize() being able to called
>> early during attach_device(), remove properties that rely on container
>> being initialized.
> It is difficult to parse the above sentence. Would deserve some rephrasing.
> 
> Also properties have a different meaning in qemu.

I think I will remove the above paragraph and instead adopt below with some
rephrasing:

Remove caps::aw_bits which requires the
bcontainer::iova_ranges to be inititalized after device is actually
initialized attached. Instead defer that to .get_cap() and call
vfio_device_get_aw_bits() directly.

This is in preparation for HostIOMMUDevice::realize() being called early during
attach_device().

Better?

>>
>> This means removing caps::aw_bits which requires the
>> bcontainer::iova_ranges to be inititalized after device is actually
> initialized

Yes

>> attached. Instead defer that to .get_cap() and call
>> vfio_device_get_aw_bits() directly.
>>
>> Suggested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>>  include/sysemu/host_iommu_device.h | 1 -
>>  backends/iommufd.c                 | 3 ++-
>>  hw/vfio/container.c                | 5 +----
>>  hw/vfio/iommufd.c                  | 1 -
>>  4 files changed, 3 insertions(+), 7 deletions(-)
>>
>> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
>> index ee6c813c8b22..20e77cf54568 100644
>> --- a/include/sysemu/host_iommu_device.h
>> +++ b/include/sysemu/host_iommu_device.h
>> @@ -24,7 +24,6 @@
>>   */
>>  typedef struct HostIOMMUDeviceCaps {
>>      uint32_t type;
>> -    uint8_t aw_bits;
> the doc comment needs to be updated accordingly.
>>  } HostIOMMUDeviceCaps;
>>  
>>  #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>> diff --git a/backends/iommufd.c b/backends/iommufd.c
>> index 5d3dfa917415..41a9dec3b2c5 100644
>> --- a/backends/iommufd.c
>> +++ b/backends/iommufd.c
>> @@ -18,6 +18,7 @@
>>  #include "qemu/error-report.h"
>>  #include "monitor/monitor.h"
>>  #include "trace.h"
>> +#include "hw/vfio/vfio-common.h"
>>  #include <sys/ioctl.h>
>>  #include <linux/iommufd.h>
>>  
>> @@ -270,7 +271,7 @@ static int hiod_iommufd_get_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
>>      case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
>>          return caps->type;
>>      case HOST_IOMMU_DEVICE_CAP_AW_BITS:
>> -        return caps->aw_bits;
>> +        return vfio_device_get_aw_bits(hiod->agent);
>>      default:
>>          error_setg(errp, "%s: unsupported capability %x", hiod->name, cap);
>>          return -EINVAL;
>> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
>> index 88ede913d6f7..c27f448ba26e 100644
>> --- a/hw/vfio/container.c
>> +++ b/hw/vfio/container.c
>> @@ -1144,7 +1144,6 @@ static bool hiod_legacy_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>>      VFIODevice *vdev = opaque;
>>  
>>      hiod->name = g_strdup(vdev->name);
>> -    hiod->caps.aw_bits = vfio_device_get_aw_bits(vdev);
>>      hiod->agent = opaque;
>>  
>>      return true;
>> @@ -1153,11 +1152,9 @@ static bool hiod_legacy_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>>  static int hiod_legacy_vfio_get_cap(HostIOMMUDevice *hiod, int cap,
>>                                      Error **errp)
>>  {
>> -    HostIOMMUDeviceCaps *caps = &hiod->caps;
>> -
>>      switch (cap) {
>>      case HOST_IOMMU_DEVICE_CAP_AW_BITS:
>> -        return caps->aw_bits;
>> +        return vfio_device_get_aw_bits(hiod->agent);
>>      default:
>>          error_setg(errp, "%s: unsupported capability %x", hiod->name, cap);
>>          return -EINVAL;
>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
>> index 325c7598d5a1..873c919e319c 100644
>> --- a/hw/vfio/iommufd.c
>> +++ b/hw/vfio/iommufd.c
>> @@ -722,7 +722,6 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>>  
>>      hiod->name = g_strdup(vdev->name);
>>      caps->type = type;
>> -    caps->aw_bits = vfio_device_get_aw_bits(vdev);
>>  
>>      return true;
>>  }
>