Re: [RFC PATCH kvmtool 05/10] vfio: Add dma map/unmap handlers

[Aneesh Kumar K.V <aneesh.kumar@kernel.org>]

Mostafa Saleh <smostafa@google.com> writes:

> On Sun, May 25, 2025 at 01:19:11PM +0530, Aneesh Kumar K.V (Arm) wrote:
>> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
>> ---
>>  include/kvm/vfio.h | 4 ++--
>>  vfio/core.c        | 7 +++++--
>>  vfio/legacy.c      | 7 +++++--
>>  3 files changed, 12 insertions(+), 6 deletions(-)
>> 
>> diff --git a/include/kvm/vfio.h b/include/kvm/vfio.h
>> index 67a528f18d33..fed692b0f265 100644
>> --- a/include/kvm/vfio.h
>> +++ b/include/kvm/vfio.h
>> @@ -126,8 +126,8 @@ void vfio_unmap_region(struct kvm *kvm, struct vfio_region *region);
>>  int vfio_pci_setup_device(struct kvm *kvm, struct vfio_device *device);
>>  void vfio_pci_teardown_device(struct kvm *kvm, struct vfio_device *vdev);
>>  
>> -int vfio_map_mem_range(struct kvm *kvm, __u64 host_addr, __u64 iova, __u64 size);
>> -int vfio_unmap_mem_range(struct kvm *kvm, __u64 iova, __u64 size);
>> +extern int (*dma_map_mem_range)(struct kvm *kvm, __u64 host_addr, __u64 iova, __u64 size);
>> +extern int (*dma_unmap_mem_range)(struct kvm *kvm, __u64 iova, __u64 size);
>>  
>>  struct kvm_mem_bank;
>>  int vfio_map_mem_bank(struct kvm *kvm, struct kvm_mem_bank *bank, void *data);
>> diff --git a/vfio/core.c b/vfio/core.c
>> index 2af30df3b2b9..32a8e0fe67c0 100644
>> --- a/vfio/core.c
>> +++ b/vfio/core.c
>> @@ -10,6 +10,9 @@ int kvm_vfio_device;
>>  LIST_HEAD(vfio_groups);
>>  struct vfio_device *vfio_devices;
>>  
>> +int (*dma_map_mem_range)(struct kvm *kvm, __u64 host_addr, __u64 iova, __u64 size);
>> +int (*dma_unmap_mem_range)(struct kvm *kvm, __u64 iova, __u64 size);
>
> I think it's better to  wrap those in an ops struct, this can be set once and
> in the next patches this can be used for init/exit instead of having such checks:
> “if (kvm->cfg.iommufd || kvm->cfg.iommufd_vdevice)”
>

Sure. I’ll revise the patch to introduce the ops struct.

-aneesh