VFIO regions already support region capabilities with a limited set of
fields. However the subdriver might have to report to the userspace
additional bits.
This adds an add_capability() hook to vfio_pci_regops.
This is aiming Witherspoon POWER9 machines which have multiple
interconnected NVIDIA V100 GPUs with coherent RAM; each GPU's RAM
is mapped to a system bus and to each of GPU internal system bus and
the GPUs use this for DMA routing as DMA trafic can go via any
of many NVLink2 (GPU-GPU or GPU-CPU) or even stay local within a GPU.
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
This is based on top of "vfio_pci: Allow mapping extra regions"
---
drivers/vfio/pci/vfio_pci_private.h | 3 +++
drivers/vfio/pci/vfio_pci.c | 6 ++++++
2 files changed, 9 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 86aab05..93c1738 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -62,6 +62,9 @@ struct vfio_pci_regops {
int (*mmap)(struct vfio_pci_device *vdev,
struct vfio_pci_region *region,
struct vm_area_struct *vma);
+ int (*add_capability)(struct vfio_pci_device *vdev,
+ struct vfio_pci_region *region,
+ struct vfio_info_cap *caps);
};
struct vfio_pci_region {
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7923314..4a3b93e 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -759,6 +759,12 @@ static long vfio_pci_ioctl(void *device_data,
if (ret)
return ret;
+ if (vdev->region[i].ops->add_capability) {
+ ret = vdev->region[i].ops->add_capability(vdev,
+ &vdev->region[i], &caps);
+ if (ret)
+ return ret;
+ }
}
}
--
2.11.0
