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vfio_pci: Allow mapping extra regions 

So far we only allowed mapping of MMIO BARs to the userspace. However
there are GPUs with on-board coherent RAM accessible via side
channels which we also want to map to the userspace. The first client
for this is NVIDIA V100 GPU with NVLink2 direct links to a POWER9
NPU-enabled CPU; such GPUs have 16GB RAM which is coherently mapped
to the system address space, we are going to export these as an extra
PCI region.

We already support extra PCI regions and this adds support for mapping
them to the userspace.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2018-12-19 19:52:30 +11:00 committed by Michael Ellerman
parent 58629c0dc3
commit a15b1883fe
2 changed files with 12 additions and 0 deletions
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9
drivers/vfio/pci/vfio_pci.c
View File

@ -1117,6 +1117,15 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
return -EINVAL;
if ((vma->vm_flags & VM_SHARED) == 0)
return -EINVAL;
if (index >= VFIO_PCI_NUM_REGIONS) {
int regnum = index - VFIO_PCI_NUM_REGIONS;
struct vfio_pci_region *region = vdev->region + regnum;
if (region && region->ops && region->ops->mmap &&
(region->flags & VFIO_REGION_INFO_FLAG_MMAP))
return region->ops->mmap(vdev, region, vma);
return -EINVAL;
}
if (index >= VFIO_PCI_ROM_REGION_INDEX)
return -EINVAL;
if (!vdev->bar_mmap_supported[index])

3
drivers/vfio/pci/vfio_pci_private.h
View File

@ -59,6 +59,9 @@ struct vfio_pci_regops {
size_t count, loff_t *ppos, bool iswrite);
void (*release)(struct vfio_pci_device *vdev,
struct vfio_pci_region *region);
int (*mmap)(struct vfio_pci_device *vdev,
struct vfio_pci_region *region,
struct vm_area_struct *vma);
};
struct vfio_pci_region {