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Commit a15b1883 authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Michael Ellerman
Browse files

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: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Acked-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 58629c0d

drivers/vfio/pci/vfio_pci.c

+9 −0
Original line number Diff line number Diff line
@@ -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])

drivers/vfio/pci/vfio_pci_private.h

+3 −0
Original line number Diff line number Diff line
@@ -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 {