Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fad4d5b1 authored by Antonios Motakis's avatar Antonios Motakis Committed by Alex Williamson
Browse files

vfio/platform: support MMAP of MMIO regions 



Allow to memory map the MMIO regions of the device so userspace can
directly access them. PIO regions are not being handled at this point.

Signed-off-by: default avatarAntonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: default avatarBaptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Tested-by: default avatarEric Auger <eric.auger@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 6e3f2645

drivers/vfio/platform/vfio_platform_common.c

+65 −0
Original line number Diff line number Diff line
@@ -55,6 +55,16 @@ static int vfio_platform_regions_init(struct vfio_platform_device *vdev) 
			if (!(res->flags & IORESOURCE_READONLY))

				vdev->regions[i].flags |=

					VFIO_REGION_INFO_FLAG_WRITE;



			/*

			 * Only regions addressed with PAGE granularity may be

			 * MMAPed securely.

			 */

			if (!(vdev->regions[i].addr & ~PAGE_MASK) &&

					!(vdev->regions[i].size & ~PAGE_MASK))

				vdev->regions[i].flags |=

					VFIO_REGION_INFO_FLAG_MMAP;



			break;

		case IORESOURCE_IO:

			vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO;
@@ -334,8 +344,63 @@ static ssize_t vfio_platform_write(void *device_data, const char __user *buf, 
	return -EINVAL;

}



static int vfio_platform_mmap_mmio(struct vfio_platform_region region,

				   struct vm_area_struct *vma)

{

	u64 req_len, pgoff, req_start;



	req_len = vma->vm_end - vma->vm_start;

	pgoff = vma->vm_pgoff &

		((1U << (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT)) - 1);

	req_start = pgoff << PAGE_SHIFT;



	if (region.size < PAGE_SIZE || req_start + req_len > region.size)

		return -EINVAL;



	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_pgoff = (region.addr >> PAGE_SHIFT) + pgoff;



	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,

			       req_len, vma->vm_page_prot);

}



static int vfio_platform_mmap(void *device_data, struct vm_area_struct *vma)

{

	struct vfio_platform_device *vdev = device_data;

	unsigned int index;



	index = vma->vm_pgoff >> (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT);



	if (vma->vm_end < vma->vm_start)

		return -EINVAL;

	if (!(vma->vm_flags & VM_SHARED))

		return -EINVAL;

	if (index >= vdev->num_regions)

		return -EINVAL;

	if (vma->vm_start & ~PAGE_MASK)

		return -EINVAL;

	if (vma->vm_end & ~PAGE_MASK)

		return -EINVAL;



	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_MMAP))

		return -EINVAL;



	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_READ)

			&& (vma->vm_flags & VM_READ))

		return -EINVAL;



	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE)

			&& (vma->vm_flags & VM_WRITE))

		return -EINVAL;



	vma->vm_private_data = vdev;



	if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)

		return vfio_platform_mmap_mmio(vdev->regions[index], vma);



	else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)

		return -EINVAL; /* not implemented */



	return -EINVAL;

}