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vfio/platform: support MMAP of MMIO regions

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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: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Antonios Motakis 2015-03-16 14:08:48 -06:00 committed by Alex Williamson
parent 6e3f264560
commit fad4d5b1f0
1 changed files with 65 additions and 0 deletions
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65
drivers/vfio/platform/vfio_platform_common.c
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@ -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;
}