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: 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>
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 4df66f5..d7fe2c7 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -55,6 +55,16 @@
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 @@
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;
}