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Subject[PATCH v5 05/10] vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions
Date
Allow userspace to mmap device regions for direct access of
fsl-mc devices.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
---
drivers/vfio/fsl-mc/vfio_fsl_mc.c | 68 ++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
index 802f3a00337f..7ceadb801082 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
@@ -30,11 +30,20 @@ static int vfio_fsl_mc_regions_init(struct vfio_fsl_mc_device *vdev)

for (i = 0; i < count; i++) {
struct resource *res = &mc_dev->regions[i];
+ int no_mmap = is_fsl_mc_bus_dprc(mc_dev);

vdev->regions[i].addr = res->start;
vdev->regions[i].size = resource_size(res);
- vdev->regions[i].flags = 0;
vdev->regions[i].type = mc_dev->regions[i].flags & IORESOURCE_BITS;
+ /*
+ * Only regions addressed with PAGE granularity may be
+ * MMAPed securely.
+ */
+ if (!no_mmap && !(vdev->regions[i].addr & ~PAGE_MASK) &&
+ !(vdev->regions[i].size & ~PAGE_MASK))
+ vdev->regions[i].flags |=
+ VFIO_REGION_INFO_FLAG_MMAP;
+
}

return 0;
@@ -163,9 +172,64 @@ static ssize_t vfio_fsl_mc_write(void *device_data, const char __user *buf,
return -EINVAL;
}

+static int vfio_fsl_mc_mmap_mmio(struct vfio_fsl_mc_region region,
+ struct vm_area_struct *vma)
+{
+ u64 size = vma->vm_end - vma->vm_start;
+ u64 pgoff, base;
+ u8 region_cacheable;
+
+ pgoff = vma->vm_pgoff &
+ ((1U << (VFIO_FSL_MC_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
+ base = pgoff << PAGE_SHIFT;
+
+ if (region.size < PAGE_SIZE || base + size > region.size)
+ return -EINVAL;
+
+ region_cacheable = (region.type & FSL_MC_REGION_CACHEABLE) &&
+ (region.type & FSL_MC_REGION_SHAREABLE);
+ if (!region_cacheable)
+ 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,
+ size, vma->vm_page_prot);
+}
+
static int vfio_fsl_mc_mmap(void *device_data, struct vm_area_struct *vma)
{
- return -EINVAL;
+ struct vfio_fsl_mc_device *vdev = device_data;
+ struct fsl_mc_device *mc_dev = vdev->mc_dev;
+ int index;
+
+ index = vma->vm_pgoff >> (VFIO_FSL_MC_OFFSET_SHIFT - PAGE_SHIFT);
+
+ if (vma->vm_end < vma->vm_start)
+ return -EINVAL;
+ if (vma->vm_start & ~PAGE_MASK)
+ return -EINVAL;
+ if (vma->vm_end & ~PAGE_MASK)
+ return -EINVAL;
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+ if (index >= mc_dev->obj_desc.region_count)
+ 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 = mc_dev;
+
+ return vfio_fsl_mc_mmap_mmio(vdev->regions[index], vma);
}

static const struct vfio_device_ops vfio_fsl_mc_ops = {
--
2.17.1
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