[PATCH] drm/amd/amdgpu: Return error if initiating read out of range on vram

[Tom St Denis]

If you initiate a read that is out of the VRAM address space return
ENXIO instead of 0.

Reads that begin below that point will read upto the VRAM limit as
before.

Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 522f773203c8..399209495265 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1468,6 +1468,9 @@ static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
 	if (size & 0x3 || *pos & 0x3)
 		return -EINVAL;
 
+	if (*pos >= adev->mc.mc_vram_size)
+		return -ENXIO;
+
 	while (size) {
 		unsigned long flags;
 		uint32_t value;
-- 
2.12.0