Commit de5372da authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Zhenyu Wang
Browse files

drm/i915/kvmgt: Fix potential Spectre v1

info.index can be indirectly controlled by user-space, hence leading
to a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

drivers/gpu/drm/i915/gvt/kvmgt.c:1232 intel_vgpu_ioctl() warn:
potential spectre issue 'vgpu->vdev.region' [r]

Fix this by sanitizing info.index before indirectly using it to index

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].


Signed-off-by: default avatarGustavo A. R. Silva <>
Signed-off-by: default avatarZhenyu Wang <>
parent 8d458ea0
......@@ -43,6 +43,8 @@
#include <linux/mdev.h>
#include <linux/debugfs.h>
#include <linux/nospec.h>
#include "i915_drv.h"
#include "gvt.h"
......@@ -1139,7 +1141,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
struct vfio_region_info info;
struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
int i, ret;
unsigned int i;
int ret;
struct vfio_region_info_cap_sparse_mmap *sparse = NULL;
size_t size;
int nr_areas = 1;
......@@ -1224,6 +1227,10 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
if (info.index >= VFIO_PCI_NUM_REGIONS +
return -EINVAL;
info.index =
i = info.index - VFIO_PCI_NUM_REGIONS;
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