Stack struct intel_gvt_gtt_entry value needs to be initialized before
being used, as the fields may contain garbage values.
W/o this patch, set_ggtt_entry prints:
-------------------------------------
274.046840: set_ggtt_entry: vgpu1:set ggtt entry 0x9bed8000ffffe900
274.046846: set_ggtt_entry: vgpu1:set ggtt entry 0xe55df001
274.046852: set_ggtt_entry: vgpu1:set ggtt entry 0x9bed8000ffffe900
0x9bed8000 is the stack grabage.
W/ this patch, set_ggtt_entry prints:
------------------------------------
274.046840: set_ggtt_entry: vgpu1:set ggtt entry 0xffffe900
274.046846: set_ggtt_entry: vgpu1:set ggtt entry 0xe55df001
274.046852: set_ggtt_entry: vgpu1:set ggtt entry 0xffffe900
v2:
- Initialize during declaration. (Zhenyu)
Fixes: 7598e8700e9a(drm/i915/gvt: Missed to cancel dma map for ggtt entries)
Cc: stable@xxxxxxxxxxxxxxx # v4.20+
Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Signed-off-by: Tina Zhang <tina.zhang@xxxxxxxxx>
---
drivers/gpu/drm/i915/gvt/gtt.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 15216c5b40aa..ebc1e5228bf5 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -2179,7 +2179,8 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
unsigned long g_gtt_index = off >> info->gtt_entry_size_shift;
unsigned long gma, gfn;
- struct intel_gvt_gtt_entry e, m;
+ struct intel_gvt_gtt_entry e = {.val64 = 0, .type = GTT_TYPE_GGTT_PTE};
+ struct intel_gvt_gtt_entry m = {.val64 = 0, .type = GTT_TYPE_GGTT_PTE};
dma_addr_t dma_addr;
int ret;
struct intel_gvt_partial_pte *partial_pte, *pos, *n;
@@ -2246,7 +2247,8 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
if (!partial_update && (ops->test_present(&e))) {
gfn = ops->get_pfn(&e);
- m = e;
+ m.val64 = e.val64;
+ m.type = e.type;
/* one PTE update may be issued in multiple writes and the
* first write may not construct a valid gfn
--
2.17.1
