On 2019.05.23 06:18:36 +0800, Tina Zhang wrote:
> 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>
> ---
Will merge this, thanks for the fix!
Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> 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
>
--
Open Source Technology Center, Intel ltd.
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