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Commit 6bdc692f authored by Tina Zhang's avatar Tina Zhang Committed by Greg Kroah-Hartman
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drm/i915/gvt: Initialize intel_gvt_gtt_entry in stack 



commit 387a4c2b55291b37e245c840813bd8a8bd06ed49 upstream.

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: 7598e870 ("drm/i915/gvt: Missed to cancel dma map for ggtt entries")
Cc: stable@vger.kernel.org # v4.20+
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: default avatarTina Zhang <tina.zhang@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fbb7e114

drivers/gpu/drm/i915/gvt/gtt.c

+4 −2
Original line number Diff line number Diff line
@@ -2161,7 +2161,8 @@ 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;
@@ -2237,7 +2238,8 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off, 


	if (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