drm/i915/gvt: use array to avoid potential buffer overflow

Array 'pdp_pair' of size 1 may use index value(s) 1..7.
Changed to pdps[8] to avoid confusion.
Signed-off-by: Xinyun Liu <xinyun.liu@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/execlist.h

@@ -146,14 +146,11 @@ struct execlist_ring_context {
 	u32 nop4;
 	u32 lri_cmd_2;
 	struct execlist_mmio_pair ctx_timestamp;
-	struct execlist_mmio_pair pdp3_UDW;
-	struct execlist_mmio_pair pdp3_LDW;
-	struct execlist_mmio_pair pdp2_UDW;
-	struct execlist_mmio_pair pdp2_LDW;
-	struct execlist_mmio_pair pdp1_UDW;
-	struct execlist_mmio_pair pdp1_LDW;
-	struct execlist_mmio_pair pdp0_UDW;
-	struct execlist_mmio_pair pdp0_LDW;
+	/*
+	 * pdps[8]={ pdp3_UDW, pdp3_LDW, pdp2_UDW, pdp2_LDW,
+	 *           pdp1_UDW, pdp1_LDW, pdp0_UDW, pdp0_LDW}
+	 */
+	struct execlist_mmio_pair pdps[8];
 };
 
 struct intel_vgpu_elsp_dwords {

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

@@ -45,11 +45,10 @@ static void set_context_pdp_root_pointer(
 		struct execlist_ring_context *ring_context,
 		u32 pdp[8])
 {
-	struct execlist_mmio_pair *pdp_pair = &ring_context->pdp3_UDW;
 	int i;
 
 	for (i = 0; i < 8; i++)
-		pdp_pair[i].val = pdp[7 - i];
+		ring_context->pdps[i].val = pdp[7 - i];
 }
 
 static void update_shadow_pdps(struct intel_vgpu_workload *workload)
@@ -1230,7 +1229,7 @@ static void read_guest_pdps(struct intel_vgpu *vgpu,
 	u64 gpa;
 	int i;
 
-	gpa = ring_context_gpa + RING_CTX_OFF(pdp3_UDW.val);
+	gpa = ring_context_gpa + RING_CTX_OFF(pdps[0].val);
 
 	for (i = 0; i < 8; i++)
 		intel_gvt_hypervisor_read_gpa(vgpu,