drm/amdgpu: check hive pointer before access

in case it is an invalid one
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c

@@ -395,12 +395,17 @@ void amdgpu_put_xgmi_hive(struct amdgpu_hive_info *hive)
 int amdgpu_xgmi_set_pstate(struct amdgpu_device *adev, int pstate)
 {
 	int ret = 0;
-	struct amdgpu_hive_info *hive = amdgpu_get_xgmi_hive(adev);
-	struct amdgpu_device *request_adev = hive->hi_req_gpu ?
-						hive->hi_req_gpu : adev;
+	struct amdgpu_hive_info *hive;
+	struct amdgpu_device *request_adev;
 	bool is_hi_req = pstate == AMDGPU_XGMI_PSTATE_MAX_VEGA20;
-	bool init_low = hive->pstate == AMDGPU_XGMI_PSTATE_UNKNOWN;
+	bool init_low;
+
+	hive = amdgpu_get_xgmi_hive(adev);
+	if (!hive)
+		return 0;
 
+	request_adev = hive->hi_req_gpu ? hive->hi_req_gpu : adev;
+	init_low = hive->pstate == AMDGPU_XGMI_PSTATE_UNKNOWN;
 	amdgpu_put_xgmi_hive(hive);
 	/* fw bug so temporarily disable pstate switching */
 	return 0;