[Nouveau] [bug report] drm/nouveau/gsp/r535: add support for booting GSP-RM

[Danilo Krummrich]

On 11/7/23 20:00, Danilo Krummrich wrote:
> On 11/7/23 15:34, Dan Carpenter wrote:
>> Hello Ben Skeggs,
>>
>> The patch 176fdcbddfd2: "drm/nouveau/gsp/r535: add support for
>> booting GSP-RM" from Sep 19, 2023 (linux-next), leads to the
>> following Smatch static checker warning:
>>
>>     drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1016 r535_gsp_rpc_unloading_guest_driver()
>>     warn: 'rpc' isn't an ERR_PTR
>>
>> drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
>>      1010 static int
>>      1011 r535_gsp_rpc_unloading_guest_driver(struct nvkm_gsp *gsp, bool suspend)
>>      1012 {
>>      1013         rpc_unloading_guest_driver_v1F_07 *rpc;
>>      1014
>>      1015         rpc = nvkm_gsp_rpc_get(gsp, NV_VGPU_MSG_FUNCTION_UNLOADING_GUEST_DRIVER, sizeof(*rpc));
>>
>> nvkm_gsp_rpc_get() returns NULL on error.
> 
> There are also code paths where it can return an ERR_PTR. I think we need to check for IS_ERR_OR_NULL()...

Sorry, this is wrong, I just saw that r535_gsp_cmdq_get() calls r535_gsp_cmdq_get()
which returns an ERR_PTR. Put it neither handles the return value of
r535_gsp_cmdq_get() as ERR_PTR nor does it pass it through.

> 
>>
>> --> 1016         if (IS_ERR(rpc))
>>      1017                 return PTR_ERR(rpc);
>>      1018
>>      1019         if (suspend) {
>>      1020                 rpc->bInPMTransition = 1;
>>      1021                 rpc->bGc6Entering = 0;
>>      1022                 rpc->newLevel = NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_3;
>>      1023         } else {
>>      1024                 rpc->bInPMTransition = 0;
>>      1025                 rpc->bGc6Entering = 0;
>>      1026                 rpc->newLevel = NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_0;
>>      1027         }
>>      1028
>>      1029         return nvkm_gsp_rpc_wr(gsp, rpc, true);
>>      1030 }
>>
>> regards,
>> dan carpenter