drm/amdgpu: Disallow partition query during reset

Reject queries to get current partition modes during reset. Also, don't
accept sysfs interface requests to switch compute partition mode while
in reset.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Lijo Lazar

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

@@ -1353,6 +1353,10 @@ static ssize_t amdgpu_gfx_get_current_compute_partition(struct device *dev,
 	struct amdgpu_device *adev = drm_to_adev(ddev);
 	int mode;
 
+	/* Only minimal precaution taken to reject requests while in reset.*/
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+
 	mode = amdgpu_xcp_query_partition_mode(adev->xcp_mgr,
 					       AMDGPU_XCP_FL_NONE);
 
@@ -1396,8 +1400,14 @@ static ssize_t amdgpu_gfx_set_compute_partition(struct device *dev,
 		return -EINVAL;
 	}
 
+	/* Don't allow a switch while under reset */
+	if (!down_read_trylock(&adev->reset_domain->sem))
+		return -EPERM;
+
 	ret = amdgpu_xcp_switch_partition_mode(adev->xcp_mgr, mode);
 
+	up_read(&adev->reset_domain->sem);
+
 	if (ret)
 		return ret;
 

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

@@ -1230,6 +1230,10 @@ static ssize_t current_memory_partition_show(
 	struct amdgpu_device *adev = drm_to_adev(ddev);
 	enum amdgpu_memory_partition mode;
 
+	/* Only minimal precaution taken to reject requests while in reset */
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+
 	mode = adev->gmc.gmc_funcs->query_mem_partition_mode(adev);
 	if ((mode >= ARRAY_SIZE(nps_desc)) ||
 	    (BIT(mode) & AMDGPU_ALL_NPS_MASK) != BIT(mode))