On 2025/5/7 18:03, Lazar, Lijo wrote:
On 5/7/2025 11:52 AM, Zhang, GuoQing (Sam) wrote:
[AMD Official Use Only - AMD Internal Distribution Only]


Please keep in mind that this is not the only scenario addressed by the
driver - for ex: a resume sequence is executed after a device reset.
This patch itself introduces unwanted sequences for other commonly used
usecases. Please rework on the series without breaking existing usecases.
Thanks,
Lijo
Hi @Lazar, Lijo<mailto:[email protected]>, Thank you for the feedback.

I also think the new code should be inside a check so that new code is
executed only on resume with different VF and do not break existing
usecases. Following is the implementation of this approach I can think of.

- introduce new field `prev_physical_node_id ` in `struct amdgpu_xgmi `.
update the fields on resume.

- put new code inside code block `if (prev_physical_node_id  !=
physical_node_id )`


Can this happen only with XGMI under this condition? Any other method
possible like preparing a 'unique signature' and matching it to identify
if it resumed on an identically configured system?

Yes, this hibernate-resume with different VF feature is only for devices with XGMI. Detecting XGMI node id change is the only way I can think of to identify the case. It's also a very simple way.

@Koenig, Christian <mailto:[email protected]> Are you OK with this approach, adding a check for the new code sequence?

Regardless, instead of having a direct check, better to wrap it inside
something like
        if (amdgpu_virt_need_migration()) or something more appropriate.

Yes, I will do that. Thank you!

Regards
Sam

Thanks,
Lijo

Is this approach acceptable? If not, can you suggest a better approach?
@Lazar, Lijo<mailto:[email protected]> @Koenig, Christian
<mailto:[email protected]> Thank you!

Regards

Sam

*From: *Lazar, Lijo<[email protected]>
*Date: *Tuesday, May 6, 2025 at 19:55
*To: *Zhang, GuoQing (Sam)<[email protected]>, amd-
[email protected] <[email protected]>
*Cc: *Zhao, Victor<[email protected]>, Chang, HaiJun
<[email protected]>, Koenig, Christian<[email protected]>,
Deucher, Alexander<[email protected]>, Zhang, Owen(SRDC)
<[email protected]>, Ma, Qing (Mark)<[email protected]>, Jiang Liu
<[email protected]>
*Subject: *Re: [PATCH v3 1/7] drm/amdgpu: update XGMI physical node id
and GMC configs on resume



On 5/6/2025 3:06 PM, Samuel Zhang wrote:
For virtual machine with vGPUs in SRIOV single device mode and XGMI
is enabled, XGMI physical node ids may change when waking up from
hiberation with different vGPU devices. So update XGMI physical node
ids on resume.

Please keep in mind that this is not the only scenario addressed by the
driver - for ex: a resume sequence is executed after a device reset.
This patch itself introduces unwanted sequences for other commonly used
usecases. Please rework on the series without breaking existing usecases.

Thanks,
Lijo

Update GPU memory controller configuration on resume if XGMI physical
node ids are changed.

Signed-off-by: Jiang Liu<[email protected]>
Signed-off-by: Samuel Zhang<[email protected]>
---
   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 24 ++++++++++++++++++++++
   drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c    |  3 +--
   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c      |  4 ++++
   3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/
drm/amd/amdgpu/amdgpu_device.c
index d477a901af84..e795af5067e5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -5040,6 +5040,27 @@ int amdgpu_device_suspend(struct drm_device
*dev, bool notify_clients)
         return 0;
   }
+static int amdgpu_device_update_xgmi_info(struct amdgpu_device *adev)
+{
+     int r;
+     unsigned int prev_physical_node_id;
+
+     /* Get xgmi info again for sriov to detect device changes */
+     if (amdgpu_sriov_vf(adev) &&
+         !(adev->flags & AMD_IS_APU) &&
+         adev->gmc.xgmi.supported &&
+         !adev->gmc.xgmi.connected_to_cpu) {
+             prev_physical_node_id = adev->gmc.xgmi.physical_node_id;
+             r = adev->gfxhub.funcs->get_xgmi_info(adev);
+             if (r)
+                     return r;
+
+             dev_info(adev->dev, "xgmi node, old id %d, new id %d\n",
+                     prev_physical_node_id, adev-
gmc.xgmi.physical_node_id);
+     }
+     return 0;
+}
+
   /**
    * amdgpu_device_resume - initiate device resume
    *
@@ -5059,6 +5080,9 @@ int amdgpu_device_resume(struct drm_device *dev,
bool notify_clients)
                 r = amdgpu_virt_request_full_gpu(adev, true);
                 if (r)
                         return r;
+             r = amdgpu_device_update_xgmi_info(adev);
+             if (r)
+                     return r;
         }
        if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/
drm/amd/amdgpu/amdgpu_gmc.c
index d1fa5e8e3937..a2abddf3c110 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -1298,8 +1298,7 @@ int amdgpu_gmc_get_nps_memranges(struct
amdgpu_device *adev,
         if (!mem_ranges || !exp_ranges)
                 return -EINVAL;
-     refresh = (adev->init_lvl->level !=
AMDGPU_INIT_LEVEL_MINIMAL_XGMI) &&
-               (adev->gmc.reset_flags & AMDGPU_GMC_INIT_RESET_NPS);
+     refresh = true;
         ret = amdgpu_discovery_get_nps_info(adev, &nps_type, &ranges,
                                             &range_cnt, refresh);
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/
amd/amdgpu/gmc_v9_0.c
index 59385da80185..1eb451a3743b 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -2533,6 +2533,10 @@ static int gmc_v9_0_resume(struct
amdgpu_ip_block *ip_block)
         struct amdgpu_device *adev = ip_block->adev;
         int r;
+     r = gmc_v9_0_mc_init(adev);
+     if (r)
+             return r;
+
         /* If a reset is done for NPS mode switch, read the memory range
          * information again.
          */

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