Patch "drm/amdgpu: Add lock around VF RLCG interface" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amdgpu: Add lock around VF RLCG interface

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amdgpu-add-lock-around-vf-rlcg-interface.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8a517f4726526705df098e74284186fe8952dd18
Author: Victor Skvortsov <victor.skvortsov@xxxxxxx>
Date:   Mon May 27 16:10:43 2024 -0400

    drm/amdgpu: Add lock around VF RLCG interface
    
    [ Upstream commit e864180ee49b4d30e640fd1e1d852b86411420c9 ]
    
    flush_gpu_tlb may be called from another thread while
    device_gpu_recover is running.
    
    Both of these threads access registers through the VF
    RLCG interface during VF Full Access. Add a lock around this interface
    to prevent race conditions between these threads.
    
    Signed-off-by: Victor Skvortsov <victor.skvortsov@xxxxxxx>
    Reviewed-by: Zhigang Luo <zhigang.luo@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index ea1bce13db941..eb663eb811563 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3561,6 +3561,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	mutex_init(&adev->grbm_idx_mutex);
 	mutex_init(&adev->mn_lock);
 	mutex_init(&adev->virt.vf_errors.lock);
+	mutex_init(&adev->virt.rlcg_reg_lock);
 	hash_init(adev->mn_hash);
 	mutex_init(&adev->psp.mutex);
 	mutex_init(&adev->notifier_lock);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index 96857ae7fb5bc..ff4f52e07cc0d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -1003,6 +1003,9 @@ static u32 amdgpu_virt_rlcg_reg_rw(struct amdgpu_device *adev, u32 offset, u32 v
 	scratch_reg1 = (void __iomem *)adev->rmmio + 4 * reg_access_ctrl->scratch_reg1;
 	scratch_reg2 = (void __iomem *)adev->rmmio + 4 * reg_access_ctrl->scratch_reg2;
 	scratch_reg3 = (void __iomem *)adev->rmmio + 4 * reg_access_ctrl->scratch_reg3;
+
+	mutex_lock(&adev->virt.rlcg_reg_lock);
+
 	if (reg_access_ctrl->spare_int)
 		spare_int = (void __iomem *)adev->rmmio + 4 * reg_access_ctrl->spare_int;
 
@@ -1058,6 +1061,9 @@ static u32 amdgpu_virt_rlcg_reg_rw(struct amdgpu_device *adev, u32 offset, u32 v
 	}
 
 	ret = readl(scratch_reg0);
+
+	mutex_unlock(&adev->virt.rlcg_reg_lock);
+
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
index fabb83e9d9aec..23b6efa9d25df 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
@@ -263,6 +263,8 @@ struct amdgpu_virt {
 
 	/* the ucode id to signal the autoload */
 	uint32_t autoload_ucode_id;
+
+	struct mutex rlcg_reg_lock;
 };
 
 struct amdgpu_video_codec_info;