Re: [PATCH v5 4/4] drm/amdgpu: fix fence fallback timer expired error

[Lazar, Lijo]

On 5/12/2025 12:11 PM, Samuel Zhang wrote:
> IH is not working after switching a new gpu index for the first time.
> 
> The msix table in virtual machine is faked. The real msix table will be
> programmed by QEMU when guest enable/disable msix interrupt. But QEMU
> accessing VF msix table (register GFXMSIX_VECT0_ADDR_LO) is blocked
> by nBIF protection if the VF isn't in exclusive access at that time.
> 
> call amdgpu_restore_msix on resume to restore msix table.
> 
> Signed-off-by: Samuel Zhang <guoqing.zh...@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c | 2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h | 1 +
>  drivers/gpu/drm/amd/amdgpu/vega20_ih.c  | 4 ++++
>  3 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> index 0e890f2785b1..f080354efec8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> @@ -245,7 +245,7 @@ static bool amdgpu_msi_ok(struct amdgpu_device *adev)
>       return true;
>  }
>  
> -static void amdgpu_restore_msix(struct amdgpu_device *adev)
> +void amdgpu_restore_msix(struct amdgpu_device *adev)
>  {
>       u16 ctrl;
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h
> index aef5c216b191..f52bd7e6d988 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.h
> @@ -149,5 +149,6 @@ void amdgpu_irq_gpu_reset_resume_helper(struct 
> amdgpu_device *adev);
>  int amdgpu_irq_add_domain(struct amdgpu_device *adev);
>  void amdgpu_irq_remove_domain(struct amdgpu_device *adev);
>  unsigned amdgpu_irq_create_mapping(struct amdgpu_device *adev, unsigned 
> src_id);
> +void amdgpu_restore_msix(struct amdgpu_device *adev);
>  
>  #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c 
> b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> index faa0dd75dd6d..53c253102449 100644
> --- a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> +++ b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> @@ -648,6 +648,10 @@ static int vega20_ih_suspend(struct amdgpu_ip_block 
> *ip_block)
>  
>  static int vega20_ih_resume(struct amdgpu_ip_block *ip_block)
>  {
> +     struct amdgpu_device *adev = ip_block->adev;
> +
> +     if (amdgpu_sriov_vf(adev))
> +             amdgpu_restore_msix(adev);

You may consider consolidating these under amdgpu_device_resume() ->
amdgpu_virt_resume_after_migration()

amdgpu_virt_resume_after_migration()
{
        virt_update_xgmi_info
        virt_vram_offset_update
        restore_msix
}

Thanks,
Lijo

>       return vega20_ih_hw_init(ip_block);
>  }
>