Re: [PATCH] drm/amdgpu/gmc: use PCI BARs for APUs in passthrough

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

Am 10.03.22 um 19:06 schrieb Alex Deucher:
> If the GPU is passed through to a guest VM, use the PCI
> BAR for CPU FB access rather than the physical address of
> carve out.  The physical address is not valid in a guest.
>
> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>

Reviewed-by: Christian König <christian.koenig@xxxxxxx>

> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 2 +-
>   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c  | 5 +++--
>   drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c  | 2 +-
>   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c  | 2 +-
>   4 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> index f60b7bd4dbf5..9887a60e8eae 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> @@ -814,7 +814,7 @@ static int gmc_v10_0_mc_init(struct amdgpu_device *adev)
>   	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
>   
>   #ifdef CONFIG_X86_64
> -	if (adev->flags & AMD_IS_APU) {
> +	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) {
>   		adev->gmc.aper_base = adev->gfxhub.funcs->get_mc_fb_offset(adev);
>   		adev->gmc.aper_size = adev->gmc.real_vram_size;
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> index 344d819b4c1b..979da6f510e8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> @@ -381,8 +381,9 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
>   	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
>   
>   #ifdef CONFIG_X86_64
> -	if (adev->flags & AMD_IS_APU &&
> -	    adev->gmc.real_vram_size > adev->gmc.aper_size) {
> +	if ((adev->flags & AMD_IS_APU) &&
> +	    adev->gmc.real_vram_size > adev->gmc.aper_size &&
> +	    !amdgpu_passthrough(adev)) {
>   		adev->gmc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
>   		adev->gmc.aper_size = adev->gmc.real_vram_size;
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> index ca9841d5669f..1932a3e4af7e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> @@ -581,7 +581,7 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
>   	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
>   
>   #ifdef CONFIG_X86_64
> -	if (adev->flags & AMD_IS_APU) {
> +	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) {
>   		adev->gmc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
>   		adev->gmc.aper_size = adev->gmc.real_vram_size;
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index 431742eb7811..5fa613d41799 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -1456,7 +1456,7 @@ static int gmc_v9_0_mc_init(struct amdgpu_device *adev)
>   	 */
>   
>   	/* check whether both host-gpu and gpu-gpu xgmi links exist */
> -	if ((adev->flags & AMD_IS_APU) ||
> +	if (((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) ||
>   	    (adev->gmc.xgmi.supported &&
>   	     adev->gmc.xgmi.connected_to_cpu)) {
>   		adev->gmc.aper_base =