Re: [PATCH] drm/msm: fix msm_gem_vma_new() allocations for managed GPUVMs

[Boris Brezillon <boris.brezillon@collabora.com>]

On Sat, 23 Aug 2025 03:12:00 +0300
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> wrote:

> Since commit 3309323241fb ("drm/gpuvm: Kill drm_gpuva_init()") MSM
> driver fails to init, failing with "[drm:msm_gpu_init] *ERROR* could not
> allocate memptrs: -22" errors. The mentioned commit reworked the
> function, but didn't take into account that op_map is initialized at the
> top of the function, while ranges might change if GPUVM is managed by
> the kernel.
> 
> Move op_mode initialization after finalizing all addresses and right
> before the drm_gpuva_init_from_op() call.
> 
> Reported-by: Danct12 <danct12@disroot.org>
> Fixes: 3309323241fb ("drm/gpuvm: Kill drm_gpuva_init()")
> Suggested-by: Rob Clark <robin.clark@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/msm/msm_gem_vma.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
> index 3f440bc1f7106f3b0091f037611d0b433e5e2c18..6df6b7c0984da57fe64de41fa54f7dea0a324c74 100644
> --- a/drivers/gpu/drm/msm/msm_gem_vma.c
> +++ b/drivers/gpu/drm/msm/msm_gem_vma.c
> @@ -368,12 +368,6 @@ struct drm_gpuva *
>  msm_gem_vma_new(struct drm_gpuvm *gpuvm, struct drm_gem_object *obj,
>  		u64 offset, u64 range_start, u64 range_end)
>  {
> -	struct drm_gpuva_op_map op_map = {
> -		.va.addr = range_start,
> -		.va.range = range_end - range_start,
> -		.gem.obj = obj,
> -		.gem.offset = offset,
> -	};
>  	struct msm_gem_vm *vm = to_msm_vm(gpuvm);
>  	struct drm_gpuvm_bo *vm_bo;
>  	struct msm_gem_vma *vma;
> @@ -402,6 +396,13 @@ msm_gem_vma_new(struct drm_gpuvm *gpuvm, struct drm_gem_object *obj,
>  	if (obj)
>  		GEM_WARN_ON((range_end - range_start) > obj->size);
>  
> +	struct drm_gpuva_op_map op_map = {
> +		.va.addr = range_start,
> +		.va.range = range_end - range_start,
> +		.gem.obj = obj,
> +		.gem.offset = offset,
> +	};

OOC, are we now allowed to declare local variables in the middle of a
code block in kernel code? I must admit that's not something I tried
doing recently, but I've had gcc warnings in the past because of that.

> +
>  	drm_gpuva_init_from_op(&vma->base, &op_map);
>  	vma->mapped = false;
>  
> 
> ---
> base-commit: 0f4c93f7eb861acab537dbe94441817a270537bf
> change-id: 20250823-msm-fix-gpuvm-init-520d87ebcf26
> 
> Best regards,