Am 29.03.2017 um 17:48 schrieb Felix Kuehling:
> Fix the start/end address calculation for address ranges that span
> multiple page directories in amdgpu_vm_alloc_levels.
>
> Add WARN_ONs if page tables aren't found. Otherwise the page table
> update would just fail silently.
>
> v2:
> * Change WARN_ON to WARN_ON_ONCE
> * Move masking of high address bits to caller
> * Add range-check for "from" and "to"
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 818747f..033852b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -275,13 +275,18 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
> memset(parent->entries, 0 , sizeof(struct amdgpu_vm_pt));
> }
>
> - from = (saddr >> shift) % amdgpu_vm_num_entries(adev, level);
> - to = (eaddr >> shift) % amdgpu_vm_num_entries(adev, level);
> + from = saddr >> shift;
> + to = eaddr >> shift;
> + if (from >= amdgpu_vm_num_entries(adev, level) ||
> + to >= amdgpu_vm_num_entries(adev, level))
> + return -EINVAL;
>
> if (to > parent->last_entry_used)
> parent->last_entry_used = to;
>
> ++level;
> + saddr = saddr & ((1 << shift) - 1);
> + eaddr = eaddr & ((1 << shift) - 1);
Why do you need this part? The modulo above should have handled that.
>
> /* walk over the address space and allocate the page tables */
> for (pt_idx = from; pt_idx <= to; ++pt_idx) {
> @@ -312,8 +317,11 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
> }
>
> if (level < adev->vm_manager.num_level) {
> - r = amdgpu_vm_alloc_levels(adev, vm, entry, saddr,
> - eaddr, level);
> + uint64_t sub_saddr = (pt_idx == from) ? saddr : 0;
> + uint64_t sub_eaddr = (pt_idx == to) ? eaddr :
> + ((1 << shift) - 1);
> + r = amdgpu_vm_alloc_levels(adev, vm, entry, sub_saddr,
> + sub_eaddr, level);
> if (r)
> return r;
> }
> @@ -957,9 +965,11 @@ static struct amdgpu_bo *amdgpu_vm_get_pt(struct amdgpu_pte_update_params *p,
> entry = &entry->entries[idx];
> }
>
> - if (level)
> + if (WARN_ON_ONCE(level))
> return NULL;
>
> + WARN_ON_ONCE(!entry->bo);
> +
Please drop those warnings. It is perfectly valid not to have the PT
allocated here.
Rather add a warning to the caller if it needs the BO.
> return entry->bo;
> }
>
