On 2021-03-29 21:36 +0200, Christian König wrote: > Am 29.03.21 um 21:27 schrieb Xi Ruoyao: > > Hi Christian, > > > > I don't think there is any constraint implemented to ensure `num_entries % > > AMDGPU_GPU_PAGES_IN_CPU_PAGE == 0`. For example, in `amdgpu_vm_bo_map()`: > > > > /* validate the parameters */ > > if (saddr & AMDGPU_GPU_PAGE_MASK || offset & AMDGPU_GPU_PAGE_MASK > > || > > size == 0 || size & AMDGPU_GPU_PAGE_MASK) > > return -EINVAL; > > > > /* snip */ > > > > saddr /= AMDGPU_GPU_PAGE_SIZE; > > eaddr /= AMDGPU_GPU_PAGE_SIZE; > > > > /* snip */ > > > > mapping->start = saddr; > > mapping->last = eaddr; > > > > > > If we really want to ensure (mapping->last - mapping->start + 1) % > > AMDGPU_GPU_PAGES_IN_CPU_PAGE == 0, then we should replace > > "AMDGPU_GPU_PAGE_MASK" > > in "validate the parameters" with "PAGE_MASK". > > Yeah, good point. > > > I tried it and it broke userspace: Xorg startup fails with EINVAL with this > > change. > > Well in theory it is possible that we always fill the GPUVM on a 4k > basis while the native page size of the CPU is larger. Let me double > check the code. > > BTW: What code base are you based on? The code your post here is quite > outdated. Linus' tree. I'll go to sleep now (it's 03:39 here :( ), when I wake up I can try to fetch drm-next or something. -- Xi Ruoyao <xry111@xxxxxxxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University
