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 The code your post here is quite outdated.
Christian.
On 2021-03-30 02:30 +0800, Xi Ruoyao wrote:
On 2021-03-30 02:21 +0800, Xi Ruoyao wrote:
On 2021-03-29 20:10 +0200, Christian König wrote:
You need to identify the root cause of this, most likely start or last are not a multiple of AMDGPU_GPU_PAGES_IN_CPU_PAGE.
I printk'ed the value of start & last, they are all a multiple of 4 (AMDGPU_GPU_PAGES_IN_CPU_PAGE).
However... `num_entries = last - start + 1` so it became some irrational thing... Either this line is wrong, or someone called amdgpu_vm_bo_update_mapping with [start, last) instead of [start, last], which is unexpected.
I added BUG_ON(num_entries % AMDGPU_GPU_PAGES_IN_CPU_PAGE != 0), get:
Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c90750>] amdgpu_vm_bo_update_mapping.constprop.0+0x218/0xae8 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c922b8>] amdgpu_vm_bo_update+0x270/0x4c0 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c823ec>] amdgpu_gem_va_ioctl+0x40c/0x430 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c1cae4>] drm_ioctl_kernel+0xcc/0x120 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c1cfd8>] drm_ioctl+0x220/0x408 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff83c5ea48>] amdgpu_drm_ioctl+0x58/0x98 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff838feac4>] sys_ioctl+0xcc/0xe8 Mar 30 02:28:27 xry111-A1901 kernel: [<ffffffff836e74f0>] syscall_common+0x34/0x58
> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1549 > Fixes: a39f2a8d7066 ("drm/amdgpu: nuke amdgpu_vm_bo_split_mapping v2") > Reported-by: Xi Ruoyao xry111@mengyan1223.wang > Reported-by: Dan Horák dan@danny.cz > Cc: stable@vger.kernel.org > Signed-off-by: Xi Ruoyao xry111@mengyan1223.wang > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c > index ad91c0c3c423..cee0cc9c8085 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c > @@ -1707,7 +1707,7 @@ static int amdgpu_vm_bo_update_mapping(struct > amdgpu_device *adev, > } > start = tmp; > > - } while (unlikely(start != last + 1)); > + } while (unlikely(start < last + 1)); > > r = vm->update_funcs->commit(¶ms, fence); > > > base-commit: a5e13c6df0e41702d2b2c77c8ad41677ebb065b3