On 3/26/25 10:43, Balbir Singh wrote: > On 3/26/25 10:21, Bert Karwatzki wrote: >> Am Mittwoch, dem 26.03.2025 um 09:45 +1100 schrieb Balbir Singh: >>> >>> >>> The second region seems to be additional, I suspect that is HMM mapping >>> from kgd2kfd_init_zone_device() >>> >>> Balbir Singh >>> >> Good guess! I inserted a printk into kgd2kfd_init_zone_device(): >> >> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c >> b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c >> index d05d199b5e44..201220e2ac42 100644 >> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c >> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c >> @@ -1049,6 +1049,8 @@ int kgd2kfd_init_zone_device(struct amdgpu_device >> *adev) >> pgmap->range.end = res->end; >> pgmap->type = MEMORY_DEVICE_PRIVATE; >> } >> + dev_info(adev->dev, "%s: range.start = 0x%llx ranges.end = 0x%llx\n", >> + __func__, pgmap->range.start, pgmap->range.end); >> >> pgmap->nr_range = 1; >> pgmap->ops = &svm_migrate_pgmap_ops; >> >> >> and get this in the case without nokaslr: >> >> [ T367] amdgpu 0000:03:00.0: kfd_migrate: kgd2kfd_init_zone_device: >> range.start = 0xafe00000000 ranges.end = 0xaffffffffff >> >> and this in the case with nokaslr: >> >> [ T365] amdgpu 0000:03:00.0: kfd_migrate: kgd2kfd_init_zone_device: >> range.start = 0x3ffe00000000 ranges.end = 0x3fffffffffff >> > > So we should ignore the second region then for the purposes of this issue. > > I think this now boils down to > > Why is the dma_get_required_mask set to all of addressable memory (46 bits) > when we have nokaslr >
I think I know the root cause of the required_mask going up and hence the use of DMA32 1. HMM calls add_pages() 2. add_pages calls update_end_of_memory_vars() 3. This updates max_pfn and that causes required_mask to go up to 46 bits Do you have CONFIG_HSA_AMD_SVM enabled? Does turning it off, fix the issue? The actual issue is the update of max_pfn. Balbir Singh
