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Some bioses > contain an identity mapping for address 0x0, which is not parsed > properly (e.g., certain Strix Halo devices). This causes the DMA > components of the device to fail to initialize (e.g., the NVMe SSD > controller), leading to a failed post. > > The failure is caused by iommu_create_device_direct_mappings(), which > is the new mapping implementation. In it, address aliasing is handled > via the following check: > > ``` > phys_addr = iommu_iova_to_phys(domain, addr); > if (!phys_addr) { > map_size += pg_size; > continue; > } > ```` Thanks for debugging and fixing it . Just wondering why can't we replace replace above check with pfn_valid() ? -Vasant > > Obviously, the iommu_iova_to_phys() signature is faulty and aliases > unmapped and 0 together, causing the allocation code to try to > re-allocate the 0 address per device. However, it has too many > instantiations to fix. Therefore, catch ret == -EADDRINUSE only when > addr == 0 and, instead of bailing, skip the mapping and print a warning. > > Closes: https://www.reddit.com/r/cachyos/comments/1r5sgr6/freeze_on_boot_after_kernel_update_to_619_fixed/ > Fixes: 789a5913b29c ("iommu/amd: Use the generic iommu page table") > Signed-off-by: Antheas Kapenekakis > --- > drivers/iommu/iommu.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 4926a43118e6..d424b7124311 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1224,6 +1224,11 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain, > ret = iommu_map(domain, addr - map_size, > addr - map_size, map_size, > entry->prot, GFP_KERNEL); > + if (ret == -EADDRINUSE && addr - map_size == 0) { > + dev_warn_once(dev, > + "iommu: identity mapping at addr 0x0 already exists, skipping\n"); > + ret = 0; > + } > if (ret) > goto out; > map_size = 0; > > base-commit: 57d76ceccee4b497eb835831206b50e72915a501