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authorLu Baolu <baolu.lu@linux.intel.com>2020-01-16 09:52:36 +0800
committerJoerg Roedel <jroedel@suse.de>2020-01-24 15:36:27 +0100
commit857f081426e5aa38313426c13373730f1345fe95 (patch)
treefd668324161acf08279b99b80b6ae264f7ecc222 /Documentation
parentiommu/vt-d: Unnecessary to handle default identity domain (diff)
downloadlinux-dev-857f081426e5aa38313426c13373730f1345fe95.tar.xz
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iommu/vt-d: Remove unnecessary WARN_ON_ONCE()
Address field in device TLB invalidation descriptor is qualified by the S field. If S field is zero, a single page at page address specified by address [63:12] is requested to be invalidated. If S field is set, the least significant bit in the address field with value 0b (say bit N) indicates the invalidation address range. The spec doesn't require the address [N - 1, 0] to be cleared, hence remove the unnecessary WARN_ON_ONCE(). Otherwise, the caller might set "mask = MAX_AGAW_PFN_WIDTH" in order to invalidating all the cached mappings on an endpoint, and below overflow error will be triggered. [...] UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1354:3 shift exponent 64 is too large for 64-bit type 'long long unsigned int' [...] Reported-and-tested-by: Frank <fgndev@posteo.de> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
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