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Lu Baolu
857f081426
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>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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