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Fenghua Yu
6e3133d901
The ENQCMD instruction implicitly accesses the PASID_MSR to fill in the pasid field of the descriptor being submitted to an accelerator. But there is no precise (and stable across kernel changes) point at which the PASID_MSR is updated from the value for one task to the next. Kernel code that uses accelerators must always use the ENQCMDS instruction which does not access the PASID_MSR. Check for use of the ENQCMD instruction in the kernel and warn on its usage. Signed-off-by: Fenghua Yu <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Reviewed-by: Tony Luck <[email protected]> Acked-by: Josh Poimboeuf <[email protected]> Link: https://lore.kernel.org/r/[email protected]