x86/mmu: Allocate/free a PASID
A PASID is allocated for an "mm" the first time any thread binds to an SVA-capable device and is freed from the "mm" when the SVA is unbound by the last thread. It's possible for the "mm" to have different PASID values in different binding/unbinding SVA cycles. The mm's PASID (non-zero for valid PASID or 0 for invalid PASID) is propagated to a per-thread PASID MSR for all threads within the mm through IPI, context switch, or inherited. This is done to ensure that a running thread has the right PASID in the MSR matching the mm's PASID. [ bp: s/SVM/SVA/g; massage. ] Suggested-by:Andy Lutomirski <luto@kernel.org> Signed-off-by:
Fenghua Yu <fenghua.yu@intel.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Reviewed-by:
Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/1600187413-163670-10-git-send-email-fenghua.yu@intel.com
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