Problems in the old code to manage SVM (Shared Virtual Memory) devices and the PASID (Process Address Space ID) led to that code being disabled.
Subsequent discussions resulted in a far simpler approach: 1) PASID life cycle is from first allocation by a process until that process exits. 2) All tasks begin with PASID disabled 3) The #GP fault handler tries to fix faulting ENQCMD instructions very early (thus avoiding complexities of the XSAVE infrastructure) Change Log: v4: - Update commit message in patch #4 (Thomas). - Update commit message in patch #5 (Thomas). - Add "Reviewed-by: Thomas Gleixner <t...@linutronix.de>" in patch #1-#3 and patch #6-#9 (Thomas). - Rebased to 5.17-rc3. v3 can be found at https://lore.kernel.org/lkml/20220128202905.2274672-7-fenghua...@intel.com/T/#m039e1a201e9894d99b117fa6005bc05724a5a4bb v3: - Rename mm_pasid_get() to mm_pasid_set() in patch #5 (Thomas). - Remove ioasid_get() because it's not used any more when the IOASID is freed on mm exit in patch #5 (Thomas). - Remove PASID's refcount exercise in ioasid_put() and rename ioasid_put() to ioasid_free() in patch #5 and #11 (Thomas). - Add Acked-by: Josh Poimboeuf <jpoim...@redhat.com> in patch #10. v2 can be found at https://lore.kernel.org/lkml/20211217220136.2762116-1-fenghua...@intel.com/ v2: - Free PASID on mm exit instead of in exit(2) or unbind() (Thomas, AndyL, PeterZ) - Directly write IA32_PASID MSR in fixup while local IRQ is still disabled (Thomas) - Simplify handling ENQCMD in objtool (PeterZ and Josh) - Define mm_pasid_get(), mm_pasid_drop(), and mm_pasid_init() in mm and call the functions from IOMMU (Dave Hansen). - A few changes in the #GP fixup function (Dave Hansen, Tony Luck). - Initial PASID value is changed to INVALID_PASID (Ashok Raj and Jacob Pan). - Add mm_pasid_init(), mm_pasid_get(), and mm_pasid_drop() functions in mm. So the mm's PASID operations are generic for both X86 and ARM (Dave Hansen). - Rename CONFIG_IOMMU_SVA_LIB to more useful and accurate CONFIG_IOMMU_SVA - Use CONFIG_IOMMU_SVA for PASID processing condition (Jacob) - The patch that cleans up old update_pasid() function is in upstream now (commit: 00ecd5401349 "iommu/vt-d: Clean up unused PASID updating functions") and therefore it's removed from this version. v1 can be found at https://lore.kernel.org/lkml/20210920192349.2602141-1-fenghua...@intel.com/T/#md6d542091da1d1159eda0a44a16e57d0c0dfb209 Fenghua Yu (10): iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA mm: Change CONFIG option for mm->pasid field iommu/ioasid: Introduce a helper to check for valid PASIDs kernel/fork: Initialize mm's PASID iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit x86/fpu: Clear PASID when copying fpstate x86/traps: Demand-populate PASID MSR via #GP x86/cpufeatures: Re-enable ENQCMD tools/objtool: Check for use of the ENQCMD instruction in the kernel docs: x86: Change documentation for SVA (Shared Virtual Addressing) Peter Zijlstra (1): sched: Define and initialize a flag to identify valid PASID in the task Documentation/x86/sva.rst | 53 ++++++++++++++---- arch/x86/include/asm/disabled-features.h | 7 ++- arch/x86/kernel/fpu/core.c | 7 +++ arch/x86/kernel/traps.c | 55 +++++++++++++++++++ drivers/iommu/Kconfig | 6 +- drivers/iommu/Makefile | 2 +- .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 5 +- drivers/iommu/intel/Kconfig | 2 +- drivers/iommu/intel/iommu.c | 4 +- drivers/iommu/intel/svm.c | 9 --- drivers/iommu/ioasid.c | 39 ++----------- drivers/iommu/iommu-sva-lib.c | 39 ++++--------- drivers/iommu/iommu-sva-lib.h | 7 +-- include/linux/ioasid.h | 21 +++---- include/linux/mm_types.h | 2 +- include/linux/sched.h | 3 + include/linux/sched/mm.h | 26 +++++++++ kernel/fork.c | 15 +++-- mm/init-mm.c | 4 ++ tools/objtool/arch/x86/decode.c | 11 +++- 20 files changed, 197 insertions(+), 120 deletions(-) -- 2.35.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
