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Subject[PATCH 0/4] x86/cpu: Use SERIALIZE in sync_core()
Date
A recent submission to LKML introduced a CPU feature flag for a new
Intel architecture Serializing Instruction, SERIALIZE [1]. Unlike the
existing Serializing Instructions, this new instruction does not have
side effects such as clobbering registers or exiting to a hypervisor.

As stated in the Intel "extensions" (ISE) manual [2], this instruction
will appear first in Sapphire Rapids and Alder Lake.

Andy Lutomirski suggested to use this instruction in sync_core() as it
serves the very purpose of this function [3].

For completeness, I picked patch #3 from Cathy's series (and has become
patch #1 here) [1]. Her series depends on such patch to build correctly.
Maybe it can be merged independently while the discussion continues?

Thanks and BR,
Ricardo

[1]. https://lore.kernel.org/kvm/1594088183-7187-1-git-send-email-cathy.zhang@intel.com/
[2]. https://software.intel.com/sites/default/files/managed/c5/15/architecture-instruction-set-extensions-programming-reference.pdf
[3]. https://lore.kernel.org/kvm/CALCETrWudiF8G8r57r5i4JefuP5biG1kHg==0O8YXb-bYS-0BA@mail.gmail.com/

Ricardo Neri (4):
x86/cpufeatures: Add enumeration for SERIALIZE instruction
x86/cpu: Relocate sync_core() to sync_core.h
x86/cpu: Refactor sync_core() for readability
x86/cpu: Use SERIALIZE in sync_core() when available

arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/processor.h | 64 ----------------------
arch/x86/include/asm/special_insns.h | 4 ++
arch/x86/include/asm/sync_core.h | 80 ++++++++++++++++++++++++++++
arch/x86/kernel/alternative.c | 1 +
arch/x86/kernel/cpu/mce/core.c | 1 +
drivers/misc/sgi-gru/grufault.c | 1 +
drivers/misc/sgi-gru/gruhandles.c | 1 +
drivers/misc/sgi-gru/grukservices.c | 1 +
9 files changed, 90 insertions(+), 64 deletions(-)

--
2.17.1

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