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From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>,
	Andy Lutomirski <luto@kernel.org>,
	x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Cathy Zhang <cathy.zhang@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Kyung Min Park <kyung.min.park@intel.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	linux-kernel@vger.kernel.org,
	Ricardo Neri <ricardo.neri@intel.com>,
	Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Subject: [PATCH 0/4] x86/cpu: Use SERIALIZE in sync_core()
Date: Sun, 26 Jul 2020 21:31:28 -0700
Message-ID: <20200727043132.15082-1-ricardo.neri-calderon@linux.intel.com> (raw)

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


             reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27  4:31 Ricardo Neri [this message]
2020-07-27  4:31 ` [PATCH 1/4] x86/cpufeatures: Add enumeration for SERIALIZE instruction Ricardo Neri
2020-07-27 12:46   ` [tip: x86/cpu] " tip-bot2 for Ricardo Neri
2020-07-27  4:31 ` [PATCH 2/4] x86/cpu: Relocate sync_core() to sync_core.h Ricardo Neri
2020-07-27 12:46   ` [tip: x86/cpu] " tip-bot2 for Ricardo Neri
2020-07-27  4:31 ` [PATCH 3/4] x86/cpu: Refactor sync_core() for readability Ricardo Neri
2020-07-27 12:46   ` [tip: x86/cpu] " tip-bot2 for Ricardo Neri
2020-07-27  4:31 ` [PATCH 4/4] x86/cpu: Use SERIALIZE in sync_core() when available Ricardo Neri
2020-07-27  5:55   ` hpa
2020-07-27  6:00     ` hpa
2020-07-27  8:36     ` peterz
2020-07-27 12:49       ` hpa
2020-07-27 13:05         ` peterz
2020-07-27 13:30           ` peterz
2020-07-28  4:41             ` Ricardo Neri
2020-07-28  8:50               ` peterz
2020-07-27 16:27     ` Luck, Tony
2020-07-27  8:20   ` peterz
2020-07-27 12:47     ` hpa
2020-07-28  0:55       ` Ricardo Neri
2020-07-28  0:36     ` Ricardo Neri
2020-07-27  8:23   ` peterz
2020-07-27 11:07 ` [PATCH 0/4] x86/cpu: Use SERIALIZE in sync_core() Ingo Molnar
2020-07-28  0:32   ` Ricardo Neri

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