From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bn3nam01on0120.outbound.protection.outlook.com ([104.47.33.120]:58346 "EHLO NAM01-BN3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1031884AbeCAPXb (ORCPT ); Thu, 1 Mar 2018 10:23:31 -0500 From: Sasha Levin To: "stable@vger.kernel.org" , "stable-commits@vger.kernel.org" CC: Andy Lutomirski , Ingo Molnar , Sasha Levin Subject: [added to the 4.1 stable tree] x86/mm: If INVPCID is available, use it to flush global mappings Date: Thu, 1 Mar 2018 15:22:30 +0000 Message-ID: <20180301152116.1486-8-alexander.levin@microsoft.com> References: <20180301152116.1486-1-alexander.levin@microsoft.com> In-Reply-To: <20180301152116.1486-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Andy Lutomirski This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ Upstream commit d8bced79af1db6734f66b42064cc773cada2ce99 ] On my Skylake laptop, INVPCID function 2 (flush absolutely everything) takes about 376ns, whereas saving flags, twiddling CR4.PGE to flush global mappings, and restoring flags takes about 539ns. Signed-off-by: Andy Lutomirski Reviewed-by: Borislav Petkov Cc: Andrew Morton Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Toshi Kani Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/ed0ef62581c0ea9c99b9bf6df726015e96d44743.145= 4096309.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/include/asm/tlbflush.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflus= h.h index ed2317f19ec7..433eeaafe498 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -152,6 +152,15 @@ static inline void __native_flush_tlb_global(void) { unsigned long flags; =20 + if (static_cpu_has(X86_FEATURE_INVPCID)) { + /* + * Using INVPCID is considerably faster than a pair of writes + * to CR4 sandwiched inside an IRQ flag save/restore. + */ + invpcid_flush_all(); + return; + } + /* * Read-modify-write to CR4 - protect it from preemption and * from interrupts. (Use the raw variant because this code can --=20 2.14.1