Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756921AbdLVIuh (ORCPT ); Fri, 22 Dec 2017 03:50:37 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:33802 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756534AbdLVIud (ORCPT ); Fri, 22 Dec 2017 03:50:33 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Borislav Petkov , Andrew Morton , Andrey Ryabinin , Andy Lutomirski , Borislav Petkov , Brian Gerst , Dave Hansen , Denys Vlasenko , "H. Peter Anvin" , Linus Torvalds , "Luis R. Rodriguez" , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Toshi Kani , linux-mm@kvack.org, Ingo Molnar Subject: [PATCH 4.4 06/78] x86/mm: If INVPCID is available, use it to flush global mappings Date: Fri, 22 Dec 2017 09:45:47 +0100 Message-Id: <20171222084557.523764571@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084556.909780563@linuxfoundation.org> References: <20171222084556.909780563@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1901 Lines: 57 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit d8bced79af1db6734f66b42064cc773cada2ce99 upstream. 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/ed0ef62581c0ea9c99b9bf6df726015e96d44743.1454096309.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/tlbflush.h | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -159,6 +159,15 @@ static inline void __native_flush_tlb_gl { unsigned long flags; + 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