From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752185AbbFYQom (ORCPT ); Thu, 25 Jun 2015 12:44:42 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38403 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbbFYQo3 (ORCPT ); Thu, 25 Jun 2015 12:44:29 -0400 From: Borislav Petkov To: Ingo Molnar Cc: LKML Subject: [PATCH 02/19] x86/msr, kvm: Remove vget_cycles() Date: Thu, 25 Jun 2015 18:43:56 +0200 Message-Id: <1435250653-30182-3-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.3.5 In-Reply-To: <1435250653-30182-1-git-send-email-bp@alien8.de> References: <1435250653-30182-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Lutomirski The only caller was KVM's read_tsc(). The only difference between vget_cycles() and native_read_tsc() was that vget_cycles() returned zero instead of crashing on TSC-less systems. KVM already checks vclock_mode() before calling that function, so the extra check is unnecessary. Also, KVM (host-side) requires the TSC to exist. Signed-off-by: Andy Lutomirski Acked-by: Paolo Bonzini Cc: Denys Vlasenko Cc: Huang Rui Cc: John Stultz Cc: Len Brown Cc: Peter Zijlstra Cc: Ralf Baechle Cc: kvm ML Cc: x86-ml Link: http://lkml.kernel.org/r/20615df14ae2eb713ea7a5f5123c1dc4c7ca993d.1434501121.git.luto@kernel.org Signed-off-by: Borislav Petkov --- arch/x86/include/asm/tsc.h | 13 ------------- arch/x86/kvm/x86.c | 2 +- 2 files changed, 1 insertion(+), 14 deletions(-) diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index fd11128faf25..3da1cc1218ac 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -32,19 +32,6 @@ static inline cycles_t get_cycles(void) return ret; } -static __always_inline cycles_t vget_cycles(void) -{ - /* - * We only do VDSOs on TSC capable CPUs, so this shouldn't - * access boot_cpu_data (which is not VDSO-safe): - */ -#ifndef CONFIG_X86_TSC - if (!cpu_has_tsc) - return 0; -#endif - return (cycles_t)native_read_tsc(); -} - extern void tsc_init(void); extern void mark_tsc_unstable(char *reason); extern int unsynchronized_tsc(void); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 26eaeb522cab..c26faf408bce 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1430,7 +1430,7 @@ static cycle_t read_tsc(void) * but no one has ever seen it happen. */ rdtsc_barrier(); - ret = (cycle_t)vget_cycles(); + ret = (cycle_t)native_read_tsc(); last = pvclock_gtod_data.clock.cycle_last; -- 2.3.5