From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751152AbdAMSr7 (ORCPT ); Fri, 13 Jan 2017 13:47:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45590 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750713AbdAMSr5 (ORCPT ); Fri, 13 Jan 2017 13:47:57 -0500 Message-Id: <20170113184715.922841941@redhat.com> User-Agent: quilt/0.60-1 Date: Fri, 13 Jan 2017 16:45:59 -0200 From: Marcelo Tosatti To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paolo Bonzini , Radim Krcmar , Richard Cochran , Miroslav Lichvar , Marcelo Tosatti Subject: [patch 1/3] KVM: x86: provide realtime host clock via vsyscall notifiers References: <20170113184557.991929678@redhat.com> Content-Disposition: inline; filename=kvm-do-realtime X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 13 Jan 2017 18:47:58 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Expose the realtime host clock and save the TSC value used for the clock calculation. Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) v2: unify nsec_base (Radim) Index: kvm-ptpdriver/arch/x86/kvm/x86.c =================================================================== --- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 08:59:03.015895353 -0200 +++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-13 15:49:14.058347822 -0200 @@ -1139,6 +1139,7 @@ u64 boot_ns; u64 nsec_base; + u64 wall_time_sec; }; static struct pvclock_gtod_data pvclock_gtod_data; @@ -1162,6 +1163,8 @@ vdata->boot_ns = boot_ns; vdata->nsec_base = tk->tkr_mono.xtime_nsec; + vdata->wall_time_sec = tk->xtime_sec; + write_seqcount_end(&vdata->seq); } #endif @@ -1623,6 +1626,28 @@ return mode; } +static int do_realtime(struct timespec *ts, cycle_t *cycle_now) +{ + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; + unsigned long seq; + int mode; + u64 ns; + + do { + seq = read_seqcount_begin(>od->seq); + mode = gtod->clock.vclock_mode; + ts->tv_sec = gtod->wall_time_sec; + ns = gtod->nsec_base; + ns += vgettsc(cycle_now); + ns >>= gtod->clock.shift; + } while (unlikely(read_seqcount_retry(>od->seq, seq))); + + ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); + ts->tv_nsec = ns; + + return mode; +} + /* returns true if host is using tsc clocksource */ static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) { @@ -1632,6 +1657,17 @@ return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC; } + +/* returns true if host is using tsc clocksource */ +static bool kvm_get_walltime_and_clockread(struct timespec *ts, + cycle_t *cycle_now) +{ + /* checked again under seqlock below */ + if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC) + return false; + + return do_realtime(ts, cycle_now) == VCLOCK_TSC; +} #endif /*