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[209.132.180.67]) by mx.google.com with ESMTP id g26si4601816otk.324.2020.02.10.00.51.31; Mon, 10 Feb 2020 00:51:42 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727763AbgBJIuD (ORCPT + 99 others); Mon, 10 Feb 2020 03:50:03 -0500 Received: from foss.arm.com ([217.140.110.172]:57604 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727754AbgBJIuB (ORCPT ); Mon, 10 Feb 2020 03:50:01 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2703931B; Mon, 10 Feb 2020 00:50:01 -0800 (PST) Received: from entos-d05.shanghai.arm.com (entos-d05.shanghai.arm.com [10.169.40.35]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6FF9C3F68F; Mon, 10 Feb 2020 00:49:55 -0800 (PST) From: Jianyong Wu To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, sean.j.christopherson@intel.com, maz@kernel.org, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, steven.price@arm.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, Kaly.Xin@arm.com, justin.he@arm.com, jianyong.wu@arm.com, nd@arm.com Subject: [RFC PATCH 6/9] ptp: arm/arm64: Enable ptp_kvm for arm/arm64 Date: Mon, 10 Feb 2020 16:49:03 +0800 Message-Id: <20200210084906.24870-7-jianyong.wu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200210084906.24870-1-jianyong.wu@arm.com> References: <20200210084906.24870-1-jianyong.wu@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, there is no mechanism to keep time sync between guest and host in arm/arm64 virtualization environment. Time in guest will drift compared with host after boot up as they may both use third party time sources to correct their time respectively. The time deviation will be in order of milliseconds. But in some scenarios,like in cloud envirenment, we ask for higher time precision. kvm ptp clock, which choose the host clock source clock as a reference clock to sync time clock between guest and host has been adopted by x86 which makes the time sync order from milliseconds to nanoseconds. This patch enables kvm ptp on arm/arm64 and improve clock sync precison significantly. Test result comparison between with kvm ptp and without it in arm/arm64 is as follows. This test derived from the result of command 'chronyc sources'. we should take more care of the last sample column which shows the offset between the local clock and the source at the last measurement. no kvm ptp in guest: MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== ^* dns1.synet.edu.cn 2 6 377 13 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 21 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 29 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 37 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 45 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 53 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 61 +1040us[+1581us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 4 -130us[ +796us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 12 -130us[ +796us] +/- 21ms ^* dns1.synet.edu.cn 2 6 377 20 -130us[ +796us] +/- 21ms in host: MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== ^* 120.25.115.20 2 7 377 72 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 92 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 112 -470us[ -603us] +/- 18ms ^* 120.25.115.20 2 7 377 2 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 22 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 43 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 63 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 83 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 103 +872ns[-6808ns] +/- 17ms ^* 120.25.115.20 2 7 377 123 +872ns[-6808ns] +/- 17ms The dns1.synet.edu.cn is the network reference clock for guest and 120.25.115.20 is the network reference clock for host. we can't get the clock error between guest and host directly, but a roughly estimated value will be in order of hundreds of us to ms. with kvm ptp in guest: chrony has been disabled in host to remove the disturb by network clock. MS Name/IP address Stratum Poll Reach LastRx Last sample ======================================================================== * PHC0 0 3 377 8 -7ns[ +1ns] +/- 3ns * PHC0 0 3 377 8 +1ns[ +16ns] +/- 3ns * PHC0 0 3 377 6 -4ns[ -0ns] +/- 6ns * PHC0 0 3 377 6 -8ns[ -12ns] +/- 5ns * PHC0 0 3 377 5 +2ns[ +4ns] +/- 4ns * PHC0 0 3 377 13 +2ns[ +4ns] +/- 4ns * PHC0 0 3 377 12 -4ns[ -6ns] +/- 4ns * PHC0 0 3 377 11 -8ns[ -11ns] +/- 6ns * PHC0 0 3 377 10 -14ns[ -20ns] +/- 4ns * PHC0 0 3 377 8 +4ns[ +5ns] +/- 4ns The PHC0 is the ptp clock which choose the host clock as its source clock. So we can be sure to say that the clock error between host and guest is in order of ns. Signed-off-by: Jianyong Wu --- drivers/clocksource/arm_arch_timer.c | 22 ++++++++++++ drivers/ptp/Kconfig | 2 +- drivers/ptp/Makefile | 6 +++- drivers/ptp/ptp_kvm_arm.c | 53 ++++++++++++++++++++++++++++ 4 files changed, 81 insertions(+), 2 deletions(-) create mode 100644 drivers/ptp/ptp_kvm_arm.c diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 4eb014fefa5b..4e57ab66165c 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1625,3 +1625,25 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) } TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init); #endif + +#if IS_ENABLED(CONFIG_PTP_1588_CLOCK_KVM) +#include +int kvm_arch_ptp_get_crosststamp(unsigned long *cycle, struct timespec64 *ts, + struct clocksource **cs) +{ + struct arm_smccc_res hvc_res; + ktime_t ktime_overall; + + arm_smccc_1_1_invoke(ARM_SMCCC_HYP_KVM_PTP_FUNC_ID, &hvc_res); + if ((int)(hvc_res.a0) < 0) + return -EOPNOTSUPP; + + ktime_overall = (long long)hvc_res.a0 << 32 | hvc_res.a1; + *ts = ktime_to_timespec64(ktime_overall); + *cycle = (long long)hvc_res.a2 << 32 | hvc_res.a3; + *cs = &clocksource_counter; + + return 0; +} +EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp); +#endif diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index 475c60dccaa4..dfb536d14b44 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -106,7 +106,7 @@ config PTP_1588_CLOCK_PCH config PTP_1588_CLOCK_KVM tristate "KVM virtual PTP clock" depends on PTP_1588_CLOCK - depends on KVM_GUEST && X86 + depends on KVM_GUEST && X86 || (ARM || ARM64) && ARM_ARCH_TIMER && ARM_PSCI_FW default y help This driver adds support for using kvm infrastructure as a PTP diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index 06837d089347..f6688de74a8e 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -3,8 +3,12 @@ # Makefile for PTP 1588 clock support. # +ifeq ($(ARCH), arm64) + ptp_kvm-y := ptp_kvm_arm.o ptp_kvm_common.o +else + ptp_kvm-y := ptp_kvm_$(ARCH).o ptp_kvm_common.o +endif ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o -ptp_kvm-y := ptp_kvm_$(ARCH).o ptp_kvm_common.o obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o obj-$(CONFIG_PTP_1588_CLOCK_DTE) += ptp_dte.o obj-$(CONFIG_PTP_1588_CLOCK_INES) += ptp_ines.o diff --git a/drivers/ptp/ptp_kvm_arm.c b/drivers/ptp/ptp_kvm_arm.c new file mode 100644 index 000000000000..9752e849e0ae --- /dev/null +++ b/drivers/ptp/ptp_kvm_arm.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Virtual PTP 1588 clock for use with KVM guests + * Copyright (C) 2019 ARM Ltd. + * All Rights Reserved + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +int kvm_arch_ptp_init(void) +{ + struct arm_smccc_res hvc_res; + + arm_smccc_1_1_invoke(ARM_SMCCC_HYP_KVM_PTP_FUNC_ID, + &hvc_res); + if ((int)(hvc_res.a0) < 0) + return -EOPNOTSUPP; + + return 0; +} + +int kvm_arch_ptp_get_clock_generic(struct timespec64 *ts, + struct arm_smccc_res *hvc_res) +{ + ktime_t ktime_overall; + + arm_smccc_1_1_invoke(ARM_SMCCC_HYP_KVM_PTP_FUNC_ID, + hvc_res); + if ((int)(hvc_res->a0) < 0) + return -EOPNOTSUPP; + + ktime_overall = (long long)hvc_res->a0 << 32 | hvc_res->a1; + *ts = ktime_to_timespec64(ktime_overall); + + return 0; +} + +int kvm_arch_ptp_get_clock(struct timespec64 *ts) +{ + struct arm_smccc_res hvc_res; + + kvm_arch_ptp_get_clock_generic(ts, &hvc_res); + + return 0; +} -- 2.17.1