From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AA08C2D0B1 for ; Tue, 10 Dec 2019 03:41:23 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id EF861208C3 for ; Tue, 10 Dec 2019 03:41:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF861208C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 98E994AF46; Mon, 9 Dec 2019 22:41:22 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ONRbMWg8BYhn; Mon, 9 Dec 2019 22:41:21 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 437F74A968; Mon, 9 Dec 2019 22:41:21 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 8CF3B4ACBE for ; Mon, 9 Dec 2019 22:41:20 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bpDfY7CmRbOc for ; Mon, 9 Dec 2019 22:41:19 -0500 (EST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1AD014A94D for ; Mon, 9 Dec 2019 22:41:19 -0500 (EST) 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 D5D581045; Mon, 9 Dec 2019 19:41:18 -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 B88233F52E; Mon, 9 Dec 2019 19:41:13 -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 Subject: [RFC PATCH v9 7/8] ptp: arm64: Enable ptp_kvm for arm64 Date: Tue, 10 Dec 2019 11:40:25 +0800 Message-Id: <20191210034026.45229-8-jianyong.wu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191210034026.45229-1-jianyong.wu@arm.com> References: <20191210034026.45229-1-jianyong.wu@arm.com> Cc: justin.he@arm.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, nd@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Currently in arm64 virtualization environment, there is no mechanism to keep time sync between guest and host. 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 some scenarios ask for higher time precision, like in cloud envirenment, we want all the VMs running in the host aquire the same level accuracy from host clock. Use of 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 enable kvm ptp on arm64 and we get the similar clock drift as found with x86 with kvm ptp. Test result comparison between with kvm ptp and without it in arm64 are as follows. This test derived from the result of command 'chronyc sources'. we should take more cure 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/ptp_kvm_arm64.c | 53 ++++++++++++++++++++++++++++ 3 files changed, 76 insertions(+), 1 deletion(-) create mode 100644 drivers/ptp/ptp_kvm_arm64.c diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 277846decd33..72260b66f02e 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1636,3 +1636,25 @@ 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_VENDOR_HYP_KVM_PTP_FUNC_ID, &hvc_res); + if ((long)(hvc_res.a0) < 0) + return -EOPNOTSUPP; + + ktime_overall = hvc_res.a0 << 32 | hvc_res.a1; + *ts = ktime_to_timespec64(ktime_overall); + *cycle = 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 9b8fee5178e8..3c31ff8eb05f 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -110,7 +110,7 @@ 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 || ARM64 && ARM_ARCH_TIMER default y help This driver adds support for using kvm infrastructure as a PTP diff --git a/drivers/ptp/ptp_kvm_arm64.c b/drivers/ptp/ptp_kvm_arm64.c new file mode 100644 index 000000000000..f3f957117865 --- /dev/null +++ b/drivers/ptp/ptp_kvm_arm64.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_VENDOR_HYP_KVM_PTP_FUNC_ID, + &hvc_res); + if ((long)(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_VENDOR_HYP_KVM_PTP_FUNC_ID, + hvc_res); + if ((long)(hvc_res->a0) < 0) + return -EOPNOTSUPP; + + ktime_overall = 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 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm