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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 B809AC433E0 for ; Fri, 19 Jun 2020 13:02:37 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 774E7208C7 for ; Fri, 19 Jun 2020 13:02:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 774E7208C7 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 160094B126; Fri, 19 Jun 2020 09:02:37 -0400 (EDT) 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 WsOxWUe8DhLK; Fri, 19 Jun 2020 09:02:35 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id BBB0A4B151; Fri, 19 Jun 2020 09:02:35 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 219FF4B126 for ; Fri, 19 Jun 2020 09:02:35 -0400 (EDT) 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 4p6RgTGFC+q3 for ; Fri, 19 Jun 2020 09:02:33 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 9B64E4B0BF for ; Fri, 19 Jun 2020 09:02:33 -0400 (EDT) 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 57F4A101E; Fri, 19 Jun 2020 06:02:33 -0700 (PDT) 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 29FCB3F6CF; Fri, 19 Jun 2020 06:02:26 -0700 (PDT) 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: [PATCH v13 8/9] ptp: arm64: Enable ptp_kvm for arm64 Date: Fri, 19 Jun 2020 21:01:19 +0800 Message-Id: <20200619130120.40556-9-jianyong.wu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200619130120.40556-1-jianyong.wu@arm.com> References: <20200619130120.40556-1-jianyong.wu@arm.com> Cc: justin.he@arm.com, Wei.Chen@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, there is no mechanism to keep time sync between guest and host in 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 as a reference clock to sync time between guest and host, has been adopted by x86 which makes the time sync order from milliseconds to nanoseconds. This patch enables kvm ptp clock for arm64 and improve clock sync precison significantly. Test result comparisons between with kvm ptp clock and without it in arm64 are 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 see that the clock difference between host and guest is in order of ns. Signed-off-by: Jianyong Wu --- drivers/clocksource/arm_arch_timer.c | 24 +++++++++++++ drivers/ptp/Kconfig | 2 +- drivers/ptp/ptp_kvm_arm64.c | 53 ++++++++++++++++++++++++++++ 3 files changed, 78 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 edc5be0ae324..69d30b407cd9 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1639,3 +1639,27 @@ 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; + + /* Currently, our guest will always use the virtual counter */ + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, + ARM_PTP_VIRT_COUNTER, &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 942f72d8151d..127e96f14f89 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 || 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/ptp_kvm_arm64.c b/drivers/ptp/ptp_kvm_arm64.c new file mode 100644 index 000000000000..704a7252b119 --- /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_FEATURES_FUNC_ID, + &hvc_res); + if (!(hvc_res.a0 | BIT(ARM_SMCCC_KVM_FUNC_KVM_PTP))) + 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 ((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 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm