From patchwork Tue Mar 30 14:54:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 412270 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 595E0C433F8 for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42FF3619EC for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232367AbhC3OzV (ORCPT ); Tue, 30 Mar 2021 10:55:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:55494 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231951AbhC3Oys (ORCPT ); Tue, 30 Mar 2021 10:54:48 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CEB2D619D0; Tue, 30 Mar 2021 14:54:47 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lRFlW-004hoo-70; Tue, 30 Mar 2021 15:54:46 +0100 From: Marc Zyngier To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@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, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com, Andre Przywara Subject: [PATCH v19 3/7] ptp: Reorganize ptp_kvm.c to make it arch-independent Date: Tue, 30 Mar 2021 15:54:26 +0100 Message-Id: <20210330145430.996981-4-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210330145430.996981-1-maz@kernel.org> References: <20210330145430.996981-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com, andre.przywara@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jianyong Wu Currently, the ptp_kvm module contains a lot of x86-specific code. Let's move this code into a new arch-specific file in the same directory, and rename the arch-independent file to ptp_kvm_common.c. Reviewed-by: Andre Przywara Signed-off-by: Jianyong Wu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-4-jianyong.wu@arm.com Acked-by: Richard Cochran --- drivers/ptp/Makefile | 1 + drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} | 84 +++++------------- drivers/ptp/ptp_kvm_x86.c | 97 +++++++++++++++++++++ include/linux/ptp_kvm.h | 19 ++++ 4 files changed, 139 insertions(+), 62 deletions(-) rename drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} (60%) create mode 100644 drivers/ptp/ptp_kvm_x86.c create mode 100644 include/linux/ptp_kvm.h diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index db5aef3bddc6..d11eeb5811d1 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -4,6 +4,7 @@ # ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o +ptp_kvm-$(CONFIG_X86) := ptp_kvm_x86.o ptp_kvm_common.o obj-$(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.c b/drivers/ptp/ptp_kvm_common.c similarity index 60% rename from drivers/ptp/ptp_kvm.c rename to drivers/ptp/ptp_kvm_common.c index 658d33fc3195..721ddcede5e1 100644 --- a/drivers/ptp/ptp_kvm.c +++ b/drivers/ptp/ptp_kvm_common.c @@ -8,11 +8,11 @@ #include #include #include +#include #include +#include #include #include -#include -#include #include #include @@ -24,56 +24,29 @@ struct kvm_ptp_clock { static DEFINE_SPINLOCK(kvm_ptp_lock); -static struct pvclock_vsyscall_time_info *hv_clock; - -static struct kvm_clock_pairing clock_pair; -static phys_addr_t clock_pair_gpa; - static int ptp_kvm_get_time_fn(ktime_t *device_time, struct system_counterval_t *system_counter, void *ctx) { - unsigned long ret; + long ret; + u64 cycle; struct timespec64 tspec; - unsigned version; - int cpu; - struct pvclock_vcpu_time_info *src; + struct clocksource *cs; spin_lock(&kvm_ptp_lock); preempt_disable_notrace(); - cpu = smp_processor_id(); - src = &hv_clock[cpu].pvti; - - do { - /* - * We are using a TSC value read in the hosts - * kvm_hc_clock_pairing handling. - * So any changes to tsc_to_system_mul - * and tsc_shift or any other pvclock - * data invalidate that measurement. - */ - version = pvclock_read_begin(src); - - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, - clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret != 0) { - pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret); - spin_unlock(&kvm_ptp_lock); - preempt_enable_notrace(); - return -EOPNOTSUPP; - } - - tspec.tv_sec = clock_pair.sec; - tspec.tv_nsec = clock_pair.nsec; - ret = __pvclock_read_cycles(src, clock_pair.tsc); - } while (pvclock_read_retry(src, version)); + ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs); + if (ret) { + spin_unlock(&kvm_ptp_lock); + preempt_enable_notrace(); + return ret; + } preempt_enable_notrace(); - system_counter->cycles = ret; - system_counter->cs = &kvm_clock; + system_counter->cycles = cycle; + system_counter->cs = cs; *device_time = timespec64_to_ktime(tspec); @@ -111,22 +84,17 @@ static int ptp_kvm_settime(struct ptp_clock_info *ptp, static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) { - unsigned long ret; + long ret; struct timespec64 tspec; spin_lock(&kvm_ptp_lock); - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, - clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret != 0) { - pr_err_ratelimited("clock offset hypercall ret %lu\n", ret); + ret = kvm_arch_ptp_get_clock(&tspec); + if (ret) { spin_unlock(&kvm_ptp_lock); - return -EOPNOTSUPP; + return ret; } - tspec.tv_sec = clock_pair.sec; - tspec.tv_nsec = clock_pair.nsec; spin_unlock(&kvm_ptp_lock); memcpy(ts, &tspec, sizeof(struct timespec64)); @@ -168,19 +136,11 @@ static int __init ptp_kvm_init(void) { long ret; - if (!kvm_para_available()) - return -ENODEV; - - clock_pair_gpa = slow_virt_to_phys(&clock_pair); - hv_clock = pvclock_get_pvti_cpu0_va(); - - if (!hv_clock) - return -ENODEV; - - ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, - KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP) - return -ENODEV; + ret = kvm_arch_ptp_init(); + if (ret) { + pr_err("fail to initialize ptp_kvm"); + return ret; + } kvm_ptp_clock.caps = ptp_kvm_caps; diff --git a/drivers/ptp/ptp_kvm_x86.c b/drivers/ptp/ptp_kvm_x86.c new file mode 100644 index 000000000000..3dd519dfc473 --- /dev/null +++ b/drivers/ptp/ptp_kvm_x86.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Virtual PTP 1588 clock for use with KVM guests + * + * Copyright (C) 2017 Red Hat Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct pvclock_vsyscall_time_info *hv_clock; + +static phys_addr_t clock_pair_gpa; +static struct kvm_clock_pairing clock_pair; + +int kvm_arch_ptp_init(void) +{ + long ret; + + if (!kvm_para_available()) + return -ENODEV; + + clock_pair_gpa = slow_virt_to_phys(&clock_pair); + hv_clock = pvclock_get_pvti_cpu0_va(); + if (!hv_clock) + return -ENODEV; + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP) + return -ENODEV; + + return 0; +} + +int kvm_arch_ptp_get_clock(struct timespec64 *ts) +{ + long ret; + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, + clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret != 0) { + pr_err_ratelimited("clock offset hypercall ret %lu\n", ret); + return -EOPNOTSUPP; + } + + ts->tv_sec = clock_pair.sec; + ts->tv_nsec = clock_pair.nsec; + + return 0; +} + +int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec, + struct clocksource **cs) +{ + struct pvclock_vcpu_time_info *src; + unsigned int version; + long ret; + int cpu; + + cpu = smp_processor_id(); + src = &hv_clock[cpu].pvti; + + do { + /* + * We are using a TSC value read in the hosts + * kvm_hc_clock_pairing handling. + * So any changes to tsc_to_system_mul + * and tsc_shift or any other pvclock + * data invalidate that measurement. + */ + version = pvclock_read_begin(src); + + ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, + clock_pair_gpa, + KVM_CLOCK_PAIRING_WALLCLOCK); + if (ret != 0) { + pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret); + return -EOPNOTSUPP; + } + tspec->tv_sec = clock_pair.sec; + tspec->tv_nsec = clock_pair.nsec; + *cycle = __pvclock_read_cycles(src, clock_pair.tsc); + } while (pvclock_read_retry(src, version)); + + *cs = &kvm_clock; + + return 0; +} diff --git a/include/linux/ptp_kvm.h b/include/linux/ptp_kvm.h new file mode 100644 index 000000000000..f960a719f0d5 --- /dev/null +++ b/include/linux/ptp_kvm.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Virtual PTP 1588 clock for use with KVM guests + * + * Copyright (C) 2017 Red Hat Inc. + */ + +#ifndef _PTP_KVM_H_ +#define _PTP_KVM_H_ + +struct timespec64; +struct clocksource; + +int kvm_arch_ptp_init(void); +int kvm_arch_ptp_get_clock(struct timespec64 *ts); +int kvm_arch_ptp_get_crosststamp(u64 *cycle, + struct timespec64 *tspec, struct clocksource **cs); + +#endif /* _PTP_KVM_H_ */ From patchwork Tue Mar 30 14:54:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 412272 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 D9B05C43446 for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFAB0619D1 for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbhC3OzV (ORCPT ); Tue, 30 Mar 2021 10:55:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:55528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231942AbhC3Oyt (ORCPT ); Tue, 30 Mar 2021 10:54:49 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B9E90619D1; Tue, 30 Mar 2021 14:54:48 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lRFlX-004hoo-1f; Tue, 30 Mar 2021 15:54:47 +0100 From: Marc Zyngier To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@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, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com Subject: [PATCH v19 4/7] time: Add mechanism to recognize clocksource in time_get_snapshot Date: Tue, 30 Mar 2021 15:54:27 +0100 Message-Id: <20210330145430.996981-5-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210330145430.996981-1-maz@kernel.org> References: <20210330145430.996981-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Thomas Gleixner System time snapshots are not conveying information about the current clocksource which was used, but callers like the PTP KVM guest implementation have the requirement to evaluate the clocksource type to select the appropriate mechanism. Introduce a clocksource id field in struct clocksource which is by default set to CSID_GENERIC (0). Clocksource implementations can set that field to a value which allows to identify the clocksource. Store the clocksource id of the current clocksource in the system_time_snapshot so callers can evaluate which clocksource was used to take the snapshot and act accordingly. Signed-off-by: Thomas Gleixner Signed-off-by: Jianyong Wu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com --- include/linux/clocksource.h | 6 ++++++ include/linux/clocksource_ids.h | 11 +++++++++++ include/linux/timekeeping.h | 12 +++++++----- kernel/time/clocksource.c | 2 ++ kernel/time/timekeeping.c | 1 + 5 files changed, 27 insertions(+), 5 deletions(-) create mode 100644 include/linux/clocksource_ids.h diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 86d143db6523..1290d0dce840 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -62,6 +63,10 @@ struct module; * 400-499: Perfect * The ideal clocksource. A must-use where * available. + * @id: Defaults to CSID_GENERIC. The id value is captured + * in certain snapshot functions to allow callers to + * validate the clocksource from which the snapshot was + * taken. * @flags: Flags describing special properties * @enable: Optional function to enable the clocksource * @disable: Optional function to disable the clocksource @@ -100,6 +105,7 @@ struct clocksource { const char *name; struct list_head list; int rating; + enum clocksource_ids id; enum vdso_clock_mode vdso_clock_mode; unsigned long flags; diff --git a/include/linux/clocksource_ids.h b/include/linux/clocksource_ids.h new file mode 100644 index 000000000000..4d8e19e05328 --- /dev/null +++ b/include/linux/clocksource_ids.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_CLOCKSOURCE_IDS_H +#define _LINUX_CLOCKSOURCE_IDS_H + +/* Enum to give clocksources a unique identifier */ +enum clocksource_ids { + CSID_GENERIC = 0, + CSID_MAX, +}; + +#endif diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index c6792cf01bc7..78a98bdff76d 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -3,6 +3,7 @@ #define _LINUX_TIMEKEEPING_H #include +#include /* Included from linux/ktime.h */ @@ -243,11 +244,12 @@ struct ktime_timestamps { * @cs_was_changed_seq: The sequence number of clocksource change events */ struct system_time_snapshot { - u64 cycles; - ktime_t real; - ktime_t raw; - unsigned int clock_was_set_seq; - u8 cs_was_changed_seq; + u64 cycles; + ktime_t real; + ktime_t raw; + enum clocksource_ids cs_id; + unsigned int clock_was_set_seq; + u8 cs_was_changed_seq; }; /** diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index cce484a2cc7c..4fe1df894ee5 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -920,6 +920,8 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) clocksource_arch_init(cs); + if (WARN_ON_ONCE((unsigned int)cs->id >= CSID_MAX)) + cs->id = CSID_GENERIC; if (cs->vdso_clock_mode < 0 || cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) { pr_warn("clocksource %s registered with invalid VDSO mode %d. Disabling VDSO support.\n", diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 6aee5768c86f..06f55f9258bf 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1048,6 +1048,7 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) do { seq = read_seqcount_begin(&tk_core.seq); now = tk_clock_read(&tk->tkr_mono); + systime_snapshot->cs_id = tk->tkr_mono.clock->id; systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq; systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq; base_real = ktime_add(tk->tkr_mono.base, From patchwork Tue Mar 30 14:54:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 412271 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 EB5E9C43445 for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D56ED619DE for ; Tue, 30 Mar 2021 14:55:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232389AbhC3OzX (ORCPT ); Tue, 30 Mar 2021 10:55:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:55612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231967AbhC3Oyw (ORCPT ); Tue, 30 Mar 2021 10:54:52 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AF2D0619C8; Tue, 30 Mar 2021 14:54:50 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lRFlY-004hoo-Q6; Tue, 30 Mar 2021 15:54:49 +0100 From: Marc Zyngier To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@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, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com Subject: [PATCH v19 6/7] KVM: arm64: Add support for the KVM PTP service Date: Tue, 30 Mar 2021 15:54:29 +0100 Message-Id: <20210330145430.996981-7-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210330145430.996981-1-maz@kernel.org> References: <20210330145430.996981-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, will@kernel.org, suzuki.poulose@arm.com, Andre.Przywara@arm.com, steven.price@arm.com, lorenzo.pieralisi@arm.com, sudeep.holla@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jianyong Wu Implement the hypervisor side of the KVM PTP interface. The service offers wall time and cycle count from host to guest. The caller must specify whether they want the host's view of either the virtual or physical counter. Signed-off-by: Jianyong Wu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com --- Documentation/virt/kvm/api.rst | 10 +++++ Documentation/virt/kvm/arm/index.rst | 1 + Documentation/virt/kvm/arm/ptp_kvm.rst | 25 ++++++++++++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/hypercalls.c | 53 ++++++++++++++++++++++++++ include/linux/arm-smccc.h | 16 ++++++++ include/uapi/linux/kvm.h | 1 + 7 files changed, 107 insertions(+) create mode 100644 Documentation/virt/kvm/arm/ptp_kvm.rst diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 38e327d4b479..987d99e39887 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6724,3 +6724,13 @@ vcpu_info is set. The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. + +8.31 KVM_CAP_PTP_KVM +-------------------- + +:Architectures: arm64 + +This capability indicates that the KVM virtual PTP service is +supported in the host. A VMM can check whether the service is +available to the guest on migration. + diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst index 3e2b2aba90fc..78a9b670aafe 100644 --- a/Documentation/virt/kvm/arm/index.rst +++ b/Documentation/virt/kvm/arm/index.rst @@ -10,3 +10,4 @@ ARM hyp-abi psci pvtime + ptp_kvm diff --git a/Documentation/virt/kvm/arm/ptp_kvm.rst b/Documentation/virt/kvm/arm/ptp_kvm.rst new file mode 100644 index 000000000000..68cffb50d8bf --- /dev/null +++ b/Documentation/virt/kvm/arm/ptp_kvm.rst @@ -0,0 +1,25 @@ +.. SPDX-License-Identifier: GPL-2.0 + +PTP_KVM support for arm/arm64 +============================= + +PTP_KVM is used for high precision time sync between host and guests. +It relies on transferring the wall clock and counter value from the +host to the guest using a KVM-specific hypercall. + +* ARM_SMCCC_HYP_KVM_PTP_FUNC_ID: 0x86000001 + +This hypercall uses the SMC32/HVC32 calling convention: + +ARM_SMCCC_HYP_KVM_PTP_FUNC_ID + ============= ========== ========== + Function ID: (uint32) 0x86000001 + Arguments: (uint32) KVM_PTP_VIRT_COUNTER(0) + KVM_PTP_PHYS_COUNTER(1) + Return Values: (int32) NOT_SUPPORTED(-1) on error, or + (uint32) Upper 32 bits of wall clock time (r0) + (uint32) Lower 32 bits of wall clock time (r1) + (uint32) Upper 32 bits of counter (r2) + (uint32) Lower 32 bits of counter (r3) + Endianness: No Restrictions. + ============= ========== ========== diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7f06ba76698d..46401798c644 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -206,6 +206,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ARM_INJECT_EXT_DABT: case KVM_CAP_SET_GUEST_DEBUG: case KVM_CAP_VCPU_ATTRIBUTES: + case KVM_CAP_PTP_KVM: r = 1; break; case KVM_CAP_ARM_SET_DEVICE_ADDR: diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 78d32c34d49c..30da78f72b3b 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -9,6 +9,55 @@ #include #include +static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) +{ + struct system_time_snapshot systime_snapshot; + u64 cycles = ~0UL; + u32 feature; + + /* + * system time and counter value must captured at the same + * time to keep consistency and precision. + */ + ktime_get_snapshot(&systime_snapshot); + + /* + * This is only valid if the current clocksource is the + * architected counter, as this is the only one the guest + * can see. + */ + if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER) + return; + + /* + * The guest selects one of the two reference counters + * (virtual or physical) with the first argument of the SMCCC + * call. In case the identifier is not supported, error out. + */ + feature = smccc_get_arg1(vcpu); + switch (feature) { + case KVM_PTP_VIRT_COUNTER: + cycles = systime_snapshot.cycles - vcpu_read_sys_reg(vcpu, CNTVOFF_EL2); + break; + case KVM_PTP_PHYS_COUNTER: + cycles = systime_snapshot.cycles; + break; + default: + return; + } + + /* + * This relies on the top bit of val[0] never being set for + * valid values of system time, because that is *really* far + * in the future (about 292 years from 1970, and at that stage + * nobody will give a damn about it). + */ + val[0] = upper_32_bits(systime_snapshot.real); + val[1] = lower_32_bits(systime_snapshot.real); + val[2] = upper_32_bits(cycles); + val[3] = lower_32_bits(cycles); +} + int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) { u32 func_id = smccc_get_function(vcpu); @@ -79,6 +128,10 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) break; case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES); + val[0] |= BIT(ARM_SMCCC_KVM_FUNC_PTP); + break; + case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: + kvm_ptp_get_time(vcpu, val); break; case ARM_SMCCC_TRNG_VERSION: case ARM_SMCCC_TRNG_FEATURES: diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 1a27bd9493fe..6861489a1890 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -103,6 +103,7 @@ /* KVM "vendor specific" services */ #define ARM_SMCCC_KVM_FUNC_FEATURES 0 +#define ARM_SMCCC_KVM_FUNC_PTP 1 #define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 #define ARM_SMCCC_KVM_NUM_FUNCS 128 @@ -114,6 +115,21 @@ #define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 +/* + * ptp_kvm is a feature used for time sync between vm and host. + * ptp_kvm module in guest kernel will get service from host using + * this hypercall ID. + */ +#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_VENDOR_HYP, \ + ARM_SMCCC_KVM_FUNC_PTP) + +/* ptp_kvm counter type ID */ +#define KVM_PTP_VIRT_COUNTER 0 +#define KVM_PTP_PHYS_COUNTER 1 + /* Paravirtualised time calls (defined by ARM DEN0057A) */ #define ARM_SMCCC_HV_PV_TIME_FEATURES \ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index f6afee209620..0e0f70c0d0dc 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1078,6 +1078,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_DIRTY_LOG_RING 192 #define KVM_CAP_X86_BUS_LOCK_EXIT 193 #define KVM_CAP_PPC_DAWR1 194 +#define KVM_CAP_PTP_KVM 195 #ifdef KVM_CAP_IRQ_ROUTING