From patchwork Mon Aug 17 08:41:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: zhukeqian X-Patchwork-Id: 11717073 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 93F14739 for ; Mon, 17 Aug 2020 08:41:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84F4920758 for ; Mon, 17 Aug 2020 08:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728007AbgHQIlt (ORCPT ); Mon, 17 Aug 2020 04:41:49 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:45202 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726538AbgHQIl2 (ORCPT ); Mon, 17 Aug 2020 04:41:28 -0400 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 63C58374DE456567A6C9; Mon, 17 Aug 2020 16:41:22 +0800 (CST) Received: from DESKTOP-5IS4806.china.huawei.com (10.174.187.22) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.487.0; Mon, 17 Aug 2020 16:41:14 +0800 From: Keqian Zhu To: , , , CC: Marc Zyngier , Steven Price , Catalin Marinas , Will Deacon , James Morse , Suzuki K Poulose , , Keqian Zhu Subject: [RFC PATCH 4/5] clocksource: arm_arch_timer: Add pvtime LPT initialization Date: Mon, 17 Aug 2020 16:41:09 +0800 Message-ID: <20200817084110.2672-5-zhukeqian1@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20200817084110.2672-1-zhukeqian1@huawei.com> References: <20200817084110.2672-1-zhukeqian1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.187.22] X-CFilter-Loop: Reflected Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Enable paravirtualized time to be used in a KVM guest if the host supports it. This allows the guest to derive a counter which is clocked at a persistent rate even when the guest is migrated. If we discover that the system supports SMCCC v1.1 then we probe to determine whether the hypervisor supports paravirtualized features and finally whether it supports "Live Physical Time" reporting. If so a shared structure is made available to the guest containing coefficients to calculate the derived clock. Signed-off-by: Steven Price Signed-off-by: Keqian Zhu --- drivers/clocksource/arm_arch_timer.c | 69 ++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 6c3e841..eb2e57a 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -26,6 +26,7 @@ #include #include +#include #include #include @@ -84,6 +85,66 @@ static int __init early_evtstrm_cfg(char *buf) } early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg); +/* PV-time LPT */ +#ifdef CONFIG_ARM64 +struct pvclock_vm_lpt_time *lpt_info; +EXPORT_SYMBOL_GPL(lpt_info); +DEFINE_STATIC_KEY_FALSE(pvclock_lpt_key_enabled); +EXPORT_SYMBOL_GPL(pvclock_lpt_key_enabled); + +static bool has_pv_lpt_clock(void) +{ + struct arm_smccc_res res; + + if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) + return false; + + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, + ARM_SMCCC_HV_PV_TIME_FEATURES, &res); + if (res.a0 != SMCCC_RET_SUCCESS) + return false; + + arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_TIME_FEATURES, + ARM_SMCCC_HV_PV_TIME_LPT, &res); + return res.a0 == SMCCC_RET_SUCCESS; +} + +static int pvclock_lpt_init(void) +{ + struct arm_smccc_res res; + + if (!has_pv_lpt_clock()) + return 0; + + arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_TIME_LPT, 0, &res); + if (res.a0 == SMCCC_RET_NOT_SUPPORTED) + return 0; + + lpt_info = memremap(res.a0, sizeof(*lpt_info), MEMREMAP_WB); + if (!lpt_info) { + pr_warn("Failed to map pvclock LPT data structure\n"); + return -EFAULT; + } + + if (le32_to_cpu(lpt_info->revision) != 0 || + le32_to_cpu(lpt_info->attributes) != 0) { + pr_warn_once("Unexpected revision or attributes " + "in pvclock LPT data structure\n"); + return -EFAULT; + } + + static_branch_enable(&pvclock_lpt_key_enabled); + pr_info("Using pvclock LPT\n"); + return 0; +} +#else /* CONFIG_ARM64 */ +static int pvclock_lpt_init(void) +{ + return 0; +} +#endif /* CONFIG_ARM64 */ + + /* * Architected system timer support. */ @@ -1285,6 +1346,10 @@ static int __init arch_timer_of_init(struct device_node *np) arch_timer_populate_kvm_info(); + ret = pvclock_lpt_init(); + if (ret) + return ret; + rate = arch_timer_get_cntfrq(); arch_timer_of_configure_rate(rate, np); @@ -1613,6 +1678,10 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) arch_timer_populate_kvm_info(); + ret = pvclock_lpt_init(); + if (ret) + return ret; + /* * When probing via ACPI, we have no mechanism to override the sysreg * CNTFRQ value. This *must* be correct.