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[2620:137:e000::1:20]) by mx.google.com with ESMTP id r3-20020a655083000000b005139191c0a7si11838337pgp.787.2023.04.17.04.31.21; Mon, 17 Apr 2023 04:31:44 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbjDQLQd (ORCPT + 99 others); Mon, 17 Apr 2023 07:16:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230003AbjDQLQ2 (ORCPT ); Mon, 17 Apr 2023 07:16:28 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 21C43D8; Mon, 17 Apr 2023 04:15:31 -0700 (PDT) Received: from loongson.cn (unknown [10.2.5.185]) by gateway (Coremail) with SMTP id _____8Dxj82cGD1kjuYdAA--.46525S3; Mon, 17 Apr 2023 17:59:56 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.185]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Bx57yWGD1kua0qAA--.48254S20; Mon, 17 Apr 2023 17:59:55 +0800 (CST) From: Tianrui Zhao To: Paolo Bonzini Cc: Huacai Chen , WANG Xuerui , Greg Kroah-Hartman , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Jens Axboe , Mark Brown , Alex Deucher , Oliver Upton , maobibo@loongson.cn, Xi Ruoyao , zhaotianrui@loongson.cn Subject: [PATCH v7 18/30] LoongArch: KVM: Implement vcpu timer operations Date: Mon, 17 Apr 2023 17:59:38 +0800 Message-Id: <20230417095950.875228-19-zhaotianrui@loongson.cn> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230417095950.875228-1-zhaotianrui@loongson.cn> References: <20230417095950.875228-1-zhaotianrui@loongson.cn> MIME-Version: 1.0 X-CM-TRANSID: AQAAf8Bx57yWGD1kua0qAA--.48254S20 X-CM-SenderInfo: p2kd03xldq233l6o00pqjv00gofq/ X-Coremail-Antispam: 1Uk129KBjvJXoWxtw18Kw4UAFyDXF1kCrWrAFb_yoW3Zw48pr WIkryIqr48Xryjgwn3AFs0vrn8W3yrK3W7Gry7J3ySyrnxJ3s8XF40gryDJFZxGFyIvF1S vryrAwn8Ar4kA3DanT9S1TB71UUUU8DqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bckFc2x0x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wA2ocxC64kIII0Yj41l84x0c7CEw4 AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF 7I0E14v26F4UJVW0owA2z4x0Y4vEx4A2jsIE14v26F4UJVW0owA2z4x0Y4vEx4A2jsIEc7 CjxVAFwI0_GcCE3s1ln4kS14v26r4a6rW5M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF 6xkI12xvs2x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6x8ErcxFaVAv8V WrMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCY1x0262kKe7AKxVW8ZVWr XwCF04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26rWl4I8I3I0E4IkC6x0Yz7v_Jr 0_Gr1l4IxYO2xFxVAFwI0_GFv_Wrylx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK 67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI 8IcVAFwI0_tr0E3s1lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4UJVW0owCI42IY6xAIw20E Y4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Cr1j6rxdMIIF0xvEx4A2jsIEc7CjxV AFwI0_Cr1j6rxdYxBIdaVFxhVjvjDU0xZFpf9x07jF89NUUUUU= X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_PASS, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1763422874471745141?= X-GMAIL-MSGID: =?utf-8?q?1763422874471745141?= Implement loongarch vcpu timer operations such as init kvm timer, require kvm timer, save kvm timer and restore kvm timer. When vcpu exit, we use kvm soft timer to emulate hardware timer. If timeout happens, the vcpu timer interrupt will be set and it is going to be handled at vcpu next entrance. Signed-off-by: Tianrui Zhao --- arch/loongarch/kvm/timer.c | 266 +++++++++++++++++++++++++++++++++++++ 1 file changed, 266 insertions(+) create mode 100644 arch/loongarch/kvm/timer.c diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c new file mode 100644 index 000000000000..2c7677248746 --- /dev/null +++ b/arch/loongarch/kvm/timer.c @@ -0,0 +1,266 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited + */ + +#include +#include +#include + +/* low level hrtimer wake routine */ +enum hrtimer_restart kvm_swtimer_wakeup(struct hrtimer *timer) +{ + struct kvm_vcpu *vcpu; + + vcpu = container_of(timer, struct kvm_vcpu, arch.swtimer); + _kvm_queue_irq(vcpu, LARCH_INT_TIMER); + rcuwait_wake_up(&vcpu->wait); + return kvm_count_timeout(vcpu); +} + +/* + * ktime_to_tick() - Scale ktime_t to a 64-bit stable timer. + * + * Caches the dynamic nanosecond bias in vcpu->arch.timer_dyn_bias. + */ +static unsigned long ktime_to_tick(struct kvm_vcpu *vcpu, ktime_t now) +{ + s64 now_ns, periods; + unsigned long delta; + + now_ns = ktime_to_ns(now); + delta = now_ns + vcpu->arch.timer_dyn_bias; + + if (delta >= vcpu->arch.timer_period) { + /* If delta is out of safe range the bias needs adjusting */ + periods = div64_s64(now_ns, vcpu->arch.timer_period); + vcpu->arch.timer_dyn_bias = -periods * vcpu->arch.timer_period; + /* Recalculate delta with new bias */ + delta = now_ns + vcpu->arch.timer_dyn_bias; + } + + /* + * We've ensured that: + * delta < timer_period + */ + return div_u64(delta * vcpu->arch.timer_mhz, MNSEC_PER_SEC); +} + +/** + * kvm_resume_hrtimer() - Resume hrtimer, updating expiry. + * @vcpu: Virtual CPU. + * @now: ktime at point of resume. + * @val: stable timer at point of resume. + * + * Resumes the timer and updates the timer expiry based on @now and @count. + */ +static void kvm_resume_hrtimer(struct kvm_vcpu *vcpu, ktime_t now, + unsigned long val) +{ + unsigned long delta; + ktime_t expire; + + /* Stable timer decreased to zero or + * initialize to zero, set 4 second timer + */ + delta = div_u64(val * MNSEC_PER_SEC, vcpu->arch.timer_mhz); + expire = ktime_add_ns(now, delta); + + /* Update hrtimer to use new timeout */ + hrtimer_cancel(&vcpu->arch.swtimer); + hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); +} + +/** + * kvm_init_timer() - Initialise stable timer. + * @vcpu: Virtual CPU. + * @timer_hz: Frequency of timer. + * + * Initialise the timer to the specified frequency, zero it, and set it going if + * it's enabled. + */ +void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz) +{ + ktime_t now; + unsigned long ticks; + struct loongarch_csrs *csr = vcpu->arch.csr; + + ticks = (unsigned long)MNSEC_PER_SEC * CSR_TCFG_VAL; + vcpu->arch.timer_mhz = timer_hz >> 20; + vcpu->arch.timer_period = div_u64(ticks, vcpu->arch.timer_mhz); + vcpu->arch.timer_dyn_bias = 0; + + /* Starting at 0 */ + ticks = 0; + now = ktime_get(); + vcpu->arch.timer_bias = ticks - ktime_to_tick(vcpu, now); + vcpu->arch.timer_bias &= CSR_TCFG_VAL; + kvm_write_sw_gcsr(csr, LOONGARCH_CSR_TVAL, ticks); +} + +/** + * kvm_count_timeout() - Push timer forward on timeout. + * @vcpu: Virtual CPU. + * + * Handle an hrtimer event by push the hrtimer forward a period. + * + * Returns: The hrtimer_restart value to return to the hrtimer subsystem. + */ +enum hrtimer_restart kvm_count_timeout(struct kvm_vcpu *vcpu) +{ + unsigned long cfg; + + /* Add the Count period to the current expiry time */ + cfg = kvm_read_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG); + if (cfg & CSR_TCFG_PERIOD) { + hrtimer_add_expires_ns(&vcpu->arch.swtimer, cfg & CSR_TCFG_VAL); + return HRTIMER_RESTART; + } else + return HRTIMER_NORESTART; +} + +/* + * kvm_restore_timer() - Restore timer state. + * @vcpu: Virtual CPU. + * + * Restore soft timer state from saved context. + */ +void kvm_restore_timer(struct kvm_vcpu *vcpu) +{ + struct loongarch_csrs *csr = vcpu->arch.csr; + ktime_t saved_ktime, now; + unsigned long val, new, delta; + int expired = 0; + unsigned long cfg; + + /* + * Set guest stable timer cfg csr + */ + cfg = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG); + kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ESTAT); + if (!(cfg & CSR_TCFG_EN)) { + kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TCFG); + kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_TVAL); + return; + } + + now = ktime_get(); + saved_ktime = vcpu->arch.stable_ktime_saved; + val = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TVAL); + + /*hrtimer not expire */ + delta = ktime_to_tick(vcpu, ktime_sub(now, saved_ktime)); + if (delta >= val) { + expired = 1; + if (cfg & CSR_TCFG_PERIOD) + new = (delta - val) % (cfg & CSR_TCFG_VAL); + else + new = 1; + } else + new = val - delta; + + new &= CSR_TCFG_VAL; + write_gcsr_timercfg(cfg); + write_gcsr_timertick(new); + if (expired) + _kvm_queue_irq(vcpu, LARCH_INT_TIMER); +} + +/* + * kvm_acquire_timer() - Switch to hard timer state. + * @vcpu: Virtual CPU. + * + * Restore hard timer state on top of existing soft timer state if possible. + * + * Since hard timer won't remain active over preemption, preemption should be + * disabled by the caller. + */ +void kvm_acquire_timer(struct kvm_vcpu *vcpu) +{ + unsigned long flags, guestcfg; + + guestcfg = read_csr_gcfg(); + if (!(guestcfg & CSR_GCFG_TIT)) + return; + + /* enable guest access to hard timer */ + write_csr_gcfg(guestcfg & ~CSR_GCFG_TIT); + + /* + * Freeze the soft-timer and sync the guest stable timer with it. We do + * this with interrupts disabled to avoid latency. + */ + local_irq_save(flags); + hrtimer_cancel(&vcpu->arch.swtimer); + local_irq_restore(flags); +} + + +/* + * _kvm_save_timer() - Switch to software emulation of guest timer. + * @vcpu: Virtual CPU. + * + * Save guest timer state and switch to software emulation of guest + * timer. The hard timer must already be in use, so preemption should be + * disabled. + */ +static ktime_t _kvm_save_timer(struct kvm_vcpu *vcpu, unsigned long *val) +{ + unsigned long end_time; + ktime_t before_time; + + before_time = ktime_get(); + + /* + * Record a final stable timer which we will transfer to the soft-timer. + */ + end_time = read_gcsr_timertick(); + *val = end_time; + + kvm_resume_hrtimer(vcpu, before_time, end_time); + return before_time; +} + +/* + * kvm_save_timer() - Save guest timer state. + * @vcpu: Virtual CPU. + * + * Save guest timer state and switch to soft guest timer if hard timer was in + * use. + */ +void kvm_save_timer(struct kvm_vcpu *vcpu) +{ + struct loongarch_csrs *csr = vcpu->arch.csr; + unsigned long guestcfg, val; + ktime_t save_ktime; + + preempt_disable(); + guestcfg = read_csr_gcfg(); + if (!(guestcfg & CSR_GCFG_TIT)) { + /* disable guest use of hard timer */ + write_csr_gcfg(guestcfg | CSR_GCFG_TIT); + + /* save hard timer state */ + kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TCFG); + if (kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG) & CSR_TCFG_EN) { + save_ktime = _kvm_save_timer(vcpu, &val); + kvm_write_sw_gcsr(csr, LOONGARCH_CSR_TVAL, val); + vcpu->arch.stable_ktime_saved = save_ktime; + if (val == CSR_TCFG_VAL) + _kvm_queue_irq(vcpu, LARCH_INT_TIMER); + } else { + kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TVAL); + } + } + + /* save timer-related state to VCPU context */ + kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT); + preempt_enable(); +} + +void kvm_reset_timer(struct kvm_vcpu *vcpu) +{ + write_gcsr_timercfg(0); + kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG, 0); + hrtimer_cancel(&vcpu->arch.swtimer); +}