From patchwork Tue Nov 7 12:04:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 13448550 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B222D2D7BF for ; Tue, 7 Nov 2023 12:04:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 107FA11A; Tue, 7 Nov 2023 04:04:19 -0800 (PST) Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8BxyerAJ0pl5Kw3AA--.34185S3; Tue, 07 Nov 2023 20:04:16 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Axji+_J0plPBo7AA--.63299S5; Tue, 07 Nov 2023 20:04:16 +0800 (CST) From: Bibo Mao To: Tianrui Zhao , Huacai Chen Cc: WANG Xuerui , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v2 3/3] LoongArch: KVM: Remove kvm_acquire_timer before entering guest Date: Tue, 7 Nov 2023 20:04:14 +0800 Message-Id: <20231107120414.1927261-4-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231107120414.1927261-1-maobibo@loongson.cn> References: <20231107120414.1927261-1-maobibo@loongson.cn> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: AQAAf8Axji+_J0plPBo7AA--.63299S5 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoWxJw47Aw4kCr1kZFWfGFW5XFc_yoWruF43pF Z7urn2qw4rXr4UGw1jya1kur45XrWkKr13Xa4kJrWFyrnIyr1YvF4kGF95XFW3J3yIyF1S vryrtw15uF4DAwbCm3ZEXasCq-sJn29KB7ZKAUJUUUU8529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUkFb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1a6r1DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVWxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44I27w Aqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jw0_WrylYx0Ex4A2jsIE 14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x 0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E 7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcV C0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07Ul4E_UUUUU= The vm timer emulation happens in two places, one is during vcpu thread context switch, the other is idle instruction emulation and before entering to guest. SW timer switching is remove during idle instruction emulation, so it is not necessary to disable SW timer before entering to guest. This patch removes SW timer handling before entering guest mode, and put it in HW restore flow when vcpu thread is sched-in. With this patch, vm timer emulation is simpler, there is SW/HW timer switch only in vcpu thread context switch scenario. Signed-off-by: Bibo Mao --- arch/loongarch/include/asm/kvm_vcpu.h | 1 - arch/loongarch/kvm/timer.c | 21 +++++++------------ arch/loongarch/kvm/vcpu.c | 29 --------------------------- 3 files changed, 7 insertions(+), 44 deletions(-) diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h index 553cfa2b2b1c..0e87652f780a 100644 --- a/arch/loongarch/include/asm/kvm_vcpu.h +++ b/arch/loongarch/include/asm/kvm_vcpu.h @@ -55,7 +55,6 @@ void kvm_save_fpu(struct loongarch_fpu *fpu); void kvm_restore_fpu(struct loongarch_fpu *fpu); void kvm_restore_fcsr(struct loongarch_fpu *fpu); -void kvm_acquire_timer(struct kvm_vcpu *vcpu); void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz); void kvm_reset_timer(struct kvm_vcpu *vcpu); void kvm_save_timer(struct kvm_vcpu *vcpu); diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c index 1d29bd21a9da..45109fa0b299 100644 --- a/arch/loongarch/kvm/timer.c +++ b/arch/loongarch/kvm/timer.c @@ -64,19 +64,6 @@ void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz) kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TVAL, 0); } -/* - * Restore hard timer state and enable guest to access timer registers - * without trap, should be called with irq disabled - */ -void kvm_acquire_timer(struct kvm_vcpu *vcpu) -{ - /* - * Freeze the soft-timer and sync the guest stable timer with it. We do - * this with interrupts disabled to avoid latency. - */ - hrtimer_cancel(&vcpu->arch.swtimer); -} - /* * Restore soft timer state from saved context. */ @@ -115,12 +102,18 @@ void kvm_restore_timer(struct kvm_vcpu *vcpu) /* * Inject timer here though sw timer should inject timer * interrupt async already, since sw timer may be cancelled - * during injecting intr async in function kvm_acquire_timer + * during injecting intr async */ kvm_queue_irq(vcpu, INT_TI); } write_gcsr_timertick(delta); + + /* + * Freeze the soft-timer and sync the guest stable timer with it. We do + * this with interrupts disabled to avoid latency. + */ + hrtimer_cancel(&vcpu->arch.swtimer); } /* diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 42663a345bd1..cf1c4d64c1b7 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -95,7 +95,6 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu) * check vmid before vcpu enter guest */ local_irq_disable(); - kvm_acquire_timer(vcpu); kvm_deliver_intr(vcpu); kvm_deliver_exception(vcpu); /* Make sure the vcpu mode has been written */ @@ -251,23 +250,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, return -EINVAL; } -/** - * kvm_migrate_count() - Migrate timer. - * @vcpu: Virtual CPU. - * - * Migrate hrtimer to the current CPU by cancelling and restarting it - * if the hrtimer is active. - * - * Must be called when the vCPU is migrated to a different CPU, so that - * the timer can interrupt the guest at the new CPU, and the timer irq can - * be delivered to the vCPU. - */ -static void kvm_migrate_count(struct kvm_vcpu *vcpu) -{ - if (hrtimer_cancel(&vcpu->arch.swtimer)) - hrtimer_restart(&vcpu->arch.swtimer); -} - static int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *val) { unsigned long gintc; @@ -796,17 +778,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) unsigned long flags; local_irq_save(flags); - if (vcpu->arch.last_sched_cpu != cpu) { - kvm_debug("[%d->%d]KVM vCPU[%d] switch\n", - vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); - /* - * Migrate the timer interrupt to the current CPU so that it - * always interrupts the guest and synchronously triggers a - * guest timer interrupt. - */ - kvm_migrate_count(vcpu); - } - /* Restore guest state to registers */ _kvm_vcpu_load(vcpu, cpu); local_irq_restore(flags);