From patchwork Wed Sep 23 06:35:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shenming Lu X-Patchwork-Id: 11794099 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 DA7DE618 for ; Wed, 23 Sep 2020 06:38:39 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A849E21D43 for ; Wed, 23 Sep 2020 06:38:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="aORQPAm1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A849E21D43 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=8fMu+88DgttQOdVIkihmlTJYGrA/D7261ydeT7la2WU=; b=aORQPAm1eWorX9rV92K43MrVzX K8k2oMGUCR1C2AlhQA/hVwUNtsJRMUP7Y7eODG4znsR6Kt0K6GFA6UEYbwXs7Oo151UBRabdQBJUi Wf6TUea5t9PGPCadyICXEwV+7/7KVvWMM8TCzojTzhPJA3qQMzBx3PaBlG5EUCxchKtJlYYFQF9DJ 8d0LPjQ///872lZu/tjEUfUBvfSmbmGKNZt8DTSBev7MtV8zT5qex33H1klqeJs6N2WJh0le8e+Ei V9ZmN5Uzmba2MIbf5NVLUUtx9F6G0MJfAEhe8GQGyc7b6X4yrdx6kLpEICcMm6IjurdNStD4+Rxfl S77z/2hQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kKyOg-000889-9r; Wed, 23 Sep 2020 06:36:58 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kKyOb-00083a-S4 for linux-arm-kernel@lists.infradead.org; Wed, 23 Sep 2020 06:36:55 +0000 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 0E9B157AA3323F5A97F2; Wed, 23 Sep 2020 14:36:41 +0800 (CST) Received: from DESKTOP-7FEPK9S.china.huawei.com (10.174.186.62) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Wed, 23 Sep 2020 14:36:33 +0800 From: Shenming Lu To: Thomas Gleixner , Jason Cooper , Marc Zyngier , , , , , James Morse , Julien Thierry , Suzuki K Poulose , Catalin Marinas , Will Deacon , Eric Auger , Christoffer Dall Subject: [PATCH] irqchip/gic-v4.1: Optimize the wait for the completion of the analysis of the VPT Date: Wed, 23 Sep 2020 14:35:43 +0800 Message-ID: <20200923063543.1920-1-lushenming@huawei.com> X-Mailer: git-send-email 2.27.0.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.174.186.62] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200923_023654_167961_3A9C5E1E X-CRM114-Status: GOOD ( 16.40 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [45.249.212.32 listed in list.dnswl.org] 0.0 RCVD_IN_MSPIKE_H4 RBL: Very Good reputation (+4) [45.249.212.32 listed in wl.mailspike.net] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: yuzenghui@huawei.com, wanghaibin.wang@huawei.com, lushenming@huawei.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Right after a vPE is made resident, the code starts polling the GICR_VPENDBASER.Dirty bit until it becomes 0, where the delay_us is set to 10. But in our measurement, it takes only hundreds of nanoseconds, or 1~2 microseconds, to finish parsing the VPT in most cases. And we also measured the time from vcpu_load() (include it) to __guest_enter() on Kunpeng 920. On average, it takes 2.55 microseconds (not first run && the VPT is empty). So 10 microseconds delay might really hurt performance. To avoid this, we can set the delay_us to 1, which is more appropriate in this situation and universal. Besides, we can delay the execution of its_wait_vpt_parse_complete() (call it from kvm_vgic_flush_hwstate() corresponding to vPE resident), giving the GIC a chance to work in parallel with the CPU on the entry path. Signed-off-by: Shenming Lu --- arch/arm64/kvm/vgic/vgic-v4.c | 18 ++++++++++++++++++ arch/arm64/kvm/vgic/vgic.c | 2 ++ drivers/irqchip/irq-gic-v3-its.c | 14 +++++++++++--- drivers/irqchip/irq-gic-v4.c | 11 +++++++++++ include/kvm/arm_vgic.h | 3 +++ include/linux/irqchip/arm-gic-v4.h | 4 ++++ 6 files changed, 49 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c index b5fa73c9fd35..1d5d2d6894d3 100644 --- a/arch/arm64/kvm/vgic/vgic-v4.c +++ b/arch/arm64/kvm/vgic/vgic-v4.c @@ -353,6 +353,24 @@ int vgic_v4_load(struct kvm_vcpu *vcpu) return err; } +void vgic_v4_wait_vpt(struct kvm_vcpu *vcpu) +{ + struct its_vpe *vpe; + + if (kvm_vgic_global_state.type == VGIC_V2 || !vgic_supports_direct_msis(vcpu->kvm)) + return; + + vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe; + + if (vpe->vpt_ready) + return; + + if (its_wait_vpt(vpe)) + return; + + vpe->vpt_ready = true; +} + static struct vgic_its *vgic_get_its(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *irq_entry) { diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index c3643b7f101b..ed810a80cda2 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -915,6 +915,8 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) if (can_access_vgic_from_kernel()) vgic_restore_state(vcpu); + + vgic_v4_wait_vpt(vcpu); } void kvm_vgic_load(struct kvm_vcpu *vcpu) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 548de7538632..b7cbc9bcab9d 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -3803,7 +3803,7 @@ static void its_wait_vpt_parse_complete(void) WARN_ON_ONCE(readq_relaxed_poll_timeout_atomic(vlpi_base + GICR_VPENDBASER, val, !(val & GICR_VPENDBASER_Dirty), - 10, 500)); + 1, 500)); } static void its_vpe_schedule(struct its_vpe *vpe) @@ -3837,7 +3837,7 @@ static void its_vpe_schedule(struct its_vpe *vpe) val |= GICR_VPENDBASER_Valid; gicr_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER); - its_wait_vpt_parse_complete(); + vpe->vpt_ready = false; } static void its_vpe_deschedule(struct its_vpe *vpe) @@ -3881,6 +3881,10 @@ static int its_vpe_set_vcpu_affinity(struct irq_data *d, void *vcpu_info) its_vpe_schedule(vpe); return 0; + case WAIT_VPT: + its_wait_vpt_parse_complete(); + return 0; + case DESCHEDULE_VPE: its_vpe_deschedule(vpe); return 0; @@ -4047,7 +4051,7 @@ static void its_vpe_4_1_schedule(struct its_vpe *vpe, gicr_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER); - its_wait_vpt_parse_complete(); + vpe->vpt_ready = false; } static void its_vpe_4_1_deschedule(struct its_vpe *vpe, @@ -4118,6 +4122,10 @@ static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info) its_vpe_4_1_schedule(vpe, info); return 0; + case WAIT_VPT: + its_wait_vpt_parse_complete(); + return 0; + case DESCHEDULE_VPE: its_vpe_4_1_deschedule(vpe, info); return 0; diff --git a/drivers/irqchip/irq-gic-v4.c b/drivers/irqchip/irq-gic-v4.c index 0c18714ae13e..36be42569872 100644 --- a/drivers/irqchip/irq-gic-v4.c +++ b/drivers/irqchip/irq-gic-v4.c @@ -258,6 +258,17 @@ int its_make_vpe_resident(struct its_vpe *vpe, bool g0en, bool g1en) return ret; } +int its_wait_vpt(struct its_vpe *vpe) +{ + struct its_cmd_info info = { }; + + WARN_ON(preemptible()); + + info.cmd_type = WAIT_VPT; + + return its_send_vpe_cmd(vpe, &info); +} + int its_invall_vpe(struct its_vpe *vpe) { struct its_cmd_info info = { diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index a8d8fdcd3723..b55a835d28a8 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -402,6 +402,9 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq, struct kvm_kernel_irq_routing_entry *irq_entry); int vgic_v4_load(struct kvm_vcpu *vcpu); + +void vgic_v4_wait_vpt(struct kvm_vcpu *vcpu); + int vgic_v4_put(struct kvm_vcpu *vcpu, bool need_db); #endif /* __KVM_ARM_VGIC_H */ diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h index 6976b8331b60..68ac2b7b9309 100644 --- a/include/linux/irqchip/arm-gic-v4.h +++ b/include/linux/irqchip/arm-gic-v4.h @@ -75,6 +75,8 @@ struct its_vpe { u16 vpe_id; /* Pending VLPIs on schedule out? */ bool pending_last; + /* VPT parse complete */ + bool vpt_ready; }; /* @@ -103,6 +105,7 @@ enum its_vcpu_info_cmd_type { PROP_UPDATE_VLPI, PROP_UPDATE_AND_INV_VLPI, SCHEDULE_VPE, + WAIT_VPT, DESCHEDULE_VPE, INVALL_VPE, PROP_UPDATE_VSGI, @@ -128,6 +131,7 @@ struct its_cmd_info { int its_alloc_vcpu_irqs(struct its_vm *vm); void its_free_vcpu_irqs(struct its_vm *vm); int its_make_vpe_resident(struct its_vpe *vpe, bool g0en, bool g1en); +int its_wait_vpt(struct its_vpe *vpe); int its_make_vpe_non_resident(struct its_vpe *vpe, bool db); int its_invall_vpe(struct its_vpe *vpe); int its_map_vlpi(int irq, struct its_vlpi_map *map);