From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 888C4C433DB for ; Tue, 9 Feb 2021 05:07:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A6A164EA6 for ; Tue, 9 Feb 2021 05:07:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbhBIFG4 (ORCPT ); Tue, 9 Feb 2021 00:06:56 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22926 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229774AbhBIFF6 (ORCPT ); Tue, 9 Feb 2021 00:05:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612847071; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+uUnGwSf0oqnSub/JjSQvM5XUCg9XUtINd+duInZ6C0=; b=DJrOkpOnqj1PKjNUT246k8+tRn+9TtqwraEEd3zNf/gwpBdv7gO+phF4iVEcQRC662wqrA v1FkIOY0gQWvJclO7Ejr/bjjV7tHD7LzZwcfIWsLMpynMXQxovZjeqU2m1/7XpZ4xT45Dt oAeRzQwDUSbOSfwxxvj5Foc0FqQR/GE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-577-_34aPoISPpCzPj-LTK_cZg-1; Tue, 09 Feb 2021 00:04:29 -0500 X-MC-Unique: _34aPoISPpCzPj-LTK_cZg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ADB4A801962; Tue, 9 Feb 2021 05:04:27 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-26.bne.redhat.com [10.64.54.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id A52E15D9C0; Tue, 9 Feb 2021 05:04:23 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.cs.columbia.edu Cc: linux-kernel@vger.kernel.org, pbonzini@redhat.com, maz@kernel.org, james.morse@arm.com, Jonathan.Cameron@huawei.com, mark.rutland@arm.com, will@kernel.org, shan.gavin@gmail.com Subject: [PATCH v2 03/17] KVM: async_pf: Make GFN slot management generic Date: Tue, 9 Feb 2021 13:03:49 +0800 Message-Id: <20210209050403.103143-4-gshan@redhat.com> In-Reply-To: <20210209050403.103143-1-gshan@redhat.com> References: <20210209050403.103143-1-gshan@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's not allowed to fire duplicate notification for same GFN on x86 platform, with help of a hash table. This mechanism is going to be used by arm64 and this makes the code generic and shareable by multiple platforms. * As this mechanism isn't needed by all platforms, a new kernel config option (CONFIG_ASYNC_PF_SLOT) is introduced so that it can be disabled at compiling time. * The code is basically copied from x86 platform and the functions are renamed to reflect the fact: (a) the input parameters are vCPU and GFN. (b) The operations are resetting, searching, adding and removing. * Helper stub is also added on !CONFIG_KVM_ASYNC_PF because we're going to use IS_ENABLED() instead of #ifdef on arm64 when the asynchronous page fault is supported. This is preparatory work to use the newly introduced functions on x86 platform and arm64 in subsequent patches. Signed-off-by: Gavin Shan --- include/linux/kvm_host.h | 18 +++++++++ virt/kvm/Kconfig | 3 ++ virt/kvm/async_pf.c | 79 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 100 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 041d93f8f4b0..b52d71030f25 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -277,6 +277,9 @@ struct kvm_vcpu { #ifdef CONFIG_KVM_ASYNC_PF struct { +#ifdef CONFIG_KVM_ASYNC_PF_SLOT + gfn_t gfns[ASYNC_PF_PER_VCPU]; +#endif u32 queued; struct list_head queue; struct list_head done; @@ -321,12 +324,27 @@ static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) return !list_empty_careful(&vcpu->async_pf.done); } +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu); +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn); +#endif + void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu); void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu); bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, unsigned long hva, struct kvm_arch_async_pf *arch); int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #else +static inline void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) { } +static inline void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) { } +static inline bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return false; +} + static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) { return false; diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 1c37ccd5d402..69a282aaa4df 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -23,6 +23,9 @@ config KVM_MMIO config KVM_ASYNC_PF bool +config KVM_ASYNC_PF_SLOT + bool + # Toggle to switch between direct notification and batch job config KVM_ASYNC_PF_SYNC bool diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 2cf864aafd0e..7bf22b20af45 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -19,6 +19,85 @@ static struct kmem_cache *async_pf_cache; +#ifdef CONFIG_KVM_ASYNC_PF_SLOT +static inline u32 kvm_async_pf_hash(gfn_t gfn) +{ + BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU)); + + return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); +} + +static inline u32 kvm_async_pf_next_slot(u32 key) +{ + return (key + 1) & (ASYNC_PF_PER_VCPU - 1); +} + +static u32 kvm_async_pf_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + int i; + u32 key = kvm_async_pf_hash(gfn); + + for (i = 0; i < ASYNC_PF_PER_VCPU && + (vcpu->async_pf.gfns[key] != gfn && + vcpu->async_pf.gfns[key] != ~0); i++) + key = kvm_async_pf_next_slot(key); + + return key; +} + +void kvm_async_pf_reset_slot(struct kvm_vcpu *vcpu) +{ + int i; + + for (i = 0; i < ASYNC_PF_PER_VCPU; i++) + vcpu->async_pf.gfns[i] = ~0; +} + +bool kvm_async_pf_find_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return vcpu->async_pf.gfns[kvm_async_pf_slot(vcpu, gfn)] == gfn; +} + +void kvm_async_pf_add_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash(gfn); + + while (vcpu->async_pf.gfns[key] != ~0) + key = kvm_async_pf_next_slot(key); + + vcpu->async_pf.gfns[key] = gfn; +} + +void kvm_async_pf_remove_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 i, j, k; + + i = j = kvm_async_pf_slot(vcpu, gfn); + + if (WARN_ON_ONCE(vcpu->async_pf.gfns[i] != gfn)) + return; + + while (true) { + vcpu->async_pf.gfns[i] = ~0; + do { + j = kvm_async_pf_next_slot(j); + if (vcpu->async_pf.gfns[j] == ~0) + return; + + k = kvm_async_pf_hash(vcpu->async_pf.gfns[j]); + /* + * k lies cyclically in ]i,j] + * | i.k.j | + * |....j i.k.| or |.k..j i...| + */ + } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j)); + + vcpu->async_pf.gfns[i] = vcpu->async_pf.gfns[j]; + i = j; + } +} +#endif /* CONFIG_KVM_ASYNC_PF_SLOT */ + int kvm_async_pf_init(void) { async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); -- 2.23.0