From nobody Wed Sep 17 05:42:37 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 814ADC4167B for ; Fri, 23 Dec 2022 01:00:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236023AbiLWBAg (ORCPT ); Thu, 22 Dec 2022 20:00:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235813AbiLWA7m (ORCPT ); Thu, 22 Dec 2022 19:59:42 -0500 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15C1026100 for ; Thu, 22 Dec 2022 16:58:25 -0800 (PST) Received: by mail-pl1-x64a.google.com with SMTP id z10-20020a170902ccca00b001898329db72so2398873ple.21 for ; Thu, 22 Dec 2022 16:58:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=RmIwb9k/SqB1LqdRcr0G+09cT+gAvGR5f8klU1SCXxI=; b=MH389gr2y0u/PUo/yBQScWfJTRoQrOiIYogq620at7Epoq+AzEq8BvkRW6dqDUDlzp giee49v09L/UiRkCySNTzRn+haVIjDqGinCLvYUWxgOfuNKJ3cvnkXDVXkPrQZzhMacS WT6mHlB9YLfgdiQt5YpevppaWySxhsMPIFqevdGTSdZw1RdRvsYXakEApD9tUXC7Mv1N EGgWND418RVwJL+LH6nWLs+4qMEOblDmmfc4oZUcG78GddkZzMysGS2VZsignqtuZni2 vitgXqRaEQQ2Ufukr8fLFSo6pk/31co2ITI+xPCTiNhse05PFUMuPIcY/aHytJewfncc XYbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=RmIwb9k/SqB1LqdRcr0G+09cT+gAvGR5f8klU1SCXxI=; b=e+f4w+bnsZTtoIH1XldPsp4n+HtitqH943gNB/rgu9f3wP5+eWk3yVfwYHD72Ga/6A KDTEo+743QZFhtP12+hPaO3Rh3R3QQKZJbMIeCzfppWjV+sUaQJeCouyy9fG+g4ZYDG3 b1hn3gBZRSHAtZ/gHRs6J18NfrnnRqF09c5h6XGmoRXEC5ykc39sir9y3/rNOfZ8JTB6 JI/gv8k+l/H0pfyW1my7yMIXnciKh1DO0+uco7VCQnnsEt0AUYFFrlcJNN/fRNGS9A5Y 7AWxbkQmsr9drPqPjFbwH+IyADjlRYzpExfATirmBnbS8gB/hLoyaUKolIjSbqnPn3nD o7Eg== X-Gm-Message-State: AFqh2kq7ilaorIJ8lLPpWHagGkPps44uw2sLjA57RIG1LXJ+pdp7R+j2 qM8NCynmmrPFGAO8WrmXcObMjutIBR0= X-Google-Smtp-Source: AMrXdXsuuT+Rfv7Ka620Z8HtXWRrUqlm2IJLYfXoad0YT0tmShcBBNAbtzi1lR42YTfgvAaxmy4Lxliq44o= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90b:701:b0:219:1d0a:34a6 with SMTP id s1-20020a17090b070100b002191d0a34a6mr180820pjz.1.1671757098036; Thu, 22 Dec 2022 16:58:18 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 23 Dec 2022 00:57:31 +0000 In-Reply-To: <20221223005739.1295925-1-seanjc@google.com> Mime-Version: 1.0 References: <20221223005739.1295925-1-seanjc@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20221223005739.1295925-20-seanjc@google.com> Subject: [PATCH 19/27] KVM: x86/mmu: Use page-track notifiers iff there are external users From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Zhenyu Wang , Zhi Wang Cc: kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, Yan Zhao , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Disable the page-track notifier code at compile time if there are no external users, i.e. if CONFIG_KVM_EXTERNAL_WRITE_TRACKING=3Dn. KVM itself now hooks emulated writes directly instead of relying on the page-track mechanism. Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/include/asm/kvm_page_track.h | 2 ++ arch/x86/kvm/mmu/page_track.c | 9 ++++---- arch/x86/kvm/mmu/page_track.h | 30 +++++++++++++++++++++++---- 4 files changed, 35 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index eec424fac0ba..e8f8e1bd96c7 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1223,7 +1223,9 @@ struct kvm_arch { * create an NX huge page (without hanging the guest). */ struct list_head possible_nx_huge_pages; +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING struct kvm_page_track_notifier_head track_notifier_head; +#endif /* * Protects marking pages unsync during page faults, as TDP MMU page * faults only take mmu_lock for read. For simplicity, the unsync diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/k= vm_page_track.h index deece45936a5..53c2adb25a07 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -55,6 +55,7 @@ void kvm_slot_page_track_remove_page(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode); =20 +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn, enum pg_level max_level); =20 @@ -64,5 +65,6 @@ kvm_page_track_register_notifier(struct kvm *kvm, void kvm_page_track_unregister_notifier(struct kvm *kvm, struct kvm_page_track_notifier_node *n); +#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */ =20 #endif diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index 2b302fd2c5dd..f932909aa9b5 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -193,6 +193,7 @@ bool kvm_slot_page_track_is_active(struct kvm *kvm, return !!READ_ONCE(slot->arch.gfn_track[mode][index]); } =20 +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING void kvm_page_track_cleanup(struct kvm *kvm) { struct kvm_page_track_notifier_head *head; @@ -208,6 +209,7 @@ int kvm_page_track_init(struct kvm *kvm) head =3D &kvm->arch.track_notifier_head; INIT_HLIST_HEAD(&head->track_notifier_list); return init_srcu_struct(&head->track_srcu); + return 0; } =20 /* @@ -254,8 +256,8 @@ EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier); * The node should figure out if the written page is the one that node is * interested in by itself. */ -void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, - int bytes) +void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *ne= w, + int bytes) { struct kvm_page_track_notifier_head *head; struct kvm_page_track_notifier_node *n; @@ -272,8 +274,6 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t = gpa, const u8 *new, if (n->track_write) n->track_write(gpa, new, bytes, n); srcu_read_unlock(&head->track_srcu, idx); - - kvm_mmu_track_write(vcpu, gpa, new, bytes); } =20 /* @@ -316,3 +316,4 @@ enum pg_level kvm_page_track_max_mapping_level(struct k= vm *kvm, gfn_t gfn, return max_level; } EXPORT_SYMBOL_GPL(kvm_page_track_max_mapping_level); +#endif diff --git a/arch/x86/kvm/mmu/page_track.h b/arch/x86/kvm/mmu/page_track.h index 89712f123ad3..1b363784aa4a 100644 --- a/arch/x86/kvm/mmu/page_track.h +++ b/arch/x86/kvm/mmu/page_track.h @@ -6,8 +6,6 @@ =20 #include =20 -int kvm_page_track_init(struct kvm *kvm); -void kvm_page_track_cleanup(struct kvm *kvm); =20 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm); int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot); @@ -21,13 +19,37 @@ bool kvm_slot_page_track_is_active(struct kvm *kvm, const struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode); =20 -void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, - int bytes); +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING +int kvm_page_track_init(struct kvm *kvm); +void kvm_page_track_cleanup(struct kvm *kvm); + +void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *ne= w, + int bytes); void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *s= lot); =20 static inline bool kvm_page_track_has_external_user(struct kvm *kvm) { return hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list); } +#else +static inline int kvm_page_track_init(struct kvm *kvm) { return 0; } +static inline void kvm_page_track_cleanup(struct kvm *kvm) { } + +static inline void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, + const u8 *new, int bytes) { } +static inline void kvm_page_track_delete_slot(struct kvm *kvm, + struct kvm_memory_slot *slot) { } + +static inline bool kvm_page_track_has_external_user(struct kvm *kvm) { ret= urn false; } + +#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */ + +static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, + const u8 *new, int bytes) +{ + __kvm_page_track_write(vcpu, gpa, new, bytes); + + kvm_mmu_track_write(vcpu, gpa, new, bytes); +} =20 #endif /* __KVM_X86_PAGE_TRACK_H */ --=20 2.39.0.314.g84b9a713c41-goog