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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 A098EC433B4 for ; Thu, 1 Apr 2021 23:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B8AD610A5 for ; Thu, 1 Apr 2021 23:38:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236579AbhDAXir (ORCPT ); Thu, 1 Apr 2021 19:38:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236415AbhDAXiV (ORCPT ); Thu, 1 Apr 2021 19:38:21 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F160AC061793 for ; Thu, 1 Apr 2021 16:38:19 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id ev19so4296277qvb.7 for ; Thu, 01 Apr 2021 16:38:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=x7Mvbj3iAstsLSOHB4o6ZE5LRtLU1ZJPyMZ93FFvwYE=; b=AiL7v12vhE9FQqqdQYzgzWFxSeNqmXOgD7oGXV9+9TOtuBXgU2cIhrQ8XWf/zPm/8P OMH6rqACuPgVHLvGhqSCpXzezfbTFzkCNpIqoQcecmJC/JTsrPJ4/4gmgrAvTyzkLH39 hlQPXGY5c3ZgkLCXcIvHnFvUwJk+rFVl+xTDoJDSeKdNbNMPxWkHnbDHK1kvzVjq7HCo tk+Ll1M+BAzU9t7JunIwn1wwCmFVUpvFS910ieU4LhuVTR7fLOsC/hGn53qB7wZyOL8A DLUR+LZwDx0BVqkN0zkxjFnyaiTio/1+ke9fnfFWFjE8J2pNns2V2U0JNEwd5MKlzGi6 z9Uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=x7Mvbj3iAstsLSOHB4o6ZE5LRtLU1ZJPyMZ93FFvwYE=; b=ous7gwtIRCAl71JoIP/scQhmWvzVFwnYhsKawUQKXKCxOxXnnfAAz21YecMxP2lREw GMGYd7xexGzay7+qspnZB5krWTU5egrF7TJdb960me3IkxckXFQNxVTQYpLP6e7Ln37F UW6+n9guxSDW/+qQJqZZrmEjNVy1zyVrCCSQOyyj1JiYpgn9ZFEQpUSpZRptlwK1bjiF CIKGy2eSSMUjjV8XiTLNKrSan9mzXYgZARK52nDvPDt10Apu9Zx3S7vo4oSy+ljafK6O wdU0UbUTw+ac1Y12NeuJrReqA7VC4zGQgfyu2NaCaSKO32hFrc143kXq05xhDWQE8b5n uFRQ== X-Gm-Message-State: AOAM532k+hb/m2msZau7B4ctFY9hoXh5fHYW6y7gnJKGqi3gmaAs6Mqj tPX3DmrzITJ51maQj+6mvQf5+7kaQp5GOfsSsEOLpAFwHCJEaUcF7FVAAgUHILYuclzX5eRGWTO WygYmsMF8A2OXyZuVak2EkoPmBBBG5QqSPPFXbWgKmiFKB+N4LrFCAKeYdT4ElN3NJjcwIoU4 X-Google-Smtp-Source: ABdhPJz1/6IkY7EkLvN8g6YPULn4xPOH++QPoiTvtYX5/4Pi2+H9UzmVvpaj30ZPesn7sxfj0HRsiIHgjxze X-Received: from bgardon.sea.corp.google.com ([2620:15c:100:202:e088:88b8:ea4a:22b6]) (user=bgardon job=sendgmr) by 2002:ad4:5614:: with SMTP id ca20mr10393824qvb.37.1617320299115; Thu, 01 Apr 2021 16:38:19 -0700 (PDT) Date: Thu, 1 Apr 2021 16:37:33 -0700 In-Reply-To: <20210401233736.638171-1-bgardon@google.com> Message-Id: <20210401233736.638171-11-bgardon@google.com> Mime-Version: 1.0 References: <20210401233736.638171-1-bgardon@google.com> X-Mailer: git-send-email 2.31.0.208.g409f899ff0-goog Subject: [PATCH v2 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU read lock From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Peter Xu , Sean Christopherson , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong , Ben Gardon Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To speed the process of disabling dirty logging, change the TDP MMU function which zaps collapsible SPTEs to run under the MMU read lock. Signed-off-by: Ben Gardon --- arch/x86/kvm/mmu/mmu.c | 14 ++++++++++---- arch/x86/kvm/mmu/tdp_mmu.c | 17 +++++++++++++---- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d03a7a8b7ea2..5939813e3043 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5612,13 +5612,19 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, write_lock(&kvm->mmu_lock); flush = slot_handle_leaf(kvm, slot, kvm_mmu_zap_collapsible_spte, true); - if (is_tdp_mmu_enabled(kvm)) - flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush); - if (flush) kvm_arch_flush_remote_tlbs_memslot(kvm, slot); - write_unlock(&kvm->mmu_lock); + + if (is_tdp_mmu_enabled(kvm)) { + flush = false; + + read_lock(&kvm->mmu_lock); + flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush); + if (flush) + kvm_arch_flush_remote_tlbs_memslot(kvm, slot); + read_unlock(&kvm->mmu_lock); + } } void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm, diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 6917403484ce..0e6ffa04e5e1 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1323,7 +1323,8 @@ static bool zap_collapsible_spte_range(struct kvm *kvm, rcu_read_lock(); tdp_root_for_each_pte(iter, root, start, end) { - if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, false)) { +retry: + if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, true)) { flush = false; continue; } @@ -1338,8 +1339,14 @@ static bool zap_collapsible_spte_range(struct kvm *kvm, pfn, PG_LEVEL_NUM)) continue; - tdp_mmu_set_spte(kvm, &iter, 0); - + if (!tdp_mmu_zap_spte_atomic(kvm, &iter)) { + /* + * The iter must explicitly re-read the SPTE because + * the atomic cmpxchg failed. + */ + iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); + goto retry; + } flush = true; } @@ -1358,7 +1365,9 @@ bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, { struct kvm_mmu_page *root; - for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, false) + lockdep_assert_held_read(&kvm->mmu_lock); + + for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) flush = zap_collapsible_spte_range(kvm, root, slot, flush); return flush; -- 2.31.0.208.g409f899ff0-goog