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=-16.4 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, URIBL_BLOCKED autolearn=ham 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 76E65C432BE for ; Mon, 2 Aug 2021 18:33:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C819610FB for ; Mon, 2 Aug 2021 18:33:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230453AbhHBSdw (ORCPT ); Mon, 2 Aug 2021 14:33:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:47990 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230399AbhHBSdv (ORCPT ); Mon, 2 Aug 2021 14:33:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627929221; 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=Y0XEacTTDUSlhr+SbKYIkZXMudH6vraVMEcqoiG/vJU=; b=b4vUMiitVwvjuYKwm7RPD+/L07xOsXcPB5N3IJcHUMjxt/SKm0yhzWySXq6hlVw3cLvA+J 9YTvsL96+k//2w4AyA5P76QMcZ5b6U4lk3y7597KEikg2+WIr3QFtXbgDIe93ASyRexYHz Hh2YEe0VAmr1I6C7PmYwxsY7hSc9S4Q= 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-2-unGUVflsMw-JuaNSVWQaZA-1; Mon, 02 Aug 2021 14:33:39 -0400 X-MC-Unique: unGUVflsMw-JuaNSVWQaZA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 43EF1824F83; Mon, 2 Aug 2021 18:33:38 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 73F043AE1; Mon, 2 Aug 2021 18:33:34 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Wanpeng Li , Thomas Gleixner , Joerg Roedel , Borislav Petkov , Sean Christopherson , Jim Mattson , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)), Suravee Suthikulpanit , Vitaly Kuznetsov , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , Maxim Levitsky Subject: [PATCH v3 01/12] Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock" Date: Mon, 2 Aug 2021 21:33:18 +0300 Message-Id: <20210802183329.2309921-2-mlevitsk@redhat.com> In-Reply-To: <20210802183329.2309921-1-mlevitsk@redhat.com> References: <20210802183329.2309921-1-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson This together with the next patch will fix a future race between kvm_zap_gfn_range and the page fault handler, which will happen when AVIC memslot is going to be only partially disabled. This is based on a patch suggested by Sean Christopherson: https://lkml.org/lkml/2021/7/22/1025 Signed-off-by: Sean Christopherson Signed-off-by: Maxim Levitsky --- arch/x86/kvm/mmu/mmu.c | 19 ++++++++----------- arch/x86/kvm/mmu/tdp_mmu.c | 15 ++++----------- arch/x86/kvm/mmu/tdp_mmu.h | 11 ++++------- 3 files changed, 16 insertions(+), 29 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index a8cdfd8d45c4..9d78cb1c0f35 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5638,8 +5638,9 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) int i; bool flush = false; + write_lock(&kvm->mmu_lock); + if (kvm_memslots_have_rmaps(kvm)) { - write_lock(&kvm->mmu_lock); for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { slots = __kvm_memslots(kvm, i); kvm_for_each_memslot(memslot, slots) { @@ -5659,22 +5660,18 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) } if (flush) kvm_flush_remote_tlbs_with_address(kvm, gfn_start, gfn_end); - write_unlock(&kvm->mmu_lock); } if (is_tdp_mmu_enabled(kvm)) { - flush = false; - - read_lock(&kvm->mmu_lock); for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, gfn_start, - gfn_end, flush, true); - if (flush) - kvm_flush_remote_tlbs_with_address(kvm, gfn_start, - gfn_end); - - read_unlock(&kvm->mmu_lock); + gfn_end, flush); } + + if (flush) + kvm_flush_remote_tlbs_with_address(kvm, gfn_start, gfn_end); + + write_unlock(&kvm->mmu_lock); } static bool slot_rmap_write_protect(struct kvm *kvm, diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 43f12f5d12c0..3e0222ce3f4e 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -777,21 +777,15 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, * non-root pages mapping GFNs strictly within that range. Returns true if * SPTEs have been cleared and a TLB flush is needed before releasing the * MMU lock. - * - * If shared is true, this thread holds the MMU lock in read mode and must - * account for the possibility that other threads are modifying the paging - * structures concurrently. If shared is false, this thread should hold the - * MMU in write mode. */ bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, - gfn_t end, bool can_yield, bool flush, - bool shared) + gfn_t end, bool can_yield, bool flush) { struct kvm_mmu_page *root; - for_each_tdp_mmu_root_yield_safe(kvm, root, as_id, shared) + for_each_tdp_mmu_root_yield_safe(kvm, root, as_id, false) flush = zap_gfn_range(kvm, root, start, end, can_yield, flush, - shared); + false); return flush; } @@ -803,8 +797,7 @@ void kvm_tdp_mmu_zap_all(struct kvm *kvm) int i; for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) - flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, max_gfn, - flush, false); + flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, max_gfn, flush); if (flush) kvm_flush_remote_tlbs(kvm); diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h index b224d126adf9..358f447d4012 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.h +++ b/arch/x86/kvm/mmu/tdp_mmu.h @@ -20,14 +20,11 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root, bool shared); bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, - gfn_t end, bool can_yield, bool flush, - bool shared); + gfn_t end, bool can_yield, bool flush); static inline bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, - gfn_t start, gfn_t end, bool flush, - bool shared) + gfn_t start, gfn_t end, bool flush) { - return __kvm_tdp_mmu_zap_gfn_range(kvm, as_id, start, end, true, flush, - shared); + return __kvm_tdp_mmu_zap_gfn_range(kvm, as_id, start, end, true, flush); } static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) { @@ -44,7 +41,7 @@ static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) */ lockdep_assert_held_write(&kvm->mmu_lock); return __kvm_tdp_mmu_zap_gfn_range(kvm, kvm_mmu_page_as_id(sp), - sp->gfn, end, false, false, false); + sp->gfn, end, false, false); } void kvm_tdp_mmu_zap_all(struct kvm *kvm); -- 2.26.3