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=-18.8 required=3.0 tests=BAYES_00,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, USER_AGENT_GIT 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 C150EC43381 for ; Mon, 11 Jan 2021 13:23:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BB81207D0 for ; Mon, 11 Jan 2021 13:23:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730463AbhAKNXk (ORCPT ); Mon, 11 Jan 2021 08:23:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:35860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732617AbhAKNRb (ORCPT ); Mon, 11 Jan 2021 08:17:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8D78D22B30; Mon, 11 Jan 2021 13:17:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610371036; bh=3pEz0FIIu+fu/KJfgYF3aR7EIsGGl7yKccvVx1G/XRc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a094M9auXmEblFJBzTMFy/JkC8MuJGWj3R2kGAABxyYaB6xeZOD8cG/W3UL79QrJi SgKkAMW6Q/G7xAAb+r8xY3Tofr7d9caGLq4Vjwyt2urAQ4xNdvK09KDLl+90ywZ3bs hC05WdZqzT2yLjJ0ivETcfmcbKfLn8+AQ0shlekg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lai Jiangshan , Paolo Bonzini Subject: [PATCH 5.10 113/145] kvm: check tlbs_dirty directly Date: Mon, 11 Jan 2021 14:02:17 +0100 Message-Id: <20210111130053.957222980@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210111130048.499958175@linuxfoundation.org> References: <20210111130048.499958175@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Lai Jiangshan commit 88bf56d04bc3564542049ec4ec168a8b60d0b48c upstream. In kvm_mmu_notifier_invalidate_range_start(), tlbs_dirty is used as: need_tlb_flush |= kvm->tlbs_dirty; with need_tlb_flush's type being int and tlbs_dirty's type being long. It means that tlbs_dirty is always used as int and the higher 32 bits is useless. We need to check tlbs_dirty in a correct way and this change checks it directly without propagating it to need_tlb_flush. Note: it's _extremely_ unlikely this neglecting of higher 32 bits can cause problems in practice. It would require encountering tlbs_dirty on a 4 billion count boundary, and KVM would need to be using shadow paging or be running a nested guest. Cc: stable@vger.kernel.org Fixes: a4ee1ca4a36e ("KVM: MMU: delay flush all tlbs on sync_page path") Signed-off-by: Lai Jiangshan Message-Id: <20201217154118.16497-1-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- virt/kvm/kvm_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -482,9 +482,8 @@ static int kvm_mmu_notifier_invalidate_r kvm->mmu_notifier_count++; need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end, range->flags); - need_tlb_flush |= kvm->tlbs_dirty; /* we've to flush the tlb before the pages can be freed */ - if (need_tlb_flush) + if (need_tlb_flush || kvm->tlbs_dirty) kvm_flush_remote_tlbs(kvm); spin_unlock(&kvm->mmu_lock);