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=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A363FC4CEC8 for ; Fri, 13 Sep 2019 02:46:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 859E72084D for ; Fri, 13 Sep 2019 02:46:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727781AbfIMCqU (ORCPT ); Thu, 12 Sep 2019 22:46:20 -0400 Received: from mga07.intel.com ([134.134.136.100]:58611 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727614AbfIMCqR (ORCPT ); Thu, 12 Sep 2019 22:46:17 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Sep 2019 19:46:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,492,1559545200"; d="scan'208";a="176159533" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by orsmga007.jf.intel.com with ESMTP; 12 Sep 2019 19:46:13 -0700 From: Sean Christopherson To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, James Harvey , Alex Willamson Subject: [PATCH 11/11] KVM: x86/mmu: Skip invalid pages during zapping iff root_count is zero Date: Thu, 12 Sep 2019 19:46:12 -0700 Message-Id: <20190913024612.28392-12-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190913024612.28392-1-sean.j.christopherson@intel.com> References: <20190913024612.28392-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Do not skip invalid shadow pages when zapping obsolete pages if the pages' root_count has reached zero, in which case the page can be immediately zapped and freed. Update the comment accordingly. Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index a7b14750cde9..5e41b1f77a6d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5692,11 +5692,12 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm) break; /* - * Since we are reversely walking the list and the invalid - * list will be moved to the head, skip the invalid page - * can help us to avoid the infinity list walking. + * Skip invalid pages with a non-zero root count, zapping pages + * with a non-zero root count will never succeed, i.e. the page + * will get thrown back on active_mmu_pages and we'll get stuck + * in an infinite loop. */ - if (sp->role.invalid) + if (sp->role.invalid && sp->root_count) continue; /* -- 2.22.0