From patchwork Fri Jul 2 22:04:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 12356641 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=-16.8 required=3.0 tests=BAYES_00, 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 28378C07E96 for ; Fri, 2 Jul 2021 22:05:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1362C61435 for ; Fri, 2 Jul 2021 22:05:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233616AbhGBWIV (ORCPT ); Fri, 2 Jul 2021 18:08:21 -0400 Received: from mga12.intel.com ([192.55.52.136]:50201 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233220AbhGBWIA (ORCPT ); Fri, 2 Jul 2021 18:08:00 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10033"; a="188472759" X-IronPort-AV: E=Sophos;i="5.83,320,1616482800"; d="scan'208";a="188472759" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jul 2021 15:05:27 -0700 X-IronPort-AV: E=Sophos;i="5.83,320,1616482800"; d="scan'208";a="642814825" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jul 2021 15:05:27 -0700 From: isaku.yamahata@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , erdemaktas@google.com, Connor Kuehl , Sean Christopherson , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Sean Christopherson Subject: [RFC PATCH v2 45/69] KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits() Date: Fri, 2 Jul 2021 15:04:51 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Sean Christopherson Return the old SPTE when clearing a SPTE and push the "old SPTE present" check to the caller. Private shadow page support will use the old SPTE in rmap_remove() to determine whether or not there is a linked private shadow page. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata Reviewed-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0259781cee6a..6b0c8c84aabe 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -542,9 +542,9 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte) * Rules for using mmu_spte_clear_track_bits: * It sets the sptep from present to nonpresent, and track the * state bits, it is used to clear the last level sptep. - * Returns non-zero if the PTE was previously valid. + * Returns the old PTE. */ -static int mmu_spte_clear_track_bits(u64 *sptep) +static u64 mmu_spte_clear_track_bits(u64 *sptep) { kvm_pfn_t pfn; u64 old_spte = *sptep; @@ -555,7 +555,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep) old_spte = __update_clear_spte_slow(sptep, shadow_init_value); if (!is_shadow_present_pte(old_spte)) - return 0; + return old_spte; pfn = spte_to_pfn(old_spte); @@ -572,7 +572,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep) if (is_dirty_spte(old_spte)) kvm_set_pfn_dirty(pfn); - return 1; + return old_spte; } /* @@ -1104,7 +1104,9 @@ static u64 *rmap_get_next(struct rmap_iterator *iter) static void drop_spte(struct kvm *kvm, u64 *sptep) { - if (mmu_spte_clear_track_bits(sptep)) + u64 old_spte = mmu_spte_clear_track_bits(sptep); + + if (is_shadow_present_pte(old_spte)) rmap_remove(kvm, sptep); }