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=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no 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 2E9B2C4727E for ; Wed, 23 Sep 2020 18:37:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEFE6235FD for ; Wed, 23 Sep 2020 18:37:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726861AbgIWShi (ORCPT ); Wed, 23 Sep 2020 14:37:38 -0400 Received: from mga14.intel.com ([192.55.52.115]:9454 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726332AbgIWShi (ORCPT ); Wed, 23 Sep 2020 14:37:38 -0400 IronPort-SDR: U7K1mg4muKoDpt4gMUOdyzARVDydOlwm06OBQvNkNstkrpstUsw/cPOlZTV7nYoGsAaYqOhkzl 2VeuDJqHi0RA== X-IronPort-AV: E=McAfee;i="6000,8403,9753"; a="160276859" X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="160276859" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2020 11:37:37 -0700 IronPort-SDR: xzdtHKopGeCmbqsC4quJMFzcNpajTENd5zQcy3HZ3WoY5zKm4LV5iC5ZpZEmgqz8j4dIJTFtCg 3bFv1hzQmQrQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="486561611" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.160]) by orsmga005.jf.intel.com with ESMTP; 23 Sep 2020 11:37:37 -0700 From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Junaid Shahid Subject: [PATCH v2 0/8] KVM: x86/mmu: ITLB multi-hit workaround fixes Date: Wed, 23 Sep 2020 11:37:27 -0700 Message-Id: <20200923183735.584-1-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Patch 1 is a minor fix for a very theoretical bug where KVM could skip the final "commit zap" when recovering shadow pages for the NX huge page mitigation. Patch 2 is cleanup that's made possible by patch 1. Patches 3-5 are the main course and fix bugs in the NX huge page accounting where shadow pages are incorrectly added to the list of disallowed huge pages. KVM doesn't actually check to see if the page could actually have been a large page when adding to the disallowed list. This result in what are effectively spurious zaps. The biggest issue is likely with shadow pages in the upper levels, i.e. levels 3 and 4, as they are either unlikely to be huge (1gb) or flat out can't be huge (512tb). And because of the way KVM zaps, the upper levels will be zapped first, i.e. KVM is likely zapping and rebuilding a decent number of its shadow pages for zero benefit. Ideally, patches 3-5 would be a single patch to ease backporting. In the end, I decided the change is probably not suitable for stable as at worst it creates an infrequent performance spike (assuming the admin isn't going crazy with the recovery frequency), and it's far from straightforward or risk free. Cramming everything into a single patch was a mess. Patches 6-8 are cleanups in related code. The 'hlevel' name in particular has been on my todo list for a while. v2: - Rebased to kvm/queue, commit e1ba1a15af73 ("KVM: SVM: Enable INVPCID feature on AMD"). Sean Christopherson (8): KVM: x86/mmu: Commit zap of remaining invalid pages when recovering lpages KVM: x86/mmu: Refactor the zap loop for recovering NX lpages KVM: x86/mmu: Move "huge page disallowed" calculation into mapping helpers KVM: x86/mmu: Capture requested page level before NX huge page workaround KVM: x86/mmu: Account NX huge page disallowed iff huge page was requested KVM: x86/mmu: Rename 'hlevel' to 'level' in FNAME(fetch) KVM: x86/mmu: Hoist ITLB multi-hit workaround check up a level KVM: x86/mmu: Track write/user faults using bools arch/x86/kvm/mmu/mmu.c | 58 +++++++++++++++++++++------------- arch/x86/kvm/mmu/paging_tmpl.h | 39 ++++++++++++----------- 2 files changed, 57 insertions(+), 40 deletions(-) -- 2.28.0