From patchwork Wed Sep 30 04:16:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11807815 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6A5E3139A for ; Wed, 30 Sep 2020 04:17:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5320A20872 for ; Wed, 30 Sep 2020 04:17:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725798AbgI3ERD (ORCPT ); Wed, 30 Sep 2020 00:17:03 -0400 Received: from mga18.intel.com ([134.134.136.126]:60793 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725306AbgI3ERD (ORCPT ); Wed, 30 Sep 2020 00:17:03 -0400 IronPort-SDR: yP2s851zwsADPoqTbfxmReqQ3cF3nFVRqxVDbSJ/VzGwIRDIDzsUI9IQ/7SX+rowT2AGgm1ove EZ7BPTq45oKg== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="150137442" X-IronPort-AV: E=Sophos;i="5.77,321,1596524400"; d="scan'208";a="150137442" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 21:17:02 -0700 IronPort-SDR: lP4CQa/l4bbc0mzz+ZwM7GnfsFmbuqynTTtO0n5TUvHt0elDV/NUxmWFCNaJzCrM49UE0mXyfN 13vH5TGP9uPQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,321,1596524400"; d="scan'208";a="415607859" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.160]) by fmsmga001.fm.intel.com with ESMTP; 29 Sep 2020 21:17:01 -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, Lai Jiangshan , Lai Jiangshan Subject: [PATCH 0/5] KVM: x86: Handle reserved CR4 bit interception in VMX Date: Tue, 29 Sep 2020 21:16:54 -0700 Message-Id: <20200930041659.28181-1-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This series stems from Lai's RFC patches to intercept LA57 and let the guest own FSGSBASE[*]. Discussion and inspection revealed that KVM does not handle the case where LA57 is supported in hardware but not exposed to the guest. This is actually true for all CR4 bits, but LA57 is currently the only bit that can be reserved and also owned by the guest. I have a unit test for this that I'll post separately. Intercepting LA57 was by far the easiest fix for the immedidate bug, and is likely the right change in the long term as there's no justification for letting the guest own LA57. The middle three patches adjust VMX's CR4 guest/host mask to intercept reserved bits. This required reworking CPUID updates to also refresh said mask at the correct time. The last past is Lai's, which let's the guest own FSGSBASE. This depends on the reserved bit handling being in place. Ran everything through unit tests, and ran the kernel's FSGSBASE selftests in a VM. [*] https://lkml.kernel.org/r/20200928083047.3349-1-jiangshanlai@gmail.com Lai Jiangshan (2): KVM: x86: Intercept LA57 to inject #GP fault when it's reserved KVM: x86: Let the guest own CR4.FSGSBASE Sean Christopherson (3): KVM: x86: Invoke vendor's vcpu_after_set_cpuid() after all common updates KVM: x86: Move call to update_exception_bitmap() into VMX code KVM: VMX: Intercept guest reserved CR4 bits to inject #GP fault arch/x86/kvm/cpuid.c | 6 +++--- arch/x86/kvm/kvm_cache_regs.h | 2 +- arch/x86/kvm/vmx/vmx.c | 18 +++++++++++++----- 3 files changed, 17 insertions(+), 9 deletions(-)