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=-3.8 required=3.0 tests=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 6FB51C7618F for ; Fri, 19 Jul 2019 20:41:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47DED2186A for ; Fri, 19 Jul 2019 20:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388123AbfGSUlV (ORCPT ); Fri, 19 Jul 2019 16:41:21 -0400 Received: from mga12.intel.com ([192.55.52.136]:46747 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728051AbfGSUlU (ORCPT ); Fri, 19 Jul 2019 16:41:20 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Jul 2019 13:41:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,283,1559545200"; d="scan'208";a="168655824" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.165]) by fmsmga008.fm.intel.com with ESMTP; 19 Jul 2019 13:41:19 -0700 From: Sean Christopherson To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Josh Poimboeuf , Peter Zijlstra Cc: "H. Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/5] KVM: VMX: Optimize VMX instrs error/fault handling Date: Fri, 19 Jul 2019 13:41:05 -0700 Message-Id: <20190719204110.18306-1-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A recent commit reworked __kvm_handle_fault_on_reboot() to play nice with objtool. An unfortunate side effect is that JMP is now inserted after most VMX instructions so that the reboot macro can use an actual CALL to kvm_spurious_fault() instead of a funky PUSH+JMP facsimile in .fixup. Rework the low level VMX instruction helpers to handle unexpected faults manually instead of relying on the "fault on reboot" macro. By using asm-goto, most helpers can branch directly to an in-function call to kvm_spurious_fault(), which can then be optimized by compilers to reside out-of-line at the end of the function instead of inline as done by "fault on reboot". The net impact relative to the current code base is more or less a nop when building with a compiler that supports __GCC_ASM_FLAG_OUTPUTS__. A bunch of code that was previously in .fixup gets moved into the slow paths of functions, but the fast paths are more basically unchanged. Without __GCC_ASM_FLAG_OUTPUTS__, manually coding the Jcc is a net positive as CC_SET() without compiler support almost always generates a SETcc+CMP+Jcc sequence, which is now replaced with a single Jcc. A small bonus is that the Jcc instrs are hinted to predict that the VMX instr will be successful. v2: - Rebased to x86/master, commit eceffd88ca20 ("Merge branch 'x86/urgent'") - Reworded changelogs to reference the commit instead lkml link for the recent changes to __kvm_handle_fault_on_reboot(). - Added Paolo's acks for patch 1-4 - Added patch 5 to do more cleanup, which was made possible by rebasing on top of the __kvm_handle_fault_on_reboot() changes. Sean Christopherson (5): objtool: KVM: x86: Check kvm_rebooting in kvm_spurious_fault() KVM: VMX: Optimize VMX instruction error and fault handling KVM: VMX: Add error handling to VMREAD helper KVM: x86: Drop ____kvm_handle_fault_on_reboot() KVM: x86: Don't check kvm_rebooting in __kvm_handle_fault_on_reboot() arch/x86/include/asm/kvm_host.h | 16 ++---- arch/x86/kvm/vmx/ops.h | 93 ++++++++++++++++++++------------- arch/x86/kvm/vmx/vmx.c | 42 +++++++++++++++ arch/x86/kvm/x86.c | 3 +- tools/objtool/check.c | 1 - 5 files changed, 104 insertions(+), 51 deletions(-) -- 2.22.0