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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 CB28AC76195 for ; Fri, 19 Jul 2019 20:41:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC62621883 for ; Fri, 19 Jul 2019 20:41:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388230AbfGSUlZ (ORCPT ); Fri, 19 Jul 2019 16:41:25 -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 S2388128AbfGSUlV (ORCPT ); Fri, 19 Jul 2019 16:41:21 -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 13:41:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,283,1559545200"; d="scan'208";a="168655834" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.165]) by fmsmga008.fm.intel.com with ESMTP; 19 Jul 2019 13:41:21 -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 3/5] KVM: VMX: Add error handling to VMREAD helper Date: Fri, 19 Jul 2019 13:41:08 -0700 Message-Id: <20190719204110.18306-4-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190719204110.18306-1-sean.j.christopherson@intel.com> References: <20190719204110.18306-1-sean.j.christopherson@intel.com> 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 Now that VMREAD flows require a taken branch, courtesy of commit 3901336ed9887 ("x86/kvm: Don't call kvm_spurious_fault() from .fixup") bite the bullet and add full error handling to VMREAD, i.e. replace the JMP added by __ex()/____kvm_handle_fault_on_reboot() with a hinted Jcc. To minimize the code footprint, add a helper function, vmread_error(), to handle both faults and failures so that the inline flow has a single CALL. Acked-by: Paolo Bonzini Cc: Josh Poimboeuf Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/ops.h | 21 +++++++++++++++++---- arch/x86/kvm/vmx/vmx.c | 8 ++++++++ 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/ops.h b/arch/x86/kvm/vmx/ops.h index 79e25d49d4d9..45eaedee2ac0 100644 --- a/arch/x86/kvm/vmx/ops.h +++ b/arch/x86/kvm/vmx/ops.h @@ -11,9 +11,8 @@ #include "vmcs.h" #define __ex(x) __kvm_handle_fault_on_reboot(x) -#define __ex_clear(x, reg) \ - ____kvm_handle_fault_on_reboot(x, "xor " reg ", " reg) +asmlinkage void vmread_error(unsigned long field, bool fault); void vmwrite_error(unsigned long field, unsigned long value); void vmclear_error(struct vmcs *vmcs, u64 phys_addr); void vmptrld_error(struct vmcs *vmcs, u64 phys_addr); @@ -68,8 +67,22 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field) { unsigned long value; - asm volatile (__ex_clear("vmread %1, %0", "%k0") - : "=r"(value) : "r"(field)); + asm volatile("1: vmread %2, %1\n\t" + ".byte 0x3e\n\t" /* branch taken hint */ + "ja 3f\n\t" + "mov %2, %%" _ASM_ARG1 "\n\t" + "xor %%" _ASM_ARG2 ", %%" _ASM_ARG2 "\n\t" + "2: call vmread_error\n\t" + "xor %k1, %k1\n\t" + "3:\n\t" + + ".pushsection .fixup, \"ax\"\n\t" + "4: mov %2, %%" _ASM_ARG1 "\n\t" + "mov $1, %%" _ASM_ARG2 "\n\t" + "jmp 2b\n\t" + ".popsection\n\t" + _ASM_EXTABLE(1b, 4b) + : ASM_CALL_CONSTRAINT, "=r"(value) : "r"(field) : "cc"); return value; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 46689019ebf7..9acf3d6395d3 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -349,6 +349,14 @@ do { \ pr_warn_ratelimited(fmt); \ } while (0) +asmlinkage void vmread_error(unsigned long field, bool fault) +{ + if (fault) + kvm_spurious_fault(); + else + vmx_insn_failed("kvm: vmread failed: field=%lx\n", field); +} + noinline void vmwrite_error(unsigned long field, unsigned long value) { vmx_insn_failed("kvm: vmwrite failed: field=%lx val=%lx err=%d\n", -- 2.22.0