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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 698F1C282E3 for ; Sat, 20 Apr 2019 05:51:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 427C02087F for ; Sat, 20 Apr 2019 05:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727860AbfDTFvC (ORCPT ); Sat, 20 Apr 2019 01:51:02 -0400 Received: from mga03.intel.com ([134.134.136.65]:59341 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727277AbfDTFvB (ORCPT ); Sat, 20 Apr 2019 01:51:01 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Apr 2019 22:51:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,372,1549958400"; d="scan'208";a="317462182" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.181]) by orsmga005.jf.intel.com with ESMTP; 19 Apr 2019 22:51:00 -0700 From: Sean Christopherson To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Joerg Roedel Cc: kvm@vger.kernel.org, Jim Mattson Subject: [PATCH 2/5] KVM: VMX: Read cached VM-Exit reason to detect external interrupt Date: Fri, 19 Apr 2019 22:50:56 -0700 Message-Id: <20190420055059.16816-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190420055059.16816-1-sean.j.christopherson@intel.com> References: <20190420055059.16816-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Generic x86 code blindly invokes the dedicated external interrupt handler blindly, i.e. vmx_handle_external_intr() is called on all VM-Exits regardless of the actual exit type. Use the already-cached EXIT_REASON to determine if the VM-Exit was due to an interrupt, thus avoiding an extra VMREAD (to query VM_EXIT_INTR_INFO) for all other types of VM-Exit. In addition to avoiding the extra VMREAD, checking the EXIT_REASON instead of VM_EXIT_INTR_INFO makes it more obvious that vmx_handle_external_intr() is called for all VM-Exits, e.g. someone unfamiliar with the flow might wonder under what condition(s) VM_EXIT_INTR_INFO does not contain a valid interrupt, which is simply not possible since KVM always runs with "ack interrupt on exit". WARN once if VM_EXIT_INTR_INFO doesn't contain a valid interrupt on an EXTERNAL_INTERRUPT VM-Exit, as such a condition would indicate a hardware bug. Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/vmcs.h | 6 +++++ arch/x86/kvm/vmx/vmx.c | 60 +++++++++++++++++++++-------------------- 2 files changed, 37 insertions(+), 29 deletions(-) diff --git a/arch/x86/kvm/vmx/vmcs.h b/arch/x86/kvm/vmx/vmcs.h index cb6079f8a227..971a46c69df4 100644 --- a/arch/x86/kvm/vmx/vmcs.h +++ b/arch/x86/kvm/vmx/vmcs.h @@ -115,6 +115,12 @@ static inline bool is_nmi(u32 intr_info) == (INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK); } +static inline bool is_external_intr(u32 intr_info) +{ + return (intr_info & (INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK)) + == (INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR); +} + enum vmcs_field_width { VMCS_FIELD_WIDTH_U16 = 0, VMCS_FIELD_WIDTH_U64 = 1, diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 79ce9c7062f9..58e83fc86ad6 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6126,42 +6126,44 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx) static void vmx_handle_external_intr(struct kvm_vcpu *vcpu) { - u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); - - if ((exit_intr_info & (INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK)) - == (INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR)) { - unsigned int vector; - unsigned long entry; - gate_desc *desc; - struct vcpu_vmx *vmx = to_vmx(vcpu); + unsigned int vector; + unsigned long entry; #ifdef CONFIG_X86_64 - unsigned long tmp; + unsigned long tmp; #endif + u32 intr_info; + + if (to_vmx(vcpu)->exit_reason != EXIT_REASON_EXTERNAL_INTERRUPT) + return; + + intr_info = vmcs_read32(VM_EXIT_INTR_INFO); + if (WARN_ONCE(!is_external_intr(intr_info), + "KVM: unexpected VM-Exit interrupt info: 0x%x", intr_info)) + return; + + vector = intr_info & INTR_INFO_VECTOR_MASK; + entry = gate_offset((gate_desc *)to_vmx(vcpu)->host_idt_base + vector); - vector = exit_intr_info & INTR_INFO_VECTOR_MASK; - desc = (gate_desc *)vmx->host_idt_base + vector; - entry = gate_offset(desc); - asm volatile( + asm volatile( #ifdef CONFIG_X86_64 - "mov %%" _ASM_SP ", %[sp]\n\t" - "and $0xfffffffffffffff0, %%" _ASM_SP "\n\t" - "push $%c[ss]\n\t" - "push %[sp]\n\t" + "mov %%" _ASM_SP ", %[sp]\n\t" + "and $0xfffffffffffffff0, %%" _ASM_SP "\n\t" + "push $%c[ss]\n\t" + "push %[sp]\n\t" #endif - "pushf\n\t" - __ASM_SIZE(push) " $%c[cs]\n\t" - CALL_NOSPEC - : + "pushf\n\t" + __ASM_SIZE(push) " $%c[cs]\n\t" + CALL_NOSPEC + : #ifdef CONFIG_X86_64 - [sp]"=&r"(tmp), + [sp]"=&r"(tmp), #endif - ASM_CALL_CONSTRAINT - : - THUNK_TARGET(entry), - [ss]"i"(__KERNEL_DS), - [cs]"i"(__KERNEL_CS) - ); - } + ASM_CALL_CONSTRAINT + : + THUNK_TARGET(entry), + [ss]"i"(__KERNEL_DS), + [cs]"i"(__KERNEL_CS) + ); } STACK_FRAME_NON_STANDARD(vmx_handle_external_intr); -- 2.21.0