From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752524AbeC0CNZ (ORCPT ); Mon, 26 Mar 2018 22:13:25 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:33679 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752307AbeC0CNL (ORCPT ); Mon, 26 Mar 2018 22:13:11 -0400 X-Google-Smtp-Source: AG47ELs03jy/9W94MOvQvUFUUdkUesFOwpt1ox9xFzjutzkGVapIMF2uD3a2SlkwNKE/UuWWXUpgGg== From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Andrew Cooper Subject: [PATCH 2/2] KVM: VMX: Add Force Emulation Prefix for "emulate the next instruction" Date: Mon, 26 Mar 2018 19:12:15 -0700 Message-Id: <1522116735-4861-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1522116735-4861-1-git-send-email-wanpengli@tencent.com> References: <1522116735-4861-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li This patch introduces a Force Emulation Prefix (ud2a; .ascii "kvm") for "emulate the next instruction", the codes will be executed by emulator instead of processor, for testing purposes. A testcase here: #include #include #define HYPERVISOR_INFO 0x40000000 #define CPUID(idx, eax, ebx, ecx, edx)\ asm volatile (\ "ud2a; .ascii \"kvm\"; 1: cpuid" \ :"=b" (*ebx), "=a" (*eax),"=c" (*ecx), "=d" (*edx)\ :"0"(idx) ); void main() { unsigned int eax,ebx,ecx,edx; char string[13]; CPUID(HYPERVISOR_INFO, &eax, &ebx, &ecx, &edx); *(unsigned int *)(string+0) = ebx; *(unsigned int *)(string+4) = ecx; *(unsigned int *)(string+8) = edx; string[12] = 0; if (strncmp(string, "KVMKVMKVM\0\0\0",12) == 0) printf("kvm guest\n"); else printf("bare hardware\n"); } Suggested-by: Andrew Cooper Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Andrew Cooper Signed-off-by: Wanpeng Li --- arch/x86/kvm/vmx.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 0f99833..90abed8 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -108,6 +108,9 @@ module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO); static bool __read_mostly nested = 0; module_param(nested, bool, S_IRUGO); +static bool __read_mostly fep = 0; +module_param(fep, bool, S_IRUGO); + static u64 __read_mostly host_xss; static bool __read_mostly enable_pml = 1; @@ -6218,8 +6221,21 @@ static int handle_machine_check(struct kvm_vcpu *vcpu) static int handle_ud(struct kvm_vcpu *vcpu) { enum emulation_result er; + int emulation_type = EMULTYPE_TRAP_UD; + + if (fep) { + char sig[5]; /* ud2; .ascii "kvm" */ + struct x86_exception e; + + kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, + kvm_get_linear_rip(vcpu), sig, sizeof(sig), &e); + if (memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) { + emulation_type = 0; + kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig)); + } + } - er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD); + er = emulate_instruction(vcpu, emulation_type); if (er == EMULATE_USER_EXIT) return 0; if (er != EMULATE_DONE) -- 2.7.4