From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755405Ab3GYJGK (ORCPT ); Thu, 25 Jul 2013 05:06:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46053 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745Ab3GYJFm (ORCPT ); Thu, 25 Jul 2013 05:05:42 -0400 From: Jason Wang To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com Cc: kvm@vger.kernel.org, Jason Wang , Gleb Natapov Subject: [PATCH V2 1/4] x86: introduce hypervisor_cpuid_base() Date: Thu, 25 Jul 2013 16:54:32 +0800 Message-Id: <1374742475-2485-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch introduce hypervisor_cpuid_base() which loop test the hypervisor existence function until the signature match and check the number of leaves if required. This could be used by Xen/KVM guest to detect the existence of hypervisor. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: Paolo Bonzini Cc: Gleb Natapov Cc: x86@kernel.org Signed-off-by: Jason Wang --- Changes from V1: - use memcpy() and uint32_t instead of strcmp() --- arch/x86/include/asm/processor.h | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 24cf5ae..7763307 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -971,6 +971,21 @@ unsigned long calc_aperfmperf_ratio(struct aperfmperf *old, return ratio; } +static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) +{ + uint32_t base, eax, signature[3]; + + for (base = 0x40000000; base < 0x40010000; base += 0x100) { + cpuid(base, &eax, &signature[0], &signature[1], &signature[2]); + + if (!memcmp(sig, signature, 12) && + (leaves == 0 || ((eax - base) >= leaves))) + return base; + } + + return 0; +} + extern unsigned long arch_align_stack(unsigned long sp); extern void free_init_pages(char *what, unsigned long begin, unsigned long end); -- 1.7.1