From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756439Ab3GWKFS (ORCPT ); Tue, 23 Jul 2013 06:05:18 -0400 Received: from terminus.zytor.com ([198.137.202.10]:57635 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755977Ab3GWKFR (ORCPT ); Tue, 23 Jul 2013 06:05:17 -0400 Message-ID: <51EE553C.40305@zytor.com> Date: Tue, 23 Jul 2013 03:04:44 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Jason Wang CC: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, gleb@redhat.com, pbonzini@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] x86: introduce hypervisor_cpuid_base() References: <1374572465-15278-1-git-send-email-jasowang@redhat.com> In-Reply-To: <1374572465-15278-1-git-send-email-jasowang@redhat.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/23/2013 02:41 AM, Jason Wang wrote: > > +static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) > +{ > + uint32_t base, eax, ebx, ecx, edx; > + char signature[13]; > + > + for (base = 0x40000000; base < 0x40010000; base += 0x100) { > + cpuid(base, &eax, &ebx, &ecx, &edx); > + *(uint32_t *)(signature + 0) = ebx; > + *(uint32_t *)(signature + 4) = ecx; > + *(uint32_t *)(signature + 8) = edx; > + signature[12] = 0; > + > + if (!strcmp(sig, signature) && > + (leaves == 0 || ((eax - base) >= leaves))) > + return base; > + } > + > + return 0; > +} > + Hmm... how about: uint32_t sign[3]; cpuid(base, &eax, &sign[0], &sign[1], &sign[2]); if (!memcmp(sig, sign, 12) && ...); -hpa