From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752103AbbJBJ0z (ORCPT ); Fri, 2 Oct 2015 05:26:55 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:33843 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751580AbbJBJ0y (ORCPT ); Fri, 2 Oct 2015 05:26:54 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: kys@microsoft.com, haiyangz@microsoft.com, x86@kernel.org, devel@linuxdriverproject.org, alex.williamson@redhat.com Subject: [PATCH] x86: guest: rely on leaf 0x40000001 to detect Hyper-V Date: Fri, 2 Oct 2015 11:26:47 +0200 Message-Id: <1443778007-27714-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The specification says that "Microsoft Hv" is actually a vendor ID field that is only used for reporting and diagnostic purposes. The actual field that you need to check is the interface ID that you get in eax when querying the HYPERV_CPUID_INTERFACE. Change ms_hyperv_platform to actually do what the specification suggests. This roughy matches what Windows looks for, though Windows actually ignores HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS completely. Signed-off-by: Paolo Bonzini --- arch/x86/kernel/cpu/mshyperv.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 381c8b9b3a33..7910e7fd705b 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -116,18 +116,16 @@ static void hv_machine_crash_shutdown(struct pt_regs *regs) static uint32_t __init ms_hyperv_platform(void) { u32 eax; - u32 hyp_signature[3]; if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) return 0; - cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, - &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); - - if (eax >= HYPERV_CPUID_MIN && - eax <= HYPERV_CPUID_MAX && - !memcmp("Microsoft Hv", hyp_signature, 12)) - return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; + eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); + if (eax >= HYPERV_CPUID_MIN && eax <= HYPERV_CPUID_MAX) { + eax = cpuid_eax(HYPERV_CPUID_INTERFACE); + if (!memcmp(&eax, "Hv#1", sizeof(eax))) + return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; + } return 0; } -- 2.5.0