Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755316AbYKJMkI (ORCPT ); Mon, 10 Nov 2008 07:40:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754723AbYKJMj4 (ORCPT ); Mon, 10 Nov 2008 07:39:56 -0500 Received: from mx2.redhat.com ([66.187.237.31]:52807 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754272AbYKJMjz (ORCPT ); Mon, 10 Nov 2008 07:39:55 -0500 Subject: Re: [PATCH 2/4] Hypervisor detection and get tsc_freq from hypervisor From: Mark McLoughlin Reply-To: Mark McLoughlin To: akataria@vmware.com Cc: Ingo Molnar , "H. Peter Anvin" , Andi Kleen , LKML , the arch/x86 maintainers , Daniel Hecht In-Reply-To: <1225129306.28018.9.camel@alok-dev1> References: <1224894104.28224.72.camel@alok-dev1> <20081027110134.GC13641@elte.hu> <1225129306.28018.9.camel@alok-dev1> Content-Type: text/plain Date: Mon, 10 Nov 2008 12:38:40 +0000 Message-Id: <1226320720.4068.54.camel@blaa> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4553 Lines: 112 Hi Alok, On Mon, 2008-10-27 at 10:41 -0700, Alok Kataria wrote: > x86: Get TSC frequency from VMware hypervisor. > > From: Alok N Kataria > > v3->v2 : Abstract the hypervisor detection and feature (tsc_freq) request > behind a hypervisor.c file > v2->v1 : Add a x86_hyper_vendor field to the cpuinfo_x86 structure. > This avoids multiple calls to the hypervisor detection function. > > This patch adds function to detect if we are running under VMware. > The current way to check if we are on VMware is following, > # check if "hypervisor present bit" is set, if so read the 0x40000000 > cpuid leaf and check for "VMwareVMware" signature. > # if the above fails, check the DMI vendors name for "VMware" string > if we find one we query the VMware hypervisor port to check if we are > under VMware. > > The DMI + "VMware hypervisor port check" is needed for older VMware products, > which don't implement the hypervisor signature cpuid leaf. > Also note that since we are checking for the DMI signature the hypervisor > port should never be accessed on native hardware. > > This patch also adds a hypervisor_get_tsc_freq function, instead of > calibrating the frequency which can be error prone in virtualized > environment, we ask the hypervisor for it. We get the frequency from > the hypervisor by accessing the hypervisor port if we are running on VMware. > Other hypervisors too can add code to the generic routine to get frequency on > their platform. > > Signed-off-by: Alok N Kataria > Signed-off-by: Dan Hecht > Cc: H. Peter Anvin > --- > > arch/x86/include/asm/cpufeature.h | 2 + > arch/x86/include/asm/hypervisor.h | 26 +++++++++++ > arch/x86/include/asm/processor.h | 4 ++ > arch/x86/include/asm/vmware.h | 26 +++++++++++ > arch/x86/kernel/cpu/Makefile | 1 > arch/x86/kernel/cpu/common.c | 2 + > arch/x86/kernel/cpu/hypervisor.c | 48 ++++++++++++++++++++ > arch/x86/kernel/cpu/vmware.c | 88 +++++++++++++++++++++++++++++++++++++ > arch/x86/kernel/setup.c | 7 +++ > arch/x86/kernel/tsc.c | 9 +++- > 10 files changed, 212 insertions(+), 1 deletions(-) > create mode 100644 arch/x86/include/asm/hypervisor.h > create mode 100644 arch/x86/include/asm/vmware.h > create mode 100644 arch/x86/kernel/cpu/hypervisor.c > create mode 100644 arch/x86/kernel/cpu/vmware.c > > > diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h > index f73e95d..78478f2 100644 > --- a/arch/x86/include/asm/cpufeature.h > +++ b/arch/x86/include/asm/cpufeature.h > @@ -117,6 +117,7 @@ > #define X86_FEATURE_XSAVE (4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */ > #define X86_FEATURE_OSXSAVE (4*32+27) /* "" XSAVE enabled in the OS */ > #define X86_FEATURE_AVX (4*32+28) /* Advanced Vector Extensions */ > +#define X86_FEATURE_HYPERVISOR (4*32+31) /* Running on a hypervisor */ I don't see you set this anywhere. > /* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */ > #define X86_FEATURE_XSTORE (5*32+ 2) /* "rng" RNG present (xstore) */ > @@ -237,6 +238,7 @@ extern const char * const x86_power_flags[32]; > #define cpu_has_xmm4_2 boot_cpu_has(X86_FEATURE_XMM4_2) > #define cpu_has_x2apic boot_cpu_has(X86_FEATURE_X2APIC) > #define cpu_has_xsave boot_cpu_has(X86_FEATURE_XSAVE) > +#define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR) ... > diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c > new file mode 100644 > index 0000000..d5d1b75 > --- /dev/null > +++ b/arch/x86/kernel/cpu/vmware.c > @@ -0,0 +1,88 @@ ... > +int vmware_platform(void) > +{ > + if (cpu_has_hypervisor) { > + unsigned int eax, ebx, ecx, edx; > + char hyper_vendor_id[13]; > + > + cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx); > + memcpy(hyper_vendor_id + 0, &ebx, 4); > + memcpy(hyper_vendor_id + 4, &ecx, 4); > + memcpy(hyper_vendor_id + 8, &edx, 4); > + hyper_vendor_id[12] = '\0'; > + if (!strcmp(hyper_vendor_id, "VMwareVMware")) > + return 1; This seems to be the only use of cpu_has_hypervisor, but this is the hypervisor detection code, so it's not clear how you intended X86_FEATURE_HYPERVISOR be set before here? Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/