Messages in this thread | | | Subject | Re: [PATCH 2/4] Hypervisor detection and get tsc_freq from hypervisor | From | Mark McLoughlin <> | Date | Mon, 10 Nov 2008 12:38:40 +0000 |
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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 <akataria@vmware.com> > > 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 <akataria@vmware.com> > Signed-off-by: Dan Hecht <dhecht@vmware.com> > Cc: H. Peter Anvin <hpa@zytor.com> > --- > > 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.
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