From 88b094fb8d4fe43b7025ea8d487059e8813e02cd Mon Sep 17 00:00:00 2001 From: Alok Kataria Date: Mon, 27 Oct 2008 10:41:46 -0700 Subject: x86: Hypervisor detection and get tsc_freq from hypervisor Impact: Changes timebase calibration on Vmware. 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 Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/processor.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/include/asm/processor.h') diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 5ca01e38326..a570eafa475 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -110,6 +110,7 @@ struct cpuinfo_x86 { /* Index into per_cpu list: */ u16 cpu_index; #endif + unsigned int x86_hyper_vendor; } __attribute__((__aligned__(SMP_CACHE_BYTES))); #define X86_VENDOR_INTEL 0 @@ -123,6 +124,9 @@ struct cpuinfo_x86 { #define X86_VENDOR_UNKNOWN 0xff +#define X86_HYPER_VENDOR_NONE 0 +#define X86_HYPER_VENDOR_VMWARE 1 + /* * capabilities of CPUs */ -- cgit v1.2.3