On Thu, 11 Dec 2014, Mark Kettenis wrote:
> > From: Alexey Suslikov <alexey.susli...@gmail.com>
> > Date: Thu, 11 Dec 2014 20:51:14 +0000 (UTC)
> >
> > Stefan Fritsch <sf <at> sfritsch.de> writes:
> >
> > > --- a/sys/arch/amd64/include/specialreg.h
> > > +++ b/sys/arch/amd64/include/specialreg.h
> > > <at> <at> -158,6 +158,7 <at> <at>
> > > #define CPUIDECX_AVX 0x10000000 /* Advanced Vector Extensions
> > */
> > > #define CPUIDECX_F16C 0x20000000 /* 16bit fp conversion */
> > > #define CPUIDECX_RDRAND 0x40000000 /* RDRAND instruction */
> > > +#define CPUIDECX_HYPERV 0x80000000 /* Hypervisor present */
> >
> > Is this flag standardized? Last time I have tried to push this, there
> > was an objection based on "reserved for future use" status of this flag.
> >
> > See http://marc.info/?l=openbsd-bugs&m=136907278229145&w=2
>
> Well, that thread started out with a questionable workaround for a
> hypervisor bug. That may have have influenced the debate about the
> flag a bit.
>
> You can be almost certain that Intel and AMD will not use that
> reserved bit for anything else. The Linux KVM virtualization business
> is too important for them. And if Microsoft Hyper-V or VMWare ESX
> sets that bit as well, this becomes an absolute certainty.
The intel manual says "Not Used, Always returns 0" which is different from
"reserved", which is stated for other bits.
FTR, jasper@ checked that vmware sets the bit while virtual box does not.
So, many but not all hypervisors set it.
> I prefer the CPUIDECX_HV name used in the diff you posted in:
OK?
diff --git a/sys/arch/amd64/amd64/identcpu.c b/sys/arch/amd64/amd64/identcpu.c
--- a/sys/arch/amd64/amd64/identcpu.c
+++ b/sys/arch/amd64/amd64/identcpu.c
@@ -129,6 +129,7 @@ const struct {
{ CPUIDECX_AVX, "AVX" },
{ CPUIDECX_F16C, "F16C" },
{ CPUIDECX_RDRAND, "RDRAND" },
+ { CPUIDECX_HV, "HV" },
}, cpu_ecpuid_ecxfeatures[] = {
{ CPUIDECX_LAHF, "LAHF" },
{ CPUIDECX_CMPLEG, "CMPLEG" },
diff --git a/sys/arch/amd64/include/specialreg.h
b/sys/arch/amd64/include/specialreg.h
--- a/sys/arch/amd64/include/specialreg.h
+++ b/sys/arch/amd64/include/specialreg.h
@@ -158,6 +158,7 @@
#define CPUIDECX_AVX 0x10000000 /* Advanced Vector Extensions */
#define CPUIDECX_F16C 0x20000000 /* 16bit fp conversion */
#define CPUIDECX_RDRAND 0x40000000 /* RDRAND instruction */
+#define CPUIDECX_HV 0x80000000 /* Running on hypervisor */
/*
* "Structured Extended Feature Flags Parameters" (CPUID function 0x7, leaf 0)
