> On Mon, May 20, 2013 at 8:59 PM, Theo de Raadt <dera...@cvs.openbsd.org>
> wrote:
> >> On Mon, May 20, 2013 at 8:42 PM, Mike Larkin <mlar...@azathoth.net> wrote:
> >> > On Mon, May 20, 2013 at 05:11:35PM +0000, Alexey E. Suslikov wrote:
> >> >> Theo de Raadt <deraadt <at> cvs.openbsd.org> writes:
> >> >>
> >> >> > If these VM's are real VM's the should start emulating the machines
> >> >> > they claim to be emulating correctly, or they should start advertising
> >> >> > that they are something "different", so that we can isolate the
> >> >> > bullshit
> >> >> > factor.
> >> >>
> >> >> Ok. I see.
> >> >>
> >> >> Could we trim that down to the following?
> >> >>
> >> >> --- sys/arch/amd64/amd64/identcpu.c.orig Mon May 20 19:58:06 2013
> >> >> +++ sys/arch/amd64/amd64/identcpu.c Mon May 20 20:01:08 2013
> >> >> @@ -127,6 +127,7 @@
> >> >> { CPUIDECX_AVX, "AVX" },
> >> >> { CPUIDECX_F16C, "F16C" },
> >> >> { CPUIDECX_RDRAND, "RDRAND" },
> >> >> + { CPUIDECX_HV, "HV" },
> >> >> }, cpu_ecpuid_ecxfeatures[] = {
> >> >> { CPUIDECX_LAHF, "LAHF" },
> >> >> { CPUIDECX_CMPLEG, "CMPLEG" },
> >> >> --- sys/arch/amd64/include/specialreg.h.orig Mon May 20 20:01:56 2013
> >> >> +++ sys/arch/amd64/include/specialreg.h Mon May 20 20:06:09 2013
> >> >> @@ -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 /* Hypervisor
> >> >> presence */
> >> >>
> >> >> /*
> >> >> * "Structured Extended Feature Flags Parameters" (CPUID function 0x7,
> >> >> leaf 0)
> >> >>
> >> >
> >> > That's certainly less objectionable but I'm not sure what useful
> >> > information
> >> > this diff provides.
> >>
> >> Seen in dmesg, HV flag will indicate operating system is run under
> >> hypervisor
> >> and weird things are possible while running kernel code which depends on
> >> CPU
> >> features.
> >>
> >> After all, it is kinda documented by AMD on page 570 of
> >> http://support.amd.com/us/Processor_TechDocs/24594_APM_v3.pdf
> >>
> >> (AMD named it RAZ, but I put meaningful name like in FreeBSD - should we
> >> put a reference to above mentioned document near the define?).
> >
> > Your statements here are trying to convince us of something which is
> > false.
> >
> > AMD says "RAZ. Reserved for use by hypervisor to indicate guest status."
> >
> > That sentence does not translate to "The hypervisor is heavily broken
> > and fails to completely emulate the machine otherwise advertised by
> > the rest of the CPUID fields".
> >
> > It does not indicate that weird things are possible. If those weird
> > things are possible, it is not because the hardware is broken, but
> > because the *emulation of the hardware* by the VM is broken!
>
> You misunderstood my point.
>
> I'm not trying to convince, but avoid useless work/talk in the future:
Yes you are. You have an agenda.
You want to make us work around a bug, rather than talk to the
originators of the problem.
