Re: [Qemu-devel] [PATCH v6 03/16] target-i386: Add cpu object access routines for Hypervisor level.

[Don Slutz]

On 10/09/12 15:13, Don Slutz wrote:
> On 10/09/12 12:25, Marcelo Tosatti wrote:
> > On Mon, Sep 24, 2012 at 10:32:05AM -0400, Don Slutz wrote:
> > > These are modeled after x86_cpuid_get_xlevel and x86_cpuid_set_xlevel.
> > >
> > > Signed-off-by: Don Slutz <address@hidden>
> > > ---
> > >   target-i386/cpu.c |   29 +++++++++++++++++++++++++++++
> > >   1 files changed, 29 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > > index 25ca986..451de12 100644
> > > --- a/target-i386/cpu.c
> > > +++ b/target-i386/cpu.c
> > > @@ -1166,6 +1166,32 @@ static void x86_cpuid_set_tsc_freq(Object 
> > > *obj, Visitor *v, void *opaque,
> > >       cpu->env.tsc_khz = value / 1000;
> > >   }
> > >   +static void x86_cpuid_get_hv_level(Object *obj, Visitor *v, void 
> > > *opaque,
> > > +                                const char *name, Error **errp)
> > > +{
> > > +    X86CPU *cpu = X86_CPU(obj);
> > > +
> > > +    visit_type_uint32(v, &cpu->env.cpuid_hv_level, name, errp);
> > > +}
> > > +
> > > +static void x86_cpuid_set_hv_level(Object *obj, Visitor *v, void 
> > > *opaque,
> > > +                                const char *name, Error **errp)
> > > +{
> > > +    X86CPU *cpu = X86_CPU(obj);
> > > +    uint32_t value;
> > > +
> > > +    visit_type_uint32(v, &value, name, errp);
> > > +    if (error_is_set(errp)) {
> > > +        return;
> > > +    }
> > > +
> > > +    if (value != 0 && value < 0x40000000) {
> > > +        value += 0x40000000;
> > > +    }
> > Whats the purpose of this? Adds ambiguity.
> Will add more info in this commit message.
>    -Don
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to address@hidden
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Not clear on how to add info in the commit message.

This is direct copy with adjustment from x86_cpuid_set_xlevel():

    if (value < 0x80000000) {
        value += 0x80000000;
    }

(Pending patch: 
http://comments.gmane.org/gmane.comp.emulators.qemu/172703 adds this)

The adjustment is that 0 is a legal value. See 
http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html

This does mean that just like xlevel=1 and xlevel=0x80000001 are the 
same; hypervisor-level=1 and hypervisor-level=0x4000001 are the same.  
If this is not wanted, I have no issue with removing it.

   -Don Slutz