Re: [Qemu-devel] [PATCH v6 06/16] target-i386: Use Hypervisor level in -machine pc, accel=tcg.

[Don Slutz]

On 10/09/12 15:01, Marcelo Tosatti wrote:
> On Mon, Sep 24, 2012 at 10:32:08AM -0400, Don Slutz wrote:
> > Also known as Paravirtualization level.
> >
> > This change is based on:
> >
> > Microsoft Hypervisor CPUID Leaves:
> >    
> > http://msdn.microsoft.com/en-us/library/windows/hardware/ff542428%28v=vs.85%29.aspx
> >
> > Linux kernel change starts with:
> >    http://fixunix.com/kernel/538707-use-cpuid-communicate-hypervisor.html
> > Also:
> >    http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> >
> > VMware documention on CPUIDs (Mechanisms to determine if software is
> > running in a VMware virtual machine):
> >    
> > http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458
> >
> > QEMU knows this as KVM_CPUID_SIGNATURE (0x40000000) in kvm on linux.
> >
> > This does not provide vendor support in tcg yet.
> >
> > Signed-off-by: Don Slutz <address@hidden>
> > ---
> >   target-i386/cpu.c |   27 +++++++++++++++++++++++++++
> >   1 files changed, 27 insertions(+), 0 deletions(-)
> >
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 48bdaf9..920278b 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -1651,6 +1651,21 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> > uint32_t count,
> >                   index =  env->cpuid_xlevel;
> >               }
> >           }
> > +    } else if (index & 0x40000000) {
> > +        if (env->cpuid_hv_level_set) {
> > +            uint32_t real_level = env->cpuid_hv_level;
> > +
> > +            /* Handle Hypervisor CPUIDs */
> > +            if (real_level < 0x40000000) {
> > +                real_level = 0x40000000;
> > +            }
> > +            if (index > real_level) {
> > +                index = real_level;
> > +            }
> > +        } else {
> > +            if (index > env->cpuid_level)
> > +                index = env->cpuid_level;
> > +        }
> Whats the purpose of this checks?
They control what happens for CPUID requests outside the defined 
ranges.  Very similar to code just above this.
> Please provide changelogs for each patch.
In progress.
> >       } else {
> >           if (index > env->cpuid_level)
> >               index = env->cpuid_level;
> > @@ -1789,6 +1804,18 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> > uint32_t count,
> >               *edx = 0;
> >           }
> >           break;
> > +    case 0x40000000:
> > +        *eax = env->cpuid_hv_level;
> > +        *ebx = 0;
> > +        *ecx = 0;
> > +        *edx = 0;
> > +        break;
> > +    case 0x40000001:
> > +        *eax = env->cpuid_kvm_features;
> > +        *ebx = 0;
> > +        *ecx = 0;
> > +        *edx = 0;
> > +        break;
> >       case 0x80000000:
> >           *eax = env->cpuid_xlevel;
> >           *ebx = env->cpuid_vendor1;
> > --
> > 1.7.1
> >
> > --
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> > the body of a message to address@hidden
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
   -Don Slutz