Re: [Qemu-devel] [PATCH v2] i386: Introduce ARAT CPU feature

[Eduardo Habkost]

On Mon, May 25, 2015 at 04:16:14PM +0200, Paolo Bonzini wrote:
> On 25/05/2015 16:06, Jan Kiszka wrote:
> >  static void pc_compat_2_3(MachineState *machine)
> >  {
> > +    x86_cpu_compat_set_features("Westmere", FEAT_6_EAX, 0, 
> > CPUID_6_EAX_ARAT);
> > +    x86_cpu_compat_set_features("SandyBridge", FEAT_6_EAX, 0,
> > +                                CPUID_6_EAX_ARAT);
> > +    x86_cpu_compat_set_features("IvyBridge", FEAT_6_EAX, 0, 
> > CPUID_6_EAX_ARAT);
> > +    x86_cpu_compat_set_features("Haswell-noTSX", FEAT_6_EAX, 0,
> > +                                CPUID_6_EAX_ARAT);
> > +    x86_cpu_compat_set_features("Haswell", FEAT_6_EAX, 0, 
> > CPUID_6_EAX_ARAT);
> > +    x86_cpu_compat_set_features("Broadwell-noTSC", FEAT_6_EAX, 0,
> > +                                CPUID_6_EAX_ARAT);
> 
> noTSX.
> 
> Also, I think this doesn't cover Q35.  Eduardo has patches to clean that
> up so that (I think) less duplication is required.

pc_compat_*() removal/deduplication will require a few PC cleanup series
to be included first, so it may take a while. But PC_COMPAT_* is not
duplicated, and with the feature flag property patch that is now in the
x86 tree[1], you can use PC_COMPAT_2_3[2] to do the above, with
something like:

  { .driver = TYPE_X86_CPU, .property = "arat", .value = "off" },

(As no CPU model had ARAT enabled in QEMU 2.3, setting it to off on
TYPE_X86_CPU is simpler than enumerating the CPU models above).

[1] https://github.com/ehabkost/qemu.git x86
[2] The following series defines PC_COMPAT_2_3:
    [PATCH v2 00/13] pc, hw, spapr: Cleanup of {HW, PC, SPAPR}_COMPAT_* macros

-- 
Eduardo