On Mon, Jun 11, 2018 at 08:25:32PM +0000, Moger, Babu wrote:
> Hi Eduardo,
> Planning to make couple of changes after testing and review. Let me know if
> I missed something.
> Will wait for your feedback before the next revision.
>
> > -----Original Message-----
> > From: kvm-ow...@vger.kernel.org [mailto:kvm-ow...@vger.kernel.org]
> > On Behalf Of Babu Moger
> > Sent: Friday, June 8, 2018 5:56 PM
> > To: m...@redhat.com; marcel.apfelb...@gmail.com; pbonz...@redhat.com;
> > r...@twiddle.net; ehabk...@redhat.com; mtosa...@redhat.com
> > Cc: qemu-devel@nongnu.org; k...@vger.kernel.org; Moger, Babu
> > <babu.mo...@amd.com>; k...@tripleback.net; ge...@hostfission.com
> > Subject: [PATCH v13 2/5] i386: Introduce auto_topoext bit to manage
> > topoext
> >
> > Introduce the auto_topoext bit to to control topoext feature.
> >
> > Also add new field auto_topoext(in X86CPUDefinition). This will
> > be used to enable topoext on newer CPU models where topoext can
> > be supported.
> >
> > Signed-off-by: Babu Moger <babu.mo...@amd.com>
> > ---
> > include/hw/i386/pc.h | 4 ++++
> > target/i386/cpu.c | 12 ++++++++++++
> > target/i386/cpu.h | 5 +++++
> > 3 files changed, 21 insertions(+)
> >
> > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> > index 04d1f8c..cc30ec3 100644
> > --- a/include/hw/i386/pc.h
> > +++ b/include/hw/i386/pc.h
> > @@ -303,6 +303,10 @@ bool e820_get_entry(int, uint32_t, uint64_t *,
> > uint64_t *);
> > .driver = TYPE_X86_CPU,\
> > .property = "legacy-cache",\
> > .value = "on",\
> > + },{\
> > + .driver = TYPE_X86_CPU,\
> > + .property = "auto-topoext",\
> > + .value = "off",\
> > },
>
> We don't need this. We are already setting this false in x86_cpu_properties.
> But we need to set it "on" for EPYC on PC_COMPAT_3_0 whenever we define it.
> That will be a separate patch. Correct?
PC_COMPAT_3_0 will exist only on QEMU 3.1. If you want to define
something as the default behavior in pc-3.0, just define it as
the default in the device code, which is exactly what you are
already doing in x86_cpu_load_def() below.
In other words, just set auto_topoext=true on the CPU model table
for EPYC, and it should be enough.
On PC_COMPAT_2_12, both would work:
{ TYPE_X86_CPU, "auto-topoext", "off" }
or
{ "EPYC" "-" TYPE_X86_CPU, "auto-topoext", "off" }.
I prefer the latter, but both would work.
>
> >
> > #define PC_COMPAT_2_11 \
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index 86fb1a4..d3411ed 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -1283,6 +1283,8 @@ struct X86CPUDefinition {
> > FeatureWordArray features;
> > const char *model_id;
> > CPUCaches *cache_info;
> > + /* Set it if topoext can be enabled in CPU models */
> > + int auto_topoext;
> > };
> >
> > static CPUCaches epyc_cache_info = {
> > @@ -3517,6 +3519,9 @@ static void x86_cpu_load_def(X86CPU *cpu,
> > X86CPUDefinition *def, Error **errp)
> > /* legacy-cache defaults to 'off' if CPU model provides cache info */
> > cpu->legacy_cache = !def->cache_info;
> >
> > + /* Set auto_topoext if both machine property and CPU model supports it
> > */
> > + cpu->auto_topoext = cpu->auto_topoext & def->auto_topoext;
>
> This could be more appropriate like this.
>
> cpu->auto_topoext = cpu->auto_topoext && def->auto_topoext;
cpu->auto_topoext is supposed to be already false, here. Why not
just:
cpu->auto_topoext = def->auto_topoext;
?
>
> > +
> > /* Special cases not set in the X86CPUDefinition structs: */
> > /* TODO: in-kernel irqchip for hvf */
> > if (kvm_enabled()) {
> > @@ -5382,6 +5387,13 @@ static Property x86_cpu_properties[] = {
> > DEFINE_PROP_BOOL("legacy-cache", X86CPU, legacy_cache, true),
> >
> > /*
> > + * auto-topoext property will be used to enable topoext feature.
> > + * This will be disabled on all the older CPU models. Will be
> > + * enabled on newer CPU modeles which can support topology extention.
> > + */
> > + DEFINE_PROP_BOOL("auto-topoext", X86CPU, auto_topoext, false),
> > +
> > + /*
> > * From "Requirements for Implementing the Microsoft
> > * Hypervisor Interface":
> > * https://docs.microsoft.com/en-us/virtualization/hyper-v-on-
> > windows/reference/tlfs
> > diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> > index 89c82be..8783d36 100644
> > --- a/target/i386/cpu.h
> > +++ b/target/i386/cpu.h
> > @@ -1409,6 +1409,11 @@ struct X86CPU {
> > */
> > bool legacy_cache;
> >
> > + /* Compatibility bits to enable topoext feature on all newer machines
> > + * Disabled on older machines. Enabled on newer CPU models
> > + */
> > + bool auto_topoext;
> > +
> > /* Compatibility bits for old machine types: */
> > bool enable_cpuid_0xb;
> >
> > --
> > 1.8.3.1
>
--
Eduardo
