> -----Original Message----- > From: Eduardo Habkost [mailto:ehabkost@xxxxxxxxxx] > Sent: Tuesday, May 8, 2018 1:34 PM > To: Moger, Babu <Babu.Moger@xxxxxxx> > Cc: mst@xxxxxxxxxx; marcel@xxxxxxxxxx; pbonzini@xxxxxxxxxx; > rth@xxxxxxxxxxx; mtosatti@xxxxxxxxxx; qemu-devel@xxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; kash@xxxxxxxxxxxxxx; geoff@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v7 4/9] i386: Add new property to control cache info > > On Tue, May 08, 2018 at 05:26:16PM +0000, Moger, Babu wrote: > > > > > > > -----Original Message----- > > > From: Eduardo Habkost [mailto:ehabkost@xxxxxxxxxx] > > > Sent: Tuesday, May 8, 2018 9:26 AM > > > To: Moger, Babu <Babu.Moger@xxxxxxx> > > > Cc: mst@xxxxxxxxxx; marcel@xxxxxxxxxx; pbonzini@xxxxxxxxxx; > > > rth@xxxxxxxxxxx; mtosatti@xxxxxxxxxx; qemu-devel@xxxxxxxxxx; > > > kvm@xxxxxxxxxxxxxxx; kash@xxxxxxxxxxxxxx; geoff@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH v7 4/9] i386: Add new property to control cache info > > > > > > On Thu, Apr 26, 2018 at 11:26:44AM -0500, Babu Moger wrote: > > > > This will be used to control the cache information. > > > > By default new information will be displayed. If user > > > > passes "-cpu legacy-cache" then older information will > > > > be displayed even if the hardware supports new information. > > > > It will be "on" for machine type "pc-q35-2.10" for compatibility. > > > > > > > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > > > > Tested-by: Geoffrey McRae <geoff@xxxxxxxxxxxxxxx> > > > > --- > > > > include/hw/i386/pc.h | 4 ++++ > > > > target/i386/cpu.c | 1 + > > > > target/i386/cpu.h | 5 +++++ > > > > 3 files changed, 10 insertions(+) > > > > > > > > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h > > > > index ffee841..d904a3c 100644 > > > > --- a/include/hw/i386/pc.h > > > > +++ b/include/hw/i386/pc.h > > > > @@ -327,6 +327,10 @@ bool e820_get_entry(int, uint32_t, uint64_t *, > > > uint64_t *); > > > > .driver = "q35-pcihost",\ > > > > .property = "x-pci-hole64-fix",\ > > > > .value = "off",\ > > > > + },{\ > > > > + .driver = TYPE_X86_CPU,\ > > > > + .property = "legacy-cache",\ > > > > + .value = "on",\ > > > > }, > > > > > > > > > > > #define PC_COMPAT_2_9 \ > > > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > > > > index 5d88363..a27b658 100644 > > > > --- a/target/i386/cpu.c > > > > +++ b/target/i386/cpu.c > > > > @@ -5138,6 +5138,7 @@ static Property x86_cpu_properties[] = { > > > > false), > > > > DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, > > > vmware_cpuid_freq, true), > > > > DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true), > > > > + DEFINE_PROP_BOOL("legacy-cache", X86CPU, legacy_cache, false), > > > > Ok. I will remove this about line and add below code in x86_cpu_load_def. > > You need this line forthe PC_COMPAT_* entry to work. > > But in this case, the default here won't matter because it will > be overwritten by x86_cpu_load_def(). So it's a good idea to add > a comment noting that the default will depend on the CPU model > being chosen, and point people to x86_cpu_load_def()). Ok. Got it. Thanks > > > > > > > > > > > > Hmm, this can get messy if we start adding cache info to other > > > CPU models in future QEMU versions. e.g.: what if we add cache > > > info to Opteron_G3 on QEMU 2.14? > > > > > > I suggest adding this to x86_cpu_load_def(): > > > > > > cpu->legacy_cache = !cpu->cache_info.valid; > > > > > > (Or equivalent code, in case cache_info is changed to be a > > > pointer) > > > > > > This way, only EPYC will have legacy-cache=false by now, making > > > it easier to write compatibility code for other CPU models in the > > > future. > > > > > > > > > > > > > > /* > > > > * From "Requirements for Implementing the Microsoft > > > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > > > > index 1213bb7..852586a 100644 > > > > --- a/target/i386/cpu.h > > > > +++ b/target/i386/cpu.h > > > > @@ -1395,6 +1395,11 @@ struct X86CPU { > > > > */ > > > > bool enable_l3_cache; > > > > > > > > + /* Compatibility bits for old machine types. > > > > + * If true present the old cache topology information > > > > + */ > > > > + bool legacy_cache; > > > > + > > > > /* Compatibility bits for old machine types: */ > > > > bool enable_cpuid_0xb; > > > > > > > > -- > > > > 2.7.4 > > > > > > > > > > -- > > > Eduardo > > -- > Eduardo
