From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57965) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fG7Qp-0001U0-Ny for qemu-devel@nongnu.org; Tue, 08 May 2018 14:33:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fG7Ql-0004rv-Rg for qemu-devel@nongnu.org; Tue, 08 May 2018 14:33:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34652) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fG7Ql-0004rd-JH for qemu-devel@nongnu.org; Tue, 08 May 2018 14:33:43 -0400 Date: Tue, 8 May 2018 15:33:33 -0300 From: Eduardo Habkost Message-ID: <20180508183333.GN25013@localhost.localdomain> References: <1524760009-24710-1-git-send-email-babu.moger@amd.com> <1524760009-24710-5-git-send-email-babu.moger@amd.com> <20180508142531.GB4903@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH v7 4/9] i386: Add new property to control cache info List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Moger, Babu" Cc: "mst@redhat.com" , "marcel@redhat.com" , "pbonzini@redhat.com" , "rth@twiddle.net" , "mtosatti@redhat.com" , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "kash@tripleback.net" , "geoff@hostfission.com" On Tue, May 08, 2018 at 05:26:16PM +0000, Moger, Babu wrote: > > > > -----Original Message----- > > From: Eduardo Habkost [mailto:ehabkost@redhat.com] > > Sent: Tuesday, May 8, 2018 9:26 AM > > To: Moger, Babu > > Cc: mst@redhat.com; marcel@redhat.com; pbonzini@redhat.com; > > rth@twiddle.net; mtosatti@redhat.com; qemu-devel@nongnu.org; > > kvm@vger.kernel.org; kash@tripleback.net; geoff@hostfission.com > > 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 > > > Tested-by: Geoffrey McRae > > > --- > > > 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()). > > > > > > > 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