From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fFnSy-0004gi-LS for qemu-devel@nongnu.org; Mon, 07 May 2018 17:14:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fFnSv-0007qJ-Ha for qemu-devel@nongnu.org; Mon, 07 May 2018 17:14:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46500) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fFnSv-0007q8-B0 for qemu-devel@nongnu.org; Mon, 07 May 2018 17:14:37 -0400 Date: Mon, 7 May 2018 18:14:27 -0300 From: Eduardo Habkost Message-ID: <20180507211427.GJ13350@localhost.localdomain> References: <1524760009-24710-1-git-send-email-babu.moger@amd.com> <1524760009-24710-10-git-send-email-babu.moger@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1524760009-24710-10-git-send-email-babu.moger@amd.com> Subject: Re: [Qemu-devel] [PATCH v7 9/9] i386: Remove generic SMT thread check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Babu Moger Cc: mst@redhat.com, marcel@redhat.com, pbonzini@redhat.com, rth@twiddle.net, mtosatti@redhat.com, geoff@hostfission.com, kash@tripleback.net, qemu-devel@nongnu.org, kvm@vger.kernel.org On Thu, Apr 26, 2018 at 11:26:49AM -0500, Babu Moger wrote: > Remove generic non-intel check while validating hyperthreading support. > Certain AMD CPUs can support hyperthreading now. > > CPU family with TOPOEXT feature can support hyperthreading now. > > Signed-off-by: Babu Moger > Tested-by: Geoffrey McRae Reviewed-by: Eduardo Habkost > --- > target/i386/cpu.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 6ebbef2..54d908f 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -4830,17 +4830,20 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) > > qemu_init_vcpu(cs); > > - /* Only Intel CPUs support hyperthreading. Even though QEMU fixes this > - * issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX > - * based on inputs (sockets,cores,threads), it is still better to gives > + /* Most Intel and certain AMD CPUs support hyperthreading. Even though QEMU > + * fixes this issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX > + * based on inputs (sockets,cores,threads), it is still better to give > * users a warning. > * > * NOTE: the following code has to follow qemu_init_vcpu(). Otherwise > * cs->nr_threads hasn't be populated yet and the checking is incorrect. > */ > - if (!IS_INTEL_CPU(env) && cs->nr_threads > 1 && !ht_warned) { > - error_report("AMD CPU doesn't support hyperthreading. Please configure" > - " -smp options properly."); > + if (IS_AMD_CPU(env) && > + !(env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) && > + cs->nr_threads > 1 && !ht_warned) { > + error_report("This family of AMD CPU doesn't support " > + "hyperthreading. Please configure -smp " > + "options properly."); > ht_warned = true; > } > > -- > 2.7.4 > > -- Eduardo