From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:58795) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmjuc-0000BJ-TA for qemu-devel@nongnu.org; Thu, 24 Jan 2019 13:39:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmjuR-0001s2-0e for qemu-devel@nongnu.org; Thu, 24 Jan 2019 13:39:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53344) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gmjuH-0001l3-V2 for qemu-devel@nongnu.org; Thu, 24 Jan 2019 13:39:20 -0500 Date: Thu, 24 Jan 2019 16:39:09 -0200 From: Eduardo Habkost Message-ID: <20190124183909.GA4136@habkost.net> References: <1548381283-16688-1-git-send-email-luwei.kang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1548381283-16688-1-git-send-email-luwei.kang@intel.com> Subject: Re: [Qemu-devel] [PATCH] i386: extended the cpuid level when Intel PT is enabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luwei Kang Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net Hi, Thanks for the patch. Comment below: On Thu, Jan 24, 2019 at 08:54:43PM -0500, Luwei Kang wrote: > Intel Processor Trace required CPUID[0x14] but the cpuid level > is 0xd when create a kvm guest with e.g. "-cpu qemu64,+intel-pt". > > Signed-off-by: Luwei Kang > --- > target/i386/cpu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 2f54125..da477b3 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5023,6 +5023,13 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp) > x86_cpu_adjust_feat_level(cpu, FEAT_C000_0001_EDX); > x86_cpu_adjust_feat_level(cpu, FEAT_SVM); > x86_cpu_adjust_feat_level(cpu, FEAT_XSAVE); > + > + /* Intel Processor Trace requires CPUID[0x14] */ > + if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) && > + kvm_enabled()) { > + x86_cpu_adjust_level(cpu, &cpu->env.cpuid_min_level, 0x14); > + } This will require a new machine-type compatibility flag to enable the new behavior, so we don't change CPUID data under the guest feet during live migration. > + > /* SVM requires CPUID[0x8000000A] */ > if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_SVM) { > x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000000A); > -- > 1.8.3.1 > -- Eduardo