From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48892) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSiqM-0005gl-3u for qemu-devel@nongnu.org; Tue, 12 Jun 2018 08:56:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSiqI-0001ei-6m for qemu-devel@nongnu.org; Tue, 12 Jun 2018 08:56:14 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33890 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fSiqI-0001eC-1O for qemu-devel@nongnu.org; Tue, 12 Jun 2018 08:56:10 -0400 Date: Tue, 12 Jun 2018 14:56:05 +0200 From: Igor Mammedov Message-ID: <20180612145605.50f64965@redhat.com> In-Reply-To: <20180608205830.308627-1-mst@redhat.com> References: <20180608205830.308627-1-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, Paolo Bonzini , Eduardo Habkost , Richard Henderson On Fri, 8 Jun 2018 23:59:19 +0300 "Michael S. Tsirkin" wrote: > When guest CPU PM is enabled, and with -cpu host, expose the host CPU > MWAIT leaf to guest so guest can make good PM decisions. > > Signed-off-by: Michael S. Tsirkin > --- > > This builds but is untested. Is this a reasonable way to go about it? > > target/i386/cpu.h | 9 +++++++++ > target/i386/cpu.c | 18 +++++++++++++----- > 2 files changed, 22 insertions(+), 5 deletions(-) > > diff --git a/target/i386/cpu.h b/target/i386/cpu.h > index 664504610e..309f804573 100644 > --- a/target/i386/cpu.h > +++ b/target/i386/cpu.h > @@ -1378,6 +1378,15 @@ struct X86CPU { > /* if true the CPUID code directly forward host cache leaves to the guest */ > bool cache_info_passthrough; > > + /* if true the CPUID code directly forwards > + * host monitor/mwait leaves to the guest */ > + struct { > + uint32_t eax; > + uint32_t ebx; > + uint32_t ecx; > + uint32_t edx; > + } mwait; > + > /* Features that were filtered out because of missing host capabilities */ > uint32_t filtered_features[FEATURE_WORDS]; > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 94260412e2..a49443de56 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -3760,11 +3760,11 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > } > break; > case 5: > - /* mwait info: needed for Core compatibility */ > - *eax = 0; /* Smallest monitor-line size in bytes */ > - *ebx = 0; /* Largest monitor-line size in bytes */ > - *ecx = CPUID_MWAIT_EMX | CPUID_MWAIT_IBE; > - *edx = 0; > + /* MONITOR/MWAIT Leaf */ > + *eax = cpu->mwait.eax; /* Smallest monitor-line size in bytes */ > + *ebx = cpu->mwait.ebx; /* Largest monitor-line size in bytes */ > + *ecx = cpu->mwait.ecx; /* flags */ > + *edx = cpu->mwait.edx; /* mwait substates */ > break; > case 6: > /* Thermal and Power Leaf */ > @@ -4595,6 +4595,14 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) > goto out; > } > > + if (xcc->host_cpuid_required && enable_cpu_pm) { > + host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, > + &cpu->mwait.ecx, &cpu->mwait.edx); > + } could this state be migrated? or 'host' is still unmigratable? also max_x86_cpu_initfn() might be better place for filling it up. > + /* We always wake on interrupt even if host does not have the capability */ > + /* mwait extended info: needed for Core compatibility */ > + cpu->mwait.ecx |= CPUID_MWAIT_EMX | CPUID_MWAIT_IBE; > + > if (cpu->apic_id == UNASSIGNED_APIC_ID) { > error_setg(errp, "apic-id property was not initialized properly"); > return;