From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [Help] Windows2012 as Guest 64+cores on KVM Halts Date: Mon, 20 Feb 2017 13:57:17 +0100 Message-ID: References: <589C099A.9090605@huawei.com> <33183CC9F5247A488A2544077AF19020DA1B4379@DGGEMA505-MBX.china.huawei.com> <105e5774-38c3-0683-ca08-64f6ed53c643@redhat.com> <33183CC9F5247A488A2544077AF19020DA1B6988@DGGEMA505-MBX.china.huawei.com> <2127602137.20489688.1486827559449.JavaMail.zimbra@redhat.com> <1486980300.17184.28.camel@redhat.com> <33183CC9F5247A488A2544077AF19020DA1BD1CA@DGGEMA505-MBX.china.huawei.com> <33183CC9F5247A488A2544077AF19020DA1C13C3@DGGEMA505-MBX.china.huawei.com> <43632326-97a1-1f60-39f4-1044cd596b66@redhat.com> <33183CC9F5247A488A2544077AF19020DA1C1608@DGGEMA505-MBX.china.huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Hangaohuai , Yan Vugenfirer , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , Radim Krcmar To: "Gonglei (Arei)" , Vadim Rozenfeld Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38942 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752513AbdBTM5X (ORCPT ); Mon, 20 Feb 2017 07:57:23 -0500 In-Reply-To: <33183CC9F5247A488A2544077AF19020DA1C1608@DGGEMA505-MBX.china.huawei.com> Sender: kvm-owner@vger.kernel.org List-ID: On 20/02/2017 12:54, Gonglei (Arei) wrote: >> >> On 20/02/2017 10:19, Gonglei (Arei) wrote: >>> Hi Paolo, >>> >>>> >>>> >>>> On 16/02/2017 02:31, Gonglei (Arei) wrote: >>>>> And the below patch works for me, I can support max 255 vcpus for >> WS2012 >>>>> with hyper-v enlightenments. >>>>> >>>>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c >>>>> index 27fd050..efe3cbc 100644 >>>>> --- a/target/i386/kvm.c >>>>> +++ b/target/i386/kvm.c >>>>> @@ -772,7 +772,7 @@ int kvm_arch_init_vcpu(CPUState *cs) >>>>> >>>>> c = &cpuid_data.entries[cpuid_i++]; >>>>> c->function = HYPERV_CPUID_IMPLEMENT_LIMITS; >>>>> - c->eax = 0x40; >>>>> + c->eax = -1; >>>>> c->ebx = 0x40; >>>>> >>>>> kvm_base = KVM_CPUID_SIGNATURE_NEXT; >>>> >>>> This needs to depend on the machine type, but apart from that I think >>> >>> I don't know why. Because the negative effects for this change don't exist >>> on current QEMU IIUC, and we don't have compatible problems for live >> migration. >> >> CPUID should never change with the same machine type and command line. >> > OK, then how do we add compat code for the CPUID change? It's not a visible property. You can add a new property, something like hv-cpuid-limits-eax. Paolo