From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerry Geis Subject: Re: kvm guest for 486 sx Date: Tue, 07 Jul 2009 09:15:59 -0400 Message-ID: <4A534A8F.2030702@pagestation.com> References: <4A525759.6090404@pagestation.com> <4A531B44.90803@redhat.com> <4A533A32.7000505@pagestation.com> <4A533CE7.2080706@redhat.com> <4A53414F.3070300@pagestation.com> <4A53448A.7050002@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail.emergencycommunicationsystems.com ([24.123.23.170]:53035 "EHLO unifiedpaging.messagenetsystems.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755378AbZGGNQP (ORCPT ); Tue, 7 Jul 2009 09:16:15 -0400 In-Reply-To: <4A53448A.7050002@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > On 07/07/2009 03:36 PM, Jerry Geis wrote: >> >> Avi Kivity wrote: >>> On 07/07/2009 03:06 PM, Jerry Geis wrote: >>>>> Try -cpu 486,-fpu. >>>>> >>>> >>>> Avi, >>>> >>>> Running this command: >>>> qemu-system-x86_64 -net nic,model=rtl8139 -net user -hda $1 >>>> -no-acpi -usb -cpu 486,-fpu & >>>> >>>> I get a seg fault: >>>> qemu-system-x86[15419]: segfault at c ip 0000000000458b95 sp >>>> 0000000041d9df90 error 4 in qemu-system-x86_64[400000+208000] >>>> >>>> >>>> I am running kvm-87 centos 5.3 x86_64. >>> >>> Add -no-kvm-irqchip. A 486 doesn't have a local APIC, which the >>> code expects. >>> >> Running with this line: >> qemu-system-x86_64 -net nic,model=rtl8139 -net user -hda $1 -no-acpi >> -usb -cpu 486,-fpu -no-kvm-irqchip & >> >> >> >> My /proc/cpuinfo shows the follow: >> processor : 0 >> vendor_id : AuthenticAMD >> cpu family : 4 >> model : 0 >> model name : 04/00 >> stepping : 0 >> fdiv_bug : no >> hlt_bug : no >> f00f_bug : no >> coma_bug : no >> fpu : yes >> fpu_exception : no >> cpuid level : 0 >> wp : yes >> flags : >> bogomips : 2965.50 >> clflush size : 32 >> power management: >> >> >> Notice FPU indicates yes and I requested -fpu on the command line. > > I think it detects the host fpu as a 487 coprocessor. Anything in > dmesg about it? Note there's no fpu in the flags: line. > > That's a kvm kernel bug. > >> also is this a 486 as it says AMD? > > You can override it if you like, -cpu 486,vendor=AuthenticAMD (I think). > Sorry - I thought the " -cpu 486,-fpu " was the way to turn off the fpu. I 'm trying to emulute a 486 sx that has no fpu. Do I not have the command line correct? qemu-system-x86_64 -net nic,model=rtl8139 -net user -hda $1 -no-acpi -usb -cpu 486,-fpu -no-kvm-irqchip the vendor_id is OK just not what I expected to see. Jerry