kvm-31 configure file bug

kvm-31 configure file bug

[Simon Gao]

Hi,

I found there is a bug with configure file shipped with kvm-31. Here is
the part of configure file:

===============================
target_cpu() {
    if [[ $(uname -m) = i?86 ]]; then
       echo x86_64
    else
        uname -m
    fi
}
===============================

!?86 will match i386, i586 and i686. On my machine,  "uname -m" returns
i686, which is obviously a 32bit kernel. Assigning to x86_64 breaks kvm
and installs qemu-system-x86_64, instead of qemu.


After making a simple change as follow, kvm-31 compiles and installs as
expected on 32bit system.  qemu also woks.

===============================
target_cpu() {
    if [[ $(uname -m) = i?86 ]]; then
       #echo x86_64
       echo i386
    else
        uname -m
    fi
}
===============================

Looks like kvm-31 only compiles when target_cpu is i386 or x86_64. Under
other situations like i486, i585, i686, compiling kvm-31 will fail.  On
many machines, "uname -m" returns i586 or i686.

Simon

-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/

Re: kvm-31 configure file bug

[Avi Kivity]

Simon Gao wrote:
> Hi,
>
> I found there is a bug with configure file shipped with kvm-31. Here is
> the part of configure file:
>
> ===============================
> target_cpu() {
>     if [[ $(uname -m) = i?86 ]]; then
>        echo x86_64
>     else
>         uname -m
>     fi
> }
> ===============================
>
> !?86 will match i386, i586 and i686. On my machine,  "uname -m" returns
> i686, which is obviously a 32bit kernel. Assigning to x86_64 breaks kvm
> and installs qemu-system-x86_64, instead of qemu.
>
>   

That's by design.  We compile qemu to support a 64-bit target so that 
live migration works between 32-bit and 64-bit hosts.


-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/

Re: kvm-31 configure file bug

[Simon Gao]

Avi Kivity wrote:
> Simon Gao wrote:
>> Hi,
>>
>> I found there is a bug with configure file shipped with kvm-31. Here is
>> the part of configure file:
>>
>> ===============================
>> target_cpu() {
>>     if [[ $(uname -m) = i?86 ]]; then
>>        echo x86_64
>>     else
>>         uname -m
>>     fi
>> }
>> ===============================
>>
>> !?86 will match i386, i586 and i686. On my machine,  "uname -m" returns
>> i686, which is obviously a 32bit kernel. Assigning to x86_64 breaks kvm
>> and installs
>> , instead of qemu.
>>
>>   
>
> That's by design.  We compile qemu to support a 64-bit target so that
> live migration works between 32-bit and 64-bit hosts.
>
>
So from kvm-31 and on, qemu command will become qemu-system-x86_64 no
matter host system is 32bit or 64bit?  So it's possible to compile 64bit
kvm qemu with only 32bit libraries?

Simon


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/

Re: kvm-31 configure file bug

[Avi Kivity]

Simon Gao wrote:
>
> So from kvm-31 and on, qemu command will become qemu-system-x86_64 no
> matter host system is 32bit or 64bit?  So it's possible to compile 64bit
> kvm qemu with only 32bit libraries?
>
>   

Yes and yes.  That's even more true for upstream qemu as well -- you can 
run a 64-bit guest on a non-64-bit capable cpu.


-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/

Re: kvm-31 configure file bug

[Simon Gao]

Avi Kivity wrote:
> Simon Gao wrote:
>>
>> So from kvm-31 and on, qemu command will become qemu-system-x86_64 no
>> matter host system is 32bit or 64bit?  So it's possible to compile 64bit
>> kvm qemu with only 32bit libraries?
>>
>>   
>
> Yes and yes.  That's even more true for upstream qemu as well -- you
> can run a 64-bit guest on a non-64-bit capable cpu.
>
I still had to change "x86_64" to "i386" in configure file. If I don't,
then guest os will hang after initial boot image splash. This happened
to kvm-31, kvm-32, kvm-33. The guest OSes worked fine with kvm-28.

Is there some parameter I should pass to make? or when I start guest OS
using qemu-system_x86_64 under 32bit Linux?

Simon

-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/

Re: kvm-31 configure file bug

[Avi Kivity]

Simon Gao wrote:
> Avi Kivity wrote:
>   
>> Simon Gao wrote:
>>     
>>> So from kvm-31 and on, qemu command will become qemu-system-x86_64 no
>>> matter host system is 32bit or 64bit?  So it's possible to compile 64bit
>>> kvm qemu with only 32bit libraries?
>>>
>>>   
>>>       
>> Yes and yes.  That's even more true for upstream qemu as well -- you
>> can run a 64-bit guest on a non-64-bit capable cpu.
>>
>>     
> I still had to change "x86_64" to "i386" in configure file. If I don't,
> then guest os will hang after initial boot image splash. This happened
> to kvm-31, kvm-32, kvm-33. The guest OSes worked fine with kvm-28.
>
> Is there some parameter I should pass to make? or when I start guest OS
> using qemu-system_x86_64 under 32bit Linux?
>
>   

It should just work.  Is there anything in dmesg when the guest hangs? 
What guest is that?

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/