[Qemu-devel] can't bot from scsi http cdrom

[Qemu-devel] can't bot from scsi http cdrom

[Vasiliy Tolstov]

Hi. I'm try to boot from http cdrom and can't do that in case of scsi:
    <disk type='network' device='cdrom'>
      <driver name='qemu' type='raw' cache='unsafe'/>
      <source protocol='http' name='/vps/rescue-4.5.2'>
        <host name='xx.xx' port='80'/>
      </source>
      <backingStore/>
      <target dev='sdb' bus='scsi'/>
      <readonly/>
      <alias name='scsi0-0-0-1'/>
      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
    </disk>

but in case of ide:
    <disk type='network' device='cdrom'>
      <driver name='qemu' type='raw' cache='unsafe'/>
      <source protocol='http' name='/vps/rescue-4.5.2'>
        <host name='xx.xx' port='80'/>
      </source>
      <backingStore/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>

all works fine.

libvirt - 1.2.10
qemu - 2.0.0
seabios - 1.7.5

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

Re: [Qemu-devel] can't bot from scsi http cdrom

[Stefan Hajnoczi]

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On Mon, Apr 06, 2015 at 01:15:24PM +0300, Vasiliy Tolstov wrote:
> Hi. I'm try to boot from http cdrom and can't do that in case of scsi:
>     <disk type='network' device='cdrom'>
>       <driver name='qemu' type='raw' cache='unsafe'/>
>       <source protocol='http' name='/vps/rescue-4.5.2'>
>         <host name='xx.xx' port='80'/>
>       </source>
>       <backingStore/>
>       <target dev='sdb' bus='scsi'/>
>       <readonly/>
>       <alias name='scsi0-0-0-1'/>
>       <address type='drive' controller='0' bus='0' target='0' unit='1'/>
>     </disk>
> 
> but in case of ide:
>     <disk type='network' device='cdrom'>
>       <driver name='qemu' type='raw' cache='unsafe'/>
>       <source protocol='http' name='/vps/rescue-4.5.2'>
>         <host name='xx.xx' port='80'/>
>       </source>
>       <backingStore/>
>       <target dev='hda' bus='ide'/>
>       <readonly/>
>       <alias name='ide0-0-0'/>
>       <address type='drive' controller='0' bus='0' target='0' unit='0'/>
>     </disk>
> 
> all works fine.
> 
> libvirt - 1.2.10
> qemu - 2.0.0
> seabios - 1.7.5

This is a libvirt question.  I have CCed the libvirt mailing list.

Stefan

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Re: [Qemu-devel] can't bot from scsi http cdrom

[Paolo Bonzini]

On 06/04/2015 12:15, Vasiliy Tolstov wrote:
> Hi. I'm try to boot from http cdrom and can't do that in case of scsi:
>     <disk type='network' device='cdrom'>
>       <driver name='qemu' type='raw' cache='unsafe'/>
>       <source protocol='http' name='/vps/rescue-4.5.2'>
>         <host name='xx.xx' port='80'/>
>       </source>
>       <backingStore/>
>       <target dev='sdb' bus='scsi'/>
>       <readonly/>
>       <alias name='scsi0-0-0-1'/>
>       <address type='drive' controller='0' bus='0' target='0' unit='1'/>
>     </disk>

Try using target='1' unit='0'.  SeaBIOS only boots from LUN0.

Paolo

> but in case of ide:
>     <disk type='network' device='cdrom'>
>       <driver name='qemu' type='raw' cache='unsafe'/>
>       <source protocol='http' name='/vps/rescue-4.5.2'>
>         <host name='xx.xx' port='80'/>
>       </source>
>       <backingStore/>
>       <target dev='hda' bus='ide'/>
>       <readonly/>
>       <alias name='ide0-0-0'/>
>       <address type='drive' controller='0' bus='0' target='0' unit='0'/>
>     </disk>
> 
> all works fine.
> 
> libvirt - 1.2.10
> qemu - 2.0.0
> seabios - 1.7.5
> 

Re: [Qemu-devel] can't bot from scsi http cdrom

[Vasiliy Tolstov]

2015-04-10 13:53 GMT+03:00 Paolo Bonzini <pbonzini@redhat.com>:
> Try using target='1' unit='0'.  SeaBIOS only boots from LUN0.


Thanks! This is works fine. Last question - does it possible to create
empty cdrom with type='network'?
I'm try this, but libvrit complains with error:
          <disk type='network' device='cdrom'>
            <driver name='qemu' type='raw'/>
            <target dev='sdb' bus='scsi' tray='open'/>
            <address type='drive' controller='0' target='1' bus='0' unit='1'/>
            <readonly/>
          </disk>



-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

[Qemu-devel] Changing media on network disks (was Re: can't bot from scsi http cdrom)

[Paolo Bonzini]

On 13/04/2015 14:34, Vasiliy Tolstov wrote:
> Thanks! This is works fine. Last question - does it possible to create
> empty cdrom with type='network'?
> I'm try this, but libvrit complains with error:
>           <disk type='network' device='cdrom'>
>             <driver name='qemu' type='raw'/>
>             <target dev='sdb' bus='scsi' tray='open'/>
>             <address type='drive' controller='0' target='1' bus='0' unit='1'/>
>             <readonly/>
>           </disk>

No, unfortunately not because "virsh change-media" wouldn't be able to
convert its argument to the required libvirt XML.  I think you would
need a new virsh change-media option, e.g. --xml, that takes a <disk>
element instead of a source path + target path pair.  However, I am not
a libvirt developer.

Paolo