libvirt users - Jan 2019 - Re: avoiding PCI bus 8 / using PCI function / virt-install

Thanks.  Maybe I'm missing something but when I try virt-install --dry-run
--print-xml it generates this snippet of XML:

    <interface type="bridge">

      <source bridge="ge_0_0_0_77"/>

      <mac address="52:54:00:01:00:4e"/>

      <model type="virtio"/>

    </interface>

but what i need (and get from virsh dumpxml) has this extra PCI line.

    <interface type='bridge'>

      <mac address='52:54:00:01:00:4e'/>

      <source bridge='ge_0_0_0_77'/>

      <target dev='vnet78'/>

      <model type='virtio'/>

      <alias name='net78'/>

     <address type='pci' domain='0x0000' bus='0x01'
slot='0x0a'
function='0x6' />

    </interface>

Did I miss something?  Do you see PCI in the XML when you do the
virt-install --dryrun approach?

Thanks







On Wed, Dec 26, 2018 at 2:57 PM Peter Crowther
<peter.crowther@melandra.com>
wrote:
> On Wed, 26 Dec 2018 at 16:26, b f31415 <bf31415@gmail.com> wrote:
>
>> If not, is there a way with one of the virt command line tools to
create
>> the XML (with the PCI addresses specified) so that I can process that
XML
>> and re-write the PCI addressing values?  Right now the only way I’ve
been
>> able to get that detailed XML file is to 1) virt-install and let the VM
>> begin the boot process and then do a 2) virsh dumpxml and then 3) virsh
>> destroy/undefine that VM, 4) modify the XML and then 5) virsh create
>> ./modified.xml.  Is there a cleaner way to do this?
>>
>
> It won't do everything you want, but check out virt-install
--print-step
> --dry-run.  This should at least allow you to get at the XML for the
> intermediate steps and remove the brittleness of defining, destroying,
> undefining the VM.
>
> Cheers,
>
> - Peter
>

On 12/26/18 6:59 PM, b f31415 wrote:
> Thanks.? Maybe I'm missing something but when I try virt-install 
> --dry-run --print-xml it generates this snippet of XML:
> 
> <interface type="bridge">
> 
> <source bridge="ge_0_0_0_77"/>
> 
> <mac address="52:54:00:01:00:4e"/>
> 
> <model type="virtio"/>
> 
> </interface>
> 
> 
> but what i need (and get from virsh dumpxml) has this extra PCI line.
> 
> <interface type='bridge'>
> 
> <mac address='52:54:00:01:00:4e'/>
> 
> <source bridge='ge_0_0_0_77'/>
> 
> <target dev='vnet78'/>
> 
> <model type='virtio'/>
> 
> <alias name='net78'/>
> 
> <address type='pci' domain='0x0000' bus='0x01'
slot='0x0a' function='0x6' />
> 
> </interface>
> 
> 
> Did I miss something?? Do you see PCI in the XML when you do the 
> virt-install --dryrun approach?
virt-install never explicitly specifies a PCI address in the XML it 
creates and sends to libvirt, and what you're seeing as the output from 
--print-xml is the XML before it has been sent to libvirt.

Additionally, in response to a question in the original mail, there is 
no way to tell virt-install (or libvirt itself) to use non-0 functions 
for devices (except to manually specify the entire PCI address).

Since 99 44/100% of users (probably much higher, but that number has 
such a nice ring to anyone who recalls the old Ivory Soap commercials 
:-) never need more devices than are possible using only function 0, 
there has been no effort made to automate assignment of non-0 functions.

So if you need this many devices, you should probably consider just 
using virt-install once to generate proto-template XML, then "virsh 
define" that template to get an XML that has an <address...> element
for
every device that needs it, write a script that condenses all the device 
PCI addresses into less slots by using non-0 functions (and saves that 
as the "final" template), and finally modify your installation to do a
series of virsh commands using that template XML as a start.


I know it sounds awkward, but there is really nothing in libvirt or 
virt-install to automate assignment of PCI devices to non-0 functions.

> On Wed, Dec 26, 2018 at 2:57 PM Peter Crowther 
> <peter.crowther at melandra.com <mailto:peter.crowther at
melandra.com>> wrote:
> 
>     On Wed, 26 Dec 2018 at 16:26, b f31415 <bf31415 at gmail.com
>     <mailto:bf31415 at gmail.com>> wrote:
> 
>         If not, is there a way with one of the virt command line tools
>         to create the XML (with the PCI addresses specified) so that I
>         can process that XML and re-write the PCI addressing values? 
>         Right now the only way I?ve been able to get that detailed XML
>         file is to 1) virt-install and let the VM begin the boot process
>         and then do a 2) virsh dumpxml and then 3) virsh
>         destroy/undefine that VM, 4) modify the XML and then 5) virsh
>         create ./modified.xml.? Is there a cleaner way to do this?
> 
> 
>     It won't do everything you want, but check out virt-install
>     --print-step --dry-run.? This should at least allow you to get at
>     the XML for the intermediate steps and remove the brittleness of
>     defining, destroying, undefining the VM.
> 
>     Cheers,
> 
>     - Peter
> 
> 
> _______________________________________________
> libvirt-users mailing list
> libvirt-users at redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
>

Thanks-- i get this eco-system setup isn't mainstream (yet).  just wanted
to double check to see if there was some pre-existing way to use the
function aspect.

B


On Wed, Jan 2, 2019 at 9:29 AM Laine Stump <laine@redhat.com> wrote:
> On 12/26/18 6:59 PM, b f31415 wrote:
> > Thanks.  Maybe I'm missing something but when I try virt-install
> > --dry-run --print-xml it generates this snippet of XML:
> >
> > <interface type="bridge">
> >
> > <source bridge="ge_0_0_0_77"/>
> >
> > <mac address="52:54:00:01:00:4e"/>
> >
> > <model type="virtio"/>
> >
> > </interface>
> >
> >
> > but what i need (and get from virsh dumpxml) has this extra PCI line.
> >
> > <interface type='bridge'>
> >
> > <mac address='52:54:00:01:00:4e'/>
> >
> > <source bridge='ge_0_0_0_77'/>
> >
> > <target dev='vnet78'/>
> >
> > <model type='virtio'/>
> >
> > <alias name='net78'/>
> >
> > <address type='pci' domain='0x0000'
bus='0x01' slot='0x0a'
> function='0x6' />
> >
> > </interface>
> >
> >
> > Did I miss something?  Do you see PCI in the XML when you do the
> > virt-install --dryrun approach?
>
> virt-install never explicitly specifies a PCI address in the XML it
> creates and sends to libvirt, and what you're seeing as the output from
> --print-xml is the XML before it has been sent to libvirt.
>
> Additionally, in response to a question in the original mail, there is
> no way to tell virt-install (or libvirt itself) to use non-0 functions
> for devices (except to manually specify the entire PCI address).
>
> Since 99 44/100% of users (probably much higher, but that number has
> such a nice ring to anyone who recalls the old Ivory Soap commercials
> :-) never need more devices than are possible using only function 0,
> there has been no effort made to automate assignment of non-0 functions.
>
> So if you need this many devices, you should probably consider just
> using virt-install once to generate proto-template XML, then "virsh
> define" that template to get an XML that has an <address...>
element for
> every device that needs it, write a script that condenses all the device
> PCI addresses into less slots by using non-0 functions (and saves that
> as the "final" template), and finally modify your installation to
do a
> series of virsh commands using that template XML as a start.
>
>
> I know it sounds awkward, but there is really nothing in libvirt or
> virt-install to automate assignment of PCI devices to non-0 functions.
>
>
> > On Wed, Dec 26, 2018 at 2:57 PM Peter Crowther
> > <peter.crowther@melandra.com
<mailto:peter.crowther@melandra.com>>
> wrote:
> >
> >     On Wed, 26 Dec 2018 at 16:26, b f31415 <bf31415@gmail.com
> >     <mailto:bf31415@gmail.com>> wrote:
> >
> >         If not, is there a way with one of the virt command line tools
> >         to create the XML (with the PCI addresses specified) so that I
> >         can process that XML and re-write the PCI addressing values?
> >         Right now the only way I’ve been able to get that detailed XML
> >         file is to 1) virt-install and let the VM begin the boot
process
> >         and then do a 2) virsh dumpxml and then 3) virsh
> >         destroy/undefine that VM, 4) modify the XML and then 5) virsh
> >         create ./modified.xml.  Is there a cleaner way to do this?
> >
> >
> >     It won't do everything you want, but check out virt-install
> >     --print-step --dry-run.  This should at least allow you to get at
> >     the XML for the intermediate steps and remove the brittleness of
> >     defining, destroying, undefining the VM.
> >
> >     Cheers,
> >
> >     - Peter
> >
> >
> > _______________________________________________
> > libvirt-users mailing list
> > libvirt-users@redhat.com
> > https://www.redhat.com/mailman/listinfo/libvirt-users
> >
>
>