[libvirt PATCH 4/4] docs: Remove one example from pci-addresses.rst

Andrea Bolognani abologna at redhat.com
Thu Apr 16 07:28:58 UTC 2020


On Wed, 2020-04-15 at 19:47 +0200, Cornelia Huck wrote:
> On Wed, 15 Apr 2020 19:31:36 +0200
> Andrea Bolognani <abologna at redhat.com> wrote:
> > -Therefore, replacing the virtio-net device definition with the following XML
> > -snippet
> > -
> > -::
> > -
> > -  <interface type='bridge'>
> > -    <source bridge='virbr0'/>
> > -    <model type='virtio'/>
> > -    <address type='pci' domain='0x0000' bus='0x01' slot='0x07' function='0x3'>
> > -      <zpci uid='0x0007' fid='0x00000003'/>
> > -    </address>
> > -  </interface>
> > -
> > -will yield the following result in a Linux guest:
> > -
> > -::
> > -
> > -  0007:00:00.0 Ethernet controller: Red Hat, Inc. Virtio network device
> 
> Hm, should that rather go somewhere else? What I wanted to show is "you
> can have the same PCI address in the XML and still get a different PCI
> address in the guest, if you change the zpci values", as that might be
> another source of confusion.

I think the previous example, specifically the last bit where you
explain how changing the PCI address completely in the domain XML
would not change what the guest OS sees because the latter is derived
from uid and fid, already drives the point home. It's really two
sides of the same coin.

Additionally, as I explained elsewhere, this document is not meant to
list every possible situation in which PCI addresses in the domain
XML and in the guest OS are out of sync, but merely to show that such
cases exist. It's valuable to mention the zPCI scenario, but we don't
need to show more than one variation of it in my opinion.

-- 
Andrea Bolognani / Red Hat / Virtualization




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