Re: [PATCH 2/2] docs: Improve zPCI section in pci-addresses.rst

On Fri, 17 Apr 2020 10:50:02 +0200 Boris Fiuczynski <fiuczy(a)linux.ibm.com&gt; wrote: > On 4/16/20 6:14 PM, Cornelia Huck wrote: >> On Thu, 16 Apr 2020 17:56:18 +0200 >> Boris Fiuczynski <fiuczy(a)linux.ibm.com&gt; wrote: >> >>> Improving the zPCI example by choosing more distinct values and >>> adding explanation for fid. >>> >>> Signed-off-by: Boris Fiuczynski <fiuczy(a)linux.ibm.com&gt; >>> --- >>> docs/pci-addresses.rst | 15 ++++++++------- >>> 1 file changed, 8 insertions(+), 7 deletions(-) >>> >>> diff --git a/docs/pci-addresses.rst b/docs/pci-addresses.rst >>> index 7c8e9edd73..4492389da5 100644 >>> --- a/docs/pci-addresses.rst >>> +++ b/docs/pci-addresses.rst >>> @@ -176,14 +176,14 @@ In the simplest case, the following XML snippet >>> <model name='pci-bridge'/> >>> <target chassisNr='1'/> >>> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'> >>> - <zpci uid='0x0002' fid='0x00000001'/> >>> + <zpci uid='0x0001' fid='0x00000000'/> >> >> Why this change? The pci-bridge does not show up in the guest anyway. > My assumption was that uid and fid for this would be autogenerated. > Since uid 0x0001 and fid 0x00000000 have been freed up due to the change > below this would be the autogenerated set. If that makes the XML look saner, no objection. > >> >>> </address> >>> </controller> >>> <interface type='bridge'> >>> <source bridge='virbr0'/> >>> <model type='virtio'/> >>> <address type='pci' domain='0x0000' bus='0x01' slot='0x01' function='0x0'> >>> - <zpci uid='0x0001' fid='0x00000000'/> >>> + <zpci uid='0x0007' fid='0x00000003'/> >>> </address> >>> </interface> >>> >>> @@ -191,21 +191,22 @@ will result in the following in a Linux guest: >>> >>> :: >>> >>> - 0001:00:00.0 Ethernet controller: Red Hat, Inc. Virtio network device >>> + 0007:00:00.0 Ethernet controller: Red Hat, Inc. Virtio network device >>> >>> Note that the PCI bridge is not visible in the guest; s390x always has a flat >>> -topology. >>> +topology. Also ``fid`` does not define slot or function of the PCI address. >> >> I find the sentence regarding 'fid' confusing. Maybe instead move up >> the explanation from below regarding uid and fid? >> >> "The PCI address in the guest is generated from..." >> > Lets join your proposal with Andreas and move his rewrite up to here. > Like: > ...topology. > The PCI address in the guest is generated from the information provided > via the ``zpci`` element: more specifically, ``uid`` is used as the PCI > domain.``fid`` doesn't appear in the PCI address itself, but it will be > used in sysfs (``/sys/bus/pci/slots/$fid/...``). Sounds good. (Also the rest of the changes.)