Re: [PATCH 2/2] docs: Improve zPCI section in pci-addresses.rst
On Thu, 16 Apr 2020 17:56:18 +0200
Boris Fiuczynski <fiuczy(a)linux.ibm.com> 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>
---
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.
</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..."
Neither are any changes in the PCI address visible in the guest; replacing
The 'neither' is now a bit confusing; what about
"Any changes in the PCI address are not visible in the guest..." ?
the PCI address for the ``virtio-net`` device with
::
- <address type='pci' domain='0x0000' bus='0x01'
slot='0x07' function='0x3'>
+ <address type='pci' domain='0x0000' bus='0x01'
slot='0x06' function='0x4'>
will result in the exactly same view in the guest, as the addresses there
If you move the fid/uid stuff up, make this
"as the fid and uid values in the zpci element remain unchanged." ?
-are generated from the information provided via the ``zpci`` element
(in
-fact, from the ``uid``).
+are generated from the information provided via the ``zpci`` element:
+the ``uid`` is used as PCI domain, and the ``fid`` is used as the PCI devices
s/devices/device's/
+slot in the sysfs.
s/the sysfs./sysfs (it does not influence the PCI device address.)/
*
Device assignment