From 53f687bbabd604f2e084e83f7ff75b65155687ec Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Wed, 15 Apr 2020 12:51:51 +0200 Subject: [PATCH] docs: add zpci information to pci-addresses.rst MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add some information on how pci address work on s390x. Signed-off-by: Cornelia Huck Signed-off-by: Ján Tomko Reviewed-by: Ján Tomko --- docs/pci-addresses.rst | 64 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/docs/pci-addresses.rst b/docs/pci-addresses.rst index 923783a151..fbc741e344 100644 --- a/docs/pci-addresses.rst +++ b/docs/pci-addresses.rst @@ -184,3 +184,67 @@ guest OS rather than as ``0001:08:00.1``, which is the address of the device on the host. Of course, all the rules and behaviors described above still apply. + + +zPCI addresses +============== + +For s390x machines, PCI addresses are handled yet differently. No +topology information is relayed in the PCI addresses; instead, the +``fid`` and ``uid`` elements of the ``zpci`` device convey information. +In the simplest case, the following XML snippet + +:: + + + + + +
+ +
+ + + + + +
+ +
+ + +will result in the following in a Linux guest:: + + 0001:00:00.0 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. + +Neither are any changes in the PCI address visible in the guest; replacing +the PCI address for the virtio-net device with + +:: + +
+ +will result in the exactly same view in the guest, as the addresses there +are generated from the information provided via the ``zpci`` element (in +fact, from the ``uid``). + +Therefore, replacing the virtio-net device definition with the following XML +snippet + +:: + + + + + +
+ +
+ + +will yield the following result in a Linux guest:: + + 0007:00:00.0 Ethernet controller: Red Hat, Inc. Virtio network device