docs/system/s390x/pcidevices.rst | 34 ++++++++++++++++++++++++++++++++ docs/system/target-s390x.rst | 1 + 2 files changed, 35 insertions(+) create mode 100644 docs/system/s390x/pcidevices.rst
Add some documentation about the zpci device and how
to use it with pci devices on s390x.
Used source: Cornelia Huck's blog post
https://people.redhat.com/~cohuck/2018/02/19/notes-on-pci-on-s390x.html
Signed-off-by: Sebastian Mitterle <smitterl@redhat.com>
---
docs/system/s390x/pcidevices.rst | 34 ++++++++++++++++++++++++++++++++
docs/system/target-s390x.rst | 1 +
2 files changed, 35 insertions(+)
create mode 100644 docs/system/s390x/pcidevices.rst
diff --git a/docs/system/s390x/pcidevices.rst b/docs/system/s390x/pcidevices.rst
new file mode 100644
index 0000000000..2086c1ca29
--- /dev/null
+++ b/docs/system/s390x/pcidevices.rst
@@ -0,0 +1,34 @@
+PCI devices on s390x
+====================
+
+PCI devices on s390x work differently than on other architectures.
+
+To start with, using a PCI device requires the additional ``zpci`` device. For example,
+in order to pass a PCI device ``0000:00:00.0`` through you'd specify::
+
+ qemu-system-s390x ... \
+ -device zpci,uid=1,fid=0,target=hostdev0,id=zpci1 \
+ -device vfio-pci,host=0000:00:00.0,id=hostdev0
+
+Here, the zpci device is joined with the PCI device via the ``target`` property.
+
+Note that we don't set bus, slot or function here for the guest as is common in other
+PCI implementations. Topology information is not available on s390x. Instead, ``uid``
+and ``fid`` determine how the device is presented to the guest operating system.
+
+In case of Linux, ``uid`` will be used in the ``domain`` part of the PCI identifier, and
+``fid`` identifies the physical slot, i.e.::
+
+ qemu-system-s390x ... \
+ -device zpci,uid=7,fid=8,target=hostdev0,id=zpci1 \
+ ...
+
+will be presented in the guest as::
+
+ # lspci -v
+ 0007:00:00.0 ...
+ Physical Slot: 00000008
+ ...
+
+Finally, note that you might have to enable the ``zpci`` feature in the cpu model in oder to use
+it.
diff --git a/docs/system/target-s390x.rst b/docs/system/target-s390x.rst
index c636f64113..fe8251bdef 100644
--- a/docs/system/target-s390x.rst
+++ b/docs/system/target-s390x.rst
@@ -33,3 +33,4 @@ Architectural features
.. toctree::
s390x/bootdevices
s390x/protvirt
+ s390x/pcidevices
--
2.37.3
On 1/25/23 18:15, Sebastian Mitterle wrote: > Add some documentation about the zpci device and how > to use it with pci devices on s390x. > > Used source: Cornelia Huck's blog post > https://people.redhat.com/~cohuck/2018/02/19/notes-on-pci-on-s390x.html > > Signed-off-by: Sebastian Mitterle <smitterl@redhat.com> > --- > docs/system/s390x/pcidevices.rst | 34 ++++++++++++++++++++++++++++++++ > docs/system/target-s390x.rst | 1 + > 2 files changed, 35 insertions(+) > create mode 100644 docs/system/s390x/pcidevices.rst > > diff --git a/docs/system/s390x/pcidevices.rst b/docs/system/s390x/pcidevices.rst > new file mode 100644 > index 0000000000..2086c1ca29 > --- /dev/null > +++ b/docs/system/s390x/pcidevices.rst > @@ -0,0 +1,34 @@ > +PCI devices on s390x > +==================== > + > +PCI devices on s390x work differently than on other architectures. > + > +To start with, using a PCI device requires the additional ``zpci`` device. For example, > +in order to pass a PCI device ``0000:00:00.0`` through you'd specify:: > + > + qemu-system-s390x ... \ > + -device zpci,uid=1,fid=0,target=hostdev0,id=zpci1 \ > + -device vfio-pci,host=0000:00:00.0,id=hostdev0 > + > +Here, the zpci device is joined with the PCI device via the ``target`` property. > + > +Note that we don't set bus, slot or function here for the guest as is common in other > +PCI implementations. Topology information is not available on s390x. Instead, ``uid`` > +and ``fid`` determine how the device is presented to the guest operating system. > + > +In case of Linux, ``uid`` will be used in the ``domain`` part of the PCI identifier, and > +``fid`` identifies the physical slot, i.e.:: > + > + qemu-system-s390x ... \ > + -device zpci,uid=7,fid=8,target=hostdev0,id=zpci1 \ > + ... > + > +will be presented in the guest as:: > + > + # lspci -v > + 0007:00:00.0 ... > + Physical Slot: 00000008 > + ... > + > +Finally, note that you might have to enable the ``zpci`` feature in the cpu model in oder to use > +it. > diff --git a/docs/system/target-s390x.rst b/docs/system/target-s390x.rst > index c636f64113..fe8251bdef 100644 > --- a/docs/system/target-s390x.rst > +++ b/docs/system/target-s390x.rst > @@ -33,3 +33,4 @@ Architectural features > .. toctree:: > s390x/bootdevices > s390x/protvirt > + s390x/pcidevices Why not under the "Device support" section ? C.
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