On Thu, Nov 07, 2024 at 06:34:49PM +0100, Andrea Bolognani wrote:
When virtio-(non-)transitional models were introduced, the
documentation was updated to include them; at the same time,
language was introduced indicating that using the existing
virtio model is no longer recommended.
This is unnecessarily harsh, and has resulted in people
incorrectly believing (through no fault of their own) that the
virtio model has been deprecated.
In reality, it's perfectly fine to use the virtio model as the
stress-free option that, while often not producing the ideal
PCI topology, will generally get the job done and work reliably
across libvirt versions and machine types.
I wonder who reviewed the harsh language back then 🤔 =D
Tweak the documentation so that it hopefully carries the
desired message across.
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
docs/formatdomain.rst | 55 ++++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 27 deletions(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index c50744b57b..75dff5a153 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
[...]
@@ -3910,11 +3909,20 @@ Note: In general you should leave this option
alone, unless you are very certain
you know what you are doing.
-Virtio transitional devices
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Virtio device models
+~~~~~~~~~~~~~~~~~~~~
+
+Virtio devices come in several variants, some of which are only applicable to
+certain machine types or scenarios. The variant can be chosen via the ``model``
+attribute, which supports the following values:
-:since:`Since 5.2.0`, some of QEMU's virtio devices, when used with PCI/PCIe
-machine types, accept the following ``model`` values:
+``virtio``
+ This is the recommended choice in the absence of guest OS specific
+ constraints, as it will will generally work correctly across a large range
+ of architectures, machine types and libvirt versions.
+
+:since:`Since 5.2.0`, the following values can additionally be used with machine
+types based on PCI (either conventional PCI or PCI Express):
I think that you cannot specify model='virtio' before 5.2.0. Maybe what
Daniel suggested, keeping the mention of compatibility with older
versions is the better way to go. From the above one might think that
model='virtio' will work on older libvirt, and it will look like it
does, but it won't get parsed.
Well, that's pretty minor in the end, so either way you decide, unless
someone objects
Reviewed-by: Martin Kletzander <mkletzan(a)redhat.com>