docs: drvqemu: Give example how to query device properties for overriding

Add an example of invoking qemu with '-device TYPE,?' to query
properties of a given type.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

diff --git a/docs/drvqemu.rst b/docs/drvqemu.rst
index 7bfb28ea9cdf68a807341ef5696247412383c6d5..b31b1785db5bfe6860734d0d0c43cc19a1fa8b6e 100644 (file)
--- a/docs/drvqemu.rst
+++ b/docs/drvqemu.rst
@@ -722,6 +722,11 @@ attribute are:
 The overrides are applied only to initial device configuration passed to QEMU
 via the commandline. Later hotplug operations will not apply any modifications.
 
+The properties of a device can be queried directly in qemu (e.g. for the
+``virtio-blk-pci`` device) via ::
+
+  # qemu-system-x86_64 -device virtio-blk-pci,?
+
 Configuring override for a device alias which is not used or attempting to
 remove a device property which is not formatted by libvirt will cause failure
 to startup the VM.