qemu_firmware: Take NVRAM format into account when matching

Commit d3016e47be5f removed a hunk very similar to the one we're
adding with the rationale that there is no actual requirement for
the NVRAM file and the NVRAM template to have the same format,
which is completely correct: while libvirt will not perform the
format conversion itself, the user can do that on their own and
everything (except RESET_NVRAM) will work just fine.

That said, we also need <nvram format='foo'/> specified on its
own with no <loader> element to result in a firmware build with a
foo-formatted NVRAM template to be picked. Right now this works
thanks to the hack at the top of qemuFirmwareFillDomain() which
copies nvram.format to loader.format, but we want to get rid of
that because it has additional side effects that can lead to
confusing outcomes in certain specific scenarios.

So reintroduce this check, but make it extremely narrow: if any
other information that can influence firmware selection is
present in the domain XML, ignore the NVRAM format entirely; if
however the NVRAM format is the only information that was
provided, consider it when looking for a match.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/qemu/qemu_firmware.c b/src/qemu/qemu_firmware.c
index e13cce08876712efa27daf74e1b109924b0f7920..8714538ba3aad70f728dbf88325669b5734eddfe 100644 (file)
--- a/src/qemu/qemu_firmware.c
+++ b/src/qemu/qemu_firmware.c
@@ -1304,6 +1304,21 @@ qemuFirmwareMatchDomain(const virDomainDef *def,
                           virStorageFileFormatTypeToString(loader->nvramTemplateFormat));
                 return false;
             }
+            /* If nvram.format was specified and no other information
+             * that can influence firmware selection was, then treat it
+             * the same as if nvram.templateFormat had been specified.
+             * This ensures that <nvram format='foo'/> continues to work
+             * as a shorthand while not getting in the way otherwise */
+            if (loader && loader->nvram && loader->nvram->format &&
+                !loader->readonly && !loader->type && !loader->secure &&
+                !loader->stateless && !loader->format && !loader->path &&
+                !loader->nvramTemplateFormat && !loader->nvramTemplate &&
+                STRNEQ(flash->nvram_template.format, virStorageFileFormatTypeToString(loader->nvram->format))) {
+                VIR_DEBUG("Discarding loader with mismatching nvram template format '%s' != '%s'",
+                          flash->nvram_template.format,
+                          virStorageFileFormatTypeToString(loader->nvram->format));
+                return false;
+            }
         } else {
             if (loader && loader->nvram &&
                 (loader->nvram->path || loader->nvram->format)) {