Re: [PATCH] qemu_hotplug: Deny changing @rss and @rss_hash_report attributes of virtio vNICs

[Laine Stump]

On 5/23/22 11:22 AM, Michal Privoznik wrote:
We have virDomainUpdateDeviceFlags() API that allows changing of
some attributes of a device whilst domain is still running (e.g.
setting different QoS, link state change on vNICs). But only very
limited set of attributes can be changed and we have to check
whether user isn't trying to sneak in a change that's not
allowed. Well, in case of a virtio vNIC we forgot to check for
@rss and @rss_hash_report attributes of <driver/>.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2082540
Signed-off-by: Michal Privoznik <mpriv...@redhat.com>
---
  src/qemu/qemu_hotplug.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Laine Stump <la...@redhat.com>

(too bad there's not an elegant automated way of pointing out when a new 
field is added that can't be updated at runtime)


diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 24df66cc9f..f795568299 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -3662,7 +3662,9 @@ qemuDomainChangeNet(virQEMUDriver *driver,
           olddev->driver.virtio.guest.tso4 != newdev->driver.virtio.guest.tso4 
||
           olddev->driver.virtio.guest.tso6 != newdev->driver.virtio.guest.tso6 
||
           olddev->driver.virtio.guest.ecn != newdev->driver.virtio.guest.ecn ||
-         olddev->driver.virtio.guest.ufo != newdev->driver.virtio.guest.ufo)) {
+         olddev->driver.virtio.guest.ufo != newdev->driver.virtio.guest.ufo ||
+         olddev->driver.virtio.rss != newdev->driver.virtio.rss ||
+         olddev->driver.virtio.rss_hash_report != 
newdev->driver.virtio.rss_hash_report)) {
          virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                         _("cannot modify virtio network device driver 
attributes"));
          goto cleanup;