* -nic model=rocker causes qemu to abort
@ 2020-04-29 16:43 Michael Tokarev
2020-05-25 18:45 ` Thomas Huth
0 siblings, 1 reply; 4+ messages in thread
From: Michael Tokarev @ 2020-04-29 16:43 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, Thomas Huth
Hi!
Just a fun case of (invalid) usage of qemu-system command line.
Someone tried -nic model=rocker, and qemu does this:
Unexpected error in object_property_find() at /build/qemu/git/qom/object.c:1029:
qemu-system-x86_64: Property '.mac' not found
Aborted
This happens after this commit:
commit 52310c3fa7dc854dd2376ae8a518141abcdb78f3
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri Mar 2 10:30:50 2018 +0100
net: allow using any PCI NICs in -net or -nic
Previously rocker rightly wasn't usable as a nic model,
and after this commit it is now possible.
While I agree this is invalid usage, perhaps qemu should not
abort like this? Maybe it should check the required property
too, before allowing this device to be a nic model?
Thanks,
/mjt
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: -nic model=rocker causes qemu to abort 2020-04-29 16:43 -nic model=rocker causes qemu to abort Michael Tokarev @ 2020-05-25 18:45 ` Thomas Huth 2020-05-25 19:46 ` Michael Tokarev 0 siblings, 1 reply; 4+ messages in thread From: Thomas Huth @ 2020-05-25 18:45 UTC (permalink / raw) To: Michael Tokarev, qemu-devel; +Cc: Paolo Bonzini, Jason Wang, Jiri Pirko On 29/04/2020 18.43, Michael Tokarev wrote: > Hi! > > Just a fun case of (invalid) usage of qemu-system command line. > Someone tried -nic model=rocker, and qemu does this: > > Unexpected error in object_property_find() at /build/qemu/git/qom/object.c:1029: > qemu-system-x86_64: Property '.mac' not found > Aborted > > This happens after this commit: > > commit 52310c3fa7dc854dd2376ae8a518141abcdb78f3 > Author: Paolo Bonzini <pbonzini@redhat.com> > Date: Fri Mar 2 10:30:50 2018 +0100 > > net: allow using any PCI NICs in -net or -nic > > > Previously rocker rightly wasn't usable as a nic model, > and after this commit it is now possible. > > While I agree this is invalid usage, perhaps qemu should not > abort like this? Maybe it should check the required property > too, before allowing this device to be a nic model? QEMU theoretically should never abort() - abort() means there is something wrong in the code ... so we should definitely fix this by other means. Some questions: 1) How is that rocker device normally used? Similar to a normal network card? Or completely different? 2) In case it is similar to a normal network card, would it make sense to allow it with -nic or -net, too? Or should we simply disallow it here? I think we could either use a list of devices that should never be allowed here, or we check for the availability of that "mac" property... Thomas ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: -nic model=rocker causes qemu to abort 2020-05-25 18:45 ` Thomas Huth @ 2020-05-25 19:46 ` Michael Tokarev 2020-05-26 5:17 ` Thomas Huth 0 siblings, 1 reply; 4+ messages in thread From: Michael Tokarev @ 2020-05-25 19:46 UTC (permalink / raw) To: Thomas Huth, qemu-devel; +Cc: Paolo Bonzini, Jason Wang, Jiri Pirko 25.05.2020 21:45, Thomas Huth wrote: > On 29/04/2020 18.43, Michael Tokarev wrote: >> Hi! >> >> Just a fun case of (invalid) usage of qemu-system command line. >> Someone tried -nic model=rocker, and qemu does this: >> >> Unexpected error in object_property_find() at /build/qemu/git/qom/object.c:1029: >> qemu-system-x86_64: Property '.mac' not found >> Aborted >> >> This happens after this commit: >> >> commit 52310c3fa7dc854dd2376ae8a518141abcdb78f3 >> Author: Paolo Bonzini <pbonzini@redhat.com> >> Date: Fri Mar 2 10:30:50 2018 +0100 >> >> net: allow using any PCI NICs in -net or -nic >> >> Previously rocker rightly wasn't usable as a nic model, >> and after this commit it is now possible. >> >> While I agree this is invalid usage, perhaps qemu should not >> abort like this? Maybe it should check the required property >> too, before allowing this device to be a nic model? > > QEMU theoretically should never abort() - abort() means there is > something wrong in the code ... so we should definitely fix this by > other means. Some questions: > > 1) How is that rocker device normally used? Similar to a normal network > card? Or completely different? Nope, this is not a network card, it is a network SWITCH, used as a regular PCI device, not network-specific. Hence the problem at hand, - before the patch this device weren't "nic-able", so to say, because while it is network-related PCI device, it is not a NIC. I guess while building a list of "nic-able" cards, we should skip some "nic-alike" devices and use some more specific criteria. Not everything which is network-related is a regular NIC. Maybe in time some other devices will appear in qemu with similar effect which will require another condition. Or adding a new field into the pci structure to indicate this device can be a NIC will solve it once for all. Or just reverting the patch :) - after all it isn't that bad to have a list of NIC-able devices outside of the device definitions, - we don't have tons of devices anyway where maintaining such a list outside of device model is a problem. Thanks, /mjt > 2) In case it is similar to a normal network card, would it make sense > to allow it with -nic or -net, too? Or should we simply disallow it > here? I think we could either use a list of devices that should never be > allowed here, or we check for the availability of that "mac" property... > > Thomas > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: -nic model=rocker causes qemu to abort 2020-05-25 19:46 ` Michael Tokarev @ 2020-05-26 5:17 ` Thomas Huth 0 siblings, 0 replies; 4+ messages in thread From: Thomas Huth @ 2020-05-26 5:17 UTC (permalink / raw) To: Michael Tokarev, qemu-devel; +Cc: Paolo Bonzini, Jason Wang, Jiri Pirko On 25/05/2020 21.46, Michael Tokarev wrote: > 25.05.2020 21:45, Thomas Huth wrote: >> On 29/04/2020 18.43, Michael Tokarev wrote: >>> Hi! >>> >>> Just a fun case of (invalid) usage of qemu-system command line. >>> Someone tried -nic model=rocker, and qemu does this: >>> >>> Unexpected error in object_property_find() at /build/qemu/git/qom/object.c:1029: >>> qemu-system-x86_64: Property '.mac' not found >>> Aborted >>> >>> This happens after this commit: >>> >>> commit 52310c3fa7dc854dd2376ae8a518141abcdb78f3 >>> Author: Paolo Bonzini <pbonzini@redhat.com> >>> Date: Fri Mar 2 10:30:50 2018 +0100 >>> >>> net: allow using any PCI NICs in -net or -nic >>> >>> Previously rocker rightly wasn't usable as a nic model, >>> and after this commit it is now possible. >>> >>> While I agree this is invalid usage, perhaps qemu should not >>> abort like this? Maybe it should check the required property >>> too, before allowing this device to be a nic model? >> >> QEMU theoretically should never abort() - abort() means there is >> something wrong in the code ... so we should definitely fix this by >> other means. Some questions: >> >> 1) How is that rocker device normally used? Similar to a normal network >> card? Or completely different? > > Nope, this is not a network card, it is a network SWITCH, used as a > regular PCI device, not network-specific. Hence the problem at hand, - > before the patch this device weren't "nic-able", so to say, because > while it is network-related PCI device, it is not a NIC. > > I guess while building a list of "nic-able" cards, we should skip some > "nic-alike" devices and use some more specific criteria. Not everything > which is network-related is a regular NIC. Ok, thanks for the explanation! So looking at the properties of the rocker and real NIC devices again, I think the solution might be simple: For -nic/-net, we should only consider devices that have a "netdev" property. I'll try to write a patch when I've got some spare minutes... Thomas ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-05-26 5:17 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-04-29 16:43 -nic model=rocker causes qemu to abort Michael Tokarev 2020-05-25 18:45 ` Thomas Huth 2020-05-25 19:46 ` Michael Tokarev 2020-05-26 5:17 ` Thomas Huth
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).