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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-06-16 16:59:00 +0000 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-06-16 16:59:33 +0000 |
| commit | 9aba81d8eb048db908c94a3c40c25a5fde0caee6 (patch) | |
| tree | b765e7fb5e9a3c2143c68b0414e0055adb70e785 /results/classifier/118/network/2951 | |
| parent | b89a938452613061c0f1f23e710281cf5c83cb29 (diff) | |
| download | qemu-analysis-9aba81d8eb048db908c94a3c40c25a5fde0caee6.tar.gz qemu-analysis-9aba81d8eb048db908c94a3c40c25a5fde0caee6.zip | |
add 18th iteration of classifier
Diffstat (limited to 'results/classifier/118/network/2951')
| -rw-r--r-- | results/classifier/118/network/2951 | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/results/classifier/118/network/2951 b/results/classifier/118/network/2951 new file mode 100644 index 000000000..f75c69930 --- /dev/null +++ b/results/classifier/118/network/2951 @@ -0,0 +1,51 @@ +network: 0.935 +graphic: 0.840 +device: 0.838 +vnc: 0.799 +peripherals: 0.796 +kernel: 0.768 +performance: 0.755 +socket: 0.693 +files: 0.689 +ppc: 0.666 +architecture: 0.629 +register: 0.614 +hypervisor: 0.583 +boot: 0.561 +risc-v: 0.536 +semantic: 0.529 +permissions: 0.501 +PID: 0.493 +arm: 0.454 +i386: 0.414 +debug: 0.413 +x86: 0.399 +TCG: 0.395 +VMM: 0.379 +user-level: 0.296 +KVM: 0.277 +assembly: 0.249 +mistranslation: 0.142 +virtual: 0.049 + +First byte of USB NIC is hardcoded to 0x40 +Description of problem: +Incus recently added support for USB attached network interfaces. +As with any network device, we generate a MAC address (using our MAC OUI) and allow the user to override that to a value of their choice. + +That's when we noticed that no matter what MAC address we set, the resulting MAC always has the prefix swapped to "40:". Looking into the code, this is done on purpose here: + +https://gitlab.com/qemu-project/qemu/-/blob/master/hw/usb/dev-network.c?ref_type=heads#L1386 + +Unfortunately there is no comment in the code or in any of the commits touching that code as far as why that is. + +We've also looked at the libvirt code handling those devices and that code seems to also assume that a user provided MAC will be correctly passed through to the guest, no mention of the odd prefix override. + +This is a bit concerning as there are valid IEEE OUI with the "40:" prefix. +So this means that QEMU may be generating collisions with actual physical MAC addresses... + +For a few months now, I've been applying this small patch to my own Incus packages (which bundle QEMU) and haven't heard or seen any obvious issue from the change. + +https://github.com/zabbly/incus/blob/daily/patches/qemu-0001-usb-net-mac.patch + +Does anyone know why this hardcoded MAC address prefix exists? |