CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2026/04/17 15:08:42
Modified files:
usr.sbin/vmd : vionet.c virtio.h vmd.h
Log message:
Fix vmd(8) vionet reset race leading to broken networking.
A driver reset races with the device asynchronously notifying tx
and rx threads. The current design finishes the reset after the
threads pause and acknowledge the reset. This can clobber device
state because a driver doesn't need to wait before reconfiguring
the device. End result is device thinks it's in a blank slate while
driver thinks device is configured and device refuses to pass packets
thinking the driver isn't ready.
This removes that async reset design and ack message from the
threads. Reset occurs immediately while emulating the write to the
register. A generation counter is used to signal to tx and rx
threads that a reset occurred between they time they finished
processing virtqueues and the time they grabbed the write lock to
change interrupt state on the device so they can safely skip
raising irq lines.
Original bug reports by mbuhl@ and stsp@.
Tested with help from stsp@, hshoexer@, and Mischa Peters.
ok mlarkin@
