Marc-André Lureau <mlur...@redhat.com> writes: > Hi > > ----- Original Message ----- >> > >> > You can't migrate the peers. >> >> Then explain the case N'=0 to me: how can you migrate the master so that >> it's connected to a server afterwards? > > Dest qemu: -incoming.. -chardev socket,path=dest-server > > That is, start your destination qemu with a destination server. The master > origin qemu will migrate the shared memory, and the dest memory will be sync > when the migration is done.
Got it! >> > It works fine in the tests. Feel free to point out races or other issues. >> >> I think I did: doorbell detection is inherently racy. >> >> If you think it isn't, please refute my reasoning. > > I gave you some clues on how I did it in ivshmem-test.c: waiting for a > signature on the memory to be mapped (and also checking that peers > received ids) > >> If it's not broken, please explain to me how the guest should find out >> whether its ivshmem device sports a doorbell. > > If you have received ID, you should be good to use the doorbell. That's not a complete answer, so let me try a different tack. What value will a read of register IVPosition yield * if the device has no doorbell: I think the answer is -1. * if the device has a doorbell, but it isn't ready, yet: I think the answer is -1. * if the device has a doorbell, and it is ready. This is the part you answered already: >= 0. Please correct mistakes.
