Re: [Qemu-devel] [PATCH] qmp: handle stop/cont in INMIGRATE state

[Paolo Bonzini]

> What happens is that a stop command while in INMIGRATE state will just
> be ignored. Actually, any stops while in a state that pauses vCPUs
> are ignored.
> 
> Also, I don't understand what you meant by "racy", care to elaborate?

    Case 1:                               Case 2:
    user runs qemu -incoming -S           user runs qemu -incoming -S
    source connects                       cont command received
    cont command received                 source connects
 
In case 1, the VM is resumed at the end of migration, in case 2 it
is not and an error is reported on QMP.  After this patch, it is always
resumed.

    Case 1:                               Case 2:
    user runs qemu -incoming              user runs qemu -incoming
    source connects                       stop command received
    stop command received                 source connects
 
In case 1, the VM runs for a blink of an eye and then stops.  In case
2 it just starts, with no error reported.

> > In addition, there's nothing that really prevents the user from
> > typing the block device's passwords before incoming migration is
> > done, so we may as well allow that.
> 
> Have you tried it? We seem to support that already.

With HMP yes, with QMP no.  You just get "An incoming migration is
expected before this command can be executed" and no clue that disks
are encrypted.

Paolo