Re: [Qemu-devel] [PATCH RFC] ps2: set the keybord output buffer size as the same as kernel

[Gonglei (Arei)]

> 
> Hi, Gerd and Juan.
> 
> Thanks for your guides about the confuse live migration about changing the
> keyboard buffer size.
> According your suggestion, I got two solutions to address the issue:
> 
> - Keep the data array 256 bytes long, change the rptr/wptr/count/data array at
> post_load(), both
>  Ps/2 keyboard and mouse. This solution can be compatible with older qemu
> versions, which can
>  do live migration each other.
> 
> -Change the data array to 16 bytes, still save as PS2_QUEUE_SIZE. Reset the
> rptr/wptr/count at
> post_load(), both ps/2 keyboard and mouse. Add VMSTATE_UNUSED(256-16) in
> struct vmstate_ps2_common.
> This solution just save the 16 bytes buffer and drop the rest, So we can't
> migrate vm to older qemu versions.
> But migration from old qemu to new qemu is ok.
> 
Sorry, the second solution also support cross-version live migration each other.

> I have tested the two solutions, but which one is better? Expect your reply.
> Thanks!
> 

Best regards,
-Gonglei