Re: [Qemu-devel] [PATCH 08/24] vhost-user: return a read error

[Marc-André Lureau]

Hi

On Mon, Jul 4, 2016 at 5:47 PM, Michael S. Tsirkin <address@hidden> wrote:
> Why does vhost_user_set_log_base need to return error?
> If backend is not there to handle this message,
> then it is not changing memory so it's ok to ignore the error.

How do you know it's not changing the memory?

Furthermore, if the migration happened, it's because backend claim
VHOST_F_LOG_ALL, thus it should really not fail

> Same logic applies to many other messages.

Pretty much all messages, the error can't be ignored, or operations
will just fail silentely randomly. I don't understand why vhost-user
io error can be ignored. Also it's quite inconsistent the way the code
is today, vhost_user_write() returns an error that is mostly ignored,
while vhost_user_read() is checked. Why having an error later when you
can report it earlier? I fail to understand the rationale of this
error handling.


-- 
Marc-André Lureau