On Mon, Aug 08, 2011 at 08:02:08AM -0500, Anthony Liguori wrote: > On 08/08/2011 07:56 AM, Michael S. Tsirkin wrote: > >On Mon, Aug 08, 2011 at 07:45:19AM -0500, Anthony Liguori wrote: > >>On 08/08/2011 05:36 AM, Michael S. Tsirkin wrote: > >>>>Thinking more closely, I don't think this right. > >>>> > >>>>Updating on map ensured that the config was refreshed after each > >>>>time the bar was mapped. In the very least, the config needs to be > >>>>refreshed during reset because the guest may write to the guest > >>>>space which should get cleared after reset. > >>>> > >>>>Regards, > >>>> > >>>>Anthony Liguori > >>> > >>>Not sure I understand. Which register, for example, > >>>do you have in mind? > >>>Could you clarify please? > >> > >>Actually, you never need to call config_get() AFAICT. It's called > >>in every read/write access. > > > >Every read, yes. But every write? Are you sure? > > Yeah, not on write, but I think this is a bug. get_config() should > be called before doing the memcpy() in order to have a proper RMW. > > Regards, > > Anthony Liguori
Probably not noticeable because guests don't do the RMW in practice. We also send the config over on migration. That's probably a bug as well ... -- MST