On Wed, 2011-07-06 at 20:58 +0300, Michael S. Tsirkin wrote: > On Wed, Jul 06, 2011 at 06:01:46PM +0300, Sasha Levin wrote: > > On Wed, 2011-07-06 at 14:42 +0300, Michael S. Tsirkin wrote: > > > On Wed, Jul 06, 2011 at 07:37:58AM +0300, Sasha Levin wrote: > > > > + if (p->sock) { > > > > + socket_write(p->sock, &data, sizeof(data)); > > > > + socket_read(p->sock, &data, sizeof(data)); > > > > + set_val(val, len, data.data); > > > > > > Same here. > > > > The socket_read() here I should leave blocking, and spin on it until I > > read something - right? > > I think it's best to exit to userspace. Since sock_recvmsg for AF_UNIX SEQPACKET is interruptible, if we fail the read here we'll take a regular MMIO exit and will allow the usermode to deal with the MMIO in a regular way. I've discussed the issue of usermode might having to handle the same MMIO read request twice with Michael, and the solution proposed was to add a new type of exit to handle this special case. After working on that solution a bit I saw it's adding a lot of code and complexity for this small issue, and I'm now thinking we may be better off with just handling reads twice in case of a signal just between socket_write() and socket_read() - once through the socket and once through a regular MMIO exit. -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html