On Wed, 26 Aug 2009, Avi Kivity wrote: > On 08/26/2009 10:13 PM, Davide Libenzi wrote: > > Ok, so why not using the eventfd counter as state? > > On the device side: > > > > void write_state(int sfd, int state) { > > u64 cnt; > > > > /* Clear the current state, sfd is in non-blocking mode */ > > read(sfd,&cnt, sizeof(cnt)); > > /* Writes new state */ > > cnt = 1 + !!state; > > write(sfd,&cnt, sizeof(cnt)); > > } > > > > > > On the hypervisor side: > > > > int read_state(int sfd) { > > u64 cnt; > > > > read(sfd,&cnt, sizeof(cnt)); > > return state - 1; > > } > > > > > > Hadn't though of read+write as set. While the 1+ is a little ugly, it's > workable. Pick what you want, as long as it always writes something != 0 :) > I see no kernel equivalent to read(), but that's easily done. Adding an in-kernel read based on "ctx", that is no problem at all. - Davide -- 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