On Thu, May 19, 2011 at 02:33:52PM +0900, Daniel Castro wrote: > Good Day, > > In order to give PV Drivers to SeaBIOS we will need to solve a few > problems, one is the following: > Does a booting kernel informs the BIOS that it will leave real mode > and not use it again? When the booting kernel uses CPU real mode for > the last time, how can we (Xen or SeaBIOS) know that real mode will no > longer be used, and hence BIOS calls will not be issued?
In the general case, no. The ACPI spec does define a mechanism for the OS to inform the BIOS that it is transitioning from "Legacy state" to "Working state" via an SMI. SeaBIOS does have code for this (see src/smm.c), but it doesn't currently do anything interesting. Unfortunately, this is only available for OSs that support ACPI. > We want upon last real mode usage to leave all Xen PV information in a > clean state, this means, closing the channel and ring between the > newly created domain and the host system. Is it required to close the channel? Can opening a new channel implicitly close the old channel (I believe this is what the virtio stuff does)? -Kevin _______________________________________________ SeaBIOS mailing list [email protected] http://www.seabios.org/mailman/listinfo/seabios
