On Fri, Nov 03, 2017 at 07:49:03AM +0100, Gerd Hoffmann wrote: > On Thu, 2017-11-02 at 16:11 +0000, Daniel P. Berrange wrote: > > On Thu, Nov 02, 2017 at 05:04:20PM +0100, Gerd Hoffmann wrote: > > > Hi, > > > > > > One problem we have with the serial console support in seabios and > > > sgabios: It can happen that both are activated. We'll go fix that > > > in > > > qemu, but that'll work for new qemu versions only, not for the old > > > already released ones. > > > > > > So I think it would be useful if seabios makes sure sgabios and > > > serial > > > console are not both active at the same time, i.e. in case we find > > > "vgaroms/sgabios.bin" being present either turn off builtin serial > > > console, or don't load sgabios (and possibly also enable builtin > > > serial > > > console). > > > > Historically libvirt will always use '-device sgabios' if the user > > has > > requested <bios useserial='yes'/>. So if that -device arg is given, > > I > > think QEMU must honour it, which implies QEMU must disable Seabios' > > own built-in serial console impl in that scenario. > > Hmm, why? The user asked for a serial console. Whenever that is > provided by seabios builtin support or the sgabios rom doesn't really > matter, no?
Surely it has ABI implications for the guest if we stop putting the sgabios option ROM into memory - changing layout of ROMS > Also, the question is what seabios should do in case both are active. > Which I think can happen today with libvirt if you configure a virtual > machine without vga (libvirt passes -machine graphics=off which > activates builtin serial console) and with "<bios useserial='yes'/>" > (enables sgabios rom). Libvirt doesn't use '-machine graphics=off' AFAIK, only '-nographic'. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
