Gerhard Wiesinger wrote: > >>Would it be possible to handle these writes through QEMU directly > >>(without > >>KVM), because performance is there very well (looking at the code there > >>is some pointer arithmetic and some memory write done)? > > > >I've noticed extremely slow VGA performance too, when installing OSes. > >It makes the difference between installing in a few minutes, and > >installing taking hours - just because of the slow VGA. > > > >So generally I use qemu for installing old versions of Windows, then > >change to KVM to run them after installing. > > > >Switching between KVM and qemu automatically based on guest code > >behaviour, and making both memory models and device models compatible > >at run time, is a difficult thing. I guess it's not worth the > >difficulty just to speed up VGA. > > I think this is very easy to distingish: > 1.) VGA Segment A000 is legacy and should be handled through QEMU > and not through KVM (because it is much more faster). Also 16 color modes > should be fast enough there. > 2.) All other flat PCI memory accesses should be handled through KVM > (there is a specialized driver loaded for that PCI device in the non > legacy OS). > > Is that easily possible? No it isn't. Distingushing addresses is trivial. You've ignored the hard part, which is switching between different virtualisation architectures... -- Jamie -- 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
