On Fri, Jul 07, 2017 at 06:17:57PM +0300, Michael S. Tsirkin wrote: > On Fri, Jul 07, 2017 at 10:39:49AM -0300, Eduardo Habkost wrote: > > On Wed, Jul 05, 2017 at 12:32:10PM +0300, Marcel Apfelbaum wrote: > > > On 05/07/2017 11:14, Thomas Huth wrote: > > > > Hi, > > > > > > > > > > Hi, > > > > > > > On 05.07.2017 08:57, Chao Peng wrote: > > > > > > > > > > Q35 has been in QEMU for quite a while. Compared to the current > > > > > default > > > > > i440FX, Q35 is probably not that mature and not widely used, however > > > > > in > > > > > some case, Q35 has advantages, for example, in supporting new > > > > > features. > > > > > For instance, we have some features require PCI-e support which is > > > > > only > > > > > available on Q35 and some others need it for EFI support. It is of > > > > > course not necessary to change it as the default but if more and more > > > > > features have dependencies on Q35 because of requiring much more > > > > > modern > > > > > features then I think it may be worth to do so. In such case we can > > > > > have > > > > > more people to use it and find problems we may know or not know. > > > > > > > > > > Agreed > > > > > > > Yes, IMHO at one point in time, we should switch the default machine > > > > type to q35. > > > > > > +1 > > > > > > > The i440FX is really quite old... > > > > > > > > > There are certainly some drawbacks: > > > > > - Compatibility: current code or script may need adjustment > > > > > > > > That might be a real concern ... > > > > > > I am not so sure about that. Developers working on upstream projects > > > should expect such changes and, for our case, > > > modifying the command line by adding "-M pc" should not be a big deal. > > > > We could print a warning for 1 or 2 releases when users don't add > > a explicit "-M pc" or "-M q35" argument to qemu-system-x86_64, > > but: > > > > > > > > The upper layers should manage the defaults by themselves so > > > are not supposed to be affected. > > > > But they would be. libvirt uses the default machine-type from > > QEMU. > > How about extending the command for supported machines with a > recommended machine type, and teaching libvirt to use that?
I don't think QEMU has enough information to decide if it should recommend "q35" or "pc". -- Eduardo
