Re: [libvirt] [Qemu-devel] Modern CPU models cannot be used with libvirt

On Thu, Mar 22, 2012 at 11:37:39AM -0500, Anthony Liguori wrote: > On 03/22/2012 04:32 AM, Gleb Natapov wrote: >> On Tue, Mar 13, 2012 at 11:53:19AM -0300, Eduardo Habkost wrote: >>> So, this problem is solved if the defaults are easily found on >>> /usr/share. >>>> What problem is solved and why are we mixing machine configuration files >> and cpu configuration files? They are different and should be treated >> differently. -nodefconfig exists only because there is not machine >> configuration files currently. With machine configuration files >> libvirt does not need -nodefconfig because it can create its own machine >> file and make QEMU use it. So specifying machine file on QEMU's command >> line implies -nodefconfig. The option itself loses its meaning and can be >> dropped. > No, -nodefconfig means "no default config". > As with many projects, we can have *some* configuration required. > The default configure should have a: > [system] > readconfig=@SYSCONFDIR(a)/cpu-models-x86_64.cfg Not @SYSCONFDIR@, but @DATADIR@. CPU models belong to /usr/share because they aren't meant to be changed by the user (I think I already explained why: because we have to be able to deploy fixes to them). > Stanza by default. If libvirt wants to reuse this, they can use > -readconfig if they use -nodefconfig. You are just repeating how you believe it should work based on the premise that "cpudefs are configuration". We're discussing/questioning this exact premise, here, and I would really appreciate to hear why the model Gleb is proposing is not valid. More precisely, this part: >> cpu-models-x86.conf is not a configuration file. It is hardware >> description file. QEMU should not lose capability just because you run >> it with -nodefconfig. -nodefconfig means that QEMU does not create >> machine for you, but all parts needed to create a machine that would have >> been created without -nodefconfig are still present. Not been able to >> create Nehalem CPU after specifying -nodefconfig is the same as not been >> able to create virtio-net i.e the bug. And the related points Gleb mentioned further in this thread.