On Tue, Sep 25, 2007 at 03:07:44PM +0200, Jocelyn Mayer wrote: > > So, running qemu without any parameters would use host capabilities if > > kvm is available and the default qemu cpu if not. The -cpu option can > > be used to override this if necessary. > > Well, it may be needed to integrate the "-cpu host" option. > But I think it's a really bad idea that running qemu without the -cpu > option would not act the same on different host. When I want to test > qemu with the same command line, I want it to behave exactly the same, > whatever the host I'm running on, like any other tool. Think about gcc, > for example, if you launch it without option, it compiles for a generic > CPU. If you want to tune the generated code, even for the host you're > running on, you have to use -mcpu/-march/-mtune. Using one command line > always have gives the same result. > Then, my opinion is that running qemu without any -cpu option should > always use a default target.
Note that in "take 3" the default is indeed to expose the "basic" default cpu features if no -cpu is specified. One must add -cpu host in order to read and expose the host cpuid.