On Thu, Feb 21, 2008 at 05:38:30PM +0200, Avi Kivity wrote: > Marcelo Tosatti wrote: > >Add basic KVM paravirt support. Avoid vm-exits on IO delays. > > > >Add KVM_GET_PARA_FEATURES ioctl so paravirt features can be reported in a > >single bitmask. This allows the host to disable features on runtime if > >appropriate, which would require one ioctl per feature otherwise. > > > >The limit of 32 features can be extended to 64 if needed, beyond that a > >new MSR is required. > > > >v1->v2: > >- replace KVM_CAP_CLOCKSOURCE with KVM_CAP_PARA_FEATURES > >- cover FEATURE_CLOCKSOURCE > > > > > > > > I don't understand the motivation for this. A handful of ioctl()s at > init time are hardly time consuming. > > There is the advantage that paravirt kernel advances are reflected > automatically without changes in userspace, but sometimes this is a > disadvantage (it means there is no way to disable it, for instance).
One ioctl per feature sounded like unnecessary code duplication. I have no problems with it though. So you prefer that way? ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
