On 10/22/2012 02:45 PM, Jan Kiszka wrote: > On 2012-10-22 14:18, Avi Kivity wrote: >> On 10/22/2012 01:45 PM, Jan Kiszka wrote: >> >>>> Indeed. git pull, recheck and call for kvm_flush_coalesced_mmio_buffer() >>>> is gone. So this will break new userspace, not old. By global you mean >>>> shared between devices (or memory regions)? >>> >>> Yes. We only have a single ring per VM, so we cannot flush multi-second >>> VGA access separately from other devices. In theory solvable by >>> introducing per-region rings that can be driven separately. >> >> But in practice unneeded. Real time VMs can disable coalescing and not >> use planar VGA modes. > > A) At least right now, we do not differentiate between the VGA modes and > if flushing is needed. So that device is generally taboo for RT cores of > the VM.
In non-planar modes the memory will be direct mapped, which overrides coalescing (since kvm or qemu never see an exit). > B) We need to disable coalescing in E1000 as well - if we want to use > that model. True. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
