Rusty Russell wrote: > On Sat, 2007-09-15 at 01:31 +0300, Dor Laor wrote: > >> Second, regardless of the channel signal notification, there are still >> real necessities for userspace hypercall handling: >> 1. For virtio drivers there is also registration hypercall for passing >> the shared memory pfns. >> Sure there are other possibilities, but why limit ourselves? >> > > I really prefer doing this the more "hardware-like" way and having the > device description say where the pages are. Surely this is simpler from > the qemu side, too? >
This is mmio style (device provides memory). DMA style (guest provides memory, device dmas it) is easier for kvm: we don't need to allocate a new memory slot, and migration is easier. Most current hardware place the descriptor ring in guest memory, not the device, since mmio is slower for the cpu than RAM. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
