I am looking at how to do memory mapped IO between host and guests under kvm. I expect to use the PCI emulation layer to present a PCI device to the guest. I see virtio_pci uses cpu_physical_memory_map() which provides either read or write mappings and notes "Use only for reads OR writes - not for read-modify-write operations." Is there an alternative method that allows large (Several MB) persistent hg memory mappings that are r/w? I would only be using this under kvm, not kqemu or plain qemu. Also it appears that PCI IO memory (cpu_register_io_memory) is provided via access functions, like the pci config space? Does this cause a page fault/vm_exit on each read or write, or is it more efficient than that? Thanks, Stephen. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
