[RFC] direct mmio for passthrough

benami
2008-04-01T11:52:13Z

This patch for PCI passthrough devices enables a guest to access a device's
memory mapped I/O regions directly, without requiring the host to trap and
emulate every MMIO access. We save the list of MMIO regions of the guest's
devices and the corresponding host MMIO regions in the host kernel. When the
guest page faults due to an access to an MMIO region, the host updates the
guest's sptes to map the correct host MMIO region. The kernel part of this
patchset applies to kvm HEAD and the userspace part applies to Amit's
pci-passthrough tree. Tested on a Lenovo M57p with an e1000 NIC assigned
directly to an FC8 guest.

Comments are appreciated.