tree 159459c9b4c3773e231e73491338b1492a7073af
parent 716b8e4dd2f7a1674bf77d49fd50139cb577e70f
author Alex Williamson <alex.williamson@redhat.com> 1352834860 -0700
committer Alex Williamson <alex.williamson@redhat.com> 1352834860 -0700

vfio-pci: Add KVM INTx acceleration

This makes use of the new level irqfd support enabling bypass of qemu
userspace both on INTx injection and unmask.  This significantly
boosts the performance of devices making use of legacy interrupts (ex.
~60% better netperf TCP_RR scores for an e1000e assigned to a Linux
guest and booted with pci=nomsi).  This also avoids flipping mmaps on
and off to simulate EOIs, so greatly improves performance of device
access in addition to interrupt latency.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>