vfio/quirks: Enable ioeventfd quirks to be handled by vfio directly

With vfio ioeventfd support, we can program vfio-pci to perform a
specified BAR write when an eventfd is triggered.  This allows the
KVM ioeventfd to be wired directly to vfio-pci, entirely avoiding
userspace handling for these events.  On the same micro-benchmark
where the ioeventfd got us to almost 90% of performance versus
disabling the GeForce quirks, this gets us to within 95%.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index a4ac583fbd..52b065421a 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -34,6 +34,7 @@ typedef struct VFIOIOEventFD {
     VFIORegion *region;
     hwaddr region_addr;
     bool dynamic; /* Added runtime, removed on device reset */
+    bool vfio;
 } VFIOIOEventFD;
 
 typedef struct VFIOQuirk {
@@ -163,6 +164,7 @@ typedef struct VFIOPCIDevice {
     bool no_kvm_msix;
     bool no_geforce_quirks;
     bool no_kvm_ioeventfd;
+    bool no_vfio_ioeventfd;
     VFIODisplay *dpy;
 } VFIOPCIDevice;