kvm: exclude ioeventfd from counting kvm_io_range limit

We can easily reach the 1000 limit by start VM with a couple
hundred I/O devices (multifunction=on). The hardcode limit
already been adjusted 3 times (6 ~ 200 ~ 300 ~ 1000).

In userspace, we already have maximum file descriptor to
limit ioeventfd count. But kvm_io_bus devices also are used
for pit, pic, ioapic, coalesced_mmio. They couldn't be limited
by maximum file descriptor.

Currently only ioeventfds take too much kvm_io_bus devices,
so just exclude it from counting kvm_io_range limit.

Also fixed one indent issue in kvm_host.h

Signed-off-by: Amos Kong <akong@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d9a3c30eab2e..e3aae6db276f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -145,7 +145,8 @@ struct kvm_io_range {
 #define NR_IOBUS_DEVS 1000
 
 struct kvm_io_bus {
-	int                   dev_count;
+	int dev_count;
+	int ioeventfd_count;
 	struct kvm_io_range range[];
 };