[Qemu-devel] [PATCH 1/5] kvm: add detail error message when fail to add ioeventfd

[Paolo Bonzini <pbonzini@redhat.com>]

From: Amos Kong <akong@redhat.com>

I try to hotplug 28 * 8 multiple-function devices to guest with
old host kernel, ioeventfds in host kernel will be exhausted, then
qemu fails to allocate ioeventfds for blk/nic devices.

It's better to add detail error here.

Signed-off-by: Amos Kong <akong@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 kvm-all.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kvm-all.c b/kvm-all.c
index c757dd2..12042f7 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -837,6 +837,8 @@ static void kvm_mem_ioeventfd_add(MemoryListener *listener,
                                data, true, int128_get64(section->size),
                                match_data);
     if (r < 0) {
+        fprintf(stderr, "%s: error adding ioeventfd: %s\n",
+                __func__, strerror(-r));
         abort();
     }
 }
@@ -869,6 +871,8 @@ static void kvm_io_ioeventfd_add(MemoryListener *listener,
                               data, true, int128_get64(section->size),
                               match_data);
     if (r < 0) {
+        fprintf(stderr, "%s: error adding ioeventfd: %s\n",
+                __func__, strerror(-r));
         abort();
     }
 }
-- 
1.8.1.4