vfio: add vfio_device_get_irq_info() helper

Add a helper similar to vfio_device_get_region_info() and use it
everywhere.

Replace a couple of needless allocations with stack variables.

As a side-effect, this fixes a minor error reporting issue in the call
from vfio_msix_early_setup().

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: John Levon <john.levon@nutanix.com>
Link: https://lore.kernel.org/qemu-devel/20250507152020.1254632-5-john.levon@nutanix.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index fde0c3fbef..ab3fabf991 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -376,8 +376,8 @@ static bool vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
                                            Error **errp)
 {
     VFIODevice *vdev = &vcdev->vdev;
-    g_autofree struct vfio_irq_info *irq_info = NULL;
-    size_t argsz;
+    struct vfio_irq_info irq_info;
+    int ret;
     int fd;
     EventNotifier *notifier;
     IOHandler *fd_read;
@@ -406,13 +406,15 @@ static bool vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
         return false;
     }
 
-    argsz = sizeof(*irq_info);
-    irq_info = g_malloc0(argsz);
-    irq_info->index = irq;
-    irq_info->argsz = argsz;
-    if (ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO,
-              irq_info) < 0 || irq_info->count < 1) {
-        error_setg_errno(errp, errno, "vfio: Error getting irq info");
+    ret = vfio_device_get_irq_info(vdev, irq, &irq_info);
+
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "vfio: Error getting irq info");
+        return false;
+    }
+
+    if (irq_info.count < 1) {
+        error_setg(errp, "vfio: Error getting irq info, count=0");
         return false;
     }