Re: [Qemu-devel] [PATCH v5] vfio/common: Introduce vfio_set_irq_signaling helper

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 12 Jun 2019 14:40:04 +0200
Eric Auger <eric.auger@redhat.com> wrote:

> The code used to assign an interrupt index/subindex to an
> eventfd is duplicated many times. Let's introduce an helper that
> allows to set/unset the signaling for an ACTION_TRIGGER,
> ACTION_MASK or ACTION_UNMASK action.
> 
> In the error message, we now use errno in case of any
> VFIO_DEVICE_SET_IRQS ioctl failure.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>

Looks good to me.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

I currently have the following, still untested patch on top (vfio-ap
doesn't use this ioctl):

From 9c2efe73d6139e8c7b2109ac2df79fe073d942fb Mon Sep 17 00:00:00 2001
From: Cornelia Huck <cohuck@redhat.com>
Date: Wed, 12 Jun 2019 18:42:29 +0200
Subject: [PATCH] vfio-ccw: use vfio_set_irq_signaling()

Make use of the new helper.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/vfio/ccw.c | 50 +++++++++++++-------------------------------------
 1 file changed, 13 insertions(+), 37 deletions(-)

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index 03a2becb3ec9..3643be0ee254 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -198,9 +198,9 @@ static void vfio_ccw_register_io_notifier(VFIOCCWDevice *vcdev, Error **errp)
 {
     VFIODevice *vdev = &vcdev->vdev;
     struct vfio_irq_info *irq_info;
-    struct vfio_irq_set *irq_set;
     size_t argsz;
-    int32_t *pfd;
+    int fd;
+    Error *local_err = NULL;
 
     if (vdev->num_irqs < VFIO_CCW_IO_IRQ_INDEX + 1) {
         error_setg(errp, "vfio: unexpected number of io irqs %u",
@@ -224,56 +224,32 @@ static void vfio_ccw_register_io_notifier(VFIOCCWDevice *vcdev, Error **errp)
         goto out_free_info;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_CCW_IO_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *) &irq_set->data;
-
-    *pfd = event_notifier_get_fd(&vcdev->io_notifier);
-    qemu_set_fd_handler(*pfd, vfio_ccw_io_notifier_handler, NULL, vcdev);
-    if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
-        error_setg(errp, "vfio: Failed to set up io notification");
-        qemu_set_fd_handler(*pfd, NULL, NULL, vcdev);
+    fd = event_notifier_get_fd(&vcdev->io_notifier);
+    qemu_set_fd_handler(fd, vfio_ccw_io_notifier_handler, NULL, vcdev);
+    if (vfio_set_irq_signaling(vdev, VFIO_CCW_IO_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, fd, &local_err)) {
+        error_propagate(errp, local_err);
+        qemu_set_fd_handler(fd, NULL, NULL, vcdev);
         event_notifier_cleanup(&vcdev->io_notifier);
     }
 
-    g_free(irq_set);
-
 out_free_info:
     g_free(irq_info);
 }
 
 static void vfio_ccw_unregister_io_notifier(VFIOCCWDevice *vcdev)
 {
-    struct vfio_irq_set *irq_set;
-    size_t argsz;
-    int32_t *pfd;
-
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_CCW_IO_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *) &irq_set->data;
-    *pfd = -1;
-
-    if (ioctl(vcdev->vdev.fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
-        error_report("vfio: Failed to de-assign device io fd: %m");
+    Error *local_err = NULL;
+
+    if (vfio_set_irq_signaling(&vcdev->vdev, VFIO_CCW_IO_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, -1, &local_err)) {
+        error_report_err(local_err);
     }
 
     qemu_set_fd_handler(event_notifier_get_fd(&vcdev->io_notifier),
                         NULL, NULL, vcdev);
     event_notifier_cleanup(&vcdev->io_notifier);
 
-    g_free(irq_set);
 }
 
 static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp)
-- 
2.20.1