[v3,07/18] xen: add event channel interface for XenDevice-s
diff mbox series

Message ID 1544525238-3527-8-git-send-email-paul.durrant@citrix.com
State New
Headers show
Series
  • Xen PV backend 'qdevification'
Related show

Commit Message

Paul Durrant Dec. 11, 2018, 10:47 a.m. UTC
The legacy PV backend infrastructure provides functions to bind, unbind
and send notifications to event channnels. Similar functionality will be
required by XenDevice implementations so this patch adds the necessary
support.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
Cc: Anthony Perard <anthony.perard@citrix.com>

v2:
 - Added error pointers to notify and unbind
---
 hw/xen/xen-bus.c         | 101 +++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/xen/xen-bus.h |  18 +++++++++
 2 files changed, 119 insertions(+)

Comments

Anthony PERARD Dec. 11, 2018, 3:24 p.m. UTC | #1
On Tue, Dec 11, 2018 at 10:47:07AM +0000, Paul Durrant wrote:
> The legacy PV backend infrastructure provides functions to bind, unbind
> and send notifications to event channnels. Similar functionality will be
> required by XenDevice implementations so this patch adds the necessary
> support.
> 
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

When and where did this review happend? I can only find my review-by tag
on v2, which is missing here.
Paul Durrant Dec. 11, 2018, 3:43 p.m. UTC | #2
> -----Original Message-----
> From: Anthony PERARD [mailto:anthony.perard@citrix.com]
> Sent: 11 December 2018 15:25
> To: Paul Durrant <Paul.Durrant@citrix.com>
> Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen-
> devel@lists.xenproject.org
> Subject: Re: [PATCH v3 07/18] xen: add event channel interface for
> XenDevice-s
> 
> On Tue, Dec 11, 2018 at 10:47:07AM +0000, Paul Durrant wrote:
> > The legacy PV backend infrastructure provides functions to bind, unbind
> > and send notifications to event channnels. Similar functionality will be
> > required by XenDevice implementations so this patch adds the necessary
> > support.
> >
> > Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> > Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> 
> When and where did this review happend? I can only find my review-by tag
> on v2, which is missing here.
> 

Oh, that must have been my mistake... I cut'n'pasted the wrong line. Apologies to Stefano and yourself... I'll fix it in v4.

  Paul

> --
> Anthony PERARD

Patch
diff mbox series

diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index faa9fd3..9443f27 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -617,6 +617,81 @@  done:
     g_free(xengnttab_segs);
 }
 
+struct XenEventChannel {
+    unsigned int local_port;
+    XenEventHandler handler;
+    void *opaque;
+    Notifier notifier;
+};
+
+static void event_notify(Notifier *n, void *data)
+{
+    XenEventChannel *channel = container_of(n, XenEventChannel, notifier);
+    unsigned long port = (unsigned long)data;
+
+    if (port == channel->local_port) {
+        channel->handler(channel->opaque);
+    }
+}
+
+XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
+                                               unsigned int port,
+                                               XenEventHandler handler,
+                                               void *opaque, Error **errp)
+{
+    XenEventChannel *channel = g_new0(XenEventChannel, 1);
+
+    channel->local_port = xenevtchn_bind_interdomain(xendev->xeh,
+                                                     xendev->frontend_id,
+                                                     port);
+    if (xendev->local_port < 0) {
+        error_setg_errno(errp, errno, "xenevtchn_bind_interdomain failed");
+
+        g_free(channel);
+        return NULL;
+    }
+
+    channel->handler = handler;
+    channel->opaque = opaque;
+    channel->notifier.notify = event_notify;
+
+    notifier_list_add(&xendev->event_notifiers, &channel->notifier);
+
+    return channel;
+}
+
+void xen_device_notify_event_channel(XenDevice *xendev,
+                                     XenEventChannel *channel,
+                                     Error **errp)
+{
+    if (!channel) {
+        error_setg(errp, "bad channel");
+        return;
+    }
+
+    if (xenevtchn_notify(xendev->xeh, channel->local_port) < 0) {
+        error_setg_errno(errp, errno, "xenevtchn_notify failed");
+    }
+}
+
+void xen_device_unbind_event_channel(XenDevice *xendev,
+                                     XenEventChannel *channel,
+                                     Error **errp)
+{
+    if (!channel) {
+        error_setg(errp, "bad channel");
+        return;
+    }
+
+    notifier_remove(&channel->notifier);
+
+    if (xenevtchn_unbind(xendev->xeh, channel->local_port) < 0) {
+        error_setg_errno(errp, errno, "xenevtchn_unbind failed");
+    }
+
+    g_free(channel);
+}
+
 static void xen_device_unrealize(DeviceState *dev, Error **errp)
 {
     XenDevice *xendev = XEN_DEVICE(dev);
@@ -641,6 +716,12 @@  static void xen_device_unrealize(DeviceState *dev, Error **errp)
     xen_device_frontend_destroy(xendev);
     xen_device_backend_destroy(xendev);
 
+    if (xendev->xeh) {
+        qemu_set_fd_handler(xenevtchn_fd(xendev->xeh), NULL, NULL, NULL);
+        xenevtchn_close(xendev->xeh);
+        xendev->xeh = NULL;
+    }
+
     if (xendev->xgth) {
         xengnttab_close(xendev->xgth);
         xendev->xgth = NULL;
@@ -657,6 +738,16 @@  static void xen_device_exit(Notifier *n, void *data)
     xen_device_unrealize(DEVICE(xendev), &error_abort);
 }
 
+static void xen_device_event(void *opaque)
+{
+    XenDevice *xendev = opaque;
+    unsigned long port = xenevtchn_pending(xendev->xeh);
+
+    notifier_list_notify(&xendev->event_notifiers, (void *)port);
+
+    xenevtchn_unmask(xendev->xeh, port);
+}
+
 static void xen_device_realize(DeviceState *dev, Error **errp)
 {
     XenDevice *xendev = XEN_DEVICE(dev);
@@ -697,6 +788,16 @@  static void xen_device_realize(DeviceState *dev, Error **errp)
     xendev->feature_grant_copy =
         (xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
 
+    xendev->xeh = xenevtchn_open(NULL, 0);
+    if (!xendev->xeh) {
+        error_setg_errno(errp, errno, "failed xenevtchn_open");
+        goto unrealize;
+    }
+
+    notifier_list_init(&xendev->event_notifiers);
+    qemu_set_fd_handler(xenevtchn_fd(xendev->xeh), xen_device_event, NULL,
+                        xendev);
+
     xen_device_backend_create(xendev, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h
index 63a09b6..f83a95c 100644
--- a/include/hw/xen/xen-bus.h
+++ b/include/hw/xen/xen-bus.h
@@ -26,6 +26,9 @@  typedef struct XenDevice {
     XenWatch *frontend_state_watch;
     xengnttab_handle *xgth;
     bool feature_grant_copy;
+    xenevtchn_handle *xeh;
+    xenevtchn_port_or_error_t local_port;
+    NotifierList event_notifiers;
 } XenDevice;
 
 typedef char *(*XenDeviceGetName)(XenDevice *xendev, Error **errp);
@@ -104,4 +107,19 @@  void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
                                 XenDeviceGrantCopySegment segs[],
                                 unsigned int nr_segs, Error **errp);
 
+typedef struct XenEventChannel XenEventChannel;
+
+typedef void (*XenEventHandler)(void *opaque);
+
+XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,
+                                               unsigned int port,
+                                               XenEventHandler handler,
+                                               void *opaque, Error **errp);
+void xen_device_notify_event_channel(XenDevice *xendev,
+                                     XenEventChannel *channel,
+                                     Error **errp);
+void xen_device_unbind_event_channel(XenDevice *xendev,
+                                     XenEventChannel *channel,
+                                     Error **errp);
+
 #endif /* HW_XEN_BUS_H */