[xen staging] tools/libxenevtchn: add xenevtchn_bind() under Mini-OS

[patchbot@xxxxxxx]

commit 0929658c719754a57b6e16e3b8da8029638f9f11
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Thu Jul 31 09:45:18 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jul 31 09:45:18 2025 +0200

    tools/libxenevtchn: add xenevtchn_bind() under Mini-OS
    
    In order to reactivate an event channel after kexec() of Mini-OS,
    libxenevtchn needs to allocate the port data for the event channel
    and set the handler again. Add a new interface xenevtchn_bind()
    for that purpose, available under Mini-OS only.
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
    Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/include/xenevtchn.h  | 13 +++++++++++++
 tools/libs/evtchn/minios.c | 17 +++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/tools/include/xenevtchn.h b/tools/include/xenevtchn.h
index 1255c85178..5748af530b 100644
--- a/tools/include/xenevtchn.h
+++ b/tools/include/xenevtchn.h
@@ -173,6 +173,19 @@ int xenevtchn_unmask(xenevtchn_handle *xce, evtchn_port_t 
port);
  */
 int xenevtchn_restrict(xenevtchn_handle *xce, domid_t domid);
 
+#ifdef __MINIOS__
+/**
+ * Bind an event channel under Mini-OS.
+ *
+ * Bind an event channel specified by its known port after a kexec() of
+ * Mini-OS. This function is available under Mini-OS only!
+ *
+ * @parm xce handle to the open evtchn interface
+ * @parm port the event channel to bind again
+ * @return 0 on success, -1 on failure with errno set appropriately.
+ */
+int xenevtchn_bind(xenevtchn_handle *xce, evtchn_port_t port);
+#endif
 #endif
 
 /*
diff --git a/tools/libs/evtchn/minios.c b/tools/libs/evtchn/minios.c
index 0d2a201438..36e4201249 100644
--- a/tools/libs/evtchn/minios.c
+++ b/tools/libs/evtchn/minios.c
@@ -259,6 +259,23 @@ xenevtchn_port_or_error_t 
xenevtchn_bind_interdomain(xenevtchn_handle *xce,
     return local_port;
 }
 
+int xenevtchn_bind(xenevtchn_handle *xce, evtchn_port_t port)
+{
+    struct port_info *port_info;
+    port_info = port_alloc(xce);
+    if ( port_info == NULL )
+        return -1;
+
+    printf("xenevtchn_bind(%"PRId32")\n", port);
+    bind_evtchn(port, evtchn_handler, xce);
+
+    port_info->bound = true;
+    port_info->port = port;
+    unmask_evtchn(port);
+
+    return 0;
+}
+
 int xenevtchn_unbind(xenevtchn_handle *xce, evtchn_port_t port)
 {
     int fd = xce->fd;
--
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