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authorDaniel De Graaf <dgdegra@tycho.nsa.gov>2011-02-03 12:19:04 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-02-14 14:16:17 -0500
commitbdc612dc6903c4ea06e40d02f84ad5e25d93459d (patch)
treef7f3e3272b21ae3c6015e86f9c1f7be31534704d /include/xen/gntalloc.h
parentdd3140588d9551235ebc2a0dacdca098e7677573 (diff)
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xen/gntalloc,gntdev: Add unmap notify ioctl
This ioctl allows the users of a shared page to be notified when the other end exits abnormally. [v2: updated description in structs] Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'include/xen/gntalloc.h')
-rw-r--r--include/xen/gntalloc.h32
1 files changed, 32 insertions, 0 deletions
diff --git a/include/xen/gntalloc.h b/include/xen/gntalloc.h
index bc3b85e..76bd580 100644
--- a/include/xen/gntalloc.h
+++ b/include/xen/gntalloc.h
@@ -47,4 +47,36 @@ struct ioctl_gntalloc_dealloc_gref {
/* Number of references to unmap */
uint32_t count;
};
+
+/*
+ * Sets up an unmap notification within the page, so that the other side can do
+ * cleanup if this side crashes. Required to implement cross-domain robust
+ * mutexes or close notification on communication channels.
+ *
+ * Each mapped page only supports one notification; multiple calls referring to
+ * the same page overwrite the previous notification. You must clear the
+ * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
+ * to occur.
+ */
+#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
+_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
+struct ioctl_gntalloc_unmap_notify {
+ /* IN parameters */
+ /* Offset in the file descriptor for a byte within the page (same as
+ * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
+ * be cleared. Otherwise, it can be any byte in the page whose
+ * notification we are adjusting.
+ */
+ uint64_t index;
+ /* Action(s) to take on unmap */
+ uint32_t action;
+ /* Event channel to notify */
+ uint32_t event_channel_port;
+};
+
+/* Clear (set to zero) the byte specified by index */
+#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
+/* Send an interrupt on the indicated event channel */
+#define UNMAP_NOTIFY_SEND_EVENT 0x2
+
#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */
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