Xen devel - Dec 2009 - [PATCH] qemu: implement cdrom eject from the guest

Hi all,
this patch allows a guest to eject the cdrom: when qemu detects that a
cdrom eject request ahs been issued by the guest, it writes eject to the
corresponding xenstore frontend, so that the toolstack can take care of
removing the current cdrom frontend\backend couple and create an empty one
instead.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

---

diff --git a/hw/ide.c b/hw/ide.c
index e8d676e..b38de55 100644
--- a/hw/ide.c
+++ b/hw/ide.c
@@ -35,6 +35,7 @@
 #include "mac_dbdma.h"
 #include "sh.h"
 #include "dma.h"
+#include "qemu-xen.h"
 
 /* debug IDE devices */
 //#define DEBUG_IDE
@@ -2100,6 +2101,7 @@ static void ide_atapi_cmd(IDEState *s)
 
             if (eject && !start) {
                 /* eject the disk */
+                xenstore_do_eject(s->bs);
                 bdrv_eject(s->bs, 1);
             } else if (eject && start) {
                 /* close the tray */
diff --git a/qemu-xen.h b/qemu-xen.h
index 29b8161..ab4b631 100644
--- a/qemu-xen.h
+++ b/qemu-xen.h
@@ -123,6 +123,8 @@ char *xenstore_read_battery_data(int battery_status);
 int xenstore_refresh_battery_status(void);
 int xenstore_pv_driver_build_blacklisted(uint16_t product_number,
                                          uint32_t build_nr);
+void xenstore_do_eject(BlockDriverState *bs);
+int xenstore_find_device(BlockDriverState *bs);
 
 /* xenfbfront.c */
 int xenfb_pv_display_init(DisplayState *ds);
diff --git a/xenstore.c b/xenstore.c
index f73c09e..05a1c22 100644
--- a/xenstore.c
+++ b/xenstore.c
@@ -26,6 +26,31 @@
 struct xs_handle *xsh = NULL;
 static char *media_filename[MAX_DRIVES+1];
 static QEMUTimer *insert_timer = NULL;
+static char *xenbus_param_paths[MAX_DRIVES+1];
+
+int xenstore_find_device(BlockDriverState *bs)
+{
+    int i;
+
+    for (i = 0; i < MAX_DRIVES + 1; i++) {
+        if (drives_table[i].bdrv == bs)
+            return i;
+    }
+    return -1;
+}
+
+void xenstore_do_eject(BlockDriverState *bs)
+{
+    int i;
+
+    i = xenstore_find_device(bs);
+    if (i == -1) {
+        fprintf(stderr, "couldn''t find disk to eject.\n");
+        return;
+    }
+    if (xenbus_param_paths[i])
+        xs_write(xsh, XBT_NULL, xenbus_param_paths[i], "eject",
strlen("eject"));
+}
 
 #define UWAIT_MAX (30*1000000) /* thirty seconds */
 #define UWAIT     (100000)     /* 1/10th second  */
@@ -510,8 +551,15 @@ void xenstore_parse_domain_config(int hvm_domid)
         /* check if it is a cdrom */
         if (danger_type && !strcmp(danger_type, "cdrom")) {
             bdrv_set_type_hint(bs, BDRV_TYPE_CDROM);
-            if (pasprintf(&buf, "%s/params", bpath) != -1)
+            if (pasprintf(&buf, "%s/params", bpath) != -1) {
+                char *buf2, *frontend;
                 xs_watch(xsh, buf, dev);
+                asprintf(&buf2, "%s/frontend", bpath);
+                frontend = xs_read(xsh, XBT_NULL, buf2, &len);
+                asprintf(&xenbus_param_paths[nb_drives],
"%s/eject", frontend);
+                free(frontend);
+                free(buf2);
+            }
         }
 
         /* open device now if media present */

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