libxl: ignore emulated IDE disks beyond the first 4

Qemu supports only 4 emulated IDE disks, when given more (or with higher
indexes), it will fail to start. Since the disks can still be accessible
using PV interface, just ignore emulated path and log a warning, instead
of rejecting the configuration altogether.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 8801e9364ebfd5f81e008c93e298329cce489348..86694f669d95c55d495e965bc8850cbe30a0d8d4 100644 (file)
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -1894,6 +1894,13 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
             }
 
             if (disks[i].is_cdrom) {
+                if (disk > 4) {
+                    LOGD(WARN, guest_domid, "Emulated CDROM can be only one of the first 4 disks.\n"
+                         "Disk %s will be available via PV drivers but not as an "
+                         "emulated disk.",
+                         disks[i].vdev);
+                    continue;
+                }
                 drive = libxl__sprintf(gc,
                          "if=ide,index=%d,readonly=on,media=cdrom,id=ide-%i",
                          disk, dev_number);
@@ -1971,6 +1978,10 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
                                                        &disks[i],
                                                        colo_mode);
                 } else {
+                    LOGD(WARN, guest_domid, "Only 4 emulated IDE disks are supported.\n"
+                         "Disk %s will be available via PV drivers but not as an "
+                         "emulated disk.",
+                         disks[i].vdev);
                     continue; /* Do not emulate this disk */
                 }