[PATCH v5 15/21] libxl: ignore emulated IDE disks beyond the first 4

[Jason Andryuk <jandryuk@xxxxxxxxx>]

From: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
---
 tools/libxl/libxl_dm.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 5e5e7a27b3..03d7a38f1f 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -1891,6 +1891,13 @@ 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);
@@ -1968,6 +1975,10 @@ 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 */
                 }
 
-- 
2.20.1