[libvirt] [PATCH v3 2/2] Add USB option capability

[Li Zhang]

From: Li Zhang <zhlcindy at linux.vnet.ibm.com>

To avoid the collision for creating USB controllers in machine->init()
and -device xx command line, it needs to set usb=off to avoid one USB
controller created in machine->init(). So that libvirt can use -device
or -usb to create USB controller sucessfully.
So QEMU_CAPS_MACHINE_USB_OPT capability is added, and it is for QEMU
v1.3.0 onwards which supports USB option.

Signed-off-by: Li Zhang <zhlcindy at linux.vnet.ibm.com>
---
 v3 -> v2:
   * Set QEMU_CAPS_MACHINE_USB_OPT with help string

 v2 -> v1:
   * Rename QEMU_CAPS_USB_OPT to QEMU_CAPS_MACHINE_USB_OPT suggested by Daniel
   * Corret QEMU version with v1.3.0 suggested by Daniel

 src/qemu/qemu_capabilities.c |    9 +++++++++
 src/qemu/qemu_capabilities.h |    1 +
 src/qemu/qemu_command.c      |    6 ++++++
 3 files changed, 16 insertions(+)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 7d459db..a5f8944 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -215,6 +215,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               "megasas",
 
               "machine-opt", /* 135 */
+              "machine-usb-opt",
     );
 
 struct _virQEMUCaps {
@@ -1096,6 +1097,10 @@ virQEMUCapsComputeCmdFlags(const char *help,
     if (strstr(help, "-machine"))
         virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_OPT);
 
+     /* USB option is supported v1.3.0 onwards */
+    if (qemuCaps->version >= 1003000)
+        virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_USB_OPT);
+
     /*
      * Handling of -incoming arg with varying features
      *  -incoming tcp    (kvm >= 79, qemu >= 0.10.0)
@@ -2453,6 +2458,10 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps,
     /* -dump-guest-core is supported for newer version*/
     virQEMUCapsSet(qemuCaps, QEMU_CAPS_DUMP_GUEST_CORE);
 
+    /* USB option is supported v1.3.0 onwards */
+    if (qemuCaps->version >= 1003000)
+        virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_USB_OPT);
+
     if (!(archstr = qemuMonitorGetTargetArch(mon)))
         goto cleanup;
 
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 2595868..091fe6e7 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -175,6 +175,7 @@ enum virQEMUCapsFlags {
     QEMU_CAPS_DTB                = 133, /* -dtb file */
     QEMU_CAPS_SCSI_MEGASAS       = 134, /* -device megasas */
     QEMU_CAPS_MACHINE_OPT        = 135, /* -machine xxxx*/
+    QEMU_CAPS_MACHINE_USB_OPT    = 136, /* -machine xxx,usb=on/off */
 
     QEMU_CAPS_LAST,                   /* this must always be the last item */
 };
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 0ee634b..2d9398b 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -5216,6 +5216,12 @@ qemuBuildMachineArgStr(virCommandPtr cmd,
         virCommandAddArg(cmd, "-machine");
         virBufferAsprintf(&buf, "%s", def->os.machine);
 
+        /* To avoid the collision of creating USB controllers when calling
+         * machine->init in QEMU, it needs to set usb=off
+         */
+        if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_MACHINE_USB_OPT))
+            virBufferAsprintf(&buf, ",usb=off");
+
         if (def->mem.dump_core) {
             if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DUMP_GUEST_CORE)) {
                 virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-- 
1.7.10.1