Re: [Qemu-devel] [PATCH] vl.c: fix -usb option assertion failure in qemu_opt_get_bool_helper()

[Chen, Tiejun]

On 2015/1/6 14:20, Shannon Zhao wrote:

On 2015/1/6 10:37, Chen, Tiejun wrote:

On 2015/1/5 20:14, Marcel Apfelbaum wrote:

On 01/05/2015 01:50 PM, Stefan Hajnoczi wrote:

On Mon, Jan 5, 2015 at 11:37 AM, Jan Kiszka <jan.kis...@siemens.com>
wrote:

On 2015-01-05 12:22, Stefan Hajnoczi wrote:

Commit 49d2e648e8087d154d8bf8b91f27c8e05e79d5a6 ("machine: remove
qemu_machine_opts global list") removed option descriptions from the
-machine QemuOptsList to avoid repeating MachineState's QOM properties.

This change broke vl.c:usb_enabled() because qemu_opt_get_bool() cannot
be used on QemuOptsList without option descriptions since QemuOpts
doesn't know the type and therefore left an unparsed string value.

This patch avoids calling qemu_opt_get_bool() to fix the assertion
failure:

    $ qemu-system-x86_64 -usb
    qemu_opt_get_bool_helper: Assertion `opt->desc && opt->desc->type
== QEMU_OPT_BOOL' failed.

Test the presence of -usb using qemu_opt_find() but use the
MachineState->usb field instead of qemu_opt_get_bool().

Cc: Marcel Apfelbaum <marce...@redhat.com>
Cc: Tiejun Chen <tiejun.c...@intel.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
   vl.c | 7 +++++--
   1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index bea9656..6e8889c 100644
--- a/vl.c
+++ b/vl.c
@@ -999,8 +999,11 @@ static int parse_name(QemuOpts *opts, void
*opaque)

   bool usb_enabled(bool default_usb)
   {
-    return qemu_opt_get_bool(qemu_get_machine_opts(), "usb",
-                             has_defaults && default_usb);
+    if (qemu_opt_find(qemu_get_machine_opts(), "usb")) {
+        return current_machine->usb;
+    } else {
+        return has_defaults && default_usb;
+    }
   }

   #ifndef _WIN32

That still leaves the other boolean machine options broken. A generic
fix would be good. Or revert the original commit until we have one.

I think we should revert the original commit.

qemu_option_get_*() callers need to be converted to query MachineState
fields instead of using QemuOpts functions.

Can this work out currently?

Hi Tiejun,

I apply your following patch and it works. At least it doesn't crash.

Thanks for your test.

Tiejun

Thanks,
Shannon

---
  util/qemu-option.c | 10 +++++-----
  1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/util/qemu-option.c b/util/qemu-option.c
index a708241..933b885 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -317,7 +317,7 @@ const char *qemu_opt_get(QemuOpts *opts, const char *name)
      }

      opt = qemu_opt_find(opts, name);
-    if (!opt) {
+    if (!opt || !opt->desc)  {
          const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
          if (desc && desc->def_value_str) {
              return desc->def_value_str;
@@ -341,7 +341,7 @@ char *qemu_opt_get_del(QemuOpts *opts, const char *name)
      }

      opt = qemu_opt_find(opts, name);
-    if (!opt) {
+    if (!opt || !opt->desc)  {
          desc = find_desc_by_name(opts->list->desc, name);
          if (desc && desc->def_value_str) {
              str = g_strdup(desc->def_value_str);
@@ -377,7 +377,7 @@ static bool qemu_opt_get_bool_helper(QemuOpts *opts, const 
char *name,
      }

      opt = qemu_opt_find(opts, name);
-    if (opt == NULL) {
+    if (!opt || !opt->desc)  {
          const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
          if (desc && desc->def_value_str) {
              parse_option_bool(name, desc->def_value_str, &ret, &error_abort);
@@ -413,7 +413,7 @@ static uint64_t qemu_opt_get_number_helper(QemuOpts *opts, 
const char *name,
      }

      opt = qemu_opt_find(opts, name);
-    if (opt == NULL) {
+    if (!opt || !opt->desc)  {
          const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
          if (desc && desc->def_value_str) {
              parse_option_number(name, desc->def_value_str, &ret, 
&error_abort);
@@ -450,7 +450,7 @@ static uint64_t qemu_opt_get_size_helper(QemuOpts *opts, 
const char *name,
      }

      opt = qemu_opt_find(opts, name);
-    if (opt == NULL) {
+    if (!opt || !opt->desc)  {
          const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
          if (desc && desc->def_value_str) {
              parse_option_size(name, desc->def_value_str, &ret, &error_abort);