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

[Shannon Zhao <zhaoshenglong@huawei.com>]

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.kiszka@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 <marcel.a@redhat.com>
>>>>> Cc: Tiejun Chen <tiejun.chen@intel.com>
>>>>> Signed-off-by: Stefan Hajnoczi <stefanha@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,
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);