From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Chen, Tiejun" <tiejun.chen@intel.com>
Subject: Re: [v10][PATCH 11/16] tools/libxl: detect and avoid
 conflicts with RDM
Date: Mon, 20 Jul 2015 23:08:47 +0800
Message-ID: <55AD0EFF.8020405@intel.com>
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

>>>> +int libxl__domain_device_construct_rdm(libxl__gc *gc,
>>>> +                                       libxl_domain_config *d_config,
>>>> +                                       uint64_t rdm_mem_boundary,
>>>> +                                       struct xc_hvm_build_args *args)
>>>> +{
>>> ...
>>>> +    /* Query all RDM entries in this platform */
>>>> +    if (strategy == LIBXL_RDM_RESERVE_STRATEGY_HOST) {
>>> ...
>>>> +    } else {
>>>> +        d_config->num_rdms = 0;
>>>> +    }
>>>
>>> Does this not override the domain configuration's num_rdms ?  I don't
>>
>> We don't have the specific "num_rdms" parameter in .cfg so I don't
>> understand what you mean here.
>
> The domain configuration specified to libxl might contain some rdms.
> Then num_rdms in the incoming config would be nonzero.

We never set d_config->num_rdms/d_config->rdms before we goes inside 
libxl__domain_device_construct_rdm(). And actually 
libxl__domain_device_construct_rdm is only one place to set 
d_config->num_rdms/d_config->rdms.

I guess this line make you or other guys confused so lets delete this 
line directly.

And if you still worry about something, I can add assert() at the 
beginning of this function like this,

assert(!d_config->num_rdms && !d_config->rdms).

Thanks
Tiejun

>
> So I think there are two problems here:
>
> 1. If that were the case you would leak the application's rdms array.
>
> 2. Anyway, if the caller specifies such an array you should use it.
>     (Fixing this would avoid (1) in any case.)
>
> Ian.
>