Re: [Xen-devel] [PATCH v3 33/52] xen/drivers/passthrough/iommu.c: let custom parameter parsing routines return errno

[Juergen Gross <jgross@xxxxxxxx>]

On 22/08/17 12:04, Jan Beulich wrote:
>>>> On 16.08.17 at 14:52, <jgross@xxxxxxxx> wrote:
>> @@ -89,44 +89,50 @@ static void __init parse_iommu_param(char *s)
>>              s += 3;
>>  
>>          ss = strchr(s, ',');
>> -        if ( ss )
>> -            *ss = '\0';
>> -
>> -        if ( !parse_bool(s) )
>> -            iommu_enable = 0;
>> -        else if ( !strcmp(s, "force") || !strcmp(s, "required") )
>> +        if ( !ss )
>> +            ss = strchr(s, '\0');
>> +
>> +        b = parse_bool(s);
> 
> I don't think this will work as intended for "iommu=yes,...". Did I
> perhaps overlook the same issue in some of the earlier patches?

I'm just of the opposite opinion: the former implementation didn't work
as intended in that case:

Let a hypervisor be built with a pre-defined command line "iommu=no".
A user supplied command line "iommu=yes" wouldn't change iommu_enable.

My patch changes that: setting iommu_enable to 0 or 1 in case
parse_bool() succeeded is the correct thing to do.

Maybe I should mention this in the commit message, though.


Juergen

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