Re: [Xen-devel] [PATCH v2 13/30] xen/x86: Clear dependent features when clearing a cpu cap

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 15/02/16 14:53, Jan Beulich wrote:
>>>> On 05.02.16 at 14:42, <andrew.cooper3@xxxxxxxxxx> wrote:
>> --- a/xen/arch/x86/cpu/common.c
>> +++ b/xen/arch/x86/cpu/common.c
>> @@ -53,8 +53,24 @@ static unsigned int cleared_caps[NCAPINTS];
>>  
>>  void __init setup_clear_cpu_cap(unsigned int cap)
>>  {
>> +    const uint32_t *dfs;
>> +    unsigned int i;
>> +
>> +    if ( test_bit(cap, cleared_caps) )
>> +            return;
>> +
>>      __clear_bit(cap, boot_cpu_data.x86_capability);
>>      __set_bit(cap, cleared_caps);
> Perhaps __test_and_set_bit() above?

Hmm yes - that won't make it atomic.

And I will fix up the style issues.

~Andrew

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