From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v2 13/30] xen/x86: Clear dependent features
 when clearing a cpu cap
Date: Mon, 15 Feb 2016 15:33:17 +0000
Message-ID: <56C1EFBD.4060004@citrix.com>
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To: Jan Beulich <JBeulich@suse.com>
Cc: Xen-devel <xen-devel@lists.xen.org>
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On 15/02/16 14:53, Jan Beulich wrote:
>>>> On 05.02.16 at 14:42, <andrew.cooper3@citrix.com> 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