Re: [PATCH v4 0/2] x86_64,entry: Clear NT on entry and speed up switch_to

From: H. Peter Anvin
Date: Mon Oct 06 2014 - 12:57:43 EST


On 10/06/2014 09:45 AM, Andy Lutomirski wrote:
> On Mon, Oct 6, 2014 at 9:41 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> On 10/06/2014 09:39 AM, Andy Lutomirski wrote:
>>> On Wed, Oct 1, 2014 at 11:49 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>>>> Anish Bhatt noticed that user programs can set RFLAGS.NT before
>>>> syscall or sysenter, and the kernel entry code doesn't filter out
>>>> NT. This causes kernel C code and, depending on thread flags, the
>>>> exit slow path to run with NT set.
>>>>
>>>
>>> Quick ping: now that the merge window is (sort of) open, what's
>>> happening with these patches?
>>>
>>> Thanks,
>>> Andy
>>>
>>
>> My preference would be to queue them up for 3.19 since they arrived late
>> in the 3.18 cycle.
>
> I see nothing wrong with deferring patch 2 for 3.19, but deferring
> patch 1, which is tagged for stable, for an entire release seems a bit
> silly to me.
>

Yes, that is probably going to get pushed later in this merge window;
that is usually how we deal with that sort of thing.

-hpa


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