Re: [PATCH] x86/special_insn: reverse __force_order logic

Nadav Amit
2020-09-02T15:34:03Z

> On Sep 2, 2020, at 5:54 AM, peterz@infradead.org wrote:
>
> On Tue, Sep 01, 2020 at 09:18:57AM -0700, Nadav Amit wrote:
>
>> Unless I misunderstand the logic, __force_order should also be used by
>> rdpkru() and wrpkru() which do not have dependency on __force_order. I
>> also did not understand why native_write_cr0() has R/W dependency on
>> __force_order, and why native_write_cr4() no longer has any dependency
>> on __force_order.
>
> There was a fairly large thread about this thing here:
>
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.kernel.org%2Fr%2F20200527135329.1172644-1-arnd%40arndb.de&amp;data=02%7C01%7Cnamit%40vmware.com%7C387b68745a984454d50708d84f3f499c%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C0%7C637346480527901622&amp;sdata=PR%2BCUy%2FYNKza6he78coaDR3x1G7BYuzFfS9SGfWZ9p8%3D&amp;reserved=0
>
> I didn't keep up, but I think the general concensus was that it's
> indeed a bit naf.

Thanks for pointer. I did not see the discussion, and embarrassingly, I have
also never figured out how to reply on lkml emails without registering to
lkml.

Anyhow, indeed, the patch that Arvind provided seems to address this issue.