Re: [RFC PATCH 00/16] x86/split_lock: Enable #AC exception for split locked accesses

From: Fenghua Yu
Date: Tue May 29 2018 - 13:40:48 EST


On Tue, May 29, 2018 at 10:28:11AM -0700, Dave Hansen wrote:
> On 05/29/2018 10:25 AM, Fenghua Yu wrote:
> > (By the way, ISE and SDM don't mention other important details, e.g.
> > the fact that operand is fetched to cache before split lock is
> > checked. Without the fact, it's hard to explain that only split lock
> > generates bus lock in chapter 8.1.4 in SDM vol3.)
>
> That's a bummer. You're working with the folks that own those documents
> to get that fixed up, right?

Yes, I already asked them to add some missing parts in future ISE and SDM.

>
> > Maybe I can add "Current TEST_CTL implementation is per-core. The patches
> > are supposed to work even when TEST_CTL is per-thread (or even per-
> > socket) in future as well."?
>
> Yes, that would be a very important part of the software implementation
> to mention.

I'll do that in the next version.

Thanks.

-Fenghua