Messages in this thread | | | Date | Tue, 26 Jun 2018 12:02:21 +0100 | From | Alan Cox <> | Subject | Re: [RFC PATCH 06/16] x86/split_lock: Save #AC setting for split lock in firmware in boot time and restore the setting in reboot |
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On Tue, 26 Jun 2018 11:05:21 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Fri, Jun 22, 2018 at 04:11:07PM +0100, Alan Cox wrote: > > On Thu, 2018-06-21 at 21:58 +0200, Peter Zijlstra wrote: > > > On Sun, May 27, 2018 at 08:45:55AM -0700, Fenghua Yu wrote: > > > > Firmware may contain split locked instructions. > > > > > > I think that's the wrong attitude. You should mandate in your BIOS > > > development guide that Firmware _MUST_NOT_ contain unaligned LOCK > > > prefixed instructions. > > > > > > > In the longer term I would agree entirely with that sentiment. > > But then how do we deal with SMIs ?
On a system doing that level of real time you don't do SMIs.
I think Thomas comment that this shouldn't be in a production kernel because the firmware people need to have their house in order before that is a fair one.
(and I've already been poking people to make sure this is documented properly as a requirement)
Alan
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