lkml.org 
[lkml]   [2023]   [May]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mmu_notifiers: Notify on pte permission upgrades
On Mon, May 22, 2023 at 04:37:25PM +1000, Alistair Popple wrote:
> This problem was discovered during testing of an ARM SMMU
> implementation that does not support broadcast TLB maintenance
> (BTM). In this case the SMMU driver uses notifiers to issue TLB
> invalidates. For read-only to read-write pte upgrades the SMMU
> continually returned a read-only PTE to the device, even though the
> CPU had a read-write PTE installed.
>
> Sending a mmu notifier event to the SMMU driver fixes the problem by
> flushing secondary TLB entries. A new notifier event type is added so
> drivers may filter out these invalidations if not required. Note a
> driver should never upgrade or install a PTE in response to this mmu
> notifier event as it is not synchronised against other PTE operations.

I don't see these SMMU driver changes anywhere. I.e. you're adding dead
code as far as I can tell.

\
 
 \ /
  Last update: 2023-05-23 08:46    [W:0.123 / U:0.628 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site