[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <16772f10955e1607fcaff9acb701ff27907a11b1.camel@intel.com>
Date: Wed, 5 May 2021 19:51:08 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "keescook@...omium.org" <keescook@...omium.org>
CC: "kernel-hardening@...ts.openwall.com"
<kernel-hardening@...ts.openwall.com>, "luto@...nel.org" <luto@...nel.org>,
"Hansen, Dave" <dave.hansen@...el.com>, "x86@...nel.org" <x86@...nel.org>,
"linux-mm@...ck.org" <linux-mm@...ck.org>, "peterz@...radead.org"
<peterz@...radead.org>, "akpm@...ux-foundation.org"
<akpm@...ux-foundation.org>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>, "rppt@...nel.org" <rppt@...nel.org>,
"linux-hardening@...r.kernel.org" <linux-hardening@...r.kernel.org>, "Weiny,
Ira" <ira.weiny@...el.com>, "Williams, Dan J" <dan.j.williams@...el.com>
Subject: Re: [PATCH RFC 0/9] PKS write protected page tables
On Tue, 2021-05-04 at 23:25 -0700, Kees Cook wrote:
> > infrastructure follow-on’s are planned to enable keys to be set to
> > the same
> > permissions globally. Since this usage needs a key to be set globally
> > read-only by default, a small temporary solution is hacked up in
> > patch 8. Long
> > term, PKS protected page tables would use a better and more generic
> > solution
> > to achieve this.
> >
> > [1]
> > https://lore.kernel.org/lkml/20210401225833.566238-1-ira.weiny@intel.com/
>
> Ah, neat!
>
> > [2]
> > https://lore.kernel.org/lkml/20210405203711.1095940-1-rick.p.edgecombe@intel.com/
>
> Ooh. What does this do for performance? It sounds like less TLB
> pressure, IIUC?
Yea, less TLB pressure, faster page table walks in theory. There was
some testing that showed having all 4k pages was bad for performance:
https://lore.kernel.org/linux-mm/213b4567-46ce-f116-9cdf-bbd0c884eb3c@linux.intel.com/
I'm not sure exactly how much breakage is needed before problems start
to show up, but there was also someone posting that large amounts of
tracing was noticeable for their workload.
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
