From: Dave Hansen <dave.hansen@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"keescook@chromium.org" <keescook@chromium.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [GIT PULL] x86/shstk for 6.4
Date: Mon, 8 May 2023 17:07:26 -0700 [thread overview]
Message-ID: <27770379-5e65-d231-f7ee-dff3975eeeda@intel.com> (raw)
In-Reply-To: <CAHk-=wiVLvz3RdZiSjLNGKKgR3s-=2goRPnNWg6cbrcwMVvndQ@mail.gmail.com>
On 5/8/23 16:31, Linus Torvalds wrote:
> On Mon, May 8, 2023 at 3:57 PM Dave Hansen <dave.hansen@intel.com> wrote:
...
>> This behavior is gone on shadow stack CPUs
>
> Ok, so Intel has actually tightened up the rules on setting dirty, and
> now guarantees that it will set dirty only if the pte is actually
> writable?
Yep:
Specifically, a processor that supports CET will never set the
dirty flag in a paging-structure entry in which the R/W flag is
clear.
and this was _absolutely_ one of the things the hardware folks did for
the benefit of software.
As for the mm->users==1 optimization, seems like something sane to
explore. I can't think of any ways off the top of my head that it would
break, but I'll go take a closer look.
next prev parent reply other threads:[~2023-05-09 0:07 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-24 21:21 [GIT PULL] x86/shstk for 6.4 Dave Hansen
2023-04-28 18:17 ` Linus Torvalds
2023-04-29 0:26 ` Edgecombe, Rick P
2023-04-29 0:40 ` Dave Hansen
2023-05-06 19:34 ` Linus Torvalds
2023-05-06 20:09 ` Linus Torvalds
2023-05-07 0:18 ` Edgecombe, Rick P
2023-05-07 0:38 ` Linus Torvalds
2023-05-07 15:57 ` Edgecombe, Rick P
2023-05-08 22:57 ` Dave Hansen
2023-05-08 23:31 ` Linus Torvalds
2023-05-08 23:47 ` Linus Torvalds
2023-05-12 17:34 ` Dave Hansen
2023-05-12 21:55 ` Linus Torvalds
2023-05-15 21:36 ` Dave Hansen
2023-05-15 21:37 ` Dave Hansen
2023-05-15 22:40 ` Linus Torvalds
2023-05-15 23:02 ` Linus Torvalds
2023-05-16 20:38 ` Linus Torvalds
2023-05-16 20:42 ` Dave Hansen
2023-05-09 0:07 ` Dave Hansen [this message]
2023-05-07 0:10 ` Edgecombe, Rick P
2023-05-07 0:19 ` Linus Torvalds
2023-05-07 16:24 ` Edgecombe, Rick P
2023-05-15 21:22 ` Deepak Gupta
2023-05-25 16:20 ` Mark Brown
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