From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Nadav Amit <namit@vmware.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Jason Baron <jbaron@akamai.com>, Jiri Kosina <jkosina@suse.cz>,
David Laight <David.Laight@ACULAB.COM>,
Borislav Petkov <bp@alien8.de>, Julia Cartwright <julia@ni.com>,
Jessica Yu <jeyu@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Edward Cree <ecree@solarflare.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH v3 5/6] x86/alternative: Use a single access in text_poke() where possible
Date: Thu, 10 Jan 2019 09:42:57 -0800 [thread overview]
Message-ID: <20190110174257.GE16556@linux.intel.com> (raw)
In-Reply-To: <20190110123243.3b9e0856@gandalf.local.home>
On Thu, Jan 10, 2019 at 12:32:43PM -0500, Steven Rostedt wrote:
> On Thu, 10 Jan 2019 11:20:04 -0600
> Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
>
> > > While I can't find a reason for hypervisors to emulate this instruction,
> > > smarter people might find ways to turn it into a security exploit.
> >
> > Interesting point... but I wonder if it's a realistic concern. BTW,
> > text_poke_bp() also relies on undocumented behavior.
>
> But we did get an official OK from Intel that it will work. Took a bit
> of arm twisting to get them to do so, but they did. And it really is
> pretty robust.
Did we (they?) list any caveats for this behavior? E.g. I'm fairly
certain atomicity guarantees go out the window if WC memtype is used.
next prev parent reply other threads:[~2019-01-10 17:43 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 22:59 [PATCH v3 0/6] Static calls Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 1/6] compiler.h: Make __ADDRESSABLE() symbol truly unique Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 2/6] static_call: Add basic static call infrastructure Josh Poimboeuf
2019-01-10 14:03 ` Edward Cree
2019-01-10 18:37 ` Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 3/6] x86/static_call: Add out-of-line static call implementation Josh Poimboeuf
2019-01-10 0:16 ` Nadav Amit
2019-01-10 16:28 ` Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 4/6] static_call: Add inline static call infrastructure Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 5/6] x86/alternative: Use a single access in text_poke() where possible Josh Poimboeuf
2019-01-10 9:32 ` Nadav Amit
2019-01-10 17:20 ` Josh Poimboeuf
2019-01-10 17:29 ` Nadav Amit
2019-01-10 17:32 ` Steven Rostedt
2019-01-10 17:42 ` Sean Christopherson [this message]
2019-01-10 17:57 ` Steven Rostedt
2019-01-10 18:04 ` Sean Christopherson
2019-01-10 18:21 ` Josh Poimboeuf
2019-01-10 18:24 ` Steven Rostedt
2019-01-11 12:10 ` Alexandre Chartre
2019-01-11 15:28 ` Josh Poimboeuf
2019-01-11 16:46 ` Alexandre Chartre
2019-01-11 16:57 ` Josh Poimboeuf
2019-01-11 17:41 ` Jason Baron
2019-01-11 17:54 ` Nadav Amit
2019-01-15 11:10 ` Alexandre Chartre
2019-01-15 16:19 ` Steven Rostedt
2019-01-15 16:45 ` Alexandre Chartre
2019-01-11 0:59 ` hpa
2019-01-11 1:34 ` Sean Christopherson
2019-01-11 8:13 ` hpa
2019-01-09 22:59 ` [PATCH v3 6/6] x86/static_call: Add inline static call implementation for x86-64 Josh Poimboeuf
2019-01-10 1:21 ` [PATCH v3 0/6] Static calls Nadav Amit
2019-01-10 16:44 ` Josh Poimboeuf
2019-01-10 17:32 ` Nadav Amit
2019-01-10 18:18 ` Josh Poimboeuf
2019-01-10 19:45 ` Nadav Amit
2019-01-10 20:32 ` Josh Poimboeuf
2019-01-10 20:48 ` Nadav Amit
2019-01-10 20:57 ` Josh Poimboeuf
2019-01-10 21:47 ` Nadav Amit
2019-01-10 17:31 ` Linus Torvalds
2019-01-10 20:51 ` H. Peter Anvin
2019-01-10 20:30 ` Peter Zijlstra
2019-01-10 20:52 ` Josh Poimboeuf
2019-01-10 23:02 ` Linus Torvalds
2019-01-11 0:56 ` Andy Lutomirski
2019-01-11 1:47 ` Nadav Amit
2019-01-11 15:15 ` Josh Poimboeuf
2019-01-11 15:48 ` Nadav Amit
2019-01-11 16:07 ` Josh Poimboeuf
2019-01-11 17:23 ` Nadav Amit
2019-01-11 19:03 ` Linus Torvalds
2019-01-11 19:17 ` Nadav Amit
2019-01-11 19:23 ` hpa
2019-01-11 19:33 ` Nadav Amit
2019-01-11 19:34 ` Linus Torvalds
2019-01-13 0:34 ` hpa
2019-01-13 0:36 ` hpa
2019-01-11 19:39 ` Jiri Kosina
2019-01-14 2:31 ` H. Peter Anvin
2019-01-14 2:40 ` H. Peter Anvin
2019-01-14 20:11 ` Andy Lutomirski
2019-01-14 22:00 ` H. Peter Anvin
2019-01-14 22:54 ` H. Peter Anvin
2019-01-15 3:05 ` Andy Lutomirski
2019-01-15 5:01 ` H. Peter Anvin
2019-01-15 5:37 ` H. Peter Anvin
2019-01-14 23:27 ` Andy Lutomirski
2019-01-14 23:51 ` Nadav Amit
2019-01-15 2:28 ` hpa
2019-01-11 20:04 ` Josh Poimboeuf
2019-01-11 20:12 ` Linus Torvalds
2019-01-11 20:31 ` Josh Poimboeuf
2019-01-11 20:46 ` Linus Torvalds
2019-01-11 21:05 ` Andy Lutomirski
2019-01-11 21:10 ` Linus Torvalds
2019-01-11 21:32 ` Josh Poimboeuf
2019-01-14 12:28 ` Peter Zijlstra
2019-01-11 21:22 ` Josh Poimboeuf
2019-01-11 21:23 ` Josh Poimboeuf
2019-01-11 21:25 ` Josh Poimboeuf
2019-01-11 21:36 ` Nadav Amit
2019-01-11 21:41 ` Josh Poimboeuf
2019-01-11 21:55 ` Steven Rostedt
2019-01-11 21:59 ` Nadav Amit
2019-01-11 21:56 ` Nadav Amit
2019-01-12 23:54 ` Andy Lutomirski
2020-02-17 21:10 ` Jann Horn
2020-02-17 21:57 ` Steven Rostedt
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