From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Andi Kleen <ak@linux.intel.com>, Paul Turner <pjt@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linux-foundation.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>,
tglx@linutronix.de, Kees Cook <keescook@google.com>,
Rik van Riel <riel@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
Jiri Kosina <jikos@kernel.org>,
gnomes@lxorguk.ukuu.org.uk, x86@kernel.org, bp@alien8.de,
rga@amazon.de, thomas.lendacky@amd.com
Subject: Re: [PATCH v2.1] x86/retpoline: Fill return stack buffer on vmexit
Date: Thu, 11 Jan 2018 15:32:06 +0100 [thread overview]
Message-ID: <20180111143206.GA6176@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1515680912.22302.351.camel@infradead.org>
On Thu, Jan 11, 2018 at 02:28:32PM +0000, David Woodhouse wrote:
> On Thu, 2018-01-11 at 08:20 -0600, Josh Poimboeuf wrote:
> >
> > This seems weird. I liked v1 a lot better. What's the problem with
> > patching in the whole thing?
> >
> > Also, if you go back to v1, it should be an easy objtool fix, just add
> > ANNOTATE_NOSPEC_ALTERNATIVE in front of it.
>
> The objection was that I was patching in a fairly long set of
> instructions. I confess I don't actually know why that's a problem,
You get a giant string of NOPs, a single jmp should be faster.
next prev parent reply other threads:[~2018-01-11 14:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-11 11:37 David Woodhouse
2018-01-11 12:26 ` Peter Zijlstra
2018-01-11 14:20 ` Josh Poimboeuf
2018-01-11 14:28 ` David Woodhouse
2018-01-11 14:32 ` Peter Zijlstra [this message]
2018-01-11 14:53 ` David Woodhouse
2018-01-11 15:04 ` Josh Poimboeuf
2018-01-11 16:10 ` David Woodhouse
2018-01-27 4:24 ` Konrad Rzeszutek Wilk
2018-01-11 15:22 ` Brian Gerst
2018-01-11 15:23 ` David Woodhouse
2018-01-11 15:28 ` Brian Gerst
2018-01-11 14:58 ` Josh Poimboeuf
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