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From: Ingo Molnar <mingo@kernel.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Borislav Petkov <bp@alien8.de>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86/asm/entry/64: better check for canonical address
Date: Fri, 27 Mar 2015 12:34:30 +0100	[thread overview]
Message-ID: <20150327113430.GC14778@gmail.com> (raw)
In-Reply-To: <CAMzpN2hZrL9WLAHrxM4dsa8wkNHWtX6NVGyhRz_MoiED6Q5X8A@mail.gmail.com>


* Brian Gerst <brgerst@gmail.com> wrote:

> > Btw., there's a neat trick we could do: in the HLT, MWAIT and 
> > ACPI-idle code we could attempt to set up RCX to match RIP, to 
> > trigger this optimization in the common 'irq interrupted the idle 
> > task' case?
> 
> sysret only returns to CPL3.

Indeed, an IRET ought to be pretty cheap for same-ring interrupt 
returns in any case.

Thanks,

	Ingo

  reply	other threads:[~2015-03-27 11:34 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-26 12:42 [PATCH] x86/asm/entry/64: better check for canonical address Denys Vlasenko
2015-03-26 18:45 ` Andy Lutomirski
2015-03-27  8:57   ` Borislav Petkov
2015-03-30 14:27   ` Denys Vlasenko
2015-03-30 14:30     ` Andy Lutomirski
2015-03-30 14:45       ` Andy Lutomirski
2015-03-27  8:11 ` Ingo Molnar
2015-03-27 10:45   ` Denys Vlasenko
2015-03-27 11:17     ` Ingo Molnar
2015-03-27 11:28       ` Brian Gerst
2015-03-27 11:34         ` Ingo Molnar [this message]
2015-03-27 12:14           ` Denys Vlasenko
2015-03-27 12:16             ` Ingo Molnar
2015-03-27 12:31               ` Denys Vlasenko
2015-03-28  9:11                 ` Ingo Molnar
2015-03-29 19:36                   ` Denys Vlasenko
2015-03-29 21:12                     ` Andy Lutomirski
2015-03-29 21:46                       ` Denys Vlasenko
2015-03-31 16:43                     ` Ingo Molnar
2015-03-31 17:08                       ` Andy Lutomirski
2015-03-31 17:31                         ` Denys Vlasenko
2015-03-27 11:27 ` Brian Gerst
2015-03-27 11:31   ` Ingo Molnar
2015-03-27 21:37     ` Andy Lutomirski
2015-04-02 17:37 ` Denys Vlasenko
2015-04-02 18:10   ` Ingo Molnar
  -- strict thread matches above, loose matches on Subject: below --
2015-04-21 16:27 Denys Vlasenko
2015-04-21 18:08 ` Andy Lutomirski
2015-04-23 15:10   ` Borislav Petkov
2015-04-23 15:41     ` Andy Lutomirski
2015-04-23 15:49       ` Borislav Petkov
2015-04-23 15:52         ` Andy Lutomirski

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