From: Richard Henderson <rth@twiddle.net>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Leon Alrae <leon.alrae@imgtec.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [PATCH 2/2] tcg/i386: Reserve register for guest_base if a segment isn't available
Date: Fri, 17 Jul 2015 07:02:09 +0100 [thread overview]
Message-ID: <55A89A61.4070005@twiddle.net> (raw)
In-Reply-To: <CAFEAcA-9+DTX2ES5bmczv1Cr_U+hHxWBZ7Go8=4Y=0XngqtH1g@mail.gmail.com>
On 07/17/2015 02:33 AM, Peter Maydell wrote:
> On 16 July 2015 at 22:25, Richard Henderson <rth@twiddle.net> wrote:
>> This saves 2 insns and 10 bytes from the implementation of
>> each memory operation.
>
> Do we have an idea of which platforms/configs don't let
> us have a segment register for guest_base?
We've only bothered to fill in code for Linux so far.
These days we should probably probe for fsgsbase insns and use those. Though I
don't know how many of the various operating systems enable that...
r~
next prev parent reply other threads:[~2015-07-17 6:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 21:25 [Qemu-devel] [PATCH for-2.4 0/2] tcg/i386 address zero-extension Richard Henderson
2015-07-16 21:25 ` [Qemu-devel] [PATCH 1/2] tcg/i386: Extend addresses for 32-bit guests Richard Henderson
2015-07-17 10:18 ` Aurelien Jarno
2015-07-16 21:25 ` [Qemu-devel] [PATCH 2/2] tcg/i386: Reserve register for guest_base if a segment isn't available Richard Henderson
2015-07-17 1:33 ` Peter Maydell
2015-07-17 6:02 ` Richard Henderson [this message]
2015-07-17 15:30 ` Paolo Bonzini
2015-07-17 15:56 ` Aurelien Jarno
2015-07-17 10:18 ` Aurelien Jarno
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