From: Avi Kivity <avi@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Josh Boyer <jwboyer@gmail.com>,
Jongman Heo <jongman.heo@samsung.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH 2/2] i387: split up <asm/i387.h> into exported and internal interfaces
Date: Tue, 28 Feb 2012 13:21:00 +0200 [thread overview]
Message-ID: <4F4CB89C.4060500@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1202211340330.5354@i5.linux-foundation.org>
On 02/21/2012 11:41 PM, Linus Torvalds wrote:
> Btw, I really don't like what arch/x86/kvm/ does with CR0.TS and the FP
> state. I'm not at all sure that's all kosher. But I don't know the
> code, so I just made sure that at no point did any of the semantics
> change.
>
Can you elaborate on what you don't like in the kvm code (apart from "it
does virtualiztion")?
btw, some time ago I did some work to lazify fpu save (as opposed to
just fpu restore) and abstract out the various users (user mode, kernel
threads, irq context, guest mode, and signal handlers). This would
allow you to run task A's user mode with task B's fpu loaded, have
preemptible kernel fpu being, avoid fpu switching while handling
signals, and run user mode with a guest fpu loaded or vice versa.
However I abandoned the effort as too complex. Perhaps a more
determined hacker can make more progress there.
--
error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Josh Boyer <jwboyer@gmail.com>,
Jongman Heo <jongman.heo@samsung.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH 2/2] i387: split up <asm/i387.h> into exported and internal interfaces
Date: Tue, 28 Feb 2012 13:21:00 +0200 [thread overview]
Message-ID: <4F4CB89C.4060500@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1202211340330.5354@i5.linux-foundation.org>
On 02/21/2012 11:41 PM, Linus Torvalds wrote:
> Btw, I really don't like what arch/x86/kvm/ does with CR0.TS and the FP
> state. I'm not at all sure that's all kosher. But I don't know the
> code, so I just made sure that at no point did any of the semantics
> change.
>
Can you elaborate on what you don't like in the kvm code (apart from "it
does virtualiztion")?
btw, some time ago I did some work to lazify fpu save (as opposed to
just fpu restore) and abstract out the various users (user mode, kernel
threads, irq context, guest mode, and signal handlers). This would
allow you to run task A's user mode with task B's fpu loaded, have
preemptible kernel fpu being, avoid fpu switching while handling
signals, and run user mode with a guest fpu loaded or vice versa.
However I abandoned the effort as too complex. Perhaps a more
determined hacker can make more progress there.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-02-28 11:21 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-19 22:23 [PATCH 0/2] More i387 state save/restore work Linus Torvalds
2012-02-19 22:26 ` [PATCH 1/2] i387: use 'restore_fpu_checking()' directly in task switching code Linus Torvalds
2012-02-19 22:37 ` [PATCH 2/2] i387: support lazy restore of FPU state Linus Torvalds
2012-02-19 22:44 ` H. Peter Anvin
2012-02-19 23:18 ` H. Peter Anvin
2012-02-19 23:56 ` Linus Torvalds
2012-02-20 7:51 ` Ingo Molnar
2012-02-20 0:53 ` [PATCH 0/2] More i387 state save/restore work Michael Neuling
2012-02-20 1:03 ` Linus Torvalds
2012-02-20 1:06 ` Linus Torvalds
2012-02-20 1:11 ` Linus Torvalds
2012-03-01 11:30 ` Benjamin Herrenschmidt
2012-02-20 2:09 ` Indan Zupancic
2012-02-20 19:46 ` [PATCH v2 0/3] " Linus Torvalds
2012-02-20 19:47 ` [PATCH v2 1/3] i387: fix up some fpu_counter confusion Linus Torvalds
2012-02-20 19:48 ` [PATCH v2 2/3] i387: use 'restore_fpu_checking()' directly in task switching code Linus Torvalds
2012-02-20 19:48 ` [PATCH v2 3/3] i387: support lazy restore of FPU state Linus Torvalds
2012-02-21 1:50 ` Josh Boyer
2012-02-21 2:10 ` Linus Torvalds
2012-02-21 2:14 ` H. Peter Anvin
2012-02-21 5:27 ` Linus Torvalds
2012-02-21 5:35 ` H. Peter Anvin
2012-02-21 14:19 ` Josh Boyer
2012-02-21 17:59 ` H. Peter Anvin
2012-02-21 18:06 ` Ingo Molnar
2012-02-21 18:26 ` Linus Torvalds
2012-02-21 21:14 ` H. Peter Anvin
2012-02-21 21:39 ` [PATCH 0/2] i387: FP state interface cleanups Linus Torvalds
2012-02-21 21:40 ` [PATCH 1/2] i387: uninline the generic FP helpers that we expose to kernel modules Linus Torvalds
2012-02-21 21:41 ` [PATCH 2/2] i387: split up <asm/i387.h> into exported and internal interfaces Linus Torvalds
2012-02-21 23:50 ` [tip:x86/fpu] i387: Split " tip-bot for Linus Torvalds
2012-02-28 11:21 ` Avi Kivity [this message]
2012-02-28 11:21 ` [PATCH 2/2] i387: split " Avi Kivity
2012-02-28 16:05 ` Linus Torvalds
2012-02-28 17:21 ` Avi Kivity
2012-02-28 17:21 ` Avi Kivity
2012-02-28 17:37 ` Linus Torvalds
2012-02-28 18:08 ` Linus Torvalds
2012-02-28 18:29 ` Avi Kivity
2012-02-28 18:29 ` Avi Kivity
2012-02-28 18:09 ` Avi Kivity
2012-02-28 18:09 ` Avi Kivity
2012-02-28 18:34 ` Linus Torvalds
2012-02-28 19:06 ` Avi Kivity
2012-02-28 19:06 ` Avi Kivity
2012-02-28 19:26 ` Linus Torvalds
2012-02-28 19:45 ` Avi Kivity
2012-02-28 19:45 ` Avi Kivity
2012-02-21 23:49 ` [tip:x86/fpu] i387: Uninline the generic FP helpers that we expose to kernel modules tip-bot for Linus Torvalds
2012-02-21 2:18 ` [PATCH v2 3/3] i387: support lazy restore of FPU state Linus Torvalds
2012-02-21 2:32 ` H. Peter Anvin
2012-02-21 2:11 ` H. Peter Anvin
2012-02-21 21:54 ` Suresh Siddha
2012-02-21 21:57 ` Linus Torvalds
2012-02-21 22:19 ` Suresh Siddha
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F4CB89C.4060500@redhat.com \
--to=avi@redhat.com \
--cc=hpa@zytor.com \
--cc=jongman.heo@samsung.com \
--cc=jwboyer@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.