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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andi Kleen <ak@muc.de>
Cc: Andrew Morton <akpm@osdl.org>,
	virtualization@lists.osdl.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Chris Wright <chrisw@sous-sol.org>
Subject: Re: [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops
Date: Sun, 06 Aug 2006 22:56:30 -0700	[thread overview]
Message-ID: <44D6D60E.5080507@goop.org> (raw)
In-Reply-To: <200608070739.33428.ak@muc.de>

Andi Kleen wrote:
> On Monday 07 August 2006 06:47, Rusty Russell wrote:
>   
>> This patch does the dumbest possible replacement of paravirtualized
>> instructions: calls through a "paravirt_ops" structure.  Currently
>> these are function implementations of native hardware: hypervisors
>> will override the ops structure with their own variants.
>>     
>
> You should call it HAL - that would make it clearer what it is.
>   

I've always found the term "HAL" to be vague to the point of 
meaningless.  What would it mean in this case:  "hypervisor abstraction 
layer"?  It certainly doesn't attempt abstract all hardware.

> I think I would prefer to patch always. Is there a particular
> reason you can't do that?
>   

Some calls just don't need patching; an indirect call is fast enough, 
and simple.  But I can't think of a good reason to not patch patchable 
calls, other than for debugging perhaps (easier to place one breakpoint 
than one per inline site).

    J

WARNING: multiple messages have this Message-ID (diff)
From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andi Kleen <ak@muc.de>
Cc: virtualization@lists.osdl.org, Andrew Morton <akpm@osdl.org>,
	Chris Wright <chrisw@sous-sol.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops
Date: Sun, 06 Aug 2006 22:56:30 -0700	[thread overview]
Message-ID: <44D6D60E.5080507@goop.org> (raw)
In-Reply-To: <200608070739.33428.ak@muc.de>

Andi Kleen wrote:
> On Monday 07 August 2006 06:47, Rusty Russell wrote:
>   
>> This patch does the dumbest possible replacement of paravirtualized
>> instructions: calls through a "paravirt_ops" structure.  Currently
>> these are function implementations of native hardware: hypervisors
>> will override the ops structure with their own variants.
>>     
>
> You should call it HAL - that would make it clearer what it is.
>   

I've always found the term "HAL" to be vague to the point of 
meaningless.  What would it mean in this case:  "hypervisor abstraction 
layer"?  It certainly doesn't attempt abstract all hardware.

> I think I would prefer to patch always. Is there a particular
> reason you can't do that?
>   

Some calls just don't need patching; an indirect call is fast enough, 
and simple.  But I can't think of a good reason to not patch patchable 
calls, other than for debugging perhaps (easier to place one breakpoint 
than one per inline site).

    J

  reply	other threads:[~2006-08-07  5:56 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-07  4:43 [PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops Rusty Russell
2006-08-07  4:45 ` [PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops Rusty Russell
2006-08-07  4:45   ` Rusty Russell
2006-08-07  4:47   ` [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops Rusty Russell
2006-08-07  4:47     ` Rusty Russell
2006-08-07  4:48     ` [PATCH 4/4] x86 paravirt_ops: binary patching infrastructure Rusty Russell
2006-08-07  4:48       ` Rusty Russell
2006-08-07  5:14       ` Rusty Russell
2006-08-07  5:38       ` Andi Kleen
2006-08-07  5:56         ` Jeremy Fitzhardinge
2006-08-07  5:56           ` Jeremy Fitzhardinge
2006-08-07  5:39     ` [PATCH 3/4] x86 paravirt_ops: implementation of paravirt_ops Andi Kleen
2006-08-07  5:56       ` Jeremy Fitzhardinge [this message]
2006-08-07  5:56         ` Jeremy Fitzhardinge
2006-08-07  6:13       ` Rusty Russell
2006-08-07  6:20         ` Andi Kleen
2006-08-07  6:20           ` Andi Kleen
2006-08-07  7:27           ` Rusty Russell
2006-08-07  5:40   ` [PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops Andi Kleen
2006-08-07  5:40     ` Andi Kleen
2006-08-07  7:50     ` Rusty Russell
2006-08-07  7:50       ` Rusty Russell
2006-08-07  8:53       ` Andi Kleen
2006-08-07 17:19         ` Dave Jones
2006-08-07 17:19           ` Dave Jones
2006-08-07  5:22 ` [PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops Jeremy Fitzhardinge
2006-08-07  5:30 ` Andi Kleen
2006-08-07  5:43   ` Jeremy Fitzhardinge
2006-08-07  6:02     ` Andi Kleen
2006-08-07  6:23       ` Jeremy Fitzhardinge
2006-08-07  6:03     ` Rusty Russell
2006-08-07  6:16       ` Andi Kleen
2006-08-07  6:04   ` Rusty Russell
2006-08-07  6:04     ` Rusty Russell
2006-08-07  6:17     ` Andi Kleen
2006-08-07  6:17       ` Andi Kleen
2006-08-07  6:27       ` Muli Ben-Yehuda
2006-08-07  6:27         ` Muli Ben-Yehuda
2006-08-07  7:34         ` Jan Engelhardt
2006-08-07  8:40           ` Muli Ben-Yehuda
2006-08-07  8:40             ` Muli Ben-Yehuda
2006-08-07 17:54             ` Jan Engelhardt
2006-08-07 17:54               ` Jan Engelhardt
2006-08-07 20:51     ` Zachary Amsden
2006-08-07 20:51       ` Zachary Amsden
2006-08-08  1:59       ` Andi Kleen
2006-08-08  1:59         ` Andi Kleen

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