From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH] paravirt.h
Date: Tue, 22 Aug 2006 20:30:04 +0100
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To: Arjan van de Ven <arjan@infradead.org>
Cc: Zachary Amsden <zach@vmware.com>, Andi Kleen <ak@muc.de>, virtualization@lists.osdl.org, Jeremy Fitzhardinge <jeremy@goop.org>, Andrew Morton <akpm@osdl.org>, Chris Wright <chrisw@sous-sol.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Ar Maw, 2006-08-22 am 20:29 +0200, ysgrifennodd Arjan van de Ven:
> > And it doesn't work for VMI or lhype, both of which might modify 
> > paravirt_ops way later in the boot process, when loaded as a module.  
> 
> doesn't this then start to have the same issues that runtime patching
> the system call table had?

It has several I can see that are if anything worse

- Stacked hypervisors stomping each others functions
- Locking required to do updates: and remember our lock functions use
methods in the array
- If we boot patch inline code to get performance natively its almost
impossible to then revert that.