Subject: Re: QEMU PIC indirection patch for in-kernel APIC work

From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/[email-masked]>
Date: Thu, 05 Apr 2007 12:58:30 +0300

Ingo Molnar wrote:
> so right now the only option for a clean codebase is the KVM in-kernel 
> code.

I strongly disagree with this.  Bad code in userspace is not an excuse 
for shoving stuff into the kernel, where maintaining it is much more 
expensive, and the cause of a mistake can be system crashes and data 
loss, affecting unrelated processes.  If we move something into the 
kernel, we'd better have a really good reason for it.

Qemu code _is_ crufty.  We can do one of three things:
1. live with it
2. fork it and clean it up
3. clean it up incrementally and merge it upstream

Currently we're doing (1).  You're suggesting a variant of (2), fork 
plus move into the kernel.  The right thing to do IMO is (3), but I 
don't see anybody volunteering.  Qemu picked up additional committers 
recently and I believe they would be receptive to cleanups.

[In the *pic/pit case, we have other reasons to push things into the 
kernel.  But "this code is crap, let's rewrite it in the kernel" is not 
a justification I'll accept.  I'd be much happier if we could quantify 
these other reasons.]

-- 
error compiling committee.c: too many arguments to function

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