From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Oren Laadan <orenl@cs.columbia.edu>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>,
containers@lists.osdl.org, Dan Smith <danms@us.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] c/r: Add CR_COPY() macro (v3)
Date: Wed, 18 Mar 2009 08:43:41 -0500 [thread overview]
Message-ID: <20090318134341.GB22636@us.ibm.com> (raw)
In-Reply-To: <49C0A80E.1040603@cs.columbia.edu>
Quoting Oren Laadan (orenl@cs.columbia.edu):
>
>
> Serge E. Hallyn wrote:
> > Quoting Dave Hansen (dave@linux.vnet.ibm.com):
> >> On Tue, 2009-03-03 at 16:57 -0800, Dan Smith wrote:
> >>> DH> Did you convince Nathan that this ends up being a good idea?
> >>>
> >>> Technically he hasn't seen this version, but my hopes are not high
> >>> that he will change his mind. If the feedback is that they're not
> >>> liked, I'll happily remove them.
> >> I just figure if Nathan feels that strongly that we'll encounter more
> >> people who feel even more so. So, I was curious if he changed his mind
> >> somehow.
> >
> > I maintain however that two strong advantages of moving the checkpoint
> > and restart of simple registers etc into a single function are:
> >
> > 1. we won't forget to add (or accidentally lose) one or the
> > other
> > 2. any actual special handling at checkpoint or restart, like
> > the loading of access registers at restart on s390x,
> > stand out
> >
>
> I, too, think that this scheme is elegant, and at the same time I, too,
> think that it obfuscates the code. Since I only touch arch-dependent code
> only if I really really must, I don't have strong opinion about it ;)
>
> However, a problem with this scheme is that checkpoint and restart
> are not fully symmetric -- on restart we must sanitize the input data
> before restoring the registers to that data. I'm not familiar with
> s390, but it is likely that by not doing so we create a security issue.
>
> Oren.
But that's exactly why I think CR_COPY() helps - the sanitation is
explicit next to some boring CR_COPY()s. It becomes clearer that
it is being done.
Anyway we've got plenty of other, bigger hurdles to clear, so while
I do have a strong opinion, I'm not planning on pushing hard either
way.
thanks,
-serge
next prev parent reply other threads:[~2009-03-18 13:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-03 15:56 [PATCH 0/3] c/r: Add s390 support Dan Smith
2009-03-03 15:56 ` [PATCH 1/3] s390: Expose a constant for the number of words representing the CRs Dan Smith
2009-03-03 16:08 ` Dave Hansen
2009-03-04 0:56 ` Dan Smith
2009-03-04 0:59 ` Dave Hansen
2009-03-03 15:56 ` [PATCH 2/3] c/r: Add CR_COPY() macro (v3) Dan Smith
2009-03-03 16:22 ` Dave Hansen
2009-03-04 0:57 ` Dan Smith
2009-03-04 1:00 ` Dave Hansen
2009-03-04 15:05 ` Serge E. Hallyn
2009-03-18 7:51 ` Oren Laadan
2009-03-18 13:43 ` Serge E. Hallyn [this message]
2009-03-04 19:53 ` Nathan Lynch
2009-03-04 20:18 ` Dave Hansen
2009-03-04 20:01 ` Nathan Lynch
2009-03-04 20:18 ` Dan Smith
2009-03-03 15:56 ` [PATCH 3/3] c/r: define s390-specific checkpoint-restart code (v7) Dan Smith
2009-03-03 22:40 ` Serge E. Hallyn
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