From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Avi Kivity <avi@qumranet.com>
Cc: Carsten Otte <cotte@de.ibm.com>, kvm <kvm@vger.kernel.org>,
Olaf Schnapper <os@de.ibm.com>,
Hollis Blanchard <hollisb@us.ibm.com>
Subject: Re: [PATCH] libkvm-s390
Date: Mon, 14 Jul 2008 14:25:33 +0200 [thread overview]
Message-ID: <200807141425.33554.borntraeger@de.ibm.com> (raw)
In-Reply-To: <487B3C09.9030406@qumranet.com>
Am Montag, 14. Juli 2008 schrieb Avi Kivity:
> Certainly. I suggest exposing this via a KVM_CAP_blah and adapting at
> runtime.
>
> Placing the guest at offset zero is dangerous, since all a guest has to
> do is place a function at guest physical address zero and wait for a
> kernel bug that calls a null function pointer (at least, it would behave
> like that on x86, provided no-execute was disabled; it may well be that
> s390 has additional protection).
Since we have separate address space for kernel and userspace this should be
fine for s390. But I totally agree that offset != 0 is better for quality and
testing. During KVM Forum time frame I found some null pointer accesses in
our userspace code when I changed offset to 1MB. In the long term we
definitely want to move our guest.
Christian
next prev parent reply other threads:[~2008-07-14 12:26 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 17:29 [PATCH] libkvm-s390 Carsten Otte
2008-07-13 8:29 ` Avi Kivity
2008-07-14 11:33 ` Christian Borntraeger
2008-07-14 11:44 ` Avi Kivity
2008-07-14 12:25 ` Christian Borntraeger [this message]
2008-07-14 15:34 ` Anthony Liguori
2008-07-14 17:00 ` Christian Borntraeger
2008-07-14 18:00 ` Anthony Liguori
2008-07-16 15:28 ` [PATCH v2/RFC] libkvm-s390 Christian Borntraeger
2008-07-17 11:08 ` Christian Ehrhardt
2008-07-17 15:28 ` [PATCH v3] libkvm-s390 Christian Borntraeger
2008-07-19 7:56 ` Avi Kivity
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