From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>,
Jan Kiszka <jan.kiszka@web.de>,
qemu-devel@nongnu.org, agraf@suse.de, kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [PATCH] Permit -mem-path without sync mmu
Date: Mon, 08 Aug 2011 11:24:09 +0300 [thread overview]
Message-ID: <4E3F9D29.2000708@redhat.com> (raw)
In-Reply-To: <20110808060328.GB20120@yookeroo.fritz.box>
On 08/08/2011 09:03 AM, David Gibson wrote:
> Second, if userspace qemu passing hugepages to kvm can cause (host)
> kernel memory corruption, that is clearly a host kernel bug. So am I
> correct in thinking this is basically just a safety feature if qemu is
> run on a buggy kernel.
Seems so, yes. 2.6.2[456] are exploitable. We only found out after
these were all released.
> Presumably this bug was corrected at some
> point? Is the presence of the SYNC_MMU feature just being used as a
> proxy for "is this kernel recent enough to have the corruption bug
> fixed"?
SYNC_MMU actually fixes the bug.
> In any case this test sure as hell needs a big comment next to it
> explaining this context.
Yes.
>
> > Why are mmu notifiers not implemented for PPC again?
>
> It's just not done yet; we're working on it. (That is, mmu notifiers
> are certainly present on PPC, it's just they're not wired up to kvm,
> yet).
>
If ppc doesn't have this issue even without SYNC_MMU, we can make the
check x86 specific.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-08-08 8:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-05 4:02 [Qemu-devel] [PATCH] Permit -mem-path without sync mmu David Gibson
2011-08-05 6:16 ` Jan Kiszka
2011-08-05 15:30 ` Marcelo Tosatti
2011-08-08 6:03 ` David Gibson
2011-08-08 8:24 ` Avi Kivity [this message]
2011-08-10 5:10 ` David Gibson
2011-08-10 9:01 ` Avi Kivity
2011-08-11 6:09 ` David Gibson
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