From: Jan Kiszka <jan.kiszka@web.de>
To: Gleb Natapov <gleb@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, kvm-devel <kvm@vger.kernel.org>
Subject: Re: Debugging an inconsistent shadow page table
Date: Sun, 26 Apr 2009 13:36:22 +0200 [thread overview]
Message-ID: <49F44736.6000001@web.de> (raw)
In-Reply-To: <20090426112749.GT24095@redhat.com>
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Gleb Natapov wrote:
> On Sun, Apr 26, 2009 at 01:11:40PM +0200, Jan Kiszka wrote:
>> That raise a question for a kvm-mmu newbie like me:
>>
>> If a page of the qemu process gets pushed around (here likely due to
>> fork()->exec(smbd)->COW), how will kvm's shadow table catch up? Via
>> MMU_NOTIFIER?
>>
>> I'm on a 2.6.25 kernel, and that means without CONFIG_MMU_NOTIFIER. So
>> far I assumed that kernels without this feature do not work optimally,
>> but they won't break my guests...
>>
> Guest memory is not COWed on fork (madvise(MADV_DONTFORK))
Yeah... but that's missing upstream! Will cross-check and then post a
fix for qemu.
Out of curiosity: What's the mechanism to update the shadow table after
swap-out/swap-in?
Jan
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next prev parent reply other threads:[~2009-04-26 11:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-25 10:36 Debugging an inconsistent shadow page table Jan Kiszka
2009-04-26 10:32 ` Avi Kivity
2009-04-26 11:11 ` Jan Kiszka
2009-04-26 11:27 ` Gleb Natapov
2009-04-26 11:34 ` Avi Kivity
2009-04-26 11:36 ` Jan Kiszka [this message]
2009-04-26 11:39 ` Gleb Natapov
2009-04-26 11:41 ` Jan Kiszka
2009-04-26 11:42 ` Avi Kivity
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