From: Paolo Bonzini <pbonzini@redhat.com>
To: yongcheng.wu@i-soft.com.cn
Cc: kvm@vger.kernel.org
Subject: Re: KVM MMU: why write-protect for the pages containing PML4/PDPT/PDT (page directory) of the guest?
Date: Thu, 13 Jun 2013 09:15:34 -0400 [thread overview]
Message-ID: <51B9C5F6.4030906@redhat.com> (raw)
In-Reply-To: <51b93c47.+9Bka02lV7rGywcp%yongcheng.wu@i-soft.com.cn>
Il 12/06/2013 23:28, yongcheng.wu@i-soft.com.cn ha scritto:
> I have a problem for shadow page table. why is write-protect for the
> pages containing PML4/PDPT/PDT (page directory) of the guest? In
> other words, need to synchronize the change of the page directory of
> the guest?
Shadow page tables are the combination of both the host and guest page
tables into a single translation. So they need to be updated every time
the host or the guest change the page tables. Updates for the host page
tables are tracked with MMU notifiers; updates for the guest page tables
are tracked with write protection.
Paolo
prev parent reply other threads:[~2013-06-13 13:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 3:28 KVM MMU: why write-protect for the pages containing PML4/PDPT/PDT (page directory) of the guest? yongcheng.wu
2013-06-13 13:15 ` Paolo Bonzini [this message]
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