From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Marcelo Tosatti <mtosatti@redhat.com>, kvm-devel <kvm@vger.kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: KVM: MMU: drop read-only large sptes when creating lower level sptes
Date: Tue, 25 Feb 2014 11:30:37 +0800 [thread overview]
Message-ID: <530C0E5D.4030308@linux.vnet.ibm.com> (raw)
In-Reply-To: <20140224165932.GA15971@amt.cnet>
On 02/25/2014 12:59 AM, Marcelo Tosatti wrote:
>
> Read-only large sptes can be created due to read-only faults as
> follows:
>
> - QEMU pagetable entry that maps guest memory is read-only
> due to COW.
> - Guest read faults such memory, COW is not broken, because
> it is a read-only fault.
> - Enable dirty logging, large spte not nuked because it is read-only.
> - Write-fault on such memory causes guest to loop endlessly
> (which must go down to level 1 because dirty logging is enabled).
Hi Marcelo,
It surprised me that the large-readonly mapping was not dropped
by mmu-notifer as this is write fault on readonly mapping in Qemu.
Hmm... i missed something?
next prev parent reply other threads:[~2014-02-25 3:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-24 16:59 KVM: MMU: drop read-only large sptes when creating lower level sptes Marcelo Tosatti
2014-02-25 3:30 ` Xiao Guangrong [this message]
2014-02-25 13:13 ` Marcelo Tosatti
2014-02-25 15:11 ` Xiao Guangrong
2014-02-25 22:52 ` Marcelo Tosatti
2014-02-25 8:23 ` Paolo Bonzini
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