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From: Andrea Arcangeli <andrea@qumranet.com>
To: Avi Kivity <avi@qumranet.com>
Cc: Marcelo Tosatti <marcelo@kvack.org>,
	kvm-devel <kvm-devel@lists.sourceforge.net>
Subject: Re: KVM: MMU: add KVM_ZAP_GFN ioctl
Date: Fri, 21 Mar 2008 12:42:14 +0100	[thread overview]
Message-ID: <20080321114214.GF7822@v2.random> (raw)
In-Reply-To: <47E253EB.3060708@qumranet.com>

On Thu, Mar 20, 2008 at 02:09:15PM +0200, Avi Kivity wrote:
> Marcelo Tosatti wrote:
> > Add an ioctl to zap all mappings to a given gfn. This allows userspace
> > remove the QEMU process mappings and the page without causing
> > inconsistency.
> >
> >   
> 
> I'm thinking of comitting rmap_nuke() to kvm.git, and the rest to the 
> external module, since this is only needed on kernels without mmu notifiers.
> 
> Andrea, is rmap_nuke() suitable for the mmu notifiers pte clear callback?

There's the usual smp race condition. The tlb must be flushed before
the final put_page in rmap_remove. And it can't be safe to call this
ioctl before sys_munmap(), so this would be the final put_page.

My kvm_unmap_hva takes care of that.

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  reply	other threads:[~2008-03-21 11:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-12 22:29 KVM: MMU: add KVM_ZAP_GFN ioctl Marcelo Tosatti
2008-03-20 12:09 ` Avi Kivity
2008-03-21 11:42   ` Andrea Arcangeli [this message]
2008-03-21 13:37     ` Marcelo Tosatti
2008-03-21 15:56       ` Andrea Arcangeli
2008-03-21 21:23         ` Marcelo Tosatti
2008-03-24  6:54           ` Andrea Arcangeli
2008-03-26 12:31             ` Andrea Arcangeli
2008-03-23  8:50       ` Avi Kivity
2008-03-23 20:23         ` Andrea Arcangeli

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