From: Joe Bonasera <joe.bonasera@sun.com>
To: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: Christian Limpach <Christian.Limpach@xensource.com>,
xen-devel <xen-devel@lists.xensource.com>,
John Byrne <john.l.byrne@hp.com>
Subject: Re: Live migration leaves page tables read-only?
Date: Mon, 11 Dec 2006 13:30:13 -0800 [thread overview]
Message-ID: <457DCDE5.1090909@sun.com> (raw)
In-Reply-To: <8A87A9A84C201449A0C56B728ACF491E04EE59@liverpoolst.ad.cl.cam.ac.uk>
Ian Pratt wrote:
>
>> Solaris implements PROT_NONE by entirely invalidating the PTE (ie. it
>> becomes zero). Hence our PTEs always had either zero or have the
> PRESENT
>> bit set. The only exception to this was adding some fixage to allow
>> for the old Xen writable page table approach which temporarily made
>> the upper table non-PRESENT.
>>
>> So you can make not-present, but non-zero entries mean anything you
> want.
>> As long as it's the guest OS that creates the entries, we'll just not
> do
>> it.
>
> Just to be confirm: in Solaris there are no not-present PTE's that
> contain machine addresses.
yes
> This means we need to implement the scheme that Keir suggested to enable
> the guest OS to tell xen/xc_save/restore about flags in not-present PTEs
> that should trigger a m2p conversion.
>
> Ian
next prev parent reply other threads:[~2006-12-11 21:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-29 0:13 Live migration leaves page tables read-only? John Byrne
2006-11-29 0:22 ` John Byrne
2006-11-29 1:36 ` Ian Pratt
2006-11-29 2:52 ` John Byrne
2006-11-29 7:42 ` Keir Fraser
2006-11-29 16:49 ` John Byrne
2006-11-30 23:36 ` John Byrne
2006-12-01 1:13 ` Ian Pratt
2006-12-09 5:40 ` John Byrne
2006-12-09 5:44 ` John Byrne
2006-12-09 8:33 ` Ian Pratt
2006-12-09 9:22 ` Keir Fraser
2006-12-09 9:34 ` Keir Fraser
2006-12-09 9:48 ` Keir Fraser
2006-12-11 17:00 ` Joe Bonasera
2006-12-11 18:29 ` Ian Pratt
2006-12-11 19:55 ` John Byrne
2006-12-11 21:30 ` Joe Bonasera [this message]
2007-01-14 4:11 ` John Byrne
2007-01-14 8:21 ` Ian Pratt
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