Re: [Xen-devel] Re: Making pages writable again in paging_log_dirty mode

[Tim Deegan <Tim.Deegan@xxxxxxxxxx>]

At 09:24 -0500 on 05 Jan (1231147482), Mike Sun wrote:
> Ah yes, I should probably explain what I'm doing.  I'm using the
> log-dirty mode to catch any writes to pages that I haven't yet
> "copied" via a background copy mechanism, similar to the live
> migration copy.  If I have copied it already, then I manually mark it
> dirty to indicate that it can be made writable again.  That's what I'm
> trying to do in this code.

Erm, did you know that if you mark the page as dirty the normal
page-fault path will fix up the shadow PTEs the next time they cause a
write fault?  Not as fast as fixing them all in bulk (a few thousand
cycles for each pagefault and VMEXIT) but should be functionally
correct.

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]

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