Ian.Pratt at eu
Jun 3, 2009, 7:37 AM
> The second problem is the difficulty in altering the hypervisor for
> those of us unfamiliar with it. For example, we spent about a hundred man-hours
> trying to implement "memory trigger" functionality, but had to abandon
> the effort. I think the group needs some level of dedicated support from
> XenSource or Citrix to answer questions.
I think you'll find that folks like Tim Deegan and Gianluca Guida would be very helpful in reviewing design proposals and commenting on patches.
I'd very much like to see the ability to add type-codes to pages that enable synchronous and asynchronous triggers[*] to be delivered to a "monitor application" when pages are accessed, written, or executed[**]. These events can be captured through a fairly simple modification to the HAP and shadow code, and then delivered to the nominated monitor application in a manner very similar to the mechanism used for delivering IO and MMIO events to qemu-dm.
[*] Synchronous triggers block the VCPU until a response from the monitor application is received, whereas asynchronous triggers may be queued until the queue fills.
[**] I'd also add a special fast-path page-type that marks a page as executable-but-read-only, but allows it to automatically revert to the writeable-but-not-executable page type without requiring a synchronous trigger to manually changing the page type.
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