Callbacks for domU into dom0

Callbacks for domU into dom0

[Tomáš Kouba]

Hello,
is there a way how to be informed (called back) in dom0,
when a specific action is taken in domU?

I would like to react on a system call being issued in domU.
If this is impossible is there any other action in domU that I can
hook my function on?

Thank you very much,

-- 
Tomas Kouba

Re: Callbacks for domU into dom0

[Mats Petersson]

At 16:46 31/10/2007, Tomáš Kouba wrote:
>Hello,
>is there a way how to be informed (called back) in dom0,
>when a specific action is taken in domU?
>
>I would like to react on a system call being issued in domU.
>If this is impossible is there any other action in domU that I can
>hook my function on?

The Xen kernel doesn't know (or care) about Linux (or Windows) system 
calls as such.
Some system calls will "do things" that the Xen kernel does care 
about, such as update page tables, which will cause an entry into the 
Xen kernel.

The only way for Xen to "know" about a system call would be if you 
modify the system call itself to perform some sort of operation that 
causes the Xen kernel to get involved with that. You could for 
example fake a MSR read or write [by "fake" I mean to a unused MSR 
number] operation inside the syscall , and then update the MSR read 
or write function to detect your system call.

Does this help you?

--
Mats


>Thank you very much,
>
>--
>Tomas Kouba
>
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