Re: generate random numbers

[George Dunlap <george.dunlap@eu.citrix.com>]

The problem is that you're choosing a random vcpu to run, without 
considering whether it *wants* to run or not.  In this case, you're 
running a vcpu before it's even been completely set up yet (write_cr3 is 
failing because the guest *has* no cr3 ready yet).

The normal way schedulers deal with this is to keep one list of all 
vcpus (or all domains), and another list with "runnable" vcpus.  You can 
keep track of which vcpus are runnable with the vcpu_wake() callback and 
by using vcpu_runnable() in schedule().

At very least, your loop in schedule should check vcpu_runnable() before 
selecting it.

 -George

michele.paolino wrote:
> Here's my random scheduler. It works until I start a virtual machine 
> (error file attached is the serial console's log).
> In xen call trace there isn't any of my functions.
> To generate random numbers I'm using the hash (MD5) of NOW() function.
> I would also Know why at boot time there are two calls at vcpu_init 
> function for vcpu with id = 0 ??
>
> Thanks
> Michele