RE: [Xen-devel] Interrupt synchronisation and HVM

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

> 
> The evtchn_upcall_mask is not respected for HVM guests. When you set
> HVM_PARAM_CALLBACK_IRQ to 0, no more interrupts will be generated at
the
> PIC or IO-APIC. But any interrupts queued up at either of those will
> eventually get propagated to the CPU.

Thanks. I wish I'd known that earlier :|

> Is there a way to de-register from an IRQ and
> hence get Windows to mask the PIC/IO-APIC line?

Yes, I was doing that previously but under Windows you can only register
and unregister an interrupt at PASSIVE_LEVEL (all interrupts and thread
switching enabled), which I didn't want to do as when I disable
interrupts for a save/suspend, I don't want windows doing that sort of
thing (eg trying to perform a paging operation or something).

I've worked around it for now by just flipping a flag to say to the ISR
to just return if it gets an interrupt after a certain point.
Save/restore suddenly seems to work perfectly!

Just to clarify, if I have masked the interrupts via
HVM_PARAM_CALLBACK_IRQ = 0, it is safe to do nothing when the interrupt
occurs right? I don't need to unset the 'pending' bits or anything?

Thanks

James

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel