Re: [PATCH 08/11] Add "wait for page" hypercall.

[Avi Kivity]

On 11/02/2009 05:13 PM, Gleb Natapov wrote:
> On Mon, Nov 02, 2009 at 03:05:11PM +0200, Avi Kivity wrote:
>    
> > On 11/01/2009 01:56 PM, Gleb Natapov wrote:
> >      
> > > We want to be able to inject async pagefault into guest event if a guest
> > > is not executing userspace code. But in this case guest may receive
> > > async page fault in non-sleepable context. In this case it will be
> > > able to make "wait for page" hypercall vcpu will be put to sleep until
> > > page is swapped in and guest can continue without reschedule.
> > >        
> > What's wrong with just 'hlt' and checking in the guest?
> >
> >      
> Halting here will leave vcpu with interrupt disabled and this will prevent
> "wake up" signal delivery.

Page faults can be delivered with interrupts disabled.

>   Enabling interrupts is also not an options
> since we can't be sure that vcpu can process interrupt at this point.
>    

That's too bad, allowing interrupts in this context can help maintain 
responsiveness.

--
error compiling committee.c: too many arguments to function

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