On Mon, 4 May 2015, Vijay Kilari wrote: > On Thu, Apr 30, 2015 at 7:59 PM, Julien Grall <julien.gr...@citrix.com> wrote: > > Hi, > > > > On 30/04/15 14:47, Stefano Stabellini wrote: > >>>>> > >>>>> If the devid is not within this range, the ITS won't recognize the > >>>>> value and > >>>>> won't be able to send the interrupt. > >>>>> > >>>>> So this is clearly not the right value. > >>>> > >>>> Sure, in that case the maximum value allowed by GITS_TYPER.Devbits. > >>>> Vijay, what is the value of GITS_TYPER.Devbits on your platform? > >>> > >>> It is 21 bits > >> > >> I would imagine that 21 bits would be plenty to find an unused devid. > >> > >> Alternatively we could use an inexistent function of a real device, such > >> as 00:00.1 (function 1 of the host bridge). > > > > As discussed IRL, this idea sounds good to me. > > > > Although I would be happy with any other way which ensure the devid is free. > > Has prototyped with 00.00.1 as device id. But I see that Dom0 boot is > slow compared to polling mode.
This is very interesting. > This could be because Dom0 has to keep > trapping on creader to check if creader is updated or not. This sounds like a plausible explanation. That's because the guest is polling, right? I think we should pause the guest vcpu until we receive the interrupt. You can do that by calling vcpu_block. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
