Re: [Xen-devel] VLAPIC and Event channel relationship or how to map PIRQ to HVM guest

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Fri, Mar 03, 2017 at 10:27:49AM -0500, Konrad Rzeszutek Wilk wrote:
> On Thu, Mar 02, 2017 at 09:11:03PM +0300, Dmitry Rockosov wrote:
> > Konrad,
> > 
> > Thank you for great help!
> > 
> > I will try xen_nopv, looks like it's what I need.
> > But I have one question about below lines of your patch to Linux kernel.
> > 
> > Does it mean, Intel X2APIC virtualization (SDM Vol.3, 29.5) will not work
> > with xen_nopv?
> 
> Nope. It will use x2APIC and LAPIC.

And adding xen-devel back to it.

Please do not drop xen-devel from the emails.
> > 
> >  bool xen_hvm_need_lapic(void)
> >  {+ if (xen_nopv)+          return false;
> > 
> > 
> > Best Regards,
> > Rockosov Dmitry
> > 
> > 2017-03-01 23:32 GMT+03:00 Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>:
> > 
> > > On Wed, Feb 22, 2017 at 12:41:16PM +0300, Dmitry Rockosov wrote:
> > > > Hello guys,
> > > >
> > > > Could someone help me with VLAPIC and Event channel relationship? I 
> > > > can't
> > > > find any good design overview for it.
> > >
> > > LAPIC is extensively described in the Intel SDM.
> > >
> > > The event channels are described in the header files, but
> > > also this https://xenbits.xenproject.org/people/dvrabel/event-
> > > channels-F.pdf
> > > may help.
> > >
> > > > Are they compatible things or not?
> > >
> > > They are not.
> > > >
> > > > Actually I want to map any PIRQ to HVM guest (for example keyboard), and
> > > > use VLAPIC to deliver virtual interrupt to HVM guest.
> > >
> > > OK, that should be OK. The problem is that Linux guests will
> > > be default use the event channel vector (243) and ignore the
> > > LAPIC machinery.
> > >
> > > > But seems like all interrupts from keyboard are working through the 
> > > > Event
> > > > Channel Upcall Interrupt with vector 243.
> > >
> > > If you boot with 'xen_nopv' it should use the normal APIC machinery.
> > >
> > > >
> > > > Please, help me or point any useful documentation.
> > > >
> > > > Thank you!
> > > >
> > > > Best Regards,
> > > > Rockosov Dmitry
> > >
> > > > _______________________________________________
> > > > Xen-devel mailing list
> > > > Xen-devel@xxxxxxxxxxxxx
> > > > https://lists.xen.org/xen-devel
> > >
> > >

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