Re: [Xen-devel] LWP Interrupt Handler

[Wei Huang <wei.huang2@xxxxxxx>]

How about the approach in attached patches? A interrupt handler is 
registered at vector 0xf6 as a delegate for guest VM. Guest VCPU can 
register interrupt handler to receive notification. I will prepare 
formal ones after receiving your comments.
Thanks,
-Wei


On 03/25/2012 07:08 PM, Zhang, Xiantao wrote:
> Please make sure the per-cpu vector is considered in your case.  For CPU's 
> built-in event, it always happens on all cpus,  but IRQ-based events may only 
> happen on some special cpus which are determined by apic's mode.
> Xiantao
>
> > -----Original Message-----
> > From: xen-devel-bounces@xxxxxxxxxxxxx [mailto:xen-devel-
> > bounces@xxxxxxxxxxxxx] On Behalf Of Keir Fraser
> > Sent: Saturday, March 24, 2012 6:50 AM
> > To: wei.huang2@xxxxxxx; xen-devel@xxxxxxxxxxxxx; Jan Beulich
> > Subject: Re: [Xen-devel] LWP Interrupt Handler
> >
> > On 23/03/2012 22:03, "Wei Huang"<wei.huang2@xxxxxxx>  wrote:
> >
> > > I am adding interrupt support for LWP, whose spec is available at
> > > http://support.amd.com/us/Processor_TechDocs/43724.pdf. Basically OS
> > > can specify an interrupt vector in LWP_CFG MSR; the interrupt will be
> > > triggered when event buffer overflows. For HVM guests, I want to
> > > re-inject this interrupt back into the guest VM. Here is one idea
> > > similar to virtualized PMU: It first registers a special interrupt
> > > handler (say on vector 0xf6) using set_intr_gate(). When triggered,
> > > this handler injects an IRQ (with vector copied from LWP_CFG) into
> > > guest VM via virtual local APIC. This worked from my test.
> > >
> > > But adding a interrupt handler seems to be an overkill. Is there any
> > > better way to create a dummy interrupt receiver on be-behalf of guest
> > > VMs? I also looked into IRQ and MSI solutions inside Xen. But most of
> > > them assume that interrupts are from physical device (but not in this
> > > LWP case, where interrupt is initiated from CPU itself); so they don't
> > > fit very well.
> > I think just allocating a vector is fine. If we get too many we could move to
> > dynamic allocation of them.
> >
> >   -- Keir
> >
> > > Thanks,
> > > -Wei
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

Attachment: RFC_amd_lwp_interrupt.txt
Description: RFC_amd_lwp_interrupt.txt

Attachment: RFC_cpu_interrupt_delegate.txt
Description: RFC_cpu_interrupt_delegate.txt

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