Re: [PATCH] PCI: hv: Use nested hypercall for retargeting interrupts

[Jinank Jain]

This was observed while testing pass-through PCI devices on the nested 
MSHV setup.

Regards,

Jinank

On 4/6/2023 4:47 AM, Wei Liu wrote:
> On Tue, Apr 04, 2023 at 11:35:46AM +0000, Jinank Jain wrote:
> > In case of nested MSHV, retargeting interrupt hypercall should be sent
> > to L0 hypervisor instead of L1 hypervisor.
> >
> > Signed-off-by: Jinank Jain <jinankjain@xxxxxxxxxxxxxxxxxxx>
> While I think this is a sensible change -- how did you discover this?
> Can you provide a bit more information?
>
> > ---
> >   drivers/pci/controller/pci-hyperv.c | 10 ++++++++--
> >   1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> > index f33370b75628..2123f632ecf7 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -704,8 +704,14 @@ static void hv_arch_irq_unmask(struct irq_data *data)
> >   		}
> >   	}
> >   
> > -	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
> > -			      params, NULL);
> > +	if (hv_nested)
> > +		res = hv_do_nested_hypercall(HVCALL_RETARGET_INTERRUPT |
> > +					     (var_size << 17),
> > +					     params, NULL);
> > +	else
> > +		res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT |
> > +				      (var_size << 17),
> > +				      params, NULL);
> >   
> >   exit_unlock:
> >   	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);
> > --
> > 2.34.1