From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pavel Fedin <p.fedin@samsung.com>
Subject: RE: [PATCH 1/7] KVM: api: add kvm_irq_routing_extended_msi
Date: Tue, 07 Jul 2015 13:57:51 +0300
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To: 'Andre Przywara' <andre.przywara@arm.com>, 'Paolo Bonzini' <pbonzini@redhat.com>, 'Christoffer Dall' <christoffer.dall@linaro.org>
Cc: eric.auger@st.com, kvm@vger.kernel.org, 'Marc Zyngier' <Marc.Zyngier@arm.com>, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org
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> I just don't want to end up with something like:
> (GICV3 && ARM64) || (GICV3 && ARM && KERNEL>4.4) || (SuperIRQC && i986)
> or
> (ARM || ARM64) && HAS_IRQ_ROUTING
> 
> Instead: If the kernel needs it, it tells you. Full stop.

 Agree.

> To be honest it's me to blame here to not having introduced the
> capability earlier. At the moment ARM has a different code path for
> KVM_SIGNAL_MSI, which does not bail out if the flag field is set. With
> Eric's patches this changes and we use the irqchip.c generic code, which
> returns -EINVAL atm. So I plan to introduce this capability already with
> the ITS emulation series, so we can just pick it up in the IRQ routing
> series.

 Then may be you follow https://lkml.org/lkml/2015/7/7/115 and replace flag with something like
KVM_SIGNAL_EXT_MSI ioctl ? After all you were one of people who voted against using flags.

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia