From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH v3 13/24] xen/arm: Implement hypercall
 PHYSDEVOP_{, un}map_pirq
Date: Mon, 19 Jan 2015 16:54:42 +0000
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To: Julien Grall <julien.grall@linaro.org>
Cc: xen-devel@lists.xenproject.org, stefano.stabellini@citrix.com, ian.campbell@citrix.com, tim@xen.org
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>>> On 13.01.15 at 15:25, <julien.grall@linaro.org> wrote:
> The physdev sub-hypercalls PHYSDEVOP_{,map}_pirq allow the toolstack to
> assign/deassign a physical IRQ to the guest (via the config options "irqs"
> for xl). The x86 version is using them with PIRQ (IRQ bound to an event
> channel). As ARM doesn't have a such concept, we could reuse it to bound
> a physical IRQ to a virtual IRQ.
> 
> For now, we allow only SPIs to be mapped to the guest.
> The type MAP_PIRQ_TYPE_GSI is used for this purpose.
> 
> Signed-off-by: Julien Grall <julien.grall@linaro.org>
> Cc: Jan Beulich <jbeulich@suse.com>
> 
> ---
>     I'm not sure it's the best solution to reuse hypercalls for a
>     different purpose. If x86 plan to have a such concept (i.e binding a
>     physical IRQ to a virtual IRQ), we could introduce new hypercalls.
>     Any thoughs?

I'm not sure either - much depends on the possible confusion this
may cause to the callers (i.e. if they live in common code, they
may expect the hypercall to do a certain thing, whereas if the
callers are all [expected to be] in arch code, then I'd consider such
overloading okay).

Jan