From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [kvmarm] [RFC PATCH 0/3] KVM: ARM: Get rid of hardcoded VGIC
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Date: Fri, 26 Oct 2012 14:41:37 +0200
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Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Christoffer Dall <c.dall@virtualopensystems.com>,
	Alexander Graf <agraf@suse.de>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	kvm-ppc <kvm-ppc@vger.kernel.org>
To: Peter Maydell <peter.maydell@linaro.org>
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On 2012-10-26 14:08, Peter Maydell wrote:
> On 26 October 2012 12:57, Paolo Bonzini <pbonzini@redhat.com> wrote:
>> If you exclude old-style PCI pass-through and limit yourself to vhost
>> and VFIO, you can treat irqfd as "the" in-kernel source of the
>> interrupt.  Then you need a mapping between MSIs and numbers used in
>> KVM_IRQFD ("GSIs").
>>
>> This is what KVM_SET_GSI_ROUTING modifies, and basically the mapping is
>> modified every time a vector is masked/unmasked in the MSI-X table.
> 
> So SET_GSI_ROUTING sets the routing for MSIs? Very logical...

See my reply to Ben: It is used for MSIs as well, but not only. The
concept is absolutely generic, you just need to define specific target
types and provide ways to associate specific sources with a virtual IRQ
number ("GSI").

Jan

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