From: Pavel Fedin <p.fedin@samsung.com>
To: 'Eric Auger' <eric.auger@linaro.org>,
'Andre Przywara' <andre.przywara@arm.com>,
'Marc Zyngier' <Marc.Zyngier@arm.com>,
christoffer.dall@linaro.org
Cc: kvm@vger.kernel.org
Subject: RE: IRQFD support with GICv3 ITS (WAS: RE: [PATCH 00/13] arm64: KVM: GICv3 ITS emulation)
Date: Thu, 18 Jun 2015 17:19:03 +0300 [thread overview]
Message-ID: <019901d0a9d1$bb47d390$31d77ab0$@samsung.com> (raw)
In-Reply-To: <558266BE.7040403@linaro.org>
Hello!
> I also have an implementation of GSI routing on ARM, basically a rebase
> of my old/first implementation of irqfd
> (https://patches.linaro.org/32261/) based on irqchip gsi routing & qemu
> part (https://lists.gnu.org/archive/html/qemu-devel/2014-07/msg01090.html).
I took a glance at it, and looks like it's already obsolete. We already have a convention of GSI number == SPI number. Kind of hardcoded default routing table which cannot be changed. It is used at least by GICv2m emulation.
I think we should maintain backwards compatibility with it. I thought about something like:
a) GSI < 8192 - correspond to SPIs and cannot be re-routed.
b) GSI >= 8192 - correspond to MSI and need to be routed before use.
During routing setup we could use either GSI with offset (starting from 8192), or raw number (starting from 0). In case of raw number we would have some complex structure of GSI field in KVM_CAP_IRQFD ioctl, similar to KVM_IRQ_LINE. Something like:
bits: | 31 ... 24 | 23 ... 0 |
field: | irq_type | irq_id |
irq_type[0]: irq_id = SPI
irq_type[3]: irq_id = GSI number routed to MSI
Consequently, we have to implement only KVM_IRQ_ROUTING_MSI type and completely ignore KVM_IRQ_ROUTING_IRQCHIP.
I hope i am clear enough...
Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia
next prev parent reply other threads:[~2015-06-18 14:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-10 8:31 IRQFD support with GICv3 ITS (WAS: RE: [PATCH 00/13] arm64: KVM: GICv3 ITS emulation) Pavel Fedin
2015-06-10 8:31 ` Pavel Fedin
2015-06-10 13:58 ` Eric Auger
2015-06-10 13:58 ` Eric Auger
2015-06-10 15:30 ` Pavel Fedin
2015-06-10 15:30 ` Pavel Fedin
2015-06-17 9:21 ` Pavel Fedin
2015-06-17 9:34 ` Marc Zyngier
2015-06-17 10:00 ` Pavel Fedin
2015-06-17 11:02 ` Andre Przywara
2015-06-17 11:46 ` Pavel Fedin
2015-06-18 6:35 ` Eric Auger
2015-06-18 14:19 ` Pavel Fedin [this message]
2015-06-10 15:38 ` Pavel Fedin
2015-06-10 15:38 ` Pavel Fedin
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