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From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 00/13] arm64: KVM: GICv3 ITS emulation
Date: Mon, 08 Jun 2015 18:13:58 +0100	[thread overview]
Message-ID: <5575CD56.5020109@arm.com> (raw)
In-Reply-To: <02ae01d0a1d9$732d2ce0$598786a0$@samsung.com>

On 08/06/15 11:54, Pavel Fedin wrote:
>  Hi!
> 
>> I'm afraid this is not enough. A write to GICR_TRANSLATER (DID+EID)
>> results in a (LPI,CPU) pair. Can you easily express the CPU part in
>> irqfd (this is a genuine question, I'm not familiar enough with that
>> part of the core)?
> 
>  But... As far as i could understand, LPI is added to a collection as a part of setup. And
> collection actually represents a destination CPU, doesn't it? And we can't have multiple
> LPIs sharing the same number and going to different CPUs. Or am i wrong? Unfortunately i
> don't have GICv3 arch reference manual.

This is true to some extent. But the point is that the result of the
translation is both an LPI and a CPU. My question was how you would
indicate convey the notion of a target vcpu when using irqfd. As far as
I know this doesn't really fit, unless we start introducing the dreaded
GSI routing...

Do we really want to go down that road?

>> Another concern
>> would be the support of GICv4, which relies on the command queue
>> handling to be handled in the kernel
> 
>  Wow, i didn't know about GICv4.

I wish I didn't know about it.

	M.
-- 
Jazz is not dead. It just smells funny...

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <marc.zyngier@arm.com>
To: Pavel Fedin <p.fedin@samsung.com>,
	Andre Przywara <Andre.Przywara@arm.com>,
	"christoffer.dall@linaro.org" <christoffer.dall@linaro.org>
Cc: "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH 00/13] arm64: KVM: GICv3 ITS emulation
Date: Mon, 08 Jun 2015 18:13:58 +0100	[thread overview]
Message-ID: <5575CD56.5020109@arm.com> (raw)
In-Reply-To: <02ae01d0a1d9$732d2ce0$598786a0$@samsung.com>

On 08/06/15 11:54, Pavel Fedin wrote:
>  Hi!
> 
>> I'm afraid this is not enough. A write to GICR_TRANSLATER (DID+EID)
>> results in a (LPI,CPU) pair. Can you easily express the CPU part in
>> irqfd (this is a genuine question, I'm not familiar enough with that
>> part of the core)?
> 
>  But... As far as i could understand, LPI is added to a collection as a part of setup. And
> collection actually represents a destination CPU, doesn't it? And we can't have multiple
> LPIs sharing the same number and going to different CPUs. Or am i wrong? Unfortunately i
> don't have GICv3 arch reference manual.

This is true to some extent. But the point is that the result of the
translation is both an LPI and a CPU. My question was how you would
indicate convey the notion of a target vcpu when using irqfd. As far as
I know this doesn't really fit, unless we start introducing the dreaded
GSI routing...

Do we really want to go down that road?

>> Another concern
>> would be the support of GICv4, which relies on the command queue
>> handling to be handled in the kernel
> 
>  Wow, i didn't know about GICv4.

I wish I didn't know about it.

	M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2015-06-08 17:13 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-29  9:53 [PATCH 00/13] arm64: KVM: GICv3 ITS emulation Andre Przywara
2015-05-29  9:53 ` Andre Przywara
2015-05-29  9:53 ` [PATCH 01/13] KVM: arm/arm64: VGIC: don't track used LRs in the distributor Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-12 17:23   ` Eric Auger
2015-05-29  9:53 ` [PATCH 02/13] KVM: extend struct kvm_msi to hold a 32-bit device ID Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09  8:49   ` Eric Auger
2015-06-09  8:49     ` Eric Auger
2015-06-28 19:12   ` Christoffer Dall
2015-06-28 19:12     ` Christoffer Dall
2015-06-29 14:53     ` Andre Przywara
2015-06-29 14:53       ` Andre Przywara
2015-06-29 15:02       ` Christoffer Dall
2015-06-29 15:02         ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 03/13] KVM: arm/arm64: add emulation model specific destroy function Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09  8:51   ` Eric Auger
2015-06-09  8:51     ` Eric Auger
2015-06-28 19:14   ` Christoffer Dall
2015-06-28 19:14     ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 04/13] KVM: arm64: Introduce new MMIO region for the ITS base address Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09  8:52   ` Eric Auger
2015-06-09  8:52     ` Eric Auger
2015-06-11 15:12     ` Andre Przywara
2015-06-11 15:12       ` Andre Przywara
2015-05-29  9:53 ` [PATCH 05/13] KVM: arm64: handle ITS related GICv3 redistributor registers Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09  8:52   ` Eric Auger
2015-06-09  8:52     ` Eric Auger
2015-06-12 17:03     ` Andre Przywara
2015-06-12 17:03       ` Andre Przywara
2015-05-29  9:53 ` [PATCH 06/13] KVM: arm64: introduce ITS emulation file with stub functions Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09  9:23   ` Eric Auger
2015-06-09  9:23     ` Eric Auger
2015-05-29  9:53 ` [PATCH 07/13] KVM: arm64: implement basic ITS register handlers Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09 13:34   ` Eric Auger
2015-06-09 13:34     ` Eric Auger
2015-06-28 19:36   ` Christoffer Dall
2015-06-28 19:36     ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 08/13] KVM: arm64: add data structures to model ITS interrupt translation Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09 15:59   ` Eric Auger
2015-06-09 15:59     ` Eric Auger
2015-05-29  9:53 ` [PATCH 09/13] KVM: arm64: handle pending bit for LPIs in ITS emulation Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-09 15:59   ` Eric Auger
2015-06-09 15:59     ` Eric Auger
2015-06-11 15:46     ` Andre Przywara
2015-06-11 15:46       ` Andre Przywara
2015-06-11 16:01       ` Marc Zyngier
2015-06-11 16:01         ` Marc Zyngier
2015-06-11 18:24         ` Eric Auger
2015-06-11 18:24           ` Eric Auger
2015-05-29  9:53 ` [PATCH 10/13] KVM: arm64: sync LPI properties and status between guest and KVM Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-11 17:44   ` Eric Auger
2015-06-11 17:44     ` Eric Auger
2015-06-28 19:33   ` Christoffer Dall
2015-06-28 19:33     ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 11/13] KVM: arm64: implement ITS command queue command handlers Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-12 15:28   ` Eric Auger
2015-06-12 15:28     ` Eric Auger
2015-06-28 19:41   ` Christoffer Dall
2015-06-28 19:41     ` Christoffer Dall
2015-07-03 15:57     ` Andre Przywara
2015-07-03 15:57       ` Andre Przywara
2015-07-03 21:01       ` Christoffer Dall
2015-07-03 21:01         ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 12/13] KVM: arm64: implement MSI injection in ITS emulation Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-11 17:43   ` Eric Auger
2015-06-11 17:43     ` Eric Auger
2015-07-06 16:46     ` Andre Przywara
2015-07-06 16:46       ` Andre Przywara
2015-07-07  8:13       ` Christoffer Dall
2015-07-07  8:13         ` Christoffer Dall
2015-05-29  9:53 ` [PATCH 13/13] KVM: arm64: enable ITS emulation as a virtual MSI controller Andre Przywara
2015-05-29  9:53   ` Andre Przywara
2015-06-12 16:05   ` Eric Auger
2015-06-12 16:05     ` Eric Auger
2015-06-18  8:43   ` Eric Auger
2015-06-18  8:43     ` Eric Auger
2015-06-18 14:22     ` Andre Przywara
2015-06-18 14:22       ` Andre Przywara
2015-06-18 15:03       ` Pavel Fedin
2015-06-18 15:03         ` Pavel Fedin
2015-06-18 19:20         ` Andre Przywara
2015-06-18 19:20           ` Andre Przywara
2015-06-08  6:53 ` [PATCH 00/13] arm64: KVM: GICv3 ITS emulation Pavel Fedin
2015-06-08  6:53   ` Pavel Fedin
2015-06-08  8:23   ` Marc Zyngier
2015-06-08  8:23     ` Marc Zyngier
2015-06-08 10:54     ` Pavel Fedin
2015-06-08 10:54       ` Pavel Fedin
2015-06-08 17:13       ` Marc Zyngier [this message]
2015-06-08 17:13         ` Marc Zyngier
2015-06-09  8:12       ` Eric Auger
2015-06-09  8:12         ` Eric Auger
2015-06-10 12:18 ` Pavel Fedin

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