From: Marc Zyngier <marc.zyngier@arm.com>
To: Pavel Fedin <p.fedin@samsung.com>,
'Andre Przywara' <andre.przywara@arm.com>,
christoffer.dall@linaro.org
Cc: eric.auger@linaro.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [PATCH v3 12/16] KVM: arm64: handle pending bit for LPIs in ITS emulation
Date: Wed, 07 Oct 2015 16:49:41 +0100 [thread overview]
Message-ID: <56153F15.1080800@arm.com> (raw)
In-Reply-To: <028c01d10117$46bd9440$d438bcc0$@samsung.com>
On 07/10/15 16:46, Pavel Fedin wrote:
> Hello!
>
>> Sure. And you then have to parse and validate all the tables each and
>> every time you're going to inject an interrupt (because the guest can
>> change the table content behind your back). You are quickly going to
>> notice that your performance is abysmal.
>
> I don't see any real problems, at least with LPI tables. If the guest changes something, it will be
> immediately available to us. I don't see any need to seriously validate something, at least here.
> Pending bit is just pending bit, and configuration is just priority value plus enable bit.
> But, well, if we think a bit better, in case of pending bit modification, the operations on both
> guest and host side have to be atomic, otherwise we can clobber our table if, for example, both host
> and guest modify adjacent bits. And there's no way to interlock with the guest. So, OK, i accept
> your point.
The pending table is the least of our concerns. Device table, ITTs,
collections. That's the real problem.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2015-10-07 15:49 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-07 14:55 [PATCH v3 00/16] KVM: arm64: GICv3 ITS emulation Andre Przywara
2015-10-07 14:55 ` [PATCH v3 01/16] KVM: arm/arm64: VGIC: don't track used LRs in the distributor Andre Przywara
2015-10-07 14:55 ` [PATCH v3 02/16] KVM: arm/arm64: remove now unused code after stay-in-LR rework Andre Przywara
2015-10-07 14:55 ` [PATCH v3 03/16] KVM: extend struct kvm_msi to hold a 32-bit device ID Andre Przywara
2015-10-07 14:55 ` [PATCH v3 04/16] KVM: arm/arm64: add emulation model specific destroy function Andre Przywara
2015-10-07 14:55 ` [PATCH v3 05/16] KVM: arm/arm64: extend arch CAP checks to allow per-VM capabilities Andre Przywara
2015-10-07 14:55 ` [PATCH v3 06/16] KVM: arm/arm64: make GIC frame address initialization model specific Andre Przywara
2015-10-07 14:55 ` [PATCH v3 07/16] KVM: arm64: Introduce new MMIO region for the ITS base address Andre Przywara
2015-10-07 14:55 ` [PATCH v3 08/16] KVM: arm64: handle ITS related GICv3 redistributor registers Andre Przywara
2015-10-22 15:46 ` Pavel Fedin
2015-10-22 15:55 ` Pavel Fedin
2015-10-07 14:55 ` [PATCH v3 09/16] KVM: arm64: introduce ITS emulation file with stub functions Andre Przywara
2015-10-07 14:55 ` [PATCH v3 10/16] KVM: arm64: implement basic ITS register handlers Andre Przywara
2015-10-07 14:55 ` [PATCH v3 11/16] KVM: arm64: add data structures to model ITS interrupt translation Andre Przywara
2015-10-07 14:55 ` [PATCH v3 12/16] KVM: arm64: handle pending bit for LPIs in ITS emulation Andre Przywara
2015-10-07 15:10 ` Pavel Fedin
2015-10-07 15:35 ` Marc Zyngier
2015-10-07 15:46 ` Pavel Fedin
2015-10-07 15:49 ` Marc Zyngier [this message]
2015-10-12 7:40 ` Pavel Fedin
2015-10-12 11:39 ` Pavel Fedin
2015-10-12 14:17 ` Andre Przywara
2015-10-07 14:55 ` [PATCH v3 13/16] KVM: arm64: sync LPI configuration and pending tables Andre Przywara
2015-10-21 11:29 ` Pavel Fedin
2015-10-07 14:55 ` [PATCH v3 14/16] KVM: arm64: implement ITS command queue command handlers Andre Przywara
2015-10-14 12:26 ` Pavel Fedin
2015-10-07 14:55 ` [PATCH v3 15/16] KVM: arm64: implement MSI injection in ITS emulation Andre Przywara
2015-11-25 13:28 ` Pavel Fedin
2015-10-07 14:55 ` [PATCH v3 16/16] KVM: arm64: enable ITS emulation as a virtual MSI controller Andre Przywara
2015-10-07 16:05 ` [PATCH v3 00/16] KVM: arm64: GICv3 ITS emulation Pavel Fedin
2015-10-07 16:22 ` Marc Zyngier
2015-10-07 18:09 ` Pavel Fedin
2015-10-07 19:48 ` Marc Zyngier
2015-10-08 8:41 ` Pavel Fedin
2015-10-10 15:37 ` Christoffer Dall
2015-10-12 14:12 ` Andre Przywara
2015-10-12 15:18 ` Pavel Fedin
2015-10-14 8:48 ` Eric Auger
2015-10-14 8:50 ` Pavel Fedin
2015-10-13 15:46 ` Pavel Fedin
2016-03-09 11:35 ` Tomasz Nowicki
2016-03-13 18:16 ` Christoffer Dall
2016-03-14 11:13 ` Andre Przywara
2016-03-14 17:29 ` Peter Maydell
2016-03-14 17:54 ` Marc Zyngier
2016-03-14 18:20 ` Andre Przywara
2016-03-14 18:36 ` Marc Zyngier
2016-03-18 9:40 ` Christoffer Dall
2016-03-18 17:14 ` Peter Maydell
2016-03-18 9:38 ` Christoffer Dall
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