From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH 3/9] irqchip: GIC: Convert to EOImode == 1
Date: Wed, 25 Jun 2014 15:46:43 +0100 [thread overview]
Message-ID: <53AAE0D3.8030008@arm.com> (raw)
In-Reply-To: <CAFEAcA_naeGVc+Rsec=Ds6Lzf345nzFj3Wg2RWY-6LWYv3euNQ@mail.gmail.com>
On 25/06/14 15:06, Peter Maydell wrote:
> On 25 June 2014 10:28, Marc Zyngier <marc.zyngier@arm•com> wrote:
>> For this case, the GIC architecture provides EOImode == 1, where:
>> - A write to the EOI register drops the priority of the interrupt and leaves
>> it active. Other interrupts at the same priority level can now be taken,
>> but the active interrupt cannot be taken again
>> - A write to the DIR marks the interrupt as inactive, meaning it can
>> now be taken again.
>>
>> We only enable this feature when booted in HYP mode. Also, as most device
>> trees are broken (they report the CPU interface size to be 4kB, while
>> the GICv2 CPU interface size is 8kB), output a warning if we're booted
>> in HYP mode, and disable the feature.
>
> Does that mean you guarantee not to write to the DEACTIVATE register
> if not booted in Hyp mode? I ask because QEMU's GIC emulation doesn't
> emulate that register, so it would be useful to know if this patch
> means newer kernels are going to fall over under TCG QEMU...
So far, I only plan to support it when booted in HYP. But it may be that
the split prio-drop/deactivate is also beneficial to threaded
interrupts, saving the writes to the distributor to mask/unmask. That
would require to be a bit more subtle in identifying a GICv2
implementation (DT binding, probably).
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2014-06-25 14:46 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-25 9:28 [RFC PATCH 0/9] ARM: Forwarding physical interrupts to a guest VM Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 1/9] genirq: Add IRQD_IRQ_FORWARDED flag and accessors Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 2/9] genirq: Allow the state of a forwarded irq to be save/restored Marc Zyngier
2014-06-27 13:10 ` Will Deacon
2014-07-07 8:40 ` Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 3/9] irqchip: GIC: Convert to EOImode == 1 Marc Zyngier
2014-06-25 12:50 ` Rob Herring
2014-06-25 13:03 ` Marc Zyngier
2014-06-25 13:18 ` Rob Herring
2014-06-25 13:56 ` Anup Patel
2014-06-25 14:03 ` Ian Campbell
2014-06-25 14:31 ` Marc Zyngier
2014-06-25 14:08 ` Rob Herring
2014-06-25 14:24 ` Marc Zyngier
2014-06-25 14:27 ` Ian Campbell
2014-06-25 20:14 ` Joel Schopp
2014-06-30 19:09 ` Stefano Stabellini
2014-07-01 8:24 ` Marc Zyngier
2014-07-01 16:34 ` Stefano Stabellini
2014-07-01 16:42 ` Marc Zyngier
2014-06-25 14:06 ` Peter Maydell
2014-06-25 14:46 ` Marc Zyngier [this message]
2014-08-06 11:30 ` Christoffer Dall
2014-07-25 12:42 ` Eric Auger
2014-06-25 9:28 ` [RFC PATCH 4/9] irqchip: GIC: add support for forwarded interrupts Marc Zyngier
2014-06-27 13:17 ` Will Deacon
2014-07-07 10:43 ` Marc Zyngier
2014-08-06 11:30 ` Christoffer Dall
2014-06-25 9:28 ` [RFC PATCH 5/9] irqchip: GICv3: Convert to EOImode == 1 Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 6/9] irqchip: GICv3: add support for forwarded interrupts Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 7/9] KVM: arm: vgic: allow dynamic mapping of physical/virtual interrupts Marc Zyngier
2014-08-03 9:48 ` Eric Auger
2014-08-04 13:13 ` Marc Zyngier
2014-08-07 15:47 ` Eric Auger
2014-08-11 8:01 ` Christoffer Dall
2014-08-11 13:22 ` Eric Auger
2014-06-25 9:28 ` [RFC PATCH 8/9] arm: KVM: timer: move the timer switch into the non-preemptible section Marc Zyngier
2014-06-25 9:28 ` [RFC PATCH 9/9] KVM: arm: timer: make the interrupt state part of the timer state Marc Zyngier
2014-06-25 14:52 ` [RFC PATCH 0/9] ARM: Forwarding physical interrupts to a guest VM Eric Auger
2014-06-26 9:31 ` Marc Zyngier
2014-06-26 12:58 ` Eric Auger
2014-06-26 14:12 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=53AAE0D3.8030008@arm.com \
--to=marc.zyngier@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox