From: Christoffer Dall <christoffer.dall@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
arm-mail-list <linux-arm-kernel@lists.infradead.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will.deacon@arm.com>,
Eric Auger <eric.auger@linaro.org>
Subject: Re: [RFC PATCH 3/9] irqchip: GIC: Convert to EOImode == 1
Date: Wed, 6 Aug 2014 13:30:54 +0200 [thread overview]
Message-ID: <20140806113054.GB14205@cbox> (raw)
In-Reply-To: <CAFEAcA_naeGVc+Rsec=Ds6Lzf345nzFj3Wg2RWY-6LWYv3euNQ@mail.gmail.com>
On Wed, Jun 25, 2014 at 03:06:33PM +0100, 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...
>
> (The correct fix, obviously, is to actually implement the QEMU
> support for split prio-drop and deactivate. Christoffer, you're our
> GIC emulation expert now, right? :-) )
>
Missed this. Sure, I can have a go at that some time, there are a
number of things I've been meaning to look at in the QEMU GIC emulation
code.
-Christoffer
next prev parent reply other threads:[~2014-08-06 11:31 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
2014-08-06 11:30 ` Christoffer Dall [this message]
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=20140806113054.GB14205@cbox \
--to=christoffer.dall@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=eric.auger@linaro.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=marc.zyngier@arm.com \
--cc=peter.maydell@linaro.org \
--cc=tglx@linutronix.de \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
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;
as well as URLs for NNTP newsgroup(s).