From: Marc Zyngier <maz@kernel.org>
To: Sunil Muthuswamy <sunilmut@microsoft.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"will@kernel.org" <will@kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Boqun Feng <Boqun.Feng@microsoft.com>,
KY Srinivasan <kys@microsoft.com>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [EXTERNAL] Re: [RFC 1/1] irqchip/gic-v3-its: Add irq domain and chip for Direct LPI without ITS
Date: Thu, 05 Aug 2021 09:35:17 +0100 [thread overview]
Message-ID: <87wnp0b86y.wl-maz@kernel.org> (raw)
In-Reply-To: <MW4PR21MB2002860BAED850B2B52D6E2BC0F19@MW4PR21MB2002.namprd21.prod.outlook.com>
On Wed, 04 Aug 2021 21:10:43 +0100,
Sunil Muthuswamy <sunilmut@microsoft.com> wrote:
>
> Thanks Marc and Robin for clarifying. I see and understand the point
> about having explicit MSI mappings in the firmware specification for
> Direct LPIs for generic hardware support.
>
> Hey Mark
I assume this is for me?
> would you be willing to consider a scoped down implementation of GIC
> Direct LPI with just an IRQ chip implementation and no Direct LPI
> PCI-MSI IRQ chip.
Could you please clarify? If you are not implementing MSIs, how can a
device signal LPIs? At the end of the day, something has to write into
the RD, and it isn't going to happen by sheer magic.
> This will allow a MSI provider (such as Hyper-V vPCI) to provide a
> PCI-MSI IRQ chip on top of the Direct LPI IRQ chip and enable
> PCI-MSI scenarios, and avoid building in assumptions in other cases
> (like PCI) where firmware specification is not available.
I really don't get what you are suggesting. Could you please describe
what you have in mind?
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2021-08-05 8:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-08 19:36 [RFC 1/1] irqchip/gic-v3-its: Add irq domain and chip for Direct LPI without ITS Sunil Muthuswamy
2021-07-11 11:09 ` Marc Zyngier
2021-07-26 15:33 ` [EXTERNAL] " Sunil Muthuswamy
2021-07-31 9:52 ` Marc Zyngier
2021-08-03 2:11 ` Sunil Muthuswamy
2021-08-03 8:35 ` Robin Murphy
2021-08-04 9:21 ` Marc Zyngier
2021-08-04 20:10 ` Sunil Muthuswamy
2021-08-05 8:35 ` Marc Zyngier [this message]
2021-08-06 19:14 ` Sunil Muthuswamy
2021-08-08 10:19 ` Marc Zyngier
2021-08-09 2:35 ` Sunil Muthuswamy
2021-08-09 9:15 ` Marc Zyngier
2021-08-10 1:10 ` Sunil Muthuswamy
2021-08-10 13:57 ` Marc Zyngier
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