From: Thomas Gleixner <tglx@linutronix.de>
To: Anup Patel <apatel@ventanamicro.com>, Jonathan Corbet <corbet@lwn.net>
Cc: Anup Patel <anup@brainfault.org>,
Atish Patra <atish.patra@linux.dev>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Alexandre Ghiti <alex@ghiti.fr>,
Andrew Jones <ajones@ventanamicro.com>,
linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org,
Anup Patel <apatel@ventanamicro.com>
Subject: Re: [PATCH] irqchip: riscv-imsic: Add kernel parameter to disable IPIs
Date: Mon, 30 Jun 2025 18:09:24 +0200 [thread overview]
Message-ID: <87wm8tmcsr.ffs@tglx> (raw)
In-Reply-To: <20250625161715.1003948-1-apatel@ventanamicro.com>
On Wed, Jun 25 2025 at 21:47, Anup Patel wrote:
$Subject...
https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#patch-subject
Is it that hard?
> When injecting IPIs to a set of harts, the IMSIC IPI support will
> do a separate MMIO write to SETIPNUM_LE register of each target
> hart. This means on a platform where IMSIC is trap-n-emulated,
> there will be N MMIO traps when injecting IPI to N target harts
> hence IPIs based on IMSIC software injected MSI is slow compared
> to the SBI IPI extension.
>
> Add a kernel parameter to disable IPIs in IMSIC driver for platforms
> with trap-n-emulated IMSIC.
Why do you need a kernel parameter for that. If the platform uses trap-n
emulation, then disable the IPI muck automatically, no?
Thanks,
tglx
next prev parent reply other threads:[~2025-06-30 16:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-25 16:17 [PATCH] irqchip: riscv-imsic: Add kernel parameter to disable IPIs Anup Patel
2025-06-30 16:09 ` Thomas Gleixner [this message]
2025-07-01 6:30 ` Anup Patel
2025-07-01 7:34 ` Thomas Gleixner
2025-07-02 11:04 ` Anup Patel
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