From: Thomas Gleixner <tglx@kernel.org>
To: "Troy Mitchell" <troy.mitchell@linux.dev>,
"Anup Patel" <anup@brainfault.org>,
"Radu Rendec" <radu@rendec.net>, "Paul Walmsley" <pjw@kernel.org>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Albert Ou" <aou@eecs.berkeley.edu>,
"Alexandre Ghiti" <alex@ghiti.fr>,
"Björn Töpel" <bjorn@rivosinc.com>
Cc: Anup Patel <apatel@ventanamicro.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Troy Mitchell <troy.mitchell@linux.dev>
Subject: Re: [PATCH v2 2/2] irqchip/riscv-aplic: Apply pending affinity changes for level MSI sources
Date: Wed, 11 Nov 2026 01:09:20 +0100 [thread overview]
Message-ID: <87fqx8tej3.ffs@fw13> (raw)
In-Reply-To: <20261110-aplic-affinity-fix-v2-2-6c143b8b4e8c@linux.dev>
On Tue, Nov 10 2026 at 12:06, Troy Mitchell wrote:
> IMSIC rejects an affinity change with -EBUSY while a previous vector
> move is still in flight, and the IRQ core then records the new mask as
> pending. The change is applied by irq_move_irq() in the IMSIC irq_ack
> callback, but level-triggered APLIC MSI interrupts are handled by
> handle_fasteoi_irq(), which never calls irq_ack.
>
> The pending change is therefore never applied. While it is pending,
> later affinity changes only update the pending mask, so the interrupt
> stays on its old CPU.
>
> Use handle_fasteoi_ack_irq() for level-triggered sources. It acks the
> interrupt before invoking the handler, so a pending affinity change is
> applied on the next interrupt, and the EOI retrigger then targets the
> new CPU.
Smart!
prev parent reply other threads:[~2026-11-11 0:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 12:06 [PATCH v2 0/2] irqchip/riscv-aplic: Use trigger specific flow handlers in MSI mode Troy Mitchell
2026-11-10 12:06 ` [PATCH v2 1/2] irqchip/riscv-aplic: Use handle_edge_irq() for edge-triggered MSI sources Troy Mitchell
2026-11-11 0:07 ` Thomas Gleixner
2026-11-11 1:11 ` Troy Mitchell
2026-11-10 12:06 ` [PATCH v2 2/2] irqchip/riscv-aplic: Apply pending affinity changes for level " Troy Mitchell
2026-11-11 0:09 ` Thomas Gleixner [this message]
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