From: Thomas Gleixner <tglx@kernel.org>
To: Naman Jain <namjain@linux.microsoft.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Wei Liu <wei.liu@kernel.org>,
"K . Y . Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Dexuan Cui <decui@microsoft.com>
Cc: "Michael Kelley" <mhklinux@outlook.com>,
"Long Li" <longli@microsoft.com>,
"Nam Cao" <namcao@linutronix.de>,
"Joerg Roedel" <joro@8bytes.org>,
"Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>,
"Vasant Hegde" <vasant.hegde@amd.com>,
"Will Deacon" <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Kees Cook" <kees@kernel.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
"Radu Rendec" <radu@rendec.net>,
"Sean Christopherson" <seanjc@google.com>,
"Kai Huang" <kai.huang@intel.com>,
"Dmitry Ilvokhin" <d@ilvokhin.com>,
"Shradha Gupta" <shradhagupta@linux.microsoft.com>,
"Christophe JAILLET" <christophe.jaillet@wanadoo.fr>,
"Thierry Reding" <treding@nvidia.com>,
"Jiri Wiesner" <jwiesner@suse.de>,
"Daniel J Blueman" <daniel@quora.org>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux.dev, linux-pci@vger.kernel.org
Subject: Re: [PATCH v3 2/3] x86/irq: Fall back to irq_chip_retrigger_hierarchy() in fixup_irqs()
Date: Mon, 07 Sep 2026 15:12:44 +0200 [thread overview]
Message-ID: <87qzj52oj7.ffs@fw13> (raw)
In-Reply-To: <20260907065129.269262-3-namjain@linux.microsoft.com>
On Mon, Sep 07 2026 at 06:51, Naman Jain wrote:
> fixup_irqs() re-injects a pending interrupt on its new target CPU by
> looking at the outermost domain chip and invoking its irq_retrigger()
> callback directly. When the outermost chip does not implement
> irq_retrigger(), the pending interrupt is silently dropped, which can
> lead to lost interrupts on CPU hot-unplug.
>
> Keep calling the outermost chip's irq_retrigger() when it is present,
> but fall back to irq_chip_retrigger_hierarchy() otherwise, which walks
> up the interrupt hierarchy until it finds a chip that implements
> irq_retrigger().
>
> While at it, use a scoped guard for desc->lock. VECTOR_RETRIGGERED is
> now set only when the retrigger succeeds instead of unconditionally,
> which is harmless today since apic_retrigger_irq() always returns 1.
>
> Suggested-by: Thomas Gleixner <tglx@kernel.org>
> Reviewed-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
next prev parent reply other threads:[~2026-09-07 13:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-07 6:51 [PATCH v3 0/3] x86/irq: Fix lost interrupts on CPU hot-unplug Naman Jain
2026-09-07 6:51 ` [PATCH v3 1/3] x86/hyperv: Set irq_retrigger for root partition PCI/MSI irqchip Naman Jain
2026-09-07 19:53 ` Michael Kelley
2026-09-08 5:43 ` Naman Jain
2026-09-08 6:25 ` Nam Cao
2026-09-08 6:27 ` Naman Jain
2026-09-07 6:51 ` [PATCH v3 2/3] x86/irq: Fall back to irq_chip_retrigger_hierarchy() in fixup_irqs() Naman Jain
2026-09-07 13:12 ` Thomas Gleixner [this message]
2026-09-07 19:54 ` Michael Kelley
2026-09-07 6:51 ` [PATCH v3 3/3] x86/irq, iommu/amd, x86/hyperv, PCI: Drop redundant irq_retrigger inits Naman Jain
2026-09-07 13:13 ` Thomas Gleixner
2026-09-07 19:54 ` Michael Kelley
2026-09-08 5:43 ` Naman Jain
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