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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	"Raj, Ashok" <ashok.raj@intel.com>, Marc Zyngier <maz@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Kevin Tian <kevin.tian@intel.com>,
	x86@kernel.org
Subject: [patch 6/8] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP
Date: Wed, 21 Jul 2021 21:11:32 +0200	[thread overview]
Message-ID: <20210721192650.687529735@linutronix.de> (raw)
In-Reply-To: <20210721191126.274946280@linutronix.de>

X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.

Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
---
 include/linux/irq.h |    2 ++
 kernel/irq/chip.c   |    5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -569,6 +569,7 @@ struct irq_chip {
  * IRQCHIP_SUPPORTS_NMI:              Chip can deliver NMIs, only for root irqchips
  * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND:  Invokes __enable_irq()/__disable_irq() for wake irqs
  *                                    in the suspend path if they are in disabled state
+ * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),
@@ -581,6 +582,7 @@ enum {
 	IRQCHIP_SUPPORTS_LEVEL_MSI		= (1 <<  7),
 	IRQCHIP_SUPPORTS_NMI			= (1 <<  8),
 	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
+	IRQCHIP_AFFINITY_PRE_STARTUP		= (1 << 10),
 };
 
 #include <linux/irqdesc.h>
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -265,8 +265,11 @@ int irq_startup(struct irq_desc *desc, b
 	} else {
 		switch (__irq_startup_managed(desc, aff, force)) {
 		case IRQ_STARTUP_NORMAL:
+			if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
+				irq_setup_affinity(desc);
 			ret = __irq_startup(desc);
-			irq_setup_affinity(desc);
+			if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP))
+				irq_setup_affinity(desc);
 			break;
 		case IRQ_STARTUP_MANAGED:
 			irq_do_set_affinity(d, aff, false);


  parent reply	other threads:[~2021-07-21 19:28 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-21 19:11 [patch 0/8] PCI/MSI, x86: Cure a couple of inconsistencies Thomas Gleixner
2021-07-21 19:11 ` [patch 1/8] PCI/MSI: Enable and mask MSIX early Thomas Gleixner
2021-07-21 21:38   ` Raj, Ashok
2021-07-21 22:51     ` Thomas Gleixner
2021-07-22 21:43   ` Bjorn Helgaas
2021-07-27 20:33     ` Thomas Gleixner
2021-07-21 19:11 ` [patch 2/8] PCI/MSI: Mask all unused MSI-X entries Thomas Gleixner
2021-07-21 22:23   ` Raj, Ashok
2021-07-21 22:57     ` Thomas Gleixner
2021-07-22 13:46       ` Marc Zyngier
2021-07-28 10:04         ` Thomas Gleixner
2021-07-22 21:45   ` Bjorn Helgaas
2021-07-21 19:11 ` [patch 3/8] PCI/MSI: Enforce that MSI-X table entry is masked for update Thomas Gleixner
2021-07-21 22:32   ` Raj, Ashok
2021-07-21 22:59     ` Thomas Gleixner
2021-07-22 21:46   ` Bjorn Helgaas
2021-07-21 19:11 ` [patch 4/8] PCI/MSI: Enforce MSI[X] entry updates to be visible Thomas Gleixner
2021-07-22 21:48   ` Bjorn Helgaas
     [not found]     ` <CAHp75VdNi4rMuRz8UrW9Haf_Ge8KmNJ0w9ykheqkVhmpXHTUyg@mail.gmail.com>
2021-07-23  8:14       ` Marc Zyngier
2021-07-21 19:11 ` [patch 5/8] PCI/MSI: Simplify msi_verify_entries() Thomas Gleixner
2021-07-21 19:11 ` Thomas Gleixner [this message]
2021-07-22 15:12   ` [patch 6/8] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP Marc Zyngier
2021-07-28 10:40     ` Thomas Gleixner
2021-07-21 19:11 ` [patch 7/8] x86/ioapic: Force affinity setup before startup Thomas Gleixner
2021-07-21 19:11 ` [patch 8/8] x86/msi: " Thomas Gleixner
2021-07-21 21:10 ` [patch 0/8] PCI/MSI, x86: Cure a couple of inconsistencies Raj, Ashok
2021-07-21 22:39   ` Thomas Gleixner
2021-07-22 15:17 ` Marc Zyngier
2021-07-22 21:43 ` Bjorn Helgaas
2021-07-27 20:38   ` Thomas Gleixner

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