From: Christoffer Dall <christoffer.dall@linaro.org>
To: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org
Cc: Marc Zyngier <marc.zyngier@arm.com>,
Christoffer Dall <cdall@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Shih-Wei Li <shihwei@cs.columbia.edu>,
kvm@vger.kernel.org
Subject: [PATCH v4 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts
Date: Fri, 20 Oct 2017 13:49:31 +0200 [thread overview]
Message-ID: <20171020114939.12554-13-christoffer.dall@linaro.org> (raw)
In-Reply-To: <20171020114939.12554-1-christoffer.dall@linaro.org>
From: Christoffer Dall <cdall@linaro.org>
It is currently unclear how to set the VCPU affinity for a percpu_devid
interrupt , since the Linux irq_data structure describes the state for
multiple interrupts, one for each physical CPU on the system. Since
each such interrupt can be associated with different VCPUs or none at
all, associating a single VCPU state with such an interrupt does not
capture the necessary semantics.
The implementers of irq_set_affinity are the Intel and AMD IOMMUs, and
the ARM GIC irqchip. The Intel and AMD callers do not appear to use
percpu_devid interrupts, and the ARM GIC implementation only checks the
pointer against NULL vs. non-NULL.
Therefore, simply update the function documentation to explain the
expected use in the context of percpu_devid interrupts, allowing future
changes or additions to irqchip implementers to do the right thing.
This allows us to set the VCPU affinity for the virtual timer interrupt
in KVM/ARM, which is a percpu_devid (PPI) interrupt.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
kernel/irq/manage.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d00132b5c325..38ec7a83bf56 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -381,7 +381,8 @@ int irq_select_affinity_usr(unsigned int irq)
/**
* irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
* @irq: interrupt number to set affinity
- * @vcpu_info: vCPU specific data
+ * @vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
+ * specific data for percpu_devid interrupts
*
* This function uses the vCPU specific data to set the vCPU
* affinity for an irq. The vCPU specific data is passed from
--
2.14.2
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts
Date: Fri, 20 Oct 2017 13:49:31 +0200 [thread overview]
Message-ID: <20171020114939.12554-13-christoffer.dall@linaro.org> (raw)
In-Reply-To: <20171020114939.12554-1-christoffer.dall@linaro.org>
From: Christoffer Dall <cdall@linaro.org>
It is currently unclear how to set the VCPU affinity for a percpu_devid
interrupt , since the Linux irq_data structure describes the state for
multiple interrupts, one for each physical CPU on the system. Since
each such interrupt can be associated with different VCPUs or none at
all, associating a single VCPU state with such an interrupt does not
capture the necessary semantics.
The implementers of irq_set_affinity are the Intel and AMD IOMMUs, and
the ARM GIC irqchip. The Intel and AMD callers do not appear to use
percpu_devid interrupts, and the ARM GIC implementation only checks the
pointer against NULL vs. non-NULL.
Therefore, simply update the function documentation to explain the
expected use in the context of percpu_devid interrupts, allowing future
changes or additions to irqchip implementers to do the right thing.
This allows us to set the VCPU affinity for the virtual timer interrupt
in KVM/ARM, which is a percpu_devid (PPI) interrupt.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
kernel/irq/manage.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d00132b5c325..38ec7a83bf56 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -381,7 +381,8 @@ int irq_select_affinity_usr(unsigned int irq)
/**
* irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
* @irq: interrupt number to set affinity
- * @vcpu_info: vCPU specific data
+ * @vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
+ * specific data for percpu_devid interrupts
*
* This function uses the vCPU specific data to set the vCPU
* affinity for an irq. The vCPU specific data is passed from
--
2.14.2
next prev parent reply other threads:[~2017-10-20 11:49 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 11:49 [PATCH v4 00/20] KVM: arm/arm64: Optimize arch timer register handling Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 01/20] irqchip/gic: Deal with broken firmware exposing only 4kB of GICv2 CPU interface Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 02/20] arm64: Implement arch_counter_get_cntpct to read the physical counter Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:41 ` Marc Zyngier
2017-10-25 13:41 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 03/20] arm64: Use physical counter for in-kernel reads when booted in EL2 Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:43 ` Marc Zyngier
2017-10-25 13:43 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 04/20] KVM: arm/arm64: Guard kvm_vgic_map_is_active against !vgic_initialized Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 05/20] KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:45 ` Marc Zyngier
2017-10-25 13:45 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 06/20] KVM: arm/arm64: Check that system supports split eoi/deactivate Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:47 ` Marc Zyngier
2017-10-25 13:47 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 07/20] KVM: arm/arm64: Make timer_arm and timer_disarm helpers more generic Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:49 ` Marc Zyngier
2017-10-25 13:49 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 08/20] KVM: arm/arm64: Rename soft timer to bg_timer Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 09/20] KVM: arm/arm64: Move timer/vgic flush/sync under disabled irq Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 10/20] KVM: arm/arm64: Use separate timer for phys timer emulation Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 13:59 ` Marc Zyngier
2017-10-25 13:59 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 11/20] KVM: arm/arm64: Move timer save/restore out of the hyp code Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall [this message]
2017-10-20 11:49 ` [PATCH v4 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts Christoffer Dall
2017-10-20 11:56 ` Thomas Gleixner
2017-10-20 11:56 ` Thomas Gleixner
2017-10-21 14:29 ` Christoffer Dall
2017-10-21 14:29 ` Christoffer Dall
2017-10-21 14:55 ` Thomas Gleixner
2017-10-21 14:55 ` Thomas Gleixner
2017-10-21 15:30 ` Christoffer Dall
2017-10-21 15:30 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 13/20] KVM: arm/arm64: Set VCPU affinity for virt timer irq Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 14/20] KVM: arm/arm64: Avoid timer save/restore in vcpu entry/exit Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 14:36 ` Marc Zyngier
2017-10-25 14:36 ` Marc Zyngier
2017-11-16 20:30 ` Jintack Lim
2017-11-16 20:30 ` Jintack Lim
2017-11-16 20:32 ` Jintack Lim
2017-11-16 20:32 ` Jintack Lim
2017-11-20 11:15 ` Christoffer Dall
2017-11-20 11:15 ` Christoffer Dall
2017-11-20 16:32 ` Jintack Lim
2017-11-20 16:32 ` Jintack Lim
2017-10-20 11:49 ` [PATCH v4 15/20] KVM: arm/arm64: Support EL1 phys timer register access in set/get reg Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-25 14:38 ` Marc Zyngier
2017-10-25 14:38 ` Marc Zyngier
2017-10-20 11:49 ` [PATCH v4 16/20] KVM: arm/arm64: Use kvm_arm_timer_set/get_reg for guest register traps Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 17/20] KVM: arm/arm64: Move phys_timer_emulate function Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 18/20] KVM: arm/arm64: Avoid phys timer emulation in vcpu entry/exit Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 19/20] KVM: arm/arm64: Get rid of kvm_timer_flush_hwstate Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
2017-10-20 11:49 ` [PATCH v4 20/20] KVM: arm/arm64: Rework kvm_timer_should_fire Christoffer Dall
2017-10-20 11:49 ` Christoffer Dall
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