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From: Marc Zyngier <marc.zyngier@arm.com>
To: Christoffer Dall <cdall@linaro.org>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Cc: kvm@vger.kernel.org, Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts
Date: Mon, 9 Oct 2017 18:48:33 +0100	[thread overview]
Message-ID: <1a21ed0e-39eb-a5a3-5cda-3a51d9f9c8da@arm.com> (raw)
In-Reply-To: <20170923004207.22356-13-cdall@linaro.org>

On 23/09/17 01:41, Christoffer Dall wrote:
> 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 573dc52..2b2c94f 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
> 

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.
-- 
Jazz is not dead. It just smells funny...

WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts
Date: Mon, 9 Oct 2017 18:48:33 +0100	[thread overview]
Message-ID: <1a21ed0e-39eb-a5a3-5cda-3a51d9f9c8da@arm.com> (raw)
In-Reply-To: <20170923004207.22356-13-cdall@linaro.org>

On 23/09/17 01:41, Christoffer Dall wrote:
> 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 573dc52..2b2c94f 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
> 

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2017-10-09 17:48 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-23  0:41 [PATCH v3 00/20] KVM: arm/arm64: Optimize arch timer register handling Christoffer Dall
2017-09-23  0:41 ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 01/20] irqchip/gic: Deal with broken firmware exposing only 4kB of GICv2 CPU interface Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 02/20] arm64: Use physical counter for in-kernel reads Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 16:10   ` Marc Zyngier
2017-10-09 16:10     ` Marc Zyngier
2017-10-17 15:33   ` Will Deacon
2017-10-17 15:33     ` Will Deacon
2017-10-18 10:00     ` Christoffer Dall
2017-10-18 10:00       ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 03/20] arm64: Use the physical counter when available for read_cycles Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 16:21   ` Marc Zyngier
2017-10-09 16:21     ` Marc Zyngier
2017-10-18 11:34     ` Christoffer Dall
2017-10-18 11:34       ` Christoffer Dall
2017-10-18 15:52       ` Marc Zyngier
2017-10-18 15:52         ` Marc Zyngier
2017-09-23  0:41 ` [PATCH v3 04/20] KVM: arm/arm64: Guard kvm_vgic_map_is_active against !vgic_initialized Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 16:22   ` Marc Zyngier
2017-10-09 16:22     ` Marc Zyngier
2017-09-23  0:41 ` [PATCH v3 05/20] KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 16:37   ` Marc Zyngier
2017-10-09 16:37     ` Marc Zyngier
2017-10-18 11:54     ` Christoffer Dall
2017-10-18 11:54       ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 06/20] KVM: arm/arm64: Check that system supports split eoi/deactivate Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 16:47   ` Marc Zyngier
2017-10-09 16:47     ` Marc Zyngier
2017-10-18 13:41     ` Christoffer Dall
2017-10-18 13:41       ` Christoffer Dall
2017-10-18 16:03       ` Marc Zyngier
2017-10-18 16:03         ` Marc Zyngier
2017-10-18 19:16         ` Christoffer Dall
2017-10-18 19:16           ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 07/20] KVM: arm/arm64: Make timer_arm and timer_disarm helpers more generic Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:05   ` Marc Zyngier
2017-10-09 17:05     ` Marc Zyngier
2017-10-18 16:47     ` Christoffer Dall
2017-10-18 16:47       ` Christoffer Dall
2017-10-18 16:53       ` Marc Zyngier
2017-10-18 16:53         ` Marc Zyngier
2017-09-23  0:41 ` [PATCH v3 08/20] KVM: arm/arm64: Rename soft timer to bg_timer Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:06   ` Marc Zyngier
2017-10-09 17:06     ` Marc Zyngier
2017-09-23  0:41 ` [PATCH v3 09/20] KVM: arm/arm64: Use separate timer for phys timer emulation Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:23   ` Marc Zyngier
2017-10-09 17:23     ` Marc Zyngier
2017-10-19  7:38     ` Christoffer Dall
2017-10-19  7:38       ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 10/20] KVM: arm/arm64: Move timer/vgic flush/sync under disabled irq Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:34   ` Marc Zyngier
2017-10-09 17:34     ` Marc Zyngier
2017-09-23  0:41 ` [PATCH v3 11/20] KVM: arm/arm64: Move timer save/restore out of the hyp code Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:47   ` Marc Zyngier
2017-10-09 17:47     ` Marc Zyngier
2017-10-19  7:46     ` Christoffer Dall
2017-10-19  7:46       ` Christoffer Dall
2017-09-23  0:41 ` [PATCH v3 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts Christoffer Dall
2017-09-23  0:41   ` Christoffer Dall
2017-10-09 17:48   ` Marc Zyngier [this message]
2017-10-09 17:48     ` Marc Zyngier
2017-09-23  0:42 ` [PATCH v3 13/20] KVM: arm/arm64: Set VCPU affinity for virt timer irq Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-09 17:52   ` Marc Zyngier
2017-10-09 17:52     ` Marc Zyngier
2017-09-23  0:42 ` [PATCH v3 14/20] KVM: arm/arm64: Avoid timer save/restore in vcpu entry/exit Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  8:47   ` Marc Zyngier
2017-10-10  8:47     ` Marc Zyngier
2017-10-19  8:15     ` Christoffer Dall
2017-10-19  8:15       ` Christoffer Dall
2017-09-23  0:42 ` [PATCH v3 15/20] KVM: arm/arm64: Support EL1 phys timer register access in set/get reg Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:10   ` Marc Zyngier
2017-10-10  9:10     ` Marc Zyngier
2017-10-19  8:32     ` Christoffer Dall
2017-10-19  8:32       ` Christoffer Dall
2017-09-23  0:42 ` [PATCH v3 16/20] KVM: arm/arm64: Use kvm_arm_timer_set/get_reg for guest register traps Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:12   ` Marc Zyngier
2017-10-10  9:12     ` Marc Zyngier
2017-09-23  0:42 ` [PATCH v3 17/20] KVM: arm/arm64: Move phys_timer_emulate function Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:21   ` Marc Zyngier
2017-10-10  9:21     ` Marc Zyngier
2017-09-23  0:42 ` [PATCH v3 18/20] KVM: arm/arm64: Avoid phys timer emulation in vcpu entry/exit Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:45   ` Marc Zyngier
2017-10-10  9:45     ` Marc Zyngier
2017-10-19  8:44     ` Christoffer Dall
2017-10-19  8:44       ` Christoffer Dall
2017-09-23  0:42 ` [PATCH v3 19/20] KVM: arm/arm64: Get rid of kvm_timer_flush_hwstate Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:46   ` Marc Zyngier
2017-10-10  9:46     ` Marc Zyngier
2017-09-23  0:42 ` [PATCH v3 20/20] KVM: arm/arm64: Rework kvm_timer_should_fire Christoffer Dall
2017-09-23  0:42   ` Christoffer Dall
2017-10-10  9:59   ` Marc Zyngier
2017-10-10  9:59     ` Marc Zyngier

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