Message-ID: <56B8DEB8.4010509@arm.com>
Date:	Mon, 8 Feb 2016 18:30:16 +0000
From:	Marc Zyngier <marc.zyngier@....com>
To:	Julien Grall <julien.grall@....com>, kvmarm@...ts.cs.columbia.edu
Cc:	christoffer.dall@...aro.org, fu.wei@...aro.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, wei@...hat.com,
	al.stone@...aro.org, Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>
Subject: Re: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC
 information

Julien,

On 08/02/16 16:47, Julien Grall wrote:
> For now, the firmware tables are parsed 2 times: once in the GIC
> drivers, the other timer when initializing the vGIC. It means code
> duplication and make more tedious to add the support for another
> firmware table (like ACPI).
> 
> Introduce a new structure and set of helpers to get/set the virtual GIC
> information. Also fill up the structure for GICv2.
> 
> Signed-off-by: Julien Grall <julien.grall@....com>
> ---
> 
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Marc Zyngier <marc.zyngier@....com>
> 
>  drivers/irqchip/irq-gic-common.c       | 13 ++++++
>  drivers/irqchip/irq-gic-common.h       |  3 ++
>  drivers/irqchip/irq-gic.c              | 78 +++++++++++++++++++++++++++++++++-
>  include/linux/irqchip/arm-gic-common.h | 34 +++++++++++++++
>  4 files changed, 127 insertions(+), 1 deletion(-)
>  create mode 100644 include/linux/irqchip/arm-gic-common.h
> 
> diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c
> index f174ce0..704caf4 100644
> --- a/drivers/irqchip/irq-gic-common.c
> +++ b/drivers/irqchip/irq-gic-common.c
> @@ -21,6 +21,19 @@
>  
>  #include "irq-gic-common.h"
>  
> +static const struct gic_kvm_info *gic_kvm_info;
> +
> +const struct gic_kvm_info *gic_get_kvm_info(void)
> +{
> +	return gic_kvm_info;
> +}
> +
> +void gic_set_kvm_info(const struct gic_kvm_info *info)
> +{
> +	WARN(gic_kvm_info != NULL, "gic_kvm_info already set\n");
> +	gic_kvm_info = info;
> +}
> +
>  void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
>  		void *data)
>  {
> diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h
> index fff697d..205e5fd 100644
> --- a/drivers/irqchip/irq-gic-common.h
> +++ b/drivers/irqchip/irq-gic-common.h
> @@ -19,6 +19,7 @@
>  
>  #include <linux/of.h>
>  #include <linux/irqdomain.h>
> +#include <linux/irqchip/arm-gic-common.h>
>  
>  struct gic_quirk {
>  	const char *desc;
> @@ -35,4 +36,6 @@ void gic_cpu_config(void __iomem *base, void (*sync_access)(void));
>  void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
>  		void *data);
>  
> +void gic_set_kvm_info(const struct gic_kvm_info *info);
> +
>  #endif /* _IRQ_GIC_COMMON_H */
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 911758c..d3a09a4 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -102,6 +102,8 @@ static struct static_key supports_deactivate = STATIC_KEY_INIT_TRUE;
>  
>  static struct gic_chip_data gic_data[CONFIG_ARM_GIC_MAX_NR] __read_mostly;
>  
> +static struct gic_kvm_info gic_v2_kvm_info;
> +
>  #ifdef CONFIG_GIC_NON_BANKED
>  static void __iomem *gic_get_percpu_base(union gic_base *base)
>  {
> @@ -1190,6 +1192,44 @@ static bool gic_check_eoimode(struct device_node *node, void __iomem **base)
>  	return true;
>  }
>  
> +static void __init gic_of_setup_kvm_info(struct device_node *node)
> +{
> +	int ret;
> +	struct resource r;
> +	unsigned int irq;
> +
> +	gic_v2_kvm_info.type = GIC_V2;
> +
> +	irq = irq_of_parse_and_map(node, 0);
> +	if (!irq)
> +		gic_v2_kvm_info.maint_irq = -1;

Please don't do that. 0 *is* the value for an invalid interrupt, and
this is what you should expose here. Same for GICv3.

> +	else
> +		gic_v2_kvm_info.maint_irq = irq;
> +
> +	ret = of_address_to_resource(node, 2, &r);
> +	if (!ret) {
> +		gic_v2_kvm_info.vctrl_base = r.start;
> +		gic_v2_kvm_info.vctrl_size = resource_size(&r);
> +	}
> +
> +	ret = of_address_to_resource(node, 3, &r);
> +	if (!ret) {
> +		if (!PAGE_ALIGNED(r.start))
> +			pr_warn("GICV physical address 0x%llx not page aligned\n",
> +				(unsigned long long)r.start);
> +		else if (!PAGE_ALIGNED(resource_size(&r)))
> +			pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
> +				(unsigned long long)resource_size(&r),
> +				PAGE_SIZE);
> +		else {
> +			gic_v2_kvm_info.vcpu_base = r.start;
> +			gic_v2_kvm_info.vcpu_size = resource_size(&r);

This tends to make me think that this should actually be a proper
resource, and not a set of arbitrary fields.

> +		}
> +	}
> +
> +	gic_set_kvm_info(&gic_v2_kvm_info);
> +}
> +
>  int __init
>  gic_of_init(struct device_node *node, struct device_node *parent)
>  {
> @@ -1219,8 +1259,10 @@ gic_of_init(struct device_node *node, struct device_node *parent)
>  
>  	__gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset,
>  			 &node->fwnode);
> -	if (!gic_cnt)
> +	if (!gic_cnt) {
>  		gic_init_physaddr(node);
> +		gic_of_setup_kvm_info(node);
> +	}
>  
>  	if (parent) {
>  		irq = irq_of_parse_and_map(node, 0);
> @@ -1247,6 +1289,32 @@ IRQCHIP_DECLARE(pl390, "arm,pl390", gic_of_init);
>  
>  #ifdef CONFIG_ACPI
>  static phys_addr_t cpu_phy_base __initdata;
> +static struct
> +{
> +	u32 maint_irq;
> +	int maint_irq_mode;
> +	phys_addr_t vctrl_base;
> +	phys_addr_t vcpu_base;
> +} acpi_data __initdata;
> +
> +static void __init gic_acpi_setup_kvm_info(void)
> +{
> +	gic_v2_kvm_info.type = GIC_V2;
> +
> +	gic_v2_kvm_info.maint_irq = acpi_register_gsi(NULL,
> +						      acpi_data.maint_irq,
> +						      acpi_data.maint_irq_mode,
> +						      ACPI_ACTIVE_HIGH);
> +	gic_v2_kvm_info.vctrl_base = acpi_data.vctrl_base;
> +	if (gic_v2_kvm_info.vctrl_base)
> +		gic_v2_kvm_info.vctrl_size = SZ_8K;
> +
> +	gic_v2_kvm_info.vcpu_base = acpi_data.vcpu_base;
> +	if (gic_v2_kvm_info.vcpu_base)
> +		gic_v2_kvm_info.vcpu_size = SZ_8K;
> +
> +	gic_set_kvm_info(&gic_v2_kvm_info);
> +}
>  
>  static int __init
>  gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
> @@ -1270,6 +1338,12 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
>  		return -EINVAL;
>  
>  	cpu_phy_base = gic_cpu_base;
> +	acpi_data.maint_irq = processor->vgic_interrupt;
> +	acpi_data.maint_irq_mode = (processor->flags & ACPI_MADT_VGIC_IRQ_MODE) ?
> +				    ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> +	acpi_data.vctrl_base = processor->gich_base_address;
> +	acpi_data.vcpu_base = processor->gicv_base_address;
> +

Maybe you can now move all the ACPI data into this acpi_data structure?
This would allow for slightly less clutter...

>  	cpu_base_assigned = 1;
>  	return 0;
>  }
> @@ -1357,6 +1431,8 @@ static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
>  	if (IS_ENABLED(CONFIG_ARM_GIC_V2M))
>  		gicv2m_init(NULL, gic_data[0].domain);
>  
> +	gic_acpi_setup_kvm_info();
> +
>  	return 0;
>  }
>  IRQCHIP_ACPI_DECLARE(gic_v2, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
> diff --git a/include/linux/irqchip/arm-gic-common.h b/include/linux/irqchip/arm-gic-common.h
> new file mode 100644
> index 0000000..30972b1
> --- /dev/null
> +++ b/include/linux/irqchip/arm-gic-common.h
> @@ -0,0 +1,34 @@
> +/*
> + * include/linux/irqchip/arm-gic-common.h
> + *
> + * Copyright (C) 2016 ARM Limited, All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#ifndef __LINUX_IRQCHIP_ARM_GIC_COMMON_H
> +#define __LINUX_IRQCHIP_ARM_GIC_COMMON_H
> +
> +#include <linux/types.h>
> +
> +enum gic_type {
> +	GIC_V2,
> +};
> +
> +struct gic_kvm_info {
> +	/* GIC type */
> +	enum gic_type	type;
> +	/* Physical address & size of virtual cpu interface */
> +	phys_addr_t	vcpu_base;
> +	resource_size_t	vcpu_size;
> +	/* Interrupt number */
> +	int		maint_irq;
> +	/* Physical address & size of virtual control interface */
> +	phys_addr_t	vctrl_base;
> +	resource_size_t	vctrl_size;
> +};
> +
> +const struct gic_kvm_info *gic_get_kvm_info(void);
> +
> +#endif /* __LINUX_IRQCHIP_ARM_GIC_COMMON_H */
> 

Thanks,

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

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