Re: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC information

Marc Zyngier
2016-02-08T18:30:16Z

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@arm.com>
> ---
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <marc.zyngier@arm.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...