Re: [PATCH v5 6/9] irqchip/gic-v3: Parse and export virtual GIC information

[Shanker Donthineni]

Hi Julien,

On 04/04/2016 06:37 AM, Julien Grall wrote:
> Fill up the recently introduced gic_kvm_info with the hardware
> information used for virtualization.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
>
> ---
>     Changes in v5:
>         - Remove the alignment check for GICV. It's already done in the
>         KVM code.
>         - Fix initialization of KVM with ACPI.
>
>     Changes in v4:
>         - Change the flow to call gic_kvm_set_info only when all the
>         mandatory information are valid.
>         - Remove unecessary code in ACPI parsing (the virtual control
>         interface doesn't exist for GICv3).
>         - Rework commit message
>         - Rework the ACPI support as it didn't collect hardware info for
>         virtualization when there is more than 1 redistributor region
>
>     Changes in v3:
>         - Add ACPI support
>
>     Changes in v2:
>         - Use 0 rather than a negative value to know when the maintenance
> IRQ
>         is not present.
>         - Use resource for vcpu and vctrl
> ---
>  drivers/irqchip/irq-gic-v3.c           | 110
> ++++++++++++++++++++++++++++++++-
>  include/linux/irqchip/arm-gic-common.h |   1 +
>  2 files changed, 110 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index 50e87e6..08afbfe 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -28,6 +28,7 @@
>  #include <linux/slab.h>
>  
>  #include <linux/irqchip.h>
> +#include <linux/irqchip/arm-gic-common.h>
>  #include <linux/irqchip/arm-gic-v3.h>
>  
>  #include <asm/cputype.h>
> @@ -56,6 +57,8 @@ struct gic_chip_data {
>  static struct gic_chip_data gic_data __read_mostly;
>  static struct static_key supports_deactivate = STATIC_KEY_INIT_TRUE;
>  
> +static struct gic_kvm_info gic_v3_kvm_info;
> +
>  #define gic_data_rdist()
> (this_cpu_ptr(gic_data.rdists.rdist))
>  #define gic_data_rdist_rd_base()	(gic_data_rdist()->rd_base)
>  #define gic_data_rdist_sgi_base()	(gic_data_rdist_rd_base() +
> SZ_64K)
> @@ -901,6 +904,30 @@ static int __init gic_validate_dist_version(void
> __iomem *dist_base)
>  	return 0;
>  }
>  
> +static void __init gic_of_setup_kvm_info(struct device_node *node)
> +{
> +	int ret;
> +	struct resource r;
> +	u32 gicv_idx;
> +
> +	gic_v3_kvm_info.type = GIC_V3;
> +
> +	gic_v3_kvm_info.maint_irq = irq_of_parse_and_map(node, 0);
> +	if (!gic_v3_kvm_info.maint_irq)
> +		return;
> +
> +	if (of_property_read_u32(node, "#redistributor-regions",
> +				 &gicv_idx))
> +		gicv_idx = 1;
> +
> +	gicv_idx += 3;	/* Also skip GICD, GICC, GICH */
> +	ret = of_address_to_resource(node, gicv_idx, &r);
> +	if (!ret)
> +		gic_v3_kvm_info.vcpu = r;
> +
> +	gic_set_kvm_info(&gic_v3_kvm_info);
> +}
> +
>  static int __init gic_of_init(struct device_node *node, struct
> device_node *parent)
>  {
>  	void __iomem *dist_base;
> @@ -952,8 +979,10 @@ static int __init gic_of_init(struct device_node
> *node, struct device_node *pare
>  
>  	err = gic_init_bases(dist_base, rdist_regs, nr_redist_regions,
>  			     redist_stride, &node->fwnode);
> -	if (!err)
> +	if (!err) {
> +		gic_of_setup_kvm_info(node);
>  		return 0;
> +	}
>  
>  out_unmap_rdist:
>  	for (i = 0; i < nr_redist_regions; i++)
> @@ -974,6 +1003,9 @@ static struct
>  	struct redist_region *redist_regs;
>  	u32 nr_redist_regions;
>  	bool single_redist;
> +	u32 maint_irq;
> +	int maint_irq_mode;
> +	phys_addr_t vcpu_base;
>  } acpi_data __initdata;
>  
>  static void __init
> @@ -1110,7 +1142,81 @@ static bool __init acpi_validate_gic_table(struct
> acpi_subtable_header *header,
>  	return true;
>  }
>  
> +static int __init gic_acpi_parse_virt_madt_gicc(struct
> acpi_subtable_header *header,
> +						const unsigned long end)
> +{
> +	struct acpi_madt_generic_interrupt *gicc =
> +		(struct acpi_madt_generic_interrupt *)header;
> +	int maint_irq_mode;
> +	static int first_madt = true;
> +
> +	maint_irq_mode = (gicc->flags & ACPI_MADT_VGIC_IRQ_MODE) ?
> +		ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> +
Do you think GICC parameters are valid for an unusable processor?
If not we need a validation check here, some thing like this to skip
GICC subtable entry.
 
            if (!(gicc->flags & ACPI_MADT_ENABLED))
                return 0;

> +	if (first_madt) {
> +		first_madt = false;
> +
> +		acpi_data.maint_irq = gicc->vgic_interrupt;
> +		acpi_data.maint_irq_mode = maint_irq_mode;
> +		acpi_data.vcpu_base = gicc->gicv_base_address;
> +
> +		return 0;
> +	}
> +
> +	/*
> +	 * The maintenance interrupt and GICV should be the same for every
> CPU
> +	 */
> +	if ((acpi_data.maint_irq != gicc->vgic_interrupt) ||
> +	    (acpi_data.maint_irq_mode != maint_irq_mode) ||
> +	    (acpi_data.vcpu_base != gicc->gicv_base_address))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static bool __init gic_acpi_collect_virt_info(void)
> +{
> +	int count;
> +
> +	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
> +				      gic_acpi_parse_virt_madt_gicc, 0);
> +
> +	return (count > 0);
> +}
> +
>  #define ACPI_GICV3_DIST_MEM_SIZE (SZ_64K)
> +#define ACPI_GICV2_VCTRL_MEM_SIZE	(SZ_4K)
> +#define ACPI_GICV2_VCPU_MEM_SIZE	(SZ_8K)
> +
> +static void __init gic_acpi_setup_kvm_info(void)
> +{
> +	int irq;
> +
> +	if (!gic_acpi_collect_virt_info()) {
> +		pr_warn("Unable to get hardware information used for
> virtualization\n");
> +		return;
> +	}
> +
> +	gic_v3_kvm_info.type = GIC_V3;
> +
> +	irq = acpi_register_gsi(NULL, acpi_data.maint_irq,
> +				acpi_data.maint_irq_mode,
> +				ACPI_ACTIVE_HIGH);
> +	if (irq <= 0)
> +		return;
> +
> +	gic_v3_kvm_info.maint_irq = irq;
> +
> +	if (acpi_data.vcpu_base) {
> +		struct resource *vcpu = &gic_v3_kvm_info.vcpu;
> +
> +		vcpu->flags = IORESOURCE_MEM;
> +		vcpu->start = acpi_data.vcpu_base;
> +		vcpu->end = vcpu->start + ACPI_GICV2_VCPU_MEM_SIZE - 1;
> +	}
> +
> +	gic_set_kvm_info(&gic_v3_kvm_info);
> +}
>  
>  static int __init
>  gic_acpi_init(struct acpi_subtable_header *header, const unsigned long
> end)
> @@ -1159,6 +1265,8 @@ gic_acpi_init(struct acpi_subtable_header *header,
> const unsigned long end)
>  		goto out_fwhandle_free;
>  
>  	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle);
> +	gic_acpi_setup_kvm_info();
> +
>  	return 0;
>  
>  out_fwhandle_free:
> diff --git a/include/linux/irqchip/arm-gic-common.h
> b/include/linux/irqchip/arm-gic-common.h
> index ef34f6f..c647b05 100644
> --- a/include/linux/irqchip/arm-gic-common.h
> +++ b/include/linux/irqchip/arm-gic-common.h
> @@ -15,6 +15,7 @@
>  
>  enum gic_type {
>  	GIC_V2,
> +	GIC_V3,
>  };
>  
>  struct gic_kvm_info {

-- 
Shanker Donthineni
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project