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

Hanjun Guo
2016-04-11T05:26:30Z

On 2016/4/4 19:37, 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@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
>
> ---
> 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;
> +
> + 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) {

Sorry, I'm not familiar with KVM, but I got a question here, will
KVM works without valid vcpu_base in GICv3 mode?

Thanks
Hanjun