root/arch/x86/xen/smp.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/slab.h>
#include <linux/cpumask.h>
#include <linux/percpu.h>

#include <xen/events.h>

#include <xen/hvc-console.h>
#include "xen-ops.h"

static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq) = { .irq = -1 };
static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq = -1 };
static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = { .irq = -1 };
static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 };

static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);

/*
 * Reschedule call back.
 */
static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
{
        inc_irq_stat(irq_resched_count);
        scheduler_ipi();

        return IRQ_HANDLED;
}

void xen_smp_intr_free(unsigned int cpu)
{
        kfree(per_cpu(xen_resched_irq, cpu).name);
        per_cpu(xen_resched_irq, cpu).name = NULL;
        if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
                unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
                per_cpu(xen_resched_irq, cpu).irq = -1;
        }
        kfree(per_cpu(xen_callfunc_irq, cpu).name);
        per_cpu(xen_callfunc_irq, cpu).name = NULL;
        if (per_cpu(xen_callfunc_irq, cpu).irq >= 0) {
                unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu).irq, NULL);
                per_cpu(xen_callfunc_irq, cpu).irq = -1;
        }
        kfree(per_cpu(xen_debug_irq, cpu).name);
        per_cpu(xen_debug_irq, cpu).name = NULL;
        if (per_cpu(xen_debug_irq, cpu).irq >= 0) {
                unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu).irq, NULL);
                per_cpu(xen_debug_irq, cpu).irq = -1;
        }
        kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
        per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
        if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
                unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
                                       NULL);
                per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
        }
}

int xen_smp_intr_init(unsigned int cpu)
{
        int rc;
        char *resched_name, *callfunc_name, *debug_name;

        resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
        if (!resched_name)
                goto fail_mem;
        per_cpu(xen_resched_irq, cpu).name = resched_name;
        rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
                                    cpu,
                                    xen_reschedule_interrupt,
                                    IRQF_PERCPU|IRQF_NOBALANCING,
                                    resched_name,
                                    NULL);
        if (rc < 0)
                goto fail;
        per_cpu(xen_resched_irq, cpu).irq = rc;

        callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
        if (!callfunc_name)
                goto fail_mem;
        per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;
        rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
                                    cpu,
                                    xen_call_function_interrupt,
                                    IRQF_PERCPU|IRQF_NOBALANCING,
                                    callfunc_name,
                                    NULL);
        if (rc < 0)
                goto fail;
        per_cpu(xen_callfunc_irq, cpu).irq = rc;

        if (!xen_fifo_events) {
                debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
                if (!debug_name)
                        goto fail_mem;

                per_cpu(xen_debug_irq, cpu).name = debug_name;
                rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu,
                                             xen_debug_interrupt,
                                             IRQF_PERCPU | IRQF_NOBALANCING,
                                             debug_name, NULL);
                if (rc < 0)
                        goto fail;
                per_cpu(xen_debug_irq, cpu).irq = rc;
        }

        callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
        if (!callfunc_name)
                goto fail_mem;

        per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
        rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
                                    cpu,
                                    xen_call_function_single_interrupt,
                                    IRQF_PERCPU|IRQF_NOBALANCING,
                                    callfunc_name,
                                    NULL);
        if (rc < 0)
                goto fail;
        per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;

        return 0;

 fail_mem:
        rc = -ENOMEM;
 fail:
        xen_smp_intr_free(cpu);
        return rc;
}

void __init xen_smp_cpus_done(unsigned int max_cpus)
{
        if (xen_hvm_domain())
                native_smp_cpus_done(max_cpus);
}

void xen_smp_send_reschedule(int cpu)
{
        xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
}

static void __xen_send_IPI_mask(const struct cpumask *mask,
                              int vector)
{
        unsigned cpu;

        for_each_cpu_and(cpu, mask, cpu_online_mask)
                xen_send_IPI_one(cpu, vector);
}

void xen_smp_send_call_function_ipi(const struct cpumask *mask)
{
        int cpu;

        __xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);

        /* Make sure other vcpus get a chance to run if they need to. */
        for_each_cpu(cpu, mask) {
                if (xen_vcpu_stolen(cpu)) {
                        HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
                        break;
                }
        }
}

void xen_smp_send_call_function_single_ipi(int cpu)
{
        __xen_send_IPI_mask(cpumask_of(cpu),
                          XEN_CALL_FUNCTION_SINGLE_VECTOR);
}

static inline int xen_map_vector(int vector)
{
        int xen_vector;

        switch (vector) {
        case RESCHEDULE_VECTOR:
                xen_vector = XEN_RESCHEDULE_VECTOR;
                break;
        case CALL_FUNCTION_VECTOR:
                xen_vector = XEN_CALL_FUNCTION_VECTOR;
                break;
        case CALL_FUNCTION_SINGLE_VECTOR:
                xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
                break;
        case IRQ_WORK_VECTOR:
                xen_vector = XEN_IRQ_WORK_VECTOR;
                break;
#ifdef CONFIG_X86_64
        case NMI_VECTOR:
        case APIC_DM_NMI: /* Some use that instead of NMI_VECTOR */
                xen_vector = XEN_NMI_VECTOR;
                break;
#endif
        default:
                xen_vector = -1;
                printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
                        vector);
        }

        return xen_vector;
}

void xen_send_IPI_mask(const struct cpumask *mask,
                              int vector)
{
        int xen_vector = xen_map_vector(vector);

        if (xen_vector >= 0)
                __xen_send_IPI_mask(mask, xen_vector);
}

void xen_send_IPI_all(int vector)
{
        int xen_vector = xen_map_vector(vector);

        if (xen_vector >= 0)
                __xen_send_IPI_mask(cpu_online_mask, xen_vector);
}

void xen_send_IPI_self(int vector)
{
        int xen_vector = xen_map_vector(vector);

        if (xen_vector >= 0)
                xen_send_IPI_one(smp_processor_id(), xen_vector);
}

void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
                                int vector)
{
        unsigned cpu;
        unsigned int this_cpu = smp_processor_id();
        int xen_vector = xen_map_vector(vector);

        if (!(num_online_cpus() > 1) || (xen_vector < 0))
                return;

        for_each_cpu_and(cpu, mask, cpu_online_mask) {
                if (this_cpu == cpu)
                        continue;

                xen_send_IPI_one(cpu, xen_vector);
        }
}

void xen_send_IPI_allbutself(int vector)
{
        xen_send_IPI_mask_allbutself(cpu_online_mask, vector);
}

static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
{
        generic_smp_call_function_interrupt();
        inc_irq_stat(irq_call_count);

        return IRQ_HANDLED;
}

static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
{
        generic_smp_call_function_single_interrupt();
        inc_irq_stat(irq_call_count);

        return IRQ_HANDLED;
}