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// SPDX-License-Identifier: GPL-2.0
/*
* Hyper-V stub IOMMU driver.
*
* Copyright (C) 2019, Microsoft, Inc.
*
* Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
*/
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <asm/apic.h>
#include <asm/cpu.h>
#include <asm/hw_irq.h>
#include <asm/io_apic.h>
#include <asm/irq_remapping.h>
#include <asm/hypervisor.h>
#include "irq_remapping.h"
#ifdef CONFIG_IRQ_REMAP
/*
* According 82093AA IO-APIC spec , IO APIC has a 24-entry Interrupt
* Redirection Table. Hyper-V exposes one single IO-APIC and so define
* 24 IO APIC remmapping entries.
*/
#define IOAPIC_REMAPPING_ENTRY 24
static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE };
static struct irq_domain *ioapic_ir_domain;
static int hyperv_ir_set_affinity(struct irq_data *data,
const struct cpumask *mask, bool force)
{
struct irq_data *parent = data->parent_data;
struct irq_cfg *cfg = irqd_cfg(data);
int ret;
/* Return error If new irq affinity is out of ioapic_max_cpumask. */
if (!cpumask_subset(mask, &ioapic_max_cpumask))
return -EINVAL;
ret = parent->chip->irq_set_affinity(parent, mask, force);
if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
return ret;
send_cleanup_vector(cfg);
return 0;
}
static struct irq_chip hyperv_ir_chip = {
.name = "HYPERV-IR",
.irq_ack = apic_ack_irq,
.irq_set_affinity = hyperv_ir_set_affinity,
};
static int hyperv_irq_remapping_alloc(struct irq_domain *domain,
unsigned int virq, unsigned int nr_irqs,
void *arg)
{
struct irq_alloc_info *info = arg;
struct irq_data *irq_data;
struct irq_desc *desc;
int ret = 0;
if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1)
return -EINVAL;
ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
if (ret < 0)
return ret;
irq_data = irq_domain_get_irq_data(domain, virq);
if (!irq_data) {
irq_domain_free_irqs_common(domain, virq, nr_irqs);
return -EINVAL;
}
irq_data->chip = &hyperv_ir_chip;
/*
* Hypver-V IO APIC irq affinity should be in the scope of
* ioapic_max_cpumask because no irq remapping support.
*/
desc = irq_data_to_desc(irq_data);
cpumask_copy(desc->irq_common_data.affinity, &ioapic_max_cpumask);
return 0;
}
static void hyperv_irq_remapping_free(struct irq_domain *domain,
unsigned int virq, unsigned int nr_irqs)
{
irq_domain_free_irqs_common(domain, virq, nr_irqs);
}
static int hyperv_irq_remapping_select(struct irq_domain *d,
struct irq_fwspec *fwspec,
enum irq_domain_bus_token bus_token)
{
/* Claim the only I/O APIC emulated by Hyper-V */
return x86_fwspec_is_ioapic(fwspec);
}
static const struct irq_domain_ops hyperv_ir_domain_ops = {
.select = hyperv_irq_remapping_select,
.alloc = hyperv_irq_remapping_alloc,
.free = hyperv_irq_remapping_free,
};
static int __init hyperv_prepare_irq_remapping(void)
{
struct fwnode_handle *fn;
int i;
if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
x86_init.hyper.msi_ext_dest_id() ||
!x2apic_supported())
return -ENODEV;
fn = irq_domain_alloc_named_id_fwnode("HYPERV-IR", 0);
if (!fn)
return -ENOMEM;
ioapic_ir_domain =
irq_domain_create_hierarchy(arch_get_ir_parent_domain(),
0, IOAPIC_REMAPPING_ENTRY, fn,
&hyperv_ir_domain_ops, NULL);
if (!ioapic_ir_domain) {
irq_domain_free_fwnode(fn);
return -ENOMEM;
}
/*
* Hyper-V doesn't provide irq remapping function for
* IO-APIC and so IO-APIC only accepts 8-bit APIC ID.
* Cpu's APIC ID is read from ACPI MADT table and APIC IDs
* in the MADT table on Hyper-v are sorted monotonic increasingly.
* APIC ID reflects cpu topology. There maybe some APIC ID
* gaps when cpu number in a socket is not power of two. Prepare
* max cpu affinity for IOAPIC irqs. Scan cpu 0-255 and set cpu
* into ioapic_max_cpumask if its APIC ID is less than 256.
*/
for (i = min_t(unsigned int, num_possible_cpus() - 1, 255); i >= 0; i--)
if (cpu_physical_id(i) < 256)
cpumask_set_cpu(i, &ioapic_max_cpumask);
return 0;
}
static int __init hyperv_enable_irq_remapping(void)
{
return IRQ_REMAP_X2APIC_MODE;
}
struct irq_remap_ops hyperv_irq_remap_ops = {
.prepare = hyperv_prepare_irq_remapping,
.enable = hyperv_enable_irq_remapping,
};
#endif
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