linux/drivers/iommu/hyperv-iommu.c
Wei Liu fb5ef35165 iommu/hyperv: setup an IO-APIC IRQ remapping domain for root partition
Just like MSI/MSI-X, IO-APIC interrupts are remapped by Microsoft
Hypervisor when Linux runs as the root partition. Implement an IRQ
domain to handle mapping and unmapping of IO-APIC interrupts.

Signed-off-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-17-wei.liu@kernel.org
2021-02-11 08:47:07 +00:00

341 lines
8.5 KiB
C

// 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 <asm/mshyperv.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 const struct irq_domain_ops hyperv_root_ir_domain_ops;
static int __init hyperv_prepare_irq_remapping(void)
{
struct fwnode_handle *fn;
int i;
const char *name;
const struct irq_domain_ops *ops;
if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
x86_init.hyper.msi_ext_dest_id() ||
!x2apic_supported())
return -ENODEV;
if (hv_root_partition) {
name = "HYPERV-ROOT-IR";
ops = &hyperv_root_ir_domain_ops;
} else {
name = "HYPERV-IR";
ops = &hyperv_ir_domain_ops;
}
fn = irq_domain_alloc_named_id_fwnode(name, 0);
if (!fn)
return -ENOMEM;
ioapic_ir_domain =
irq_domain_create_hierarchy(arch_get_ir_parent_domain(),
0, IOAPIC_REMAPPING_ENTRY, fn, ops, NULL);
if (!ioapic_ir_domain) {
irq_domain_free_fwnode(fn);
return -ENOMEM;
}
if (hv_root_partition)
return 0; /* The rest is only relevant to guests */
/*
* 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,
};
/* IRQ remapping domain when Linux runs as the root partition */
struct hyperv_root_ir_data {
u8 ioapic_id;
bool is_level;
struct hv_interrupt_entry entry;
};
static void
hyperv_root_ir_compose_msi_msg(struct irq_data *irq_data, struct msi_msg *msg)
{
u64 status;
u32 vector;
struct irq_cfg *cfg;
int ioapic_id;
struct cpumask *affinity;
int cpu;
struct hv_interrupt_entry entry;
struct hyperv_root_ir_data *data = irq_data->chip_data;
struct IO_APIC_route_entry e;
cfg = irqd_cfg(irq_data);
affinity = irq_data_get_effective_affinity_mask(irq_data);
cpu = cpumask_first_and(affinity, cpu_online_mask);
vector = cfg->vector;
ioapic_id = data->ioapic_id;
if (data->entry.source == HV_DEVICE_TYPE_IOAPIC
&& data->entry.ioapic_rte.as_uint64) {
entry = data->entry;
status = hv_unmap_ioapic_interrupt(ioapic_id, &entry);
if (status != HV_STATUS_SUCCESS)
pr_debug("%s: unexpected unmap status %lld\n", __func__, status);
data->entry.ioapic_rte.as_uint64 = 0;
data->entry.source = 0; /* Invalid source */
}
status = hv_map_ioapic_interrupt(ioapic_id, data->is_level, cpu,
vector, &entry);
if (status != HV_STATUS_SUCCESS) {
pr_err("%s: map hypercall failed, status %lld\n", __func__, status);
return;
}
data->entry = entry;
/* Turn it into an IO_APIC_route_entry, and generate MSI MSG. */
e.w1 = entry.ioapic_rte.low_uint32;
e.w2 = entry.ioapic_rte.high_uint32;
memset(msg, 0, sizeof(*msg));
msg->arch_data.vector = e.vector;
msg->arch_data.delivery_mode = e.delivery_mode;
msg->arch_addr_lo.dest_mode_logical = e.dest_mode_logical;
msg->arch_addr_lo.dmar_format = e.ir_format;
msg->arch_addr_lo.dmar_index_0_14 = e.ir_index_0_14;
}
static int hyperv_root_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;
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_root_ir_chip = {
.name = "HYPERV-ROOT-IR",
.irq_ack = apic_ack_irq,
.irq_set_affinity = hyperv_root_ir_set_affinity,
.irq_compose_msi_msg = hyperv_root_ir_compose_msi_msg,
};
static int hyperv_root_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 hyperv_root_ir_data *data;
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;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data) {
irq_domain_free_irqs_common(domain, virq, nr_irqs);
return -ENOMEM;
}
irq_data = irq_domain_get_irq_data(domain, virq);
if (!irq_data) {
kfree(data);
irq_domain_free_irqs_common(domain, virq, nr_irqs);
return -EINVAL;
}
data->ioapic_id = info->devid;
data->is_level = info->ioapic.is_level;
irq_data->chip = &hyperv_root_ir_chip;
irq_data->chip_data = data;
return 0;
}
static void hyperv_root_irq_remapping_free(struct irq_domain *domain,
unsigned int virq, unsigned int nr_irqs)
{
struct irq_data *irq_data;
struct hyperv_root_ir_data *data;
struct hv_interrupt_entry *e;
int i;
for (i = 0; i < nr_irqs; i++) {
irq_data = irq_domain_get_irq_data(domain, virq + i);
if (irq_data && irq_data->chip_data) {
data = irq_data->chip_data;
e = &data->entry;
if (e->source == HV_DEVICE_TYPE_IOAPIC
&& e->ioapic_rte.as_uint64)
hv_unmap_ioapic_interrupt(data->ioapic_id,
&data->entry);
kfree(data);
}
}
irq_domain_free_irqs_common(domain, virq, nr_irqs);
}
static const struct irq_domain_ops hyperv_root_ir_domain_ops = {
.select = hyperv_irq_remapping_select,
.alloc = hyperv_root_irq_remapping_alloc,
.free = hyperv_root_irq_remapping_free,
};
#endif