path: root/drivers/iommu/intel_irq_remapping.c

// SPDX-License-Identifier: GPL-2.0

#define pr_fmt(fmt)     "DMAR-IR: " fmt

#include <linux/interrupt.h>
#include <linux/dmar.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/hpet.h>
#include <linux/pci.h>
#include <linux/irq.h>
#include <linux/intel-iommu.h>
#include <linux/acpi.h>
#include <linux/irqdomain.h>
#include <linux/crash_dump.h>
#include <asm/io_apic.h>
#include <asm/smp.h>
#include <asm/cpu.h>
#include <asm/irq_remapping.h>
#include <asm/pci-direct.h>
#include <asm/msidef.h>

#include "irq_remapping.h"

enum irq_mode {
	IRQ_REMAPPING,
	IRQ_POSTING,
};

struct ioapic_scope {
	struct intel_iommu *iommu;
	unsigned int id;
	unsigned int bus;	/* PCI bus number */
	unsigned int devfn;	/* PCI devfn number */
};

struct hpet_scope {
	struct intel_iommu *iommu;
	u8 id;
	unsigned int bus;
	unsigned int devfn;
};

struct irq_2_iommu {
	struct intel_iommu *iommu;
	u16 irte_index;
	u16 sub_handle;
	u8  irte_mask;
	enum irq_mode mode;
};

struct intel_ir_data {
	struct irq_2_iommu			irq_2_iommu;
	struct irte				irte_entry;
	union {
		struct msi_msg			msi_entry;
	};
};

#define IR_X2APIC_MODE(mode) (mode ? (1 << 11) : 0)
#define IRTE_DEST(dest) ((eim_mode) ? dest : dest << 8)

static int __read_mostly eim_mode;
static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
static struct hpet_scope ir_hpet[MAX_HPET_TBS];

/*
 * Lock ordering:
 * ->dmar_global_lock
 *	->irq_2_ir_lock
 *		->qi->q_lock
 *	->iommu->register_lock
 * Note:
 * intel_irq_remap_ops.{supported,prepare,enable,disable,reenable} are called
 * in single-threaded environment with interrupt disabled, so no need to tabke
 * the dmar_global_lock.
 */
DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
static const struct irq_domain_ops intel_ir_domain_ops;

static void iommu_disable_irq_remapping(struct intel_iommu *iommu);
static int __init parse_ioapics_under_ir(void);

static bool ir_pre_enabled(struct intel_iommu *iommu)
{
	return (iommu->flags & VTD_FLAG_IRQ_REMAP_PRE_ENABLED);
}

static void clear_ir_pre_enabled(struct intel_iommu *iommu)
{
	iommu->flags &= ~VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
}

static void init_ir_status(struct intel_iommu *iommu)
{
	u32 gsts;

	gsts = readl(iommu->reg + DMAR_GSTS_REG);
	if (gsts & DMA_GSTS_IRES)
		iommu->flags |= VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
}

static int alloc_irte(struct intel_iommu *iommu, int irq,
		      struct irq_2_iommu *irq_iommu, u16 count)
{
	struct ir_table *table = iommu->ir_table;
	unsigned int mask = 0;
	unsigned long flags;
	int index;

	if (!count || !irq_iommu)
		return -1;

	if (count > 1) {
		count = __roundup_pow_of_two(count);
		mask = ilog2(count);
	}

	if (mask > ecap_max_handle_mask(iommu->ecap)) {
		pr_err("Requested mask %x exceeds the max invalidation handle"
		       " mask value %Lx\n", mask,
		       ecap_max_handle_mask(iommu->ecap));
		return -1;
	}

	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
	index = bitmap_find_free_region(table->bitmap,
					INTR_REMAP_TABLE_ENTRIES, mask);
	if (index < 0) {
		pr_warn("IR%d: can't allocate an IRTE\n", iommu->seq_id);
	} else {
		irq_iommu->iommu = iommu;
		irq_iommu->irte_index =  index;
		irq_iommu->sub_handle = 0;
		irq_iommu->irte_mask = mask;
		irq_iommu->mode = IRQ_REMAPPING;
	}
	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);

	return index;
}

static int qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
{
	struct qi_desc desc;

	desc.qw0 = QI_IEC_IIDEX(index) | QI_IEC_TYPE | QI_IEC_IM(mask)
		   | QI_IEC_SELECTIVE;
	desc.qw1 = 0;
	desc.qw2 = 0;
	desc.qw3 = 0;

	return qi_submit_sync(&desc, iommu);
}

static int modify_irte(struct irq_2_iommu *irq_iommu,
		       struct irte *irte_modified)
{
	struct intel_iommu *iommu;
	unsigned long flags;
	struct irte *irte;
	int rc, index;

	if (!irq_iommu)
		return -1;

	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);

	iommu = irq_iommu->iommu;

	index = irq_iommu->irte_index + irq_iommu->sub_handle;
	irte = &iommu->ir_table->base[index];

#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE)
	if ((irte->pst == 1) || (irte_modified->pst == 1)) {
		bool ret;

		ret = cmpxchg_double(&irte->low, &irte->high,
				     irte->low, irte->high,
				     irte_modified->low, irte_modified->high);
		/*
		 * We use cmpxchg16 to atomically update the 128-bit IRTE,
		 * and it cannot be updated by the hardware or other processors
		 * behind us, so the return value of cmpxchg16 should be the
		 * same as the old value.
		 */
		WARN_ON(!ret);
	} else
#endif
	{
		set_64bit(&irte->low, irte_modified->low);
		set_64bit(&irte->high, irte_modified->high);
	}
	__iommu_flush_cache(iommu, irte, sizeof(*irte));

	rc = qi_flush_iec(iommu, index, 0);

	/* Update iommu mode according to the IRTE mode */
	irq_iommu->mode = irte->pst ? IRQ_POSTING : IRQ_REMAPPING;
	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);

	return rc;
}

static struct intel_iommu *map_hpet_to_ir(u8 hpet_id)
{
	int i;

	for (i = 0; i < MAX_HPET_TBS; i++)
		if (ir_hpet[i].id == hpet_id && ir_hpet[i].iommu)
			return ir_hpet[i].iommu;
	return NULL;
}

static struct intel_iommu *map_ioapic_to_ir(int apic)
{
	int i;

	for (i = 0; i < MAX_IO_APICS; i++)
		if (ir_ioapic[i].id == apic && ir_ioapic[i].iommu)
			return ir_ioapic[i].iommu;
	return NULL;
}

static struct intel_iommu *map_dev_to_ir(struct pci_dev *dev)
{
	struct dmar_drhd_unit *drhd;

	drhd = dmar_find_matched_drhd_unit(dev);
	if (!drhd)
		return NULL;

	return drhd->iommu;
}

static int clear_entries(struct irq_2_iommu *irq_iommu)
{
	struct irte *start, *entry, *end;
	struct intel_iommu *iommu;
	int index;

	if (irq_iommu->sub_handle)
		return 0;

	iommu = irq_iommu->iommu;
	index = irq_iommu->irte_index;

	start = iommu->ir_table->base + index;
	end = start + (1 << irq_iommu->irte_mask);

	for (entry = start; entry < end; entry++) {
		set_64bit(&entry->low, 0);
		set_64bit(&entry->high, 0);
	}
	bitmap_release_region(iommu->ir_table->bitmap, index,
			      irq_iommu->irte_mask);

	return qi_flush_iec(iommu, index, irq_iommu->irte_mask);
}

/*
 * source validation type
 */
#define SVT_NO_VERIFY		0x0  /* no verification is required */
#define SVT_VERIFY_SID_SQ	0x1  /* verify using SID and SQ fields */
#define SVT_VERIFY_BUS		0x2  /* verify bus of request-id */

/*
 * source-id qualifier
 */
#define SQ_ALL_16	0x0  /* verify all 16 bits of request-id */
#define SQ_13_IGNORE_1	0x1  /* verify most significant 13 bits, ignore
			      * the third least significant bit
			      */
#define SQ_13_IGNORE_2	0x2  /* verify most significant 13 bits, ignore
			      * the second and third least significant bits
			      */
#define SQ_13_IGNORE_3	0x3  /* verify most significant 13 bits, ignore
			      * the least three significant bits
			      */

/*
 * set SVT, SQ and SID fields of irte to verify
 * source ids of interrupt requests
 */
static void set_irte_sid(struct irte *irte, unsigned int svt,
			 unsigned int sq, unsigned int sid)
{
	if (disable_sourceid_checking)
		svt = SVT_NO_VERIFY;
	irte->svt = svt;
	irte->sq = sq;
	irte->sid = sid;
}

/*
 * Set an IRTE to match only the bus number. Interrupt requests that reference
 * this IRTE must have a requester-id whose bus number is between or equal
 * to the start_bus and end_bus arguments.
 */
static void set_irte_verify_bus(struct irte *irte, unsigned int start_bus,
				unsigned int end_bus)
{
	set_irte_sid(irte, SVT_VERIFY_BUS, SQ_ALL_16,
		     (start_bus << 8) | end_bus);
}

static int set_ioapic_sid(struct irte *irte, int apic)
{
	int i;
	u16 sid = 0;

	if (!irte)
		return -1;