1 files changed, 418 insertions, 0 deletions
diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c
new file mode 100644
index 000000000000..c3ba12b1bc07
--- /dev/null
+++ b/arch/x86/hyperv/irqdomain.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Irqdomain for Linux to run as the root partition on Microsoft Hypervisor.
+ *
+ * Authors:
+ *  Sunil Muthuswamy <sunilmut@microsoft.com>
+ *  Wei Liu <wei.liu@kernel.org>
+ */
+
+#include <linux/pci.h>
+#include <linux/irq.h>
+#include <linux/export.h>
+#include <linux/irqchip/irq-msi-lib.h>
+#include <asm/mshyperv.h>
+
+static int hv_map_interrupt(union hv_device_id device_id, bool level,
+		int cpu, int vector, struct hv_interrupt_entry *entry)
+{
+	struct hv_input_map_device_interrupt *input;
+	struct hv_output_map_device_interrupt *output;
+	struct hv_device_interrupt_descriptor *intr_desc;
+	unsigned long flags;
+	u64 status;
+	int nr_bank, var_size;
+
+	local_irq_save(flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	intr_desc = &input->interrupt_descriptor;
+	memset(input, 0, sizeof(*input));
+	input->partition_id = hv_current_partition_id;
+	input->device_id = device_id.as_uint64;
+	intr_desc->interrupt_type = HV_X64_INTERRUPT_TYPE_FIXED;
+	intr_desc->vector_count = 1;
+	intr_desc->target.vector = vector;
+
+	if (level)
+		intr_desc->trigger_mode = HV_INTERRUPT_TRIGGER_MODE_LEVEL;
+	else
+		intr_desc->trigger_mode = HV_INTERRUPT_TRIGGER_MODE_EDGE;
+
+	intr_desc->target.vp_set.valid_bank_mask = 0;
+	intr_desc->target.vp_set.format = HV_GENERIC_SET_SPARSE_4K;
+	nr_bank = cpumask_to_vpset(&(intr_desc->target.vp_set), cpumask_of(cpu));
+	if (nr_bank < 0) {
+		local_irq_restore(flags);
+		pr_err("%s: unable to generate VP set\n", __func__);
+		return -EINVAL;
+	}
+	intr_desc->target.flags = HV_DEVICE_INTERRUPT_TARGET_PROCESSOR_SET;
+
+	/*
+	 * var-sized hypercall, var-size starts after vp_mask (thus
+	 * vp_set.format does not count, but vp_set.valid_bank_mask
+	 * does).
+	 */
+	var_size = nr_bank + 1;
+
+	status = hv_do_rep_hypercall(HVCALL_MAP_DEVICE_INTERRUPT, 0, var_size,
+			input, output);
+	*entry = output->interrupt_entry;
+
+	local_irq_restore(flags);
+
+	if (!hv_result_success(status))
+		hv_status_err(status, "\n");
+
+	return hv_result_to_errno(status);
+}
+
+static int hv_unmap_interrupt(u64 id, struct hv_interrupt_entry *old_entry)
+{
+	unsigned long flags;
+	struct hv_input_unmap_device_interrupt *input;
+	struct hv_interrupt_entry *intr_entry;
+	u64 status;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	memset(input, 0, sizeof(*input));
+	intr_entry = &input->interrupt_entry;
+	input->partition_id = hv_current_partition_id;
+	input->device_id = id;
+	*intr_entry = *old_entry;
+
+	status = hv_do_hypercall(HVCALL_UNMAP_DEVICE_INTERRUPT, input, NULL);
+	local_irq_restore(flags);
+
+	if (!hv_result_success(status))
+		hv_status_err(status, "\n");
+
+	return hv_result_to_errno(status);
+}
+
+#ifdef CONFIG_PCI_MSI
+struct rid_data {
+	struct pci_dev *bridge;
+	u32 rid;
+};
+
+static int get_rid_cb(struct pci_dev *pdev, u16 alias, void *data)
+{
+	struct rid_data *rd = data;
+	u8 bus = PCI_BUS_NUM(rd->rid);
+
+	if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus) {
+		rd->bridge = pdev;
+		rd->rid = alias;
+	}
+
+	return 0;
+}
+
+static union hv_device_id hv_build_pci_dev_id(struct pci_dev *dev)
+{
+	union hv_device_id dev_id;
+	struct rid_data data = {
+		.bridge = NULL,
+		.rid = PCI_DEVID(dev->bus->number, dev->devfn)
+	};
+
+	pci_for_each_dma_alias(dev, get_rid_cb, &data);
+
+	dev_id.as_uint64 = 0;
+	dev_id.device_type = HV_DEVICE_TYPE_PCI;
+	dev_id.pci.segment = pci_domain_nr(dev->bus);
+
+	dev_id.pci.bdf.bus = PCI_BUS_NUM(data.rid);
+	dev_id.pci.bdf.device = PCI_SLOT(data.rid);
+	dev_id.pci.bdf.function = PCI_FUNC(data.rid);
+	dev_id.pci.source_shadow = HV_SOURCE_SHADOW_NONE;
+
+	if (data.bridge) {
+		int pos;
+
+		/*
+		 * Microsoft Hypervisor requires a bus range when the bridge is
+		 * running in PCI-X mode.
+		 *
+		 * To distinguish conventional vs PCI-X bridge, we can check
+		 * the bridge's PCI-X Secondary Status Register, Secondary Bus
+		 * Mode and Frequency bits. See PCI Express to PCI/PCI-X Bridge
+		 * Specification Revision 1.0 5.2.2.1.3.
+		 *
+		 * Value zero means it is in conventional mode, otherwise it is
+		 * in PCI-X mode.
+		 */
+
+		pos = pci_find_capability(data.bridge, PCI_CAP_ID_PCIX);
+		if (pos) {
+			u16 status;
+
+			pci_read_config_word(data.bridge, pos +
+					PCI_X_BRIDGE_SSTATUS, &status);
+
+			if (status & PCI_X_SSTATUS_FREQ) {
+				/* Non-zero, PCI-X mode */
+				u8 sec_bus, sub_bus;
+
+				dev_id.pci.source_shadow = HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE;
+
+				pci_read_config_byte(data.bridge, PCI_SECONDARY_BUS, &sec_bus);
+				dev_id.pci.shadow_bus_range.secondary_bus = sec_bus;
+				pci_read_config_byte(data.bridge, PCI_SUBORDINATE_BUS, &sub_bus);
+				dev_id.pci.shadow_bus_range.subordinate_bus = sub_bus;
+			}
+		}
+	}
+
+	return dev_id;
+}
+
+/**
+ * hv_map_msi_interrupt() - "Map" the MSI IRQ in the hypervisor.
+ * @data:      Describes the IRQ
+ * @out_entry: Hypervisor (MSI) interrupt entry (can be NULL)
+ *
+ * Map the IRQ in the hypervisor by issuing a MAP_DEVICE_INTERRUPT hypercall.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int hv_map_msi_interrupt(struct irq_data *data,
+			 struct hv_interrupt_entry *out_entry)
+{
+	struct irq_cfg *cfg = irqd_cfg(data);
+	struct hv_interrupt_entry dummy;
+	union hv_device_id device_id;
+	struct msi_desc *msidesc;
+	struct pci_dev *dev;
+	int cpu;
+
+	msidesc = irq_data_get_msi_desc(data);
+	dev = msi_desc_to_pci_dev(msidesc);
+	device_id = hv_build_pci_dev_id(dev);
+	cpu = cpumask_first(irq_data_get_effective_affinity_mask(data));
+
+	return hv_map_interrupt(device_id, false, cpu, cfg->vector,
+				out_entry ? out_entry : &dummy);
+}
+EXPORT_SYMBOL_GPL(hv_map_msi_interrupt);
+
+static inline void entry_to_msi_msg(struct hv_interrupt_entry *entry, struct msi_msg *msg)
+{
+	/* High address is always 0 */
+	msg->address_hi = 0;
+	msg->address_lo = entry->msi_entry.address.as_uint32;
+	msg->data = entry->msi_entry.data.as_uint32;
+}
+
+static int hv_unmap_msi_interrupt(struct pci_dev *dev, struct hv_interrupt_entry *old_entry);
+static void hv_irq_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct hv_interrupt_entry *stored_entry;
+	struct irq_cfg *cfg = irqd_cfg(data);
+	struct msi_desc *msidesc;
+	struct pci_dev *dev;
+	int ret;
+
+	msidesc = irq_data_get_msi_desc(data);
+	dev = msi_desc_to_pci_dev(msidesc);
+
+	if (!cfg) {
+		pr_debug("%s: cfg is NULL", __func__);
+		return;
+	}
+
+	if (data->chip_data) {
+		/*
+		 * This interrupt is already mapped. Let's unmap first.
+		 *
+		 * We don't use retarget interrupt hypercalls here because
+		 * Microsoft Hypervisor doesn't allow root to change the vector
+		 * or specify VPs outside of the set that is initially used
+		 * during mapping.
+		 */
+		stored_entry = data->chip_data;
+		data->chip_data = NULL;
+
+		ret = hv_unmap_msi_interrupt(dev, stored_entry);
+
+		kfree(stored_entry);
+
+		if (ret)
+			return;
+	}
+
+	stored_entry = kzalloc(sizeof(*stored_entry), GFP_ATOMIC);
+	if (!stored_entry) {
+		pr_debug("%s: failed to allocate chip data\n", __func__);
+		return;
+	}
+
+	ret = hv_map_msi_interrupt(data, stored_entry);
+	if (ret) {
+		kfree(stored_entry);
+		return;
+	}
+
+	data->chip_data = stored_entry;
+	entry_to_msi_msg(data->chip_data, msg);
+
+	return;
+}
+
+static int hv_unmap_msi_interrupt(struct pci_dev *dev, struct hv_interrupt_entry *old_entry)
+{
+	return hv_unmap_interrupt(hv_build_pci_dev_id(dev).as_uint64, old_entry);
+}
+
+static void hv_teardown_msi_irq(struct pci_dev *dev, struct irq_data *irqd)
+{
+	struct hv_interrupt_entry old_entry;
+	struct msi_msg msg;
+
+	if (!irqd->chip_data) {
+		pr_debug("%s: no chip data\n!", __func__);
+		return;
+	}
+
+	old_entry = *(struct hv_interrupt_entry *)irqd->chip_data;
+	entry_to_msi_msg(&old_entry, &msg);
+
+	kfree(irqd->chip_data);
+	irqd->chip_data = NULL;
+
+	(void)hv_unmap_msi_interrupt(dev, &old_entry);
+}
+
+/*
+ * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
+ * which implement the MSI or MSI-X Capability Structure.
+ */
+static struct irq_chip hv_pci_msi_controller = {
+	.name			= "HV-PCI-MSI",
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_compose_msi_msg	= hv_irq_compose_msi_msg,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+static bool hv_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
+				 struct irq_domain *real_parent, struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info))
+		return false;
+
+	chip->flags |= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED;
+
+	info->ops->msi_prepare = pci_msi_prepare;
+
+	return true;
+}
+
+#define HV_MSI_FLAGS_SUPPORTED	(MSI_GENERIC_FLAGS_MASK | MSI_FLAG_PCI_MSIX)
+#define HV_MSI_FLAGS_REQUIRED	(MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS)
+
+static struct msi_parent_ops hv_msi_parent_ops = {
+	.supported_flags	= HV_MSI_FLAGS_SUPPORTED,
+	.required_flags		= HV_MSI_FLAGS_REQUIRED,
+	.bus_select_token	= DOMAIN_BUS_NEXUS,
+	.bus_select_mask	= MATCH_PCI_MSI,
+	.chip_flags		= MSI_CHIP_FLAG_SET_ACK,
+	.prefix			= "HV-",
+	.init_dev_msi_info	= hv_init_dev_msi_info,
+};
+
+static int hv_msi_domain_alloc(struct irq_domain *d, unsigned int virq, unsigned int nr_irqs,
+			       void *arg)
+{
+	/*
+	 * TODO: The allocation bits of hv_irq_compose_msi_msg(), i.e. everything except
+	 * entry_to_msi_msg() should be in here.
+	 */
+
+	int ret;
+
+	ret = irq_domain_alloc_irqs_parent(d, virq, nr_irqs, arg);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < nr_irqs; ++i) {
+		irq_domain_set_info(d, virq + i, 0, &hv_pci_msi_controller, NULL,
+				    handle_edge_irq, NULL, "edge");
+	}
+	return 0;
+}
+
+static void hv_msi_domain_free(struct irq_domain *d, unsigned int virq, unsigned int nr_irqs)
+{
+	for (int i = 0; i < nr_irqs; ++i) {
+		struct irq_data *irqd = irq_domain_get_irq_data(d, virq);
+		struct msi_desc *desc;
+
+		desc = irq_data_get_msi_desc(irqd);
+		if (!desc || !desc->irq || WARN_ON_ONCE(!dev_is_pci(desc->dev)))
+			continue;
+
+		hv_teardown_msi_irq(to_pci_dev(desc->dev), irqd);
+	}
+	irq_domain_free_irqs_top(d, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops hv_msi_domain_ops = {
+	.select	= msi_lib_irq_domain_select,
+	.alloc	= hv_msi_domain_alloc,
+	.free	= hv_msi_domain_free,
+};
+
+struct irq_domain * __init hv_create_pci_msi_domain(void)
+{
+	struct irq_domain *d = NULL;
+
+	struct irq_domain_info info = {
+		.fwnode		= irq_domain_alloc_named_fwnode("HV-PCI-MSI"),
+		.ops		= &hv_msi_domain_ops,
+		.parent		= x86_vector_domain,
+	};
+
+	if (info.fwnode)
+		d = msi_create_parent_irq_domain(&info, &hv_msi_parent_ops);
+
+	/* No point in going further if we can't get an irq domain */
+	BUG_ON(!d);
+
+	return d;
+}
+
+#endif /* CONFIG_PCI_MSI */
+
+int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry)
+{
+	union hv_device_id device_id;
+
+	device_id.as_uint64 = 0;
+	device_id.device_type = HV_DEVICE_TYPE_IOAPIC;
+	device_id.ioapic.ioapic_id = (u8)ioapic_id;
+
+	return hv_unmap_interrupt(device_id.as_uint64, entry);
+}
+EXPORT_SYMBOL_GPL(hv_unmap_ioapic_interrupt);
+
+int hv_map_ioapic_interrupt(int ioapic_id, bool level, int cpu, int vector,
+		struct hv_interrupt_entry *entry)
+{
+	union hv_device_id device_id;
+
+	device_id.as_uint64 = 0;
+	device_id.device_type = HV_DEVICE_TYPE_IOAPIC;
+	device_id.ioapic.ioapic_id = (u8)ioapic_id;
+
+	return hv_map_interrupt(device_id, level, cpu, vector, entry);
+}
+EXPORT_SYMBOL_GPL(hv_map_ioapic_interrupt);