PCI: hv: Make the code arch neutral

This patch makes the Hyper-V vPCI code architectural neutral by
introducing an irqchip that takes care of architectural
dependencies. This allows for the implementation of Hyper-V vPCI
for other architecture such as ARM64.

There are no functional changes expected from this patch.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>

MAINTAINERS

@@ -8688,6 +8688,8 @@ F:	drivers/iommu/hyperv-iommu.c
 F:	drivers/net/ethernet/microsoft/
 F:	drivers/net/hyperv/
 F:	drivers/pci/controller/pci-hyperv-intf.c
+F:	drivers/pci/controller/pci-hyperv-irqchip.c
+F:	drivers/pci/controller/pci-hyperv-irqchip.h
 F:	drivers/pci/controller/pci-hyperv.c
 F:	drivers/scsi/storvsc_drv.c
 F:	drivers/uio/uio_hv_generic.c

arch/x86/include/asm/hyperv-tlfs.h

@@ -585,6 +585,39 @@ enum hv_interrupt_type {
 	HV_X64_INTERRUPT_TYPE_MAXIMUM           = 0x000A,
 };
 
+union hv_msi_address_register {
+	u32 as_uint32;
+	struct {
+		u32 reserved1:2;
+		u32 destination_mode:1;
+		u32 redirection_hint:1;
+		u32 reserved2:8;
+		u32 destination_id:8;
+		u32 msi_base:12;
+	};
+} __packed;
+
+union hv_msi_data_register {
+	u32 as_uint32;
+	struct {
+		u32 vector:8;
+		u32 delivery_mode:3;
+		u32 reserved1:3;
+		u32 level_assert:1;
+		u32 trigger_mode:1;
+		u32 reserved2:16;
+	};
+} __packed;
+
+/* HvRetargetDeviceInterrupt hypercall */
+union hv_msi_entry {
+	u64 as_uint64;
+	struct {
+		union hv_msi_address_register address;
+		union hv_msi_data_register data;
+	} __packed;
+};
+
 #include <asm-generic/hyperv-tlfs.h>
 
 #endif

arch/x86/include/asm/mshyperv.h

@@ -176,13 +176,6 @@ bool hv_vcpu_is_preempted(int vcpu);
 static inline void hv_apic_init(void) {}
 #endif
 
-static inline void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
-					      struct msi_desc *msi_desc)
-{
-	msi_entry->address.as_uint32 = msi_desc->msg.address_lo;
-	msi_entry->data.as_uint32 = msi_desc->msg.data;
-}
-
 struct irq_domain *hv_create_pci_msi_domain(void);
 
 int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,

drivers/pci/controller/Makefile

@@ -2,7 +2,7 @@
 obj-$(CONFIG_PCIE_CADENCE) += cadence/
 obj-$(CONFIG_PCI_FTPCI100) += pci-ftpci100.o
 obj-$(CONFIG_PCI_IXP4XX) += pci-ixp4xx.o
-obj-$(CONFIG_PCI_HYPERV) += pci-hyperv.o
+obj-$(CONFIG_PCI_HYPERV) += pci-hyperv.o pci-hyperv-irqchip.o
 obj-$(CONFIG_PCI_HYPERV_INTERFACE) += pci-hyperv-intf.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_AARDVARK) += pci-aardvark.o

drivers/pci/controller/pci-hyperv-irqchip.c

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Hyper-V vPCI irqchip.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Sunil Muthuswamy <sunilmut@microsoft.com>
+ */
+
+#include <asm/mshyperv.h>
+#include <linux/acpi.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/msi.h>
+
+#ifdef CONFIG_X86_64
+int hv_pci_irqchip_init(struct irq_domain **parent_domain,
+			bool *fasteoi_handler,
+			u8 *delivery_mode)
+{
+	*parent_domain = x86_vector_domain;
+	*fasteoi_handler = false;
+	*delivery_mode = APIC_DELIVERY_MODE_FIXED;
+
+	return 0;
+}
+
+void hv_pci_irqchip_free(void) {}
+
+unsigned int hv_msi_get_int_vector(struct irq_data *data)
+{
+	struct irq_cfg *cfg = irqd_cfg(data);
+
+	return cfg->vector;
+}
+
+void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
+				struct msi_desc *msi_desc)
+{
+	msi_entry->address.as_uint32 = msi_desc->msg.address_lo;
+	msi_entry->data.as_uint32 = msi_desc->msg.data;
+}
+
+int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
+		   int nvec, msi_alloc_info_t *info)
+{
+	return pci_msi_prepare(domain, dev, nvec, info);
+}
+
+#endif

drivers/pci/controller/pci-hyperv-irqchip.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Architecture specific vector management for the Hyper-V vPCI.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Sunil Muthuswamy <sunilmut@microsoft.com>
+ */
+
+int hv_pci_irqchip_init(struct irq_domain **parent_domain,
+			bool *fasteoi_handler,
+			u8 *delivery_mode);
+
+void hv_pci_irqchip_free(void);
+unsigned int hv_msi_get_int_vector(struct irq_data *data);
+void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
+				struct msi_desc *msi_desc);
+
+int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
+		   int nvec, msi_alloc_info_t *info);

drivers/pci/controller/pci-hyperv.c

@@ -43,14 +43,12 @@
 #include <linux/pci-ecam.h>
 #include <linux/delay.h>
 #include <linux/semaphore.h>
-#include <linux/irqdomain.h>
-#include <asm/irqdomain.h>
-#include <asm/apic.h>
 #include <linux/irq.h>
 #include <linux/msi.h>
 #include <linux/hyperv.h>
 #include <linux/refcount.h>
 #include <asm/mshyperv.h>
+#include "pci-hyperv-irqchip.h"
 
 /*
  * Protocol versions. The low word is the minor version, the high word the
@@ -81,6 +79,10 @@ static enum pci_protocol_version_t pci_protocol_versions[] = {
 	PCI_PROTOCOL_VERSION_1_1,
 };
 
+static struct irq_domain *parent_domain;
+static bool fasteoi;
+static u8 delivery_mode;
+
 #define PCI_CONFIG_MMIO_LENGTH	0x2000
 #define CFG_PAGE_OFFSET 0x1000
 #define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)
@@ -1217,7 +1219,6 @@ static void hv_irq_mask(struct irq_data *data)
 static void hv_irq_unmask(struct irq_data *data)
 {
 	struct msi_desc *msi_desc = irq_data_get_msi_desc(data);
-	struct irq_cfg *cfg = irqd_cfg(data);
 	struct hv_retarget_device_interrupt *params;
 	struct hv_pcibus_device *hbus;
 	struct cpumask *dest;
@@ -1246,11 +1247,12 @@ static void hv_irq_unmask(struct irq_data *data)
 			   (hbus->hdev->dev_instance.b[7] << 8) |
 			   (hbus->hdev->dev_instance.b[6] & 0xf8) |
 			   PCI_FUNC(pdev->devfn);
-	params->int_target.vector = cfg->vector;
+	params->int_target.vector = hv_msi_get_int_vector(data);
 
 	/*
-	 * Honoring apic->delivery_mode set to APIC_DELIVERY_MODE_FIXED by
-	 * setting the HV_DEVICE_INTERRUPT_TARGET_MULTICAST flag results in a
+	 * For x64, honoring apic->delivery_mode set to
+	 * APIC_DELIVERY_MODE_FIXED by setting the
+	 * HV_DEVICE_INTERRUPT_TARGET_MULTICAST flag results in a
 	 * spurious interrupt storm. Not doing so does not seem to have a
 	 * negative effect (yet?).
 	 */
@@ -1347,7 +1349,7 @@ static u32 hv_compose_msi_req_v1(
 	int_pkt->wslot.slot = slot;
 	int_pkt->int_desc.vector = vector;
 	int_pkt->int_desc.vector_count = 1;
-	int_pkt->int_desc.delivery_mode = APIC_DELIVERY_MODE_FIXED;
+	int_pkt->int_desc.delivery_mode = delivery_mode;
 
 	/*
 	 * Create MSI w/ dummy vCPU set, overwritten by subsequent retarget in
@@ -1377,7 +1379,7 @@ static u32 hv_compose_msi_req_v2(
 	int_pkt->wslot.slot = slot;
 	int_pkt->int_desc.vector = vector;
 	int_pkt->int_desc.vector_count = 1;
-	int_pkt->int_desc.delivery_mode = APIC_DELIVERY_MODE_FIXED;
+	int_pkt->int_desc.delivery_mode = delivery_mode;
 	cpu = hv_compose_msi_req_get_cpu(affinity);
 	int_pkt->int_desc.processor_array[0] =
 		hv_cpu_number_to_vp_number(cpu);
@@ -1397,7 +1399,7 @@ static u32 hv_compose_msi_req_v3(
 	int_pkt->int_desc.vector = vector;
 	int_pkt->int_desc.reserved = 0;
 	int_pkt->int_desc.vector_count = 1;
-	int_pkt->int_desc.delivery_mode = APIC_DELIVERY_MODE_FIXED;
+	int_pkt->int_desc.delivery_mode = delivery_mode;
 	cpu = hv_compose_msi_req_get_cpu(affinity);
 	int_pkt->int_desc.processor_array[0] =
 		hv_cpu_number_to_vp_number(cpu);
@@ -1419,7 +1421,6 @@ static u32 hv_compose_msi_req_v3(
  */
 static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
-	struct irq_cfg *cfg = irqd_cfg(data);
 	struct hv_pcibus_device *hbus;
 	struct vmbus_channel *channel;
 	struct hv_pci_dev *hpdev;
@@ -1470,22 +1471,22 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
 					dest,
 					hpdev->desc.win_slot.slot,
-					cfg->vector);
+					hv_msi_get_int_vector(data));
 		break;
 
 	case PCI_PROTOCOL_VERSION_1_2:
 	case PCI_PROTOCOL_VERSION_1_3:
 		size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
 					dest,
 					hpdev->desc.win_slot.slot,
-					cfg->vector);
+					hv_msi_get_int_vector(data));
 		break;
 
 	case PCI_PROTOCOL_VERSION_1_4:
 		size = hv_compose_msi_req_v3(&ctxt.int_pkts.v3,
 					dest,
 					hpdev->desc.win_slot.slot,
-					cfg->vector);
+					hv_msi_get_int_vector(data));
 		break;
 
 	default:
@@ -1601,7 +1602,7 @@ static struct irq_chip hv_msi_irq_chip = {
 };
 
 static struct msi_domain_ops hv_msi_ops = {
-	.msi_prepare	= pci_msi_prepare,
+	.msi_prepare	= hv_msi_prepare,
 	.msi_free	= hv_msi_free,
 };
 
@@ -1625,12 +1626,13 @@ static int hv_pcie_init_irq_domain(struct hv_pcibus_device *hbus)
 	hbus->msi_info.flags = (MSI_FLAG_USE_DEF_DOM_OPS |
 		MSI_FLAG_USE_DEF_CHIP_OPS | MSI_FLAG_MULTI_PCI_MSI |
 		MSI_FLAG_PCI_MSIX);
-	hbus->msi_info.handler = handle_edge_irq;
-	hbus->msi_info.handler_name = "edge";
+	hbus->msi_info.handler =
+		fasteoi ? handle_fasteoi_irq : handle_edge_irq;
+	hbus->msi_info.handler_name = fasteoi ? "fasteoi" : "edge";
 	hbus->msi_info.data = hbus;
 	hbus->irq_domain = pci_msi_create_irq_domain(hbus->fwnode,
 						     &hbus->msi_info,
-						     x86_vector_domain);
+						     parent_domain);
 	if (!hbus->irq_domain) {
 		dev_err(&hbus->hdev->device,
 			"Failed to build an MSI IRQ domain\n");
@@ -3531,13 +3533,21 @@ static void __exit exit_hv_pci_drv(void)
 	hvpci_block_ops.read_block = NULL;
 	hvpci_block_ops.write_block = NULL;
 	hvpci_block_ops.reg_blk_invalidate = NULL;
+
+	hv_pci_irqchip_free();
 }
 
 static int __init init_hv_pci_drv(void)
 {
+	int ret;
+
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
+	ret = hv_pci_irqchip_init(&parent_domain, &fasteoi, &delivery_mode);
+	if (ret)
+		return ret;
+
 	/* Set the invalid domain number's bit, so it will not be used */
 	set_bit(HVPCI_DOM_INVALID, hvpci_dom_map);
 
@@ -3546,7 +3556,11 @@ static int __init init_hv_pci_drv(void)
 	hvpci_block_ops.write_block = hv_write_config_block;
 	hvpci_block_ops.reg_blk_invalidate = hv_register_block_invalidate;
 
-	return vmbus_driver_register(&hv_pci_drv);
+	ret = vmbus_driver_register(&hv_pci_drv);
+	if (ret)
+		hv_pci_irqchip_free();
+
+	return ret;
 }
 
 module_init(init_hv_pci_drv);

include/asm-generic/hyperv-tlfs.h

@@ -539,39 +539,6 @@ enum hv_interrupt_source {
 	HV_INTERRUPT_SOURCE_IOAPIC,
 };
 
-union hv_msi_address_register {
-	u32 as_uint32;
-	struct {
-		u32 reserved1:2;
-		u32 destination_mode:1;
-		u32 redirection_hint:1;
-		u32 reserved2:8;
-		u32 destination_id:8;
-		u32 msi_base:12;
-	};
-} __packed;
-
-union hv_msi_data_register {
-	u32 as_uint32;
-	struct {
-		u32 vector:8;
-		u32 delivery_mode:3;
-		u32 reserved1:3;
-		u32 level_assert:1;
-		u32 trigger_mode:1;
-		u32 reserved2:16;
-	};
-} __packed;
-
-/* HvRetargetDeviceInterrupt hypercall */
-union hv_msi_entry {
-	u64 as_uint64;
-	struct {
-		union hv_msi_address_register address;
-		union hv_msi_data_register data;
-	} __packed;
-};
-
 union hv_ioapic_rte {
 	u64 as_uint64;