[PATCH v8 0/2] PCI: hv: Hyper-V vPCI for arm64

[PATCH v8 0/2] PCI: hv: Hyper-V vPCI for arm64

[Sunil Muthuswamy]

From: Sunil Muthuswamy <sunilmut@microsoft.com>

Current Hyper-V vPCI code only compiles and works for x86. There are some
hardcoded assumptions about the architectural IRQ chip and other arch
defines.

Add support for Hyper-V vPCI for arm64 by first breaking the current hard
coded dependency using a set of new interfaces and implementing those for
x86 first. That is in the first patch. The second patch adds support for
Hyper-V vPCI for arm64 by implementing the above mentioned interfaces. That
is done by introducing a Hyper-V vPCI specific MSI IRQ domain & chip for
allocating SPI vectors.

changes in v1 -> v2:
 - Moved the irqchip implementation to drivers/pci as suggested
   by Marc Zyngier
 - Addressed Multi-MSI handling issues identified by Marc Zyngier
 - Addressed lock/synchronization primitive as suggested by Marc
   Zyngier
 - Addressed other code feedback from Marc Zyngier

changes in v2 -> v3:
 - Addressed comments from Bjorn Helgaas about patch formatting and
   verbiage
 - Using 'git send-email' to ensure that the patch series is correctly
   threaded. Feedback by Bjorn Helgaas
 - Fixed Hyper-V vPCI build break for module build, reported by Boqun Feng

changes in v3 -> v4:
 - Removed the separate file for IRQ chip that was there in previous
   iterations and moved the IRQ chip implementation to pci-hyperv.c.
   Feedback by Michael Kelley and Marc Zyngier.
 - Addressed various comments from Marc Zyngier about structuring and
   layout.
 - Addressed comment from Marc Zyngier about IRQ affinity and other
   miscellaneous comments.

changes in v4 -> v5:
 - Fixed an issue with picking the right cpu for irq affinity, identified
   by Marc Zyngier.

changes in v5 -> v6:
 - Minor comment updates suggested by Michael Kelley.

changes in v6 -> v7:
 - Addressed feedback from Marc Zyngier about IRQ cleanup in the error path
   and explicitly setting the IRQ trigger type.
 - Address feedback from Bjorn Helgaas about subject line format.

changes in v7 -> v8:
 - Addressed feedback from Michael Kelley about the cpu mask to use for the
   initial interrupt affinity and IRQ cleanup in the error path.

Sunil Muthuswamy (2):
  PCI: hv: Make the code arch neutral by adding arch specific interfaces
  PCI: hv: Add arm64 Hyper-V vPCI support

 arch/arm64/include/asm/hyperv-tlfs.h |   9 +
 arch/x86/include/asm/hyperv-tlfs.h   |  33 +++
 arch/x86/include/asm/mshyperv.h      |   7 -
 drivers/pci/Kconfig                  |   2 +-
 drivers/pci/controller/Kconfig       |   2 +-
 drivers/pci/controller/pci-hyperv.c  | 312 ++++++++++++++++++++++++---
 include/asm-generic/hyperv-tlfs.h    |  33 ---
 7 files changed, 331 insertions(+), 67 deletions(-)


base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf
-- 
2.25.1

[PATCH v8 1/2] PCI: hv: Make the code arch neutral by adding arch specific interfaces

[Sunil Muthuswamy]

From: Sunil Muthuswamy <sunilmut@microsoft.com>

Encapsulate arch dependencies in Hyper-V vPCI through a set of
arch-dependent interfaces. Adding these arch specific interfaces will
allow for an implementation for other architectures, such as arm64.

There are no functional changes expected from this patch.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
---
In v2, v3, v4, v5, v6, v7 & v8:
 Changes are described in the cover letter. No changes from v4 -> v5,
 v6 -> v7 or v7 -> v8.

 arch/x86/include/asm/hyperv-tlfs.h  | 33 ++++++++++++
 arch/x86/include/asm/mshyperv.h     |  7 ---
 drivers/pci/controller/pci-hyperv.c | 79 ++++++++++++++++++++---------
 include/asm-generic/hyperv-tlfs.h   | 33 ------------
 4 files changed, 87 insertions(+), 65 deletions(-)

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 381e88122a5f..0a9407dc0859 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -602,6 +602,39 @@ 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
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index da3972fe5a7a..a1c3dceff8eb 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -169,13 +169,6 @@ 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,
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 6733cb14e775..ead7d6cb6bf1 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -43,9 +43,6 @@
 #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>
@@ -583,6 +580,42 @@ struct hv_pci_compl {
 
 static void hv_pci_onchannelcallback(void *context);
 
+#ifdef CONFIG_X86
+#define DELIVERY_MODE	APIC_DELIVERY_MODE_FIXED
+#define FLOW_HANDLER	handle_edge_irq
+#define FLOW_NAME	"edge"
+
+static int hv_pci_irqchip_init(void)
+{
+	return 0;
+}
+
+static struct irq_domain *hv_pci_get_root_domain(void)
+{
+	return x86_vector_domain;
+}
+
+static unsigned int hv_msi_get_int_vector(struct irq_data *data)
+{
+	struct irq_cfg *cfg = irqd_cfg(data);
+
+	return cfg->vector;
+}
+
+static 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;
+}
+
+static 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 /* CONFIG_X86 */
+
 /**
  * hv_pci_generic_compl() - Invoked for a completion packet
  * @context:		Set up by the sender of the packet.
@@ -1191,14 +1224,6 @@ static void hv_msi_free(struct irq_domain *domain, struct msi_domain_info *info,
 	put_pcichild(hpdev);
 }
 
-static int hv_set_affinity(struct irq_data *data, const struct cpumask *dest,
-			   bool force)
-{
-	struct irq_data *parent = data->parent_data;
-
-	return parent->chip->irq_set_affinity(parent, dest, force);
-}
-
 static void hv_irq_mask(struct irq_data *data)
 {
 	pci_msi_mask_irq(data);
@@ -1217,7 +1242,6 @@ 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;
@@ -1246,7 +1270,7 @@ 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
@@ -1347,7 +1371,7 @@ 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 +1401,7 @@ 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 +1421,7 @@ 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 +1443,6 @@ 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;
@@ -1470,7 +1493,7 @@ 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:
@@ -1478,14 +1501,14 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		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:
@@ -1594,14 +1617,14 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 static struct irq_chip hv_msi_irq_chip = {
 	.name			= "Hyper-V PCIe MSI",
 	.irq_compose_msi_msg	= hv_compose_msi_msg,
-	.irq_set_affinity	= hv_set_affinity,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
 	.irq_ack		= irq_chip_ack_parent,
 	.irq_mask		= hv_irq_mask,
 	.irq_unmask		= hv_irq_unmask,
 };
 
 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 +1648,12 @@ 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 = FLOW_HANDLER;
+	hbus->msi_info.handler_name = FLOW_NAME;
 	hbus->msi_info.data = hbus;
 	hbus->irq_domain = pci_msi_create_irq_domain(hbus->fwnode,
 						     &hbus->msi_info,
-						     x86_vector_domain);
+						     hv_pci_get_root_domain());
 	if (!hbus->irq_domain) {
 		dev_err(&hbus->hdev->device,
 			"Failed to build an MSI IRQ domain\n");
@@ -3542,9 +3565,15 @@ static void __exit exit_hv_pci_drv(void)
 
 static int __init init_hv_pci_drv(void)
 {
+	int ret;
+
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
+	ret = hv_pci_irqchip_init();
+	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);
 
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 8ed6733d5146..8f97c2927bee 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -540,39 +540,6 @@ 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;
 
-- 
2.25.1

[PATCH v8 2/2] PCI: hv: Add arm64 Hyper-V vPCI support

[Sunil Muthuswamy]

From: Sunil Muthuswamy <sunilmut@microsoft.com>

Add arm64 Hyper-V vPCI support by implementing the arch specific
interfaces. Introduce an IRQ domain and chip specific to Hyper-v vPCI that
is based on SPIs. The IRQ domain parents itself to the arch GIC IRQ domain
for basic vector management.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
---
In v2, v3, v4, v5, v6, v7 & v8:
 Changes are described in the cover letter.

 arch/arm64/include/asm/hyperv-tlfs.h |   9 +
 drivers/pci/Kconfig                  |   2 +-
 drivers/pci/controller/Kconfig       |   2 +-
 drivers/pci/controller/pci-hyperv.c  | 235 ++++++++++++++++++++++++++-
 4 files changed, 245 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/hyperv-tlfs.h b/arch/arm64/include/asm/hyperv-tlfs.h
index 4d964a7f02ee..bc6c7ac934a1 100644
--- a/arch/arm64/include/asm/hyperv-tlfs.h
+++ b/arch/arm64/include/asm/hyperv-tlfs.h
@@ -64,6 +64,15 @@
 #define HV_REGISTER_STIMER0_CONFIG	0x000B0000
 #define HV_REGISTER_STIMER0_COUNT	0x000B0001
 
+union hv_msi_entry {
+	u64 as_uint64[2];
+	struct {
+		u64 address;
+		u32 data;
+		u32 reserved;
+	} __packed;
+};
+
 #include <asm-generic/hyperv-tlfs.h>
 
 #endif
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 43e615aa12ff..d98fafdd0f99 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -184,7 +184,7 @@ config PCI_LABEL
 
 config PCI_HYPERV
 	tristate "Hyper-V PCI Frontend"
-	depends on X86_64 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && SYSFS
+	depends on ((X86 && X86_64) || ARM64) && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && SYSFS
 	select PCI_HYPERV_INTERFACE
 	help
 	  The PCI device frontend driver allows the kernel to import arbitrary
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 93b141110537..2536abcc045a 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -281,7 +281,7 @@ config PCIE_BRCMSTB
 
 config PCI_HYPERV_INTERFACE
 	tristate "Hyper-V PCI Interface"
-	depends on X86 && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && X86_64
+	depends on ((X86 && X86_64) || ARM64) && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN
 	help
 	  The Hyper-V PCI Interface is a helper driver allows other drivers to
 	  have a common interface with the Hyper-V PCI frontend driver.
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index ead7d6cb6bf1..b941aa43f909 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -47,6 +47,8 @@
 #include <linux/msi.h>
 #include <linux/hyperv.h>
 #include <linux/refcount.h>
+#include <linux/irqdomain.h>
+#include <linux/acpi.h>
 #include <asm/mshyperv.h>
 
 /*
@@ -614,7 +616,230 @@ static int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
 {
 	return pci_msi_prepare(domain, dev, nvec, info);
 }
-#endif /* CONFIG_X86 */
+#elif defined(CONFIG_ARM64)
+/*
+ * SPI vectors to use for vPCI; arch SPIs range is [32, 1019], but leaving a bit
+ * of room at the start to allow for SPIs to be specified through ACPI and
+ * starting with a power of two to satisfy power of 2 multi-MSI requirement.
+ */
+#define HV_PCI_MSI_SPI_START	64
+#define HV_PCI_MSI_SPI_NR	(1020 - HV_PCI_MSI_SPI_START)
+#define DELIVERY_MODE		0
+#define FLOW_HANDLER		NULL
+#define FLOW_NAME		NULL
+#define hv_msi_prepare		NULL
+
+struct hv_pci_chip_data {
+	DECLARE_BITMAP(spi_map, HV_PCI_MSI_SPI_NR);
+	struct mutex	map_lock;
+};
+
+/* Hyper-V vPCI MSI GIC IRQ domain */
+static struct irq_domain *hv_msi_gic_irq_domain;
+
+/* Hyper-V PCI MSI IRQ chip */
+static struct irq_chip hv_arm64_msi_irq_chip = {
+	.name = "MSI",
+	.irq_set_affinity = irq_chip_set_affinity_parent,
+	.irq_eoi = irq_chip_eoi_parent,
+	.irq_mask = irq_chip_mask_parent,
+	.irq_unmask = irq_chip_unmask_parent
+};
+
+static unsigned int hv_msi_get_int_vector(struct irq_data *irqd)
+{
+	return irqd->parent_data->hwirq;
+}
+
+static void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
+				       struct msi_desc *msi_desc)
+{
+	msi_entry->address = ((u64)msi_desc->msg.address_hi << 32) |
+			      msi_desc->msg.address_lo;
+	msi_entry->data = msi_desc->msg.data;
+}
+
+/*
+ * @nr_bm_irqs:		Indicates the number of IRQs that were allocated from
+ *			the bitmap.
+ * @nr_dom_irqs:	Indicates the number of IRQs that were allocated from
+ *			the parent domain.
+ */
+static void hv_pci_vec_irq_free(struct irq_domain *domain,
+				unsigned int virq,
+				unsigned int nr_bm_irqs,
+				unsigned int nr_dom_irqs)
+{
+	struct hv_pci_chip_data *chip_data = domain->host_data;
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	int first = d->hwirq - HV_PCI_MSI_SPI_START;
+	int i;
+
+	mutex_lock(&chip_data->map_lock);
+	bitmap_release_region(chip_data->spi_map,
+			      first,
+			      get_count_order(nr_bm_irqs));
+	mutex_unlock(&chip_data->map_lock);
+	for (i = 0; i < nr_dom_irqs; i++) {
+		if (i)
+			d = irq_domain_get_irq_data(domain, virq + i);
+		irq_domain_reset_irq_data(d);
+	}
+
+	irq_domain_free_irqs_parent(domain, virq, nr_dom_irqs);
+}
+
+static void hv_pci_vec_irq_domain_free(struct irq_domain *domain,
+				       unsigned int virq,
+				       unsigned int nr_irqs)
+{
+	hv_pci_vec_irq_free(domain, virq, nr_irqs, nr_irqs);
+}
+
+static int hv_pci_vec_alloc_device_irq(struct irq_domain *domain,
+				       unsigned int nr_irqs,
+				       irq_hw_number_t *hwirq)
+{
+	struct hv_pci_chip_data *chip_data = domain->host_data;
+	unsigned int index;
+
+	/* Find and allocate region from the SPI bitmap */
+	mutex_lock(&chip_data->map_lock);
+	index = bitmap_find_free_region(chip_data->spi_map,
+					HV_PCI_MSI_SPI_NR,
+					get_count_order(nr_irqs));
+	mutex_unlock(&chip_data->map_lock);
+	if (index < 0)
+		return -ENOSPC;
+
+	*hwirq = index + HV_PCI_MSI_SPI_START;
+
+	return 0;
+}
+
+static int hv_pci_vec_irq_gic_domain_alloc(struct irq_domain *domain,
+					   unsigned int virq,
+					   irq_hw_number_t hwirq)
+{
+	struct irq_fwspec fwspec;
+	struct irq_data *d;
+	int ret;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 2;
+	fwspec.param[0] = hwirq;
+	fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (ret)
+		return ret;
+
+	/*
+	 * Since the interrupt specifier is not coming from ACPI or DT, the
+	 * trigger type will need to be set explicitly. Otherwise, it will be
+	 * set to whatever is in the GIC configuration.
+	 */
+	d = irq_domain_get_irq_data(domain->parent, virq);
+
+	return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+}
+
+static int hv_pci_vec_irq_domain_alloc(struct irq_domain *domain,
+				       unsigned int virq, unsigned int nr_irqs,
+				       void *args)
+{
+	irq_hw_number_t hwirq;
+	unsigned int i;
+	int ret;
+
+	ret = hv_pci_vec_alloc_device_irq(domain, nr_irqs, &hwirq);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = hv_pci_vec_irq_gic_domain_alloc(domain, virq + i,
+						      hwirq + i);
+		if (ret) {
+			hv_pci_vec_irq_free(domain, virq, nr_irqs, i);
+			return ret;
+		}
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i,
+					      hwirq + i,
+					      &hv_arm64_msi_irq_chip,
+					      domain->host_data);
+		pr_debug("pID:%d vID:%u\n", (int)(hwirq + i), virq + i);
+	}
+
+	return 0;
+}
+
+/*
+ * Pick the first cpu as the irq affinity that can be temporarily used for
+ * composing MSI from the hypervisor. GIC will eventually set the right
+ * affinity for the irq and the 'unmask' will retarget the interrupt to that
+ * cpu.
+ */
+static int hv_pci_vec_irq_domain_activate(struct irq_domain *domain,
+					  struct irq_data *irqd, bool reserve)
+{
+	int cpu = cpumask_first(cpu_present_mask);
+
+	irq_data_update_effective_affinity(irqd, cpumask_of(cpu));
+
+	return 0;
+}
+
+static const struct irq_domain_ops hv_pci_domain_ops = {
+	.alloc	= hv_pci_vec_irq_domain_alloc,
+	.free	= hv_pci_vec_irq_domain_free,
+	.activate = hv_pci_vec_irq_domain_activate,
+};
+
+static int hv_pci_irqchip_init(void)
+{
+	static struct hv_pci_chip_data *chip_data;
+	struct fwnode_handle *fn = NULL;
+	int ret = -ENOMEM;
+
+	chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
+	if (!chip_data)
+		return ret;
+
+	mutex_init(&chip_data->map_lock);
+	fn = irq_domain_alloc_named_fwnode("hv_vpci_arm64");
+	if (!fn)
+		goto free_chip;
+
+	/*
+	 * IRQ domain once enabled, should not be removed since there is no
+	 * way to ensure that all the corresponding devices are also gone and
+	 * no interrupts will be generated.
+	 */
+	hv_msi_gic_irq_domain = acpi_irq_create_hierarchy(0, HV_PCI_MSI_SPI_NR,
+							  fn, &hv_pci_domain_ops,
+							  chip_data);
+
+	if (!hv_msi_gic_irq_domain) {
+		pr_err("Failed to create Hyper-V arm64 vPCI MSI IRQ domain\n");
+		goto free_chip;
+	}
+
+	return 0;
+
+free_chip:
+	kfree(chip_data);
+	if (fn)
+		irq_domain_free_fwnode(fn);
+
+	return ret;
+}
+
+static struct irq_domain *hv_pci_get_root_domain(void)
+{
+	return hv_msi_gic_irq_domain;
+}
+#endif /* CONFIG_ARM64 */
 
 /**
  * hv_pci_generic_compl() - Invoked for a completion packet
@@ -1227,6 +1452,8 @@ static void hv_msi_free(struct irq_domain *domain, struct msi_domain_info *info,
 static void hv_irq_mask(struct irq_data *data)
 {
 	pci_msi_mask_irq(data);
+	if (data->parent_data->chip->irq_mask)
+		irq_chip_mask_parent(data);
 }
 
 /**
@@ -1343,6 +1570,8 @@ static void hv_irq_unmask(struct irq_data *data)
 		dev_err(&hbus->hdev->device,
 			"%s() failed: %#llx", __func__, res);
 
+	if (data->parent_data->chip->irq_unmask)
+		irq_chip_unmask_parent(data);
 	pci_msi_unmask_irq(data);
 }
 
@@ -1618,7 +1847,11 @@ static struct irq_chip hv_msi_irq_chip = {
 	.name			= "Hyper-V PCIe MSI",
 	.irq_compose_msi_msg	= hv_compose_msi_msg,
 	.irq_set_affinity	= irq_chip_set_affinity_parent,
+#ifdef CONFIG_X86
 	.irq_ack		= irq_chip_ack_parent,
+#elif defined(CONFIG_ARM64)
+	.irq_eoi		= irq_chip_eoi_parent,
+#endif
 	.irq_mask		= hv_irq_mask,
 	.irq_unmask		= hv_irq_unmask,
 };
-- 
2.25.1

RE: [PATCH v8 1/2] PCI: hv: Make the code arch neutral by adding arch specific interfaces

[Michael Kelley (LINUX)]

From: Sunil Muthuswamy <sunilmut@linux.microsoft.com> Sent: Wednesday, January 5, 2022 11:33 AM
> 
> Encapsulate arch dependencies in Hyper-V vPCI through a set of
> arch-dependent interfaces. Adding these arch specific interfaces will
> allow for an implementation for other architectures, such as arm64.
> 
> There are no functional changes expected from this patch.
> 
> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
> ---
> In v2, v3, v4, v5, v6, v7 & v8:
>  Changes are described in the cover letter. No changes from v4 -> v5,
>  v6 -> v7 or v7 -> v8.
> 
>  arch/x86/include/asm/hyperv-tlfs.h  | 33 ++++++++++++
>  arch/x86/include/asm/mshyperv.h     |  7 ---
>  drivers/pci/controller/pci-hyperv.c | 79 ++++++++++++++++++++---------
>  include/asm-generic/hyperv-tlfs.h   | 33 ------------
>  4 files changed, 87 insertions(+), 65 deletions(-)
> 

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

RE: [PATCH v8 2/2] PCI: hv: Add arm64 Hyper-V vPCI support

[Michael Kelley (LINUX)]

From: Sunil Muthuswamy <sunilmut@linux.microsoft.com> Sent: Wednesday, January 5, 2022 11:33 AM
> 
> Add arm64 Hyper-V vPCI support by implementing the arch specific
> interfaces. Introduce an IRQ domain and chip specific to Hyper-v vPCI that
> is based on SPIs. The IRQ domain parents itself to the arch GIC IRQ domain
> for basic vector management.
> 
> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
> ---
> In v2, v3, v4, v5, v6, v7 & v8:
>  Changes are described in the cover letter.
> 
>  arch/arm64/include/asm/hyperv-tlfs.h |   9 +
>  drivers/pci/Kconfig                  |   2 +-
>  drivers/pci/controller/Kconfig       |   2 +-
>  drivers/pci/controller/pci-hyperv.c  | 235 ++++++++++++++++++++++++++-
>  4 files changed, 245 insertions(+), 3 deletions(-)
> 

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Re: [PATCH v8 0/2] PCI: hv: Hyper-V vPCI for arm64

[Lorenzo Pieralisi]

On Wed, 5 Jan 2022 11:32:34 -0800, Sunil Muthuswamy wrote:
> From: Sunil Muthuswamy <sunilmut@microsoft.com>
> 
> Current Hyper-V vPCI code only compiles and works for x86. There are some
> hardcoded assumptions about the architectural IRQ chip and other arch
> defines.
> 
> Add support for Hyper-V vPCI for arm64 by first breaking the current hard
> coded dependency using a set of new interfaces and implementing those for
> x86 first. That is in the first patch. The second patch adds support for
> Hyper-V vPCI for arm64 by implementing the above mentioned interfaces. That
> is done by introducing a Hyper-V vPCI specific MSI IRQ domain & chip for
> allocating SPI vectors.
> 
> [...]

Applied to pci/hv, thanks!

[1/2] PCI: hv: Make the code arch neutral by adding arch specific interfaces
      https://git.kernel.org/lpieralisi/pci/c/6c63f4da30
[2/2] PCI: hv: Add arm64 Hyper-V vPCI support
      https://git.kernel.org/lpieralisi/pci/c/c10bdb758c

Thanks,
Lorenzo