describe the msi entry for HVCALL_RETARGET_INTERRUPT. The structure is
needed because its layout may be different from architecture to
architecture.

Also add a new generic interface hv_set_msi_address_from_desc() to allow
different archs to set the msi address from msi_desc.

No functional change, only preparation for the future support of virtual
PCI on non-x86 architectures.

Signed-off-by: Boqun Feng (Microsoft) <redacted>
---
 arch/x86/include/asm/hyperv-tlfs.h  | 11 +++++++++--
 arch/x86/include/asm/mshyperv.h     |  5 +++++
 drivers/pci/controller/pci-hyperv.c |  4 ++--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 4a76e442481a..953b3ad38746 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h

@@ -912,11 +912,18 @@ struct hv_partition_assist_pg {
 	u32 tlb_lock_count;
 };
 
+union hv_msi_entry {
+	u64 as_uint64;
+	struct {
+		u32 address;
+		u32 data;
+	} __packed;
+};
+
 struct hv_interrupt_entry {
 	u32 source;			/* 1 for MSI(-X) */
 	u32 reserved1;
-	u32 address;
-	u32 data;
+	union hv_msi_entry msi_entry;
 } __packed;
 
 /*

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 6b79515abb82..3bdaa3b6e68f 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h

@@ -240,6 +240,11 @@ bool hv_vcpu_is_preempted(int vcpu);
 static inline void hv_apic_init(void) {}
 #endif
 
+#define hv_set_msi_address_from_desc(msi_entry, msi_desc)	\
+do {								\
+	(msi_entry)->address = (msi_desc)->msg.address_lo;	\
+} while (0)

+
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 0d9b74503577..2240f2b3643e 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c

@@ -1170,8 +1170,8 @@ static void hv_irq_unmask(struct irq_data *data)
 	memset(params, 0, sizeof(*params));
 	params->partition_id = HV_PARTITION_ID_SELF;
 	params->int_entry.source = 1; /* MSI(-X) */
-	params->int_entry.address = msi_desc->msg.address_lo;
-	params->int_entry.data = msi_desc->msg.data;
+	hv_set_msi_address_from_desc(&params->int_entry.msi_entry, msi_desc);
+	params->int_entry.msi_entry.data = msi_desc->msg.data;