Hyper-V: pci: controller: Introduce arch-specific init/exit interface

To allow architectures to run specific code before init
or after exit.

Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Boqun Feng (Microsoft) <boqun.feng@gmail.com>
Signed-off-by: Allen Pais <apais@microsoft.com>
[tyhicks: Forward port around commit 7d815f4 ("PCI: hv: Add check
 for hyperv_initialized in init_hv_pci_drv()")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>

Author: allenpais

arch/x86/include/asm/mshyperv.h

@@ -227,6 +227,14 @@ static inline u8 hv_msi_irq_delivery_mode(void)
 	return dest_Fixed;
 }
 
+/* Architecture specific Hyper-V PCI MSI initialization and cleanup routines */
+static inline int hv_pci_arch_init(void)
+{
+	return 0;
+}
+
+static inline void hv_pci_arch_free(void) {}
+
 #ifdef CONFIG_X86_64
 void hv_apic_init(void);
 void __init hv_init_spinlocks(void);

drivers/pci/controller/pci-hyperv.c

@@ -3501,13 +3501,21 @@ 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_arch_free();
 }
 
 static int __init init_hv_pci_drv(void)
 {
+	int ret;
+
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
+	ret = hv_pci_arch_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);