drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num

This patch exposes the mapping between Linux CPU number and Hyper-V virtual
processor number.  This is necessary because the hypervisor needs to know which
virtual processors to target when making a mapping in the Interrupt Redirection
Table in the I/O MMU.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 3297731..c01b689 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1193,6 +1193,23 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 }
 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
 
+/**
+ * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
+ * @cpu_number: CPU number in Linux terms
+ *
+ * This function returns the mapping between the Linux processor
+ * number and the hypervisor's virtual processor number, useful
+ * in making hypercalls and such that talk about specific
+ * processors.
+ *
+ * Return: Virtual processor number in Hyper-V terms
+ */
+int vmbus_cpu_number_to_vp_number(int cpu_number)
+{
+       return hv_context.vp_index[cpu_number];
+}
+EXPORT_SYMBOL_GPL(vmbus_cpu_number_to_vp_number);
+
 static int vmbus_acpi_add(struct acpi_device *device)
 {
        acpi_status result;

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 8fdc17b..fddb3e0 100644 (file)
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -983,6 +983,8 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
                        resource_size_t size, resource_size_t align,
                        bool fb_overlap_ok);
 
+int vmbus_cpu_number_to_vp_number(int cpu_number);
+
 /**
  * VMBUS_DEVICE - macro used to describe a specific hyperv vmbus device
  *