[PATCH RESEND 08/27] drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num

From: K. Y. Srinivasan
Date: Fri Dec 11 2015 - 21:55:30 EST


From: Jake Oshins <jakeo@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/vmbus_drv.c | 17 +++++++++++++++++
include/linux/hyperv.h | 2 ++
2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 3297731..c01b689 100644
--- 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
--- 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
*
--
1.7.4.1

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