#include <linux/hyperv.h>
 #include <linux/uio.h>
 #include <linux/interrupt.h>
+#include <asm/page.h>
 
 #include "hyperv_vmbus.h"
 
 #define NUM_PAGES_SPANNED(addr, len) \
 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
 
+static unsigned long virt_to_hvpfn(void *addr)
+{
+       unsigned long paddr;
+
+       if (is_vmalloc_addr(addr))
+               paddr = page_to_phys(vmalloc_to_page(addr)) +
+                                        offset_in_page(addr);
+       else
+               paddr = __pa(addr);
+
+       return  paddr >> PAGE_SHIFT;
+}
+
 /*
  * vmbus_setevent- Trigger an event notification on the specified
  * channel.
                gpadl_header->range[0].byte_offset = 0;
                gpadl_header->range[0].byte_count = size;
                for (i = 0; i < pfncount; i++)
-                       gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
-                               kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
+                       gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
+                               kbuffer + PAGE_SIZE * i);
                *msginfo = msgheader;
 
                pfnsum = pfncount;
                         * so the hypervisor guarantees that this is ok.
                         */
                        for (i = 0; i < pfncurr; i++)
-                               gpadl_body->pfn[i] = slow_virt_to_phys(
-                                       kbuffer + PAGE_SIZE * (pfnsum + i)) >>
-                                       PAGE_SHIFT;
+                               gpadl_body->pfn[i] = virt_to_hvpfn(
+                                       kbuffer + PAGE_SIZE * (pfnsum + i));
 
                        /* add to msg header */
                        list_add_tail(&msgbody->msglistentry,
                gpadl_header->range[0].byte_offset = 0;
                gpadl_header->range[0].byte_count = size;
                for (i = 0; i < pagecount; i++)
-                       gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
-                               kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
+                       gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
+                               kbuffer + PAGE_SIZE * i);
 
                *msginfo = msgheader;
        }