diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 67d9b5a..1ce131f 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -14,6 +14,7 @@
 
 #include <uapi/linux/hyperv.h>
 
+#include <linux/mm.h>
 #include <linux/types.h>
 #include <linux/scatterlist.h>
 #include <linux/list.h>
@@ -23,12 +24,55 @@
 #include <linux/mod_devicetable.h>
 #include <linux/interrupt.h>
 #include <linux/reciprocal_div.h>
+#include <asm/hyperv-tlfs.h>
 
 #define MAX_PAGE_BUFFER_COUNT				32
 #define MAX_MULTIPAGE_BUFFER_COUNT			32 /* 128K */
 
 #pragma pack(push, 1)
 
+/*
+ * Types for GPADL, decides is how GPADL header is created.
+ *
+ * It doesn't make much difference between BUFFER and RING if PAGE_SIZE is the
+ * same as HV_HYP_PAGE_SIZE.
+ *
+ * If PAGE_SIZE is bigger than HV_HYP_PAGE_SIZE, the headers of ring buffers
+ * will be of PAGE_SIZE, however, only the first HV_HYP_PAGE will be put
+ * into gpadl, therefore the number for HV_HYP_PAGE and the indexes of each
+ * HV_HYP_PAGE will be different between different types of GPADL, for example
+ * if PAGE_SIZE is 64K:
+ *
+ * BUFFER:
+ *
+ * gva:    |--       64k      --|--       64k      --| ... |
+ * gpa:    | 4k | 4k | ... | 4k | 4k | 4k | ... | 4k |
+ * index:  0    1    2     15   16   17   18 .. 31   32 ...
+ *         |    |    ...   |    |    |   ...    |   ...
+ *         v    V          V    V    V          V
+ * gpadl:  | 4k | 4k | ... | 4k | 4k | 4k | ... | 4k | ... |
+ * index:  0    1    2 ... 15   16   17   18 .. 31   32 ...
+ *
+ * RING:
+ *
+ *         | header  |           data           | header  |     data      |
+ * gva:    |-- 64k --|--       64k      --| ... |-- 64k --|-- 64k --| ... |
+ * gpa:    | 4k | .. | 4k | 4k | ... | 4k | ... | 4k | .. | 4k | .. | ... |
+ * index:  0    1    16   17   18    31   ...   n   n+1  n+16 ...         2n
+ *         |         /    /          /          |         /               /
+ *         |        /    /          /           |        /               /
+ *         |       /    /   ...    /    ...     |       /      ...      /
+ *         |      /    /          /             |      /               /
+ *         |     /    /          /              |     /               /
+ *         V    V    V          V               V    V               v
+ * gpadl:  | 4k | 4k |   ...    |    ...        | 4k | 4k |  ...     |
+ * index:  0    1    2   ...    16   ...       n-15 n-14 n-13  ...  2n-30
+ */
+enum hv_gpadl_type {
+	HV_GPADL_BUFFER,
+	HV_GPADL_RING
+};
+
 /* Single-page buffer */
 struct hv_page_buffer {
 	u32 len;
@@ -111,15 +155,19 @@
 	} feature_bits;
 
 	/* Pad it to PAGE_SIZE so that data starts on page boundary */
-	u8	reserved2[4028];
+	u8	reserved2[PAGE_SIZE - 68];
 
 	/*
 	 * Ring data starts here + RingDataStartOffset
 	 * !!! DO NOT place any fields below this !!!
 	 */
-	u8 buffer[0];
+	u8 buffer[];
 } __packed;
 
+/* Calculate the proper size of a ringbuffer, it must be page-aligned */
+#define VMBUS_RING_SIZE(payload_sz) PAGE_ALIGN(sizeof(struct hv_ring_buffer) + \
+					       (payload_sz))
+
 struct hv_ring_buffer_info {
 	struct hv_ring_buffer *ring_buffer;
 	u32 ring_size;			/* Include the shared header */
@@ -182,19 +230,21 @@
  * 2 . 4  (Windows 8)
  * 3 . 0  (Windows 8 R2)
  * 4 . 0  (Windows 10)
+ * 4 . 1  (Windows 10 RS3)
  * 5 . 0  (Newer Windows 10)
+ * 5 . 1  (Windows 10 RS4)
+ * 5 . 2  (Windows Server 2019, RS5)
  */
 
 #define VERSION_WS2008  ((0 << 16) | (13))
 #define VERSION_WIN7    ((1 << 16) | (1))
 #define VERSION_WIN8    ((2 << 16) | (4))
 #define VERSION_WIN8_1    ((3 << 16) | (0))
-#define VERSION_WIN10	((4 << 16) | (0))
+#define VERSION_WIN10 ((4 << 16) | (0))
+#define VERSION_WIN10_V4_1 ((4 << 16) | (1))
 #define VERSION_WIN10_V5 ((5 << 16) | (0))
-
-#define VERSION_INVAL -1
-
-#define VERSION_CURRENT VERSION_WIN10_V5
+#define VERSION_WIN10_V5_1 ((5 << 16) | (1))
+#define VERSION_WIN10_V5_2 ((5 << 16) | (2))
 
 /* Make maximum size of pipe payload of 16K */
 #define MAX_PIPE_DATA_PAYLOAD		(sizeof(u8) * 16384)
@@ -311,7 +361,7 @@
 struct gpa_range {
 	u32 byte_count;
 	u32 byte_offset;
-	u64 pfn_array[0];
+	u64 pfn_array[];
 };
 
 /*
@@ -423,7 +473,7 @@
 	CHANNELMSG_19				= 19,
 	CHANNELMSG_20				= 20,
 	CHANNELMSG_TL_CONNECT_REQUEST		= 21,
-	CHANNELMSG_22				= 22,
+	CHANNELMSG_MODIFYCHANNEL		= 22,
 	CHANNELMSG_TL_CONNECT_RESULT		= 23,
 	CHANNELMSG_COUNT
 };
@@ -561,7 +611,7 @@
 	u32 gpadl;
 	u16 range_buflen;
 	u16 rangecount;
-	struct gpa_range range[0];
+	struct gpa_range range[];
 } __packed;
 
 /* This is the followup packet that contains more PFNs. */
@@ -569,7 +619,7 @@
 	struct vmbus_channel_message_header header;
 	u32 msgnumber;
 	u32 gpadl;
-	u64 pfn[0];
+	u64 pfn[];
 } __packed;
 
 struct vmbus_channel_gpadl_created {
@@ -618,6 +668,13 @@
 	guid_t host_service_id;
 } __packed;
 
+/* Modify Channel parameters, cf. vmbus_send_modifychannel() */
+struct vmbus_channel_modifychannel {
+	struct vmbus_channel_message_header header;
+	u32 child_relid;
+	u32 target_vp;
+} __packed;
+
 struct vmbus_channel_version_response {
 	struct vmbus_channel_message_header header;
 	u8 version_supported;
@@ -670,7 +727,7 @@
 	 * The channel message that goes out on the "wire".
 	 * It will contain at minimum the VMBUS_CHANNEL_MESSAGE_HEADER header
 	 */
-	unsigned char msg[0];
+	unsigned char msg[];
 };
 
 struct vmbus_close_msg {
@@ -687,11 +744,6 @@
 	} u;
 };
 
-enum hv_numa_policy {
-	HV_BALANCED = 0,
-	HV_LOCALIZED,
-};
-
 enum vmbus_device_type {
 	HV_IDE = 0,
 	HV_SCSI,
@@ -769,6 +821,15 @@
 	void (*onchannel_callback)(void *context);
 	void *channel_callback_context;
 
+	void (*change_target_cpu_callback)(struct vmbus_channel *channel,
+			u32 old, u32 new);
+
+	/*
+	 * Synchronize channel scheduling and channel removal; see the inline
+	 * comments in vmbus_chan_sched() and vmbus_reset_channel_cb().
+	 */
+	spinlock_t sched_lock;
+
 	/*
 	 * A channel can be marked for one of three modes of reading:
 	 *   BATCHED - callback called from taslket and should read
@@ -790,22 +851,16 @@
 	u64 sig_event;
 
 	/*
-	 * Starting with win8, this field will be used to specify
-	 * the target virtual processor on which to deliver the interrupt for
-	 * the host to guest communication.
-	 * Prior to win8, incoming channel interrupts would only
-	 * be delivered on cpu 0. Setting this value to 0 would
-	 * preserve the earlier behavior.
+	 * Starting with win8, this field will be used to specify the
+	 * target CPU on which to deliver the interrupt for the host
+	 * to guest communication.
+	 *
+	 * Prior to win8, incoming channel interrupts would only be
+	 * delivered on CPU 0. Setting this value to 0 would preserve
+	 * the earlier behavior.
 	 */
-	u32 target_vp;
-	/* The corresponding CPUID in the guest */
 	u32 target_cpu;
 	/*
-	 * State to manage the CPU affiliation of channels.
-	 */
-	struct cpumask alloced_cpus_in_node;
-	int numa_node;
-	/*
 	 * Support for sub-channels. For high performance devices,
 	 * it will be useful to have multiple sub-channels to support
 	 * a scalable communication infrastructure with the host.
@@ -834,12 +889,6 @@
 	void (*chn_rescind_callback)(struct vmbus_channel *channel);
 
 	/*
-	 * The spinlock to protect the structure. It is being used to protect
-	 * test-and-set access to various attributes of the structure as well
-	 * as all sc_list operations.
-	 */
-	spinlock_t lock;
-	/*
 	 * All Sub-channels of a primary channel are linked here.
 	 */
 	struct list_head sc_list;
@@ -852,11 +901,6 @@
 	 * Support per-channel state for use by vmbus drivers.
 	 */
 	void *per_channel_state;
-	/*
-	 * To support per-cpu lookup mapping of relid to channel,
-	 * link up channels based on their CPU affinity.
-	 */
-	struct list_head percpu_list;
 
 	/*
 	 * Defer freeing channel until after all cpu's have
@@ -895,21 +939,16 @@
 	 */
 	bool low_latency;
 
-	/*
-	 * NUMA distribution policy:
-	 * We support two policies:
-	 * 1) Balanced: Here all performance critical channels are
-	 *    distributed evenly amongst all the NUMA nodes.
-	 *    This policy will be the default policy.
-	 * 2) Localized: All channels of a given instance of a
-	 *    performance critical service will be assigned CPUs
-	 *    within a selected NUMA node.
-	 */
-	enum hv_numa_policy affinity_policy;
-
 	bool probe_done;
 
 	/*
+	 * Cache the device ID here for easy access; this is useful, in
+	 * particular, in situations where the channel's device_obj has
+	 * not been allocated/initialized yet.
+	 */
+	u16 device_id;
+
+	/*
 	 * We must offload the handling of the primary/sub channels
 	 * from the single-threaded vmbus_connection.work_queue to
 	 * two different workqueue, otherwise we can block
@@ -934,6 +973,21 @@
 	 * full outbound ring buffer.
 	 */
 	u64 out_full_first;
+
+	/* enabling/disabling fuzz testing on the channel (default is false)*/
+	bool fuzz_testing_state;
+
+	/*
+	 * Interrupt delay will delay the guest from emptying the ring buffer
+	 * for a specific amount of time. The delay is in microseconds and will
+	 * be between 1 to a maximum of 1000, its default is 0 (no delay).
+	 * The  Message delay will delay guest reading on a per message basis
+	 * in microseconds between 1 to 1000 with the default being 0
+	 * (no delay).
+	 */
+	u32 fuzz_testing_interrupt_delay;
+	u32 fuzz_testing_message_delay;
+
 };
 
 static inline bool is_hvsock_channel(const struct vmbus_channel *c)
@@ -947,12 +1001,6 @@
 	return c->offermsg.offer.sub_channel_index != 0;
 }
 
-static inline void set_channel_affinity_state(struct vmbus_channel *c,
-					      enum hv_numa_policy policy)
-{
-	c->affinity_policy = policy;
-}
-
 static inline void set_channel_read_mode(struct vmbus_channel *c,
 					enum hv_callback_mode mode)
 {
@@ -1000,7 +1048,7 @@
 	c->low_latency = false;
 }
 
-void vmbus_onmessage(void *context);
+void vmbus_onmessage(struct vmbus_channel_message_header *hdr);
 
 int vmbus_request_offers(void);
 
@@ -1182,6 +1230,10 @@
 
 	struct vmbus_channel *channel;
 	struct kset	     *channels_kset;
+
+	/* place holder to keep track of the dir for hv device in debugfs */
+	struct dentry *debug_dir;
+
 };
 
 
@@ -1414,6 +1466,8 @@
 	void (*util_cb)(void *);
 	int (*util_init)(struct hv_util_service *);
 	void (*util_deinit)(void);
+	int (*util_pre_suspend)(void);
+	int (*util_pre_resume)(void);
 };
 
 struct vmbuspipe_hdr {
@@ -1508,6 +1562,7 @@
 
 int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
 				  const guid_t *shv_host_servie_id);
+int vmbus_send_modifychannel(u32 child_relid, u32 target_vp);
 void vmbus_set_event(struct vmbus_channel *channel);
 
 /* Get the start of the ring buffer. */
@@ -1623,4 +1678,22 @@
 
 extern struct hyperv_pci_block_ops hvpci_block_ops;
 
+static inline unsigned long virt_to_hvpfn(void *addr)
+{
+	phys_addr_t paddr;
+
+	if (is_vmalloc_addr(addr))
+		paddr = page_to_phys(vmalloc_to_page(addr)) +
+				     offset_in_page(addr);
+	else
+		paddr = __pa(addr);
+
+	return  paddr >> HV_HYP_PAGE_SHIFT;
+}
+
+#define NR_HV_HYP_PAGES_IN_PAGE	(PAGE_SIZE / HV_HYP_PAGE_SIZE)
+#define offset_in_hvpage(ptr)	((unsigned long)(ptr) & ~HV_HYP_PAGE_MASK)
+#define HVPFN_UP(x)	(((x) + HV_HYP_PAGE_SIZE-1) >> HV_HYP_PAGE_SHIFT)
+#define page_to_hvpfn(page)	(page_to_pfn(page) * NR_HV_HYP_PAGES_IN_PAGE)
+
 #endif /* _HYPERV_H */