Merge tag 'hyperv-next-signed-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V updates from Wei Liu:

 - harden VMBus (Andres Beltran)

 - clean up VMBus driver (Matheus Castello)

 - fix hv_balloon reporting (Vitaly Kuznetsov)

 - fix a potential OOB issue (Andrea Parri)

 - remove an obsolete TODO item (Stefan Eschenbacher)

* tag 'hyperv-next-signed-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  hv_balloon: do adjust_managed_page_count() when ballooning/un-ballooning
  hv_balloon: simplify math in alloc_balloon_pages()
  drivers/hv: remove obsolete TODO and fix misleading typo in comment
  drivers: hv: vmbus: Fix checkpatch SPLIT_STRING
  hv_netvsc: Validate number of allocated sub-channels
  drivers: hv: vmbus: Fix call msleep using < 20ms
  drivers: hv: vmbus: Fix checkpatch LINE_SPACING
  drivers: hv: vmbus: Replace symbolic permissions by octal permissions
  drivers: hv: Fix hyperv_record_panic_msg path on comment
  hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening
  scsi: storvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening
  Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 1ce131f29f3b..5ddb479c4d4c 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -764,6 +764,23 @@ enum vmbus_device_type {
 	HV_UNKNOWN,
 };
 
+/*
+ * Provides request ids for VMBus. Encapsulates guest memory
+ * addresses and stores the next available slot in req_arr
+ * to generate new ids in constant time.
+ */
+struct vmbus_requestor {
+	u64 *req_arr;
+	unsigned long *req_bitmap; /* is a given slot available? */
+	u32 size;
+	u64 next_request_id;
+	spinlock_t req_lock; /* provides atomicity */
+};
+
+#define VMBUS_NO_RQSTOR U64_MAX
+#define VMBUS_RQST_ERROR (U64_MAX - 1)
+#define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2)
+
 struct vmbus_device {
 	u16  dev_type;
 	guid_t guid;
@@ -988,8 +1005,14 @@ struct vmbus_channel {
 	u32 fuzz_testing_interrupt_delay;
 	u32 fuzz_testing_message_delay;
 
+	/* request/transaction ids for VMBus */
+	struct vmbus_requestor requestor;
+	u32 rqstor_size;
 };
 
+u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr);
+u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id);
+
 static inline bool is_hvsock_channel(const struct vmbus_channel *c)
 {
 	return !!(c->offermsg.offer.chn_flags &