UserClient: Support large message blocks

flagersgit · Oct 5, 2022 · 4ac2471 · 4ac2471
1 parent 79c3992
commit 4ac2471
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Showing 2 changed files with 41 additions and 19 deletions.
diff --git a/MacHyperVSupport/Controller/HyperVUserClient.cpp b/MacHyperVSupport/Controller/HyperVUserClient.cpp
@@ -41,12 +41,12 @@ bool HyperVUserClient::start(IOService *provider) {
   //
   // Populate notification message info.
   //
-  _notificationMsg.header.msgh_bits        = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
-  _notificationMsg.header.msgh_size        = sizeof (_notificationMsg);
-  _notificationMsg.header.msgh_remote_port = MACH_PORT_NULL;
-  _notificationMsg.header.msgh_local_port  = MACH_PORT_NULL;
-  _notificationMsg.header.msgh_reserved    = 0;
-  _notificationMsg.header.msgh_id          = 0;
+  _notificationMsg.standard.header.msgh_bits        = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
+  _notificationMsg.standard.header.msgh_size        = sizeof (_notificationMsg.standard);
+  _notificationMsg.standard.header.msgh_remote_port = MACH_PORT_NULL;
+  _notificationMsg.standard.header.msgh_local_port  = MACH_PORT_NULL;
+  _notificationMsg.standard.header.msgh_reserved    = 0;
+  _notificationMsg.standard.header.msgh_id          = 0;
 
   HVDBGLOG("Initialized Hyper-V user client");
   return true;
@@ -91,19 +91,27 @@ IOReturn HyperVUserClient::registerNotificationPort(mach_port_t port, UInt32 typ
   }
 
   HVDBGLOG("Registering notification port 0x%p", port);
-  _notificationMsg.header.msgh_remote_port = port;
+  _notificationMsg.standard.header.msgh_remote_port = port;
   return kIOReturnSuccess;
 }
 
 IOReturn HyperVUserClient::notifyClientApplication(HyperVUserClientNotificationType type, void *data, UInt32 dataLength) {
-  if (dataLength > sizeof (_notificationMsg.data)) {
+  if (dataLength > sizeof (_notificationMsg.large.data)) {
     return kIOReturnMessageTooLarge;
   }
 
   HVDBGLOG("Sending notification type %u with %u bytes of data", type, dataLength);
-  _notificationMsg.type = type;
-  memcpy(_notificationMsg.data, data, dataLength);
-  _notificationMsg.dataLength = dataLength;
+  _notificationMsg.standard.type = type;
+  memcpy(_notificationMsg.standard.data, data, dataLength);
+
+  if (dataLength > sizeof (_notificationMsg.standard.data)) {
+    _notificationMsg.standard.header.msgh_size = sizeof (_notificationMsg.large.data);
+    _notificationMsg.large.dataLength = dataLength;
+  } else {
+    _notificationMsg.standard.header.msgh_size = sizeof (_notificationMsg.standard.data);
+    _notificationMsg.standard.dataLength = dataLength;
+  }
+
 
-  return mach_msg_send_from_kernel(&_notificationMsg.header, _notificationMsg.header.msgh_size);
+  return mach_msg_send_from_kernel(&_notificationMsg.standard.header, _notificationMsg.standard.header.msgh_size);
 }
diff --git a/MacHyperVSupport/Controller/HyperVUserClient.h b/MacHyperVSupport/Controller/HyperVUserClient.h
@@ -11,7 +11,8 @@
 #include <libkern/OSTypes.h>
 #include <mach/message.h>
 
-#define kHyperVUserClientNotificationMessageDataLength 64
+#define kHyperVUserClientNotificationMessageDataStandardLength 64
+#define kHyperVUserClientNotificationMessageDataLargeLength (kHyperVUserClientNotificationMessageDataStandardLength + (6 * 1024))
 
 typedef enum : UInt32 {
   kHyperVUserClientNotificationTypePerformShutdown = 0x66697368,
@@ -24,15 +25,28 @@ typedef struct {
   UInt32 microseconds;
 } HyperVUserClientTimeData;
 
-typedef struct {
-  mach_msg_header_t                header;
-  HyperVUserClientNotificationType type;
-  UInt8                            data[kHyperVUserClientNotificationMessageDataLength];
-  UInt32                           dataLength;
 
+typedef union {
+  struct {
+    mach_msg_header_t                header;
+    HyperVUserClientNotificationType type;
+    UInt8                            data[kHyperVUserClientNotificationMessageDataStandardLength];
+    UInt32                           dataLength;
+
+#ifndef KERNEL
+    mach_msg_trailer_t               trailer;
+#endif
+  } standard;
+  struct {
+    mach_msg_header_t                header;
+    HyperVUserClientNotificationType type;
+    UInt8                            data[kHyperVUserClientNotificationMessageDataLargeLength];
+    UInt32                           dataLength;
+
 #ifndef KERNEL
-  mach_msg_trailer_t               trailer;
+    mach_msg_trailer_t               trailer;
 #endif
+  } large;
 } HyperVUserClientNotificationMessage;
 
 #endif