HvCallPostMessage

The HvCallPostMessage hypercall attempts to post (that is, send asynchronously) a message to the specified connection, which has an associated destination port. If the message is successfully posted, then it will be queued for delivery to a virtual processor within the partition associated with the port.

Interface

HV_STATUS
HvCallPostMessage(
   _In_ HV_CONNECTION_ID ConnectionId,
   _In_ HV_MESSAGE_TYPE MessageType,
   _In_ UINT32 PayloadSize,
   _In_reads_bytes_(PayloadSize) PCVOID Message
   );

Call Code

0x005C (Simple)

Input Parameters

Name	Offset	Size	Information Provided
ConnectionId	0	4	Specifies the ID of the connection.
RsvdZ	4	4
MessageType	8	4	Specifies the message type that will appear within the message header. The caller can specify any 32-bit message type whose most significant bit is cleared, with the exception of zero.
PayloadSize	12	4	Specifies the number of bytes that are included in the message.
Message	16	240	Secifies the payload of the message—up to 240 bytes total. Only the first n bytes are actually sent to the destination partition, where n is provided in the PayloadSize parameter.

Return Values

Status code	Error Condition
HV_STATUS_ACCESS_DENIED	The caller’s partition does not possess the PostMessages privilege.
HV_STATUS_INVALID_CONNECTION_ID	The specified connection ID is invalid.
HV_STATUS_INVALID_PORT_ID	The port associated with the specified connection has been deleted.
	The port associated with the specified connection belongs to a partition that is not in the “active” state.
	The port associated with the specified connection is not a "message" type port.
HV_STATUS_INVALID_PARAMETER	The most significant bit of the specified message type is set.
	The MessageType parameter specifies a value of zero.
	The specified payload size exceeds 240 bytes.
HV_STATUS_INSUFFICIENT_BUFFERS	The port has no available guest message buffers.
HV_STATUS_INVALID_VP_INDEX	The target VP no longer exists or there are no available VPs to which the message can be posted.
HV_STATUS_INVALID_SYNIC_STATE	The target VP’s SynIC is disabled and cannot accept posted messages.
	The target VP’s SIM page is disabled.