HV_MESSAGE

SynIC messages are of fixed size composed of a message header (which includes the message type and information about where the message originated) followed by the payload. Messages that are sent in response to HvCallPostMessage contain the port ID. Intercept messages contain the partition ID of the partition whose virtual processor generated the intercept. Timer intercepts do not have an origination ID (that is, the specified ID is zero).

The MessagePending flag indicates whether or not there are any messages pending in the message queue of the synthetic interrupt source. If there are, then an “end of message” must be performed by the guest after emptying the message slot. This allows for opportunistic writes to the EOM MSR (only when required). Note that this flag may be set by the hypervisor upon message delivery or at any time afterwards. The flag should be tested after the message slot has been emptied and if set, then there are one or more pending messages and the “end of message” should be performed.

Syntax

#define HV_MESSAGE_SIZE 256
#define HV_MESSAGE_MAX_PAYLOAD_BYTE_COUNT 240
#define HV_MESSAGE_MAX_PAYLOAD_QWORD_COUNT 30

typedef struct
{
   UINT8 MessagePending:1;
   UINT8 Reserved:7;
} HV_MESSAGE_FLAGS;

typedef struct
{
   HV_MESSAGE_TYPE MessageType;
   UINT8 PayloadSize;
   HV_MESSAGE_FLAGS MessageFlags;
   UINT16 Reserved;
   union
   {
       UINT64 OriginationId;
       HV_PARTITION_ID Sender;
       HV_PORT_ID Port;
   };
} HV_MESSAGE_HEADER;

typedef struct
{
   HV_MESSAGE_HEADER Header;
   UINT64 Payload[HV_MESSAGE_MAX_PAYLOAD_QWORD_COUNT];
} HV_MESSAGE;