On Thu, Jul 29, 2021 at 04:26:54PM +0200, Siddharth Chandrasekaran wrote:

On Thu, Jul 29, 2021 at 02:07:05PM +0000, Wei Liu wrote:

quoted

On Thu, Jul 29, 2021 at 03:52:46PM +0200, Vitaly Kuznetsov wrote:

quoted

Siddharth Chandrasekaran [off-list ref] writes:

quoted

According to Hyper-V TLFS Version 6.0b, struct hv_message_header members
should be defined in the order:

    message_type, reserved, message_flags, payload_size

but we have it defined in the order:

    message_type, payload_size, message_flags, reserved

that is, the payload_size and reserved members swapped.

Indeed,

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

Well. I think TLFS is wrong. Let me ask around.

TBH, I hadn't considered that possibility :). I assumed it was a
regression on our side. But I spent some time tracing the history of that
struct all the way back to when it was in staging (in 2009) and now I'm
inclined to believe a later version of TLFS is at fault here.

Based on what we decide in this thread, I will open an issue on the TLFS
GitHub repository.

I have confirmation TLFS is wrong and shall be fixed. Feel free to open
an issue on GitHub too.

Wei.