From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Monday, February 1, 2021 6:48 AM
>
> Restrict the protocol version(s) that will be negotiated with the host
> to be 5.2 or greater if the guest is running isolated. This reduces the
> footprint of the code that will be exercised by Confidential VMs and
> hence the exposure to bugs and vulnerabilities.
>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> ---
> drivers/hv/connection.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index 11170d9a2e1a5..c83612cddb995 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -244,6 +244,13 @@ int vmbus_connect(void)
> break;
> }
>
> + if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
> + pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
> + version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
> + ret = -EINVAL;
> + goto cleanup;
> + }
> +
> vmbus_proto_version = version;
> pr_info("Vmbus version:%d.%d\n",
> version >> 16, version & 0xFFFF);
> --
> 2.25.1
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
