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Drivers: hv: vmbus: enable VMBus protocol version 5.0

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With VMBus protocol 5.0, we're able to better support new features, e.g.
running two or more VMBus drivers simultaneously in a single VM -- note:
we can't simply load the current VMBus driver twice, instead, a secondary
VMBus driver must be implemented.

This patch adds the support for the new VMBus protocol, which is available
on new Windows hosts, by:

1) We still use SINT2 for compatibility;
2) We must use Connection ID 4 for the Initiate Contact Message, and for
subsequent messages, we must use the Message Connection ID field in
the host-returned VersionResponse Message.

Notes for developers of the secondary VMBus driver:
1) Must use VMBus protocol 5.0 as well;
2) Must use a different SINT number that is not in use.
3) Must use Connection ID 4 for the Initiate Contact Message, and for
subsequent messages, must use the Message Connection ID field in
the host-returned VersionResponse Message.
4) It's possible that the primary VMBus driver using protocol version 4.0
can work with a secondary VMBus driver using protocol version 5.0, but it's
recommended that both should use 5.0 for new Hyper-V features in the future.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dexuan Cui
2018-05-12 02:30:33 -07:00
committed by Greg Kroah-Hartman
parent e19f70aa02
commit ae20b25430
3 changed files with 69 additions and 4 deletions
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44
drivers/hv/connection.c
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@@ -63,6 +63,9 @@ static __u32 vmbus_get_next_version(__u32 current_version)
case (VERSION_WIN10):
return VERSION_WIN8_1;
case (VERSION_WIN10_V5):
return VERSION_WIN10;
case (VERSION_WS2008):
default:
return VERSION_INVAL;
@@ -80,9 +83,29 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
memset(msg, 0, sizeof(*msg));
msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
msg->vmbus_version_requested = version;
msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
/*
* VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
* VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
* and for subsequent messages, we must use the Message Connection ID
* field in the host-returned Version Response Message. And, with
* VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
* the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
* compatibility.
*
* On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
*/
if (version >= VERSION_WIN10_V5) {
msg->msg_sint = VMBUS_MESSAGE_SINT;
vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
} else {
msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
}
msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
/*
@@ -137,6 +160,10 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
/* Check if successful */
if (msginfo->response.version_response.version_supported) {
vmbus_connection.conn_state = CONNECTED;
if (version >= VERSION_WIN10_V5)
vmbus_connection.msg_conn_id =
msginfo->response.version_response.msg_conn_id;
} else {
return -ECONNREFUSED;
}
@@ -354,13 +381,14 @@ void vmbus_on_event(unsigned long data)
*/
int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
{
struct vmbus_channel_message_header *hdr;
union hv_connection_id conn_id;
int ret = 0;
int retries = 0;
u32 usec = 1;
conn_id.asu32 = 0;
conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
conn_id.u.id = vmbus_connection.msg_conn_id;
/*
* hv_post_message() can have transient failures because of
@@ -372,6 +400,18 @@ int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
switch (ret) {
case HV_STATUS_INVALID_CONNECTION_ID:
/*
* See vmbus_negotiate_version(): VMBus protocol 5.0
* requires that we must use
* VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
* Contact message, but on old hosts that only
* support VMBus protocol 4.0 or lower, here we get
* HV_STATUS_INVALID_CONNECTION_ID and we should
* return an error immediately without retrying.
*/
hdr = (struct vmbus_channel_message_header *)buffer;
if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
return -EINVAL;
/*
* We could get this if we send messages too
* frequently.