[PATCH 07/28] Drivers: hv: Support handling multiple VMBUS versions

K. Y. Srinivasan
2012-12-01T14:27:42Z

The current code hard coded the vmbus version independent of the host
it was running on. Add code to dynamically negotiate the most appropriate
version.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
drivers/hv/connection.c | 165 +++++++++++++++++++++++++++++++---------------
include/linux/hyperv.h | 6 --
2 files changed, 111 insertions(+), 60 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index d1019a7..2b56a3f 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -40,15 +40,111 @@ struct vmbus_connection vmbus_connection = {
};

/*
+ * VMBUS version is 32 bit entity broken up into
+ * two 16 bit quantities: major_number. minor_number.
+ *
+ * 0 . 13 (Windows Server 2008)
+ * 1 . 1 (Windows 7)
+ * 2 . 4 (Windows 8)
+ */
+
+#define VERSION_WS2008 ((0 << 16) | (13))
+#define VERSION_WIN7 ((1 << 16) | (1))
+#define VERSION_WIN8 ((2 << 16) | (4))
+
+#define VERSION_INVAL -1
+
+static __u32 vmbus_get_next_version(__u32 current_version)
+{
+ switch (current_version) {
+ case (VERSION_WIN7):
+ return VERSION_WS2008;
+
+ case (VERSION_WIN8):
+ return VERSION_WIN7;
+
+ case (VERSION_WS2008):
+ default:
+ return VERSION_INVAL;
+ }
+}
+
+static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
+ __u32 version)
+{
+ int ret = 0;
+ struct vmbus_channel_initiate_contact *msg;
+ unsigned long flags;
+ int t;
+
+ init_completion(&msginfo->waitevent);
+
+ msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
+
+ msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
+ msg->vmbus_version_requested = version;
+ msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
+ msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
+ msg->monitor_page2 = virt_to_phys(
+ (void *)((unsigned long)vmbus_connection.monitor_pages +
+ PAGE_SIZE));
+
+ /*
+ * Add to list before we send the request since we may
+ * receive the response before returning from this routine
+ */
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_add_tail(&msginfo->msglistentry,
+ &vmbus_connection.chn_msg_list);
+
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+ ret = vmbus_post_msg(msg,
+ sizeof(struct vmbus_channel_initiate_contact));
+ if (ret != 0) {
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_del(&msginfo->msglistentry);
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
+ flags);
+ return ret;
+ }
+
+ /* Wait for the connection response */
+ t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
+ if (t == 0) {
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
+ flags);
+ list_del(&msginfo->msglistentry);
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
+ flags);
+ return -ETIMEDOUT;
+ }
+
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_del(&msginfo->msglistentry);
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+ /* Check if successful */
+ if (msginfo->response.version_response.version_supported) {
+ vmbus_connection.conn_state = CONNECTED;
+ } else {
+ pr_err("Unable to connect, "
+ "Version %d not supported by Hyper-V\n",
+ version);
+ return -ECONNREFUSED;
+ }
+
+ return ret;
+}
+
+/*
* vmbus_connect - Sends a connect request on the partition service connection
*/
int vmbus_connect(void)
{
int ret = 0;
- int t;
struct vmbus_channel_msginfo *msginfo = NULL;
- struct vmbus_channel_initiate_contact *msg;
- unsigned long flags;
+ __u32 version;

/* Initialize the vmbus connection */
vmbus_connection.conn_state = CONNECTING;
@@ -99,64 +195,25 @@ int vmbus_connect(void)
goto cleanup;
}

- init_completion(&msginfo->waitevent);
-
- msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
-
- msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
- msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
- msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
- msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
- msg->monitor_page2 = virt_to_phys(
- (void *)((unsigned long)vmbus_connection.monitor_pages +
- PAGE_SIZE));
-
/*
- * Add to list before we send the request since we may
- * receive the response before returning from this routine
+ * Negotiate a compatible VMBUS version number with the
+ * host. We start with the highest number we can support
+ * and work our way down until we negotiate a compatible
+ * version.
*/
- spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
- list_add_tail(&msginfo->msglistentry,
- &vmbus_connection.chn_msg_list);
-
- spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

- ret = vmbus_post_msg(msg,
- sizeof(struct vmbus_channel_initiate_contact));
- if (ret != 0) {
- spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
- list_del(&msginfo->msglistentry);
- spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
- flags);
- goto cleanup;
- }
+ version = VERSION_WS2008;

- /* Wait for the connection response */
- t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
- if (t == 0) {
- spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
- flags);
- list_del(&msginfo->msglistentry);
- spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
- flags);
- ret = -ETIMEDOUT;
- goto cleanup;
- }
+ do {
+ ret = vmbus_negotiate_version(msginfo, version);
+ if (ret == 0)
+ break;

- spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
- list_del(&msginfo->msglistentry);
- spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+ version = vmbus_get_next_version(version);
+ } while (version != VERSION_INVAL);

- /* Check if successful */
- if (msginfo->response.version_response.version_supported) {
- vmbus_connection.conn_state = CONNECTED;
- } else {
- pr_err("Unable to connect, "
- "Version %d not supported by Hyper-V\n",
- VMBUS_REVISION_NUMBER);
- ret = -ECONNREFUSED;
+ if (version == VERSION_INVAL)
goto cleanup;
- }

kfree(msginfo);
return 0;
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 1ffe84d..b097bf9 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -406,12 +406,6 @@ hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi,
#define HV_DRV_VERSION "3.1"

-/*
- * A revision number of vmbus that is used for ensuring both ends on a
- * partition are using compatible versions.
- */
-#define VMBUS_REVISION_NUMBER 13
-
/* Make maximum size of pipe payload of 16K */
#define MAX_PIPE_DATA_PAYLOAD (sizeof(u8) * 16384)

--
1.7.4.1