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-rw-r--r--drivers/hv/connection.c20
-rw-r--r--drivers/hv/hv.c7
-rw-r--r--drivers/hv/hyperv_vmbus.h11
-rw-r--r--drivers/hv/vmbus_drv.c20
4 files changed, 31 insertions, 27 deletions
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 74e77de89b4f..f4bd306d2cef 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -69,7 +69,6 @@ MODULE_PARM_DESC(max_version,
int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
{
int ret = 0;
- unsigned int cur_cpu;
struct vmbus_channel_initiate_contact *msg;
unsigned long flags;
@@ -102,24 +101,7 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
- /*
- * We want all channel messages to be delivered on CPU 0.
- * This has been the behavior pre-win8. This is not
- * perf issue and having all channel messages delivered on CPU 0
- * would be ok.
- * For post win8 hosts, we support receiving channel messagges on
- * all the CPUs. This is needed for kexec to work correctly where
- * the CPU attempting to connect may not be CPU 0.
- */
- if (version >= VERSION_WIN8_1) {
- cur_cpu = get_cpu();
- msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
- vmbus_connection.connect_cpu = cur_cpu;
- put_cpu();
- } else {
- msg->target_vcpu = 0;
- vmbus_connection.connect_cpu = 0;
- }
+ msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
/*
* Add to list before we send the request since we may
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 6098e0cbdb4b..e2b331045464 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -250,6 +250,13 @@ int hv_synic_cleanup(unsigned int cpu)
unsigned long flags;
/*
+ * Hyper-V does not provide a way to change the connect CPU once
+ * it is set; we must prevent the connect CPU from going offline.
+ */
+ if (cpu == VMBUS_CONNECT_CPU)
+ return -EBUSY;
+
+ /*
* Search for channels which are bound to the CPU we're about to
* cleanup. In case we find one and vmbus is still connected we need to
* fail, this will effectively prevent CPU offlining. There is no way
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index ab560ac9c040..000740d053a2 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -212,12 +212,13 @@ enum vmbus_connect_state {
#define MAX_SIZE_CHANNEL_MESSAGE HV_MESSAGE_PAYLOAD_BYTE_COUNT
-struct vmbus_connection {
- /*
- * CPU on which the initial host contact was made.
- */
- int connect_cpu;
+/*
+ * The CPU that Hyper-V will interrupt for VMBUS messages, such as
+ * CHANNELMSG_OFFERCHANNEL and CHANNELMSG_RESCIND_CHANNELOFFER.
+ */
+#define VMBUS_CONNECT_CPU 0
+struct vmbus_connection {
u32 msg_conn_id;
atomic_t offer_in_progress;
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 3a05e1bc359c..495337ec68f1 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1109,14 +1109,28 @@ void vmbus_on_msg_dpc(unsigned long data)
/*
* If we are handling the rescind message;
* schedule the work on the global work queue.
+ *
+ * The OFFER message and the RESCIND message should
+ * not be handled by the same serialized work queue,
+ * because the OFFER handler may call vmbus_open(),
+ * which tries to open the channel by sending an
+ * OPEN_CHANNEL message to the host and waits for
+ * the host's response; however, if the host has
+ * rescinded the channel before it receives the
+ * OPEN_CHANNEL message, the host just silently
+ * ignores the OPEN_CHANNEL message; as a result,
+ * the guest's OFFER handler hangs for ever, if we
+ * handle the RESCIND message in the same serialized
+ * work queue: the RESCIND handler can not start to
+ * run before the OFFER handler finishes.
*/
- schedule_work_on(vmbus_connection.connect_cpu,
+ schedule_work_on(VMBUS_CONNECT_CPU,
&ctx->work);
break;
case CHANNELMSG_OFFERCHANNEL:
atomic_inc(&vmbus_connection.offer_in_progress);
- queue_work_on(vmbus_connection.connect_cpu,
+ queue_work_on(VMBUS_CONNECT_CPU,
vmbus_connection.work_queue,
&ctx->work);
break;
@@ -1164,7 +1178,7 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel)
INIT_WORK(&ctx->work, vmbus_onmessage_work);
- queue_work_on(vmbus_connection.connect_cpu,
+ queue_work_on(VMBUS_CONNECT_CPU,
vmbus_connection.work_queue,
&ctx->work);
}