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authorVitaly Kuznetsov <vkuznets@redhat.com>2016-04-30 19:21:33 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-20 09:52:38 +0200
commit43fea648af714b0578f20bfadfec18858e67430d (patch)
tree6577729e68459ee56e06184f3564d82f0c510831
parenteaee7976cf2af79c294ab41d651c0e52488ca868 (diff)
Drivers: hv: kvp: fix IP Failover
commit 4dbfc2e68004c60edab7e8fd26784383dd3ee9bc upstream. Hyper-V VMs can be replicated to another hosts and there is a feature to set different IP for replicas, it is called 'Failover TCP/IP'. When such guest starts Hyper-V host sends it KVP_OP_SET_IP_INFO message as soon as we finish negotiation procedure. The problem is that it can happen (and it actually happens) before userspace daemon connects and we reply with HV_E_FAIL to the message. As there are no repetitions we fail to set the requested IP. Solve the issue by postponing our reply to the negotiation message till userspace daemon is connected. We can't wait too long as there is a host-side timeout (cca. 75 seconds) and if we fail to reply in this time frame the whole KVP service will become inactive. The solution is not ideal - if it takes userspace daemon more than 60 seconds to connect IP Failover will still fail but I don't see a solution with our current separation between kernel and userspace parts. Other two modules (VSS and FCOPY) don't require such delay, leave them untouched. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hv/hv_kvp.c31
-rw-r--r--drivers/hv/hyperv_vmbus.h5
2 files changed, 36 insertions, 0 deletions
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index cd3fb0151e8a..ff0a42618b50 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -78,9 +78,11 @@ static void kvp_send_key(struct work_struct *dummy);
static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
static void kvp_timeout_func(struct work_struct *dummy);
+static void kvp_host_handshake_func(struct work_struct *dummy);
static void kvp_register(int);
static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
+static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
static const char kvp_devname[] = "vmbus/hv_kvp";
@@ -131,6 +133,11 @@ static void kvp_timeout_func(struct work_struct *dummy)
hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
}
+static void kvp_host_handshake_func(struct work_struct *dummy)
+{
+ hv_poll_channel(kvp_transaction.recv_channel, hv_kvp_onchannelcallback);
+}
+
static int kvp_handle_handshake(struct hv_kvp_msg *msg)
{
switch (msg->kvp_hdr.operation) {
@@ -155,6 +162,12 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
pr_debug("KVP: userspace daemon ver. %d registered\n",
KVP_OP_REGISTER);
kvp_register(dm_reg_value);
+
+ /*
+ * If we're still negotiating with the host cancel the timeout
+ * work to not poll the channel twice.
+ */
+ cancel_delayed_work_sync(&kvp_host_handshake_work);
hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
return 0;
@@ -595,7 +608,22 @@ void hv_kvp_onchannelcallback(void *context)
struct icmsg_negotiate *negop = NULL;
int util_fw_version;
int kvp_srv_version;
+ static enum {NEGO_NOT_STARTED,
+ NEGO_IN_PROGRESS,
+ NEGO_FINISHED} host_negotiatied = NEGO_NOT_STARTED;
+ if (host_negotiatied == NEGO_NOT_STARTED &&
+ kvp_transaction.state < HVUTIL_READY) {
+ /*
+ * If userspace daemon is not connected and host is asking
+ * us to negotiate we need to delay to not lose messages.
+ * This is important for Failover IP setting.
+ */
+ host_negotiatied = NEGO_IN_PROGRESS;
+ schedule_delayed_work(&kvp_host_handshake_work,
+ HV_UTIL_NEGO_TIMEOUT * HZ);
+ return;
+ }
if (kvp_transaction.state > HVUTIL_READY)
return;
@@ -673,6 +701,8 @@ void hv_kvp_onchannelcallback(void *context)
vmbus_sendpacket(channel, recv_buffer,
recvlen, requestid,
VM_PKT_DATA_INBAND, 0);
+
+ host_negotiatied = NEGO_FINISHED;
}
}
@@ -711,6 +741,7 @@ hv_kvp_init(struct hv_util_service *srv)
void hv_kvp_deinit(void)
{
kvp_transaction.state = HVUTIL_DEVICE_DYING;
+ cancel_delayed_work_sync(&kvp_host_handshake_work);
cancel_delayed_work_sync(&kvp_timeout_work);
cancel_work_sync(&kvp_sendkey_work);
hvutil_transport_destroy(hvt);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 75e383e6d03d..15e06493c53a 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -36,6 +36,11 @@
#define HV_UTIL_TIMEOUT 30
/*
+ * Timeout for guest-host handshake for services.
+ */
+#define HV_UTIL_NEGO_TIMEOUT 60
+
+/*
* The below CPUID leaves are present if VersionAndFeatures.HypervisorPresent
* is set by CPUID(HVCPUID_VERSION_FEATURES).
*/