diff options
Diffstat (limited to 'drivers/hv/channel_mgmt.c')
| -rw-r--r-- | drivers/hv/channel_mgmt.c | 86 |
1 files changed, 76 insertions, 10 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index f0ed730e2e4e..caf6d0c4bc1b 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -333,7 +333,6 @@ fw_error: negop->icversion_data[1].minor = icmsg_minor; return found_match; } - EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp); /* @@ -593,10 +592,10 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) * CPUS_READ_UNLOCK CPUS_WRITE_UNLOCK * * Forbids: CPU1's LOAD from *not* seing CPU2's STORE && - * CPU2's SEARCH from *not* seeing CPU1's INSERT + * CPU2's SEARCH from *not* seeing CPU1's INSERT * * Forbids: CPU2's SEARCH from seeing CPU1's INSERT && - * CPU2's LOAD from *not* seing CPU1's STORE + * CPU2's LOAD from *not* seing CPU1's STORE */ cpus_read_lock(); @@ -756,6 +755,12 @@ static void init_vp_index(struct vmbus_channel *channel) free_cpumask_var(available_mask); } +#define UNLOAD_DELAY_UNIT_MS 10 /* 10 milliseconds */ +#define UNLOAD_WAIT_MS (100*1000) /* 100 seconds */ +#define UNLOAD_WAIT_LOOPS (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS) +#define UNLOAD_MSG_MS (5*1000) /* Every 5 seconds */ +#define UNLOAD_MSG_LOOPS (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS) + static void vmbus_wait_for_unload(void) { int cpu; @@ -773,12 +778,17 @@ static void vmbus_wait_for_unload(void) * vmbus_connection.unload_event. If not, the last thing we can do is * read message pages for all CPUs directly. * - * Wait no more than 10 seconds so that the panic path can't get - * hung forever in case the response message isn't seen. + * Wait up to 100 seconds since an Azure host must writeback any dirty + * data in its disk cache before the VMbus UNLOAD request will + * complete. This flushing has been empirically observed to take up + * to 50 seconds in cases with a lot of dirty data, so allow additional + * leeway and for inaccuracies in mdelay(). But eventually time out so + * that the panic path can't get hung forever in case the response + * message isn't seen. */ - for (i = 0; i < 1000; i++) { + for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) { if (completion_done(&vmbus_connection.unload_event)) - break; + goto completed; for_each_online_cpu(cpu) { struct hv_per_cpu_context *hv_cpu @@ -801,9 +811,18 @@ static void vmbus_wait_for_unload(void) vmbus_signal_eom(msg, message_type); } - mdelay(10); + /* + * Give a notice periodically so someone watching the + * serial output won't think it is completely hung. + */ + if (!(i % UNLOAD_MSG_LOOPS)) + pr_notice("Waiting for VMBus UNLOAD to complete\n"); + + mdelay(UNLOAD_DELAY_UNIT_MS); } + pr_err("Continuing even though VMBus UNLOAD did not complete\n"); +completed: /* * We're crashing and already got the UNLOAD_RESPONSE, cleanup all * maybe-pending messages on all CPUs to be able to receive new @@ -827,6 +846,11 @@ static void vmbus_unload_response(struct vmbus_channel_message_header *hdr) /* * This is a global event; just wakeup the waiting thread. * Once we successfully unload, we can cleanup the monitor state. + * + * NB. A malicious or compromised Hyper-V could send a spurious + * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call + * of the complete() below. Make sure that unload_event has been + * initialized by the time this complete() is executed. */ complete(&vmbus_connection.unload_event); } @@ -842,7 +866,7 @@ void vmbus_initiate_unload(bool crash) if (vmbus_proto_version < VERSION_WIN8_1) return; - init_completion(&vmbus_connection.unload_event); + reinit_completion(&vmbus_connection.unload_event); memset(&hdr, 0, sizeof(struct vmbus_channel_message_header)); hdr.msgtype = CHANNELMSG_UNLOAD; vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header), @@ -980,7 +1004,7 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr) * UNLOCK channel_mutex * * Forbids: r1 == valid_relid && - * channels[valid_relid] == channel + * channels[valid_relid] == channel * * Note. r1 can be INVALID_RELID only for an hv_sock channel. * None of the hv_sock channels which were present before the @@ -1313,6 +1337,46 @@ static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr) } /* + * vmbus_onmodifychannel_response - Modify Channel response handler. + * + * This is invoked when we received a response to our channel modify request. + * Find the matching request, copy the response and signal the requesting thread. + */ +static void vmbus_onmodifychannel_response(struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_modifychannel_response *response; + struct vmbus_channel_msginfo *msginfo; + unsigned long flags; + + response = (struct vmbus_channel_modifychannel_response *)hdr; + + trace_vmbus_onmodifychannel_response(response); + + /* + * Find the modify msg, copy the response and signal/unblock the wait event. + */ + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, msglistentry) { + struct vmbus_channel_message_header *responseheader = + (struct vmbus_channel_message_header *)msginfo->msg; + + if (responseheader->msgtype == CHANNELMSG_MODIFYCHANNEL) { + struct vmbus_channel_modifychannel *modifymsg; + + modifymsg = (struct vmbus_channel_modifychannel *)msginfo->msg; + if (modifymsg->child_relid == response->child_relid) { + memcpy(&msginfo->response.modify_response, response, + sizeof(*response)); + complete(&msginfo->waitevent); + break; + } + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +/* * vmbus_ongpadl_torndown - GPADL torndown handler. * * This is invoked when we received a response to our gpadl teardown request. @@ -1429,6 +1493,8 @@ channel_message_table[CHANNELMSG_COUNT] = { { CHANNELMSG_TL_CONNECT_REQUEST, 0, NULL, 0}, { CHANNELMSG_MODIFYCHANNEL, 0, NULL, 0}, { CHANNELMSG_TL_CONNECT_RESULT, 0, NULL, 0}, + { CHANNELMSG_MODIFYCHANNEL_RESPONSE, 1, vmbus_onmodifychannel_response, + sizeof(struct vmbus_channel_modifychannel_response)}, }; /* |