From 54e19d34011fea26d39aa74781131de0ce642a01 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Sat, 25 Jan 2020 21:49:44 -0800 Subject: [PATCH] hv_utils: Add the support of hibernation Add util_pre_suspend() and util_pre_resume() for some hv_utils devices (e.g. kvp/vss/fcopy), because they need special handling before util_suspend() calls vmbus_close(). For kvp, all the possible pending work items should be cancelled. For vss and fcopy, some extra clean-up needs to be done, i.e. fake a THAW message for hv_vss_daemon and fake a CANCEL_FCOPY message for hv_fcopy_daemon, otherwise when the VM resums back, the daemons can end up in an inconsistent state (i.e. the file systems are frozen but will never be thawed; the file transmitted via fcopy may not be complete). Note: there is an extra patch for the daemons: "Tools: hv: Reopen the devices if read() or write() returns errors", because the hv_utils driver can not guarantee the whole transaction finishes completely once util_suspend() starts to run (at this time, all the userspace processes are frozen). util_probe() disables channel->callback_event to avoid the race with the channel callback. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin --- drivers/hv/hv_fcopy.c | 54 +++++++++++++++++++++++++++++++++- drivers/hv/hv_kvp.c | 43 +++++++++++++++++++++++++-- drivers/hv/hv_snapshot.c | 55 ++++++++++++++++++++++++++++++++-- drivers/hv/hv_util.c | 62 ++++++++++++++++++++++++++++++++++++++- drivers/hv/hyperv_vmbus.h | 6 ++++ include/linux/hyperv.h | 2 ++ 6 files changed, 216 insertions(+), 6 deletions(-) diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c index 08fa4a5de644..bb9ba3f7c794 100644 --- a/drivers/hv/hv_fcopy.c +++ b/drivers/hv/hv_fcopy.c @@ -346,9 +346,61 @@ int hv_fcopy_init(struct hv_util_service *srv) return 0; } +static void hv_fcopy_cancel_work(void) +{ + cancel_delayed_work_sync(&fcopy_timeout_work); + cancel_work_sync(&fcopy_send_work); +} + +int hv_fcopy_pre_suspend(void) +{ + struct vmbus_channel *channel = fcopy_transaction.recv_channel; + struct hv_fcopy_hdr *fcopy_msg; + + /* + * Fake a CANCEL_FCOPY message for the user space daemon in case the + * daemon is in the middle of copying some file. It doesn't matter if + * there is already a message pending to be delivered to the user + * space since we force fcopy_transaction.state to be HVUTIL_READY, so + * the user space daemon's write() will fail with EINVAL (see + * fcopy_on_msg()), and the daemon will reset the device by closing + * and re-opening it. + */ + fcopy_msg = kzalloc(sizeof(*fcopy_msg), GFP_KERNEL); + if (!fcopy_msg) + return -ENOMEM; + + tasklet_disable(&channel->callback_event); + + fcopy_msg->operation = CANCEL_FCOPY; + + hv_fcopy_cancel_work(); + + /* We don't care about the return value. */ + hvutil_transport_send(hvt, fcopy_msg, sizeof(*fcopy_msg), NULL); + + kfree(fcopy_msg); + + fcopy_transaction.state = HVUTIL_READY; + + /* tasklet_enable() will be called in hv_fcopy_pre_resume(). */ + return 0; +} + +int hv_fcopy_pre_resume(void) +{ + struct vmbus_channel *channel = fcopy_transaction.recv_channel; + + tasklet_enable(&channel->callback_event); + + return 0; +} + void hv_fcopy_deinit(void) { fcopy_transaction.state = HVUTIL_DEVICE_DYING; - cancel_delayed_work_sync(&fcopy_timeout_work); + + hv_fcopy_cancel_work(); + hvutil_transport_destroy(hvt); } diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c index ae7c028dc5a8..e74b144b8f3d 100644 --- a/drivers/hv/hv_kvp.c +++ b/drivers/hv/hv_kvp.c @@ -758,11 +758,50 @@ hv_kvp_init(struct hv_util_service *srv) return 0; } -void hv_kvp_deinit(void) +static void hv_kvp_cancel_work(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); +} + +int hv_kvp_pre_suspend(void) +{ + struct vmbus_channel *channel = kvp_transaction.recv_channel; + + tasklet_disable(&channel->callback_event); + + /* + * If there is a pending transtion, it's unnecessary to tell the host + * that the transaction will fail, because that is implied when + * util_suspend() calls vmbus_close() later. + */ + hv_kvp_cancel_work(); + + /* + * Forece the state to READY to handle the ICMSGTYPE_NEGOTIATE message + * later. The user space daemon may go out of order and its write() + * may fail with EINVAL: this doesn't matter since the daemon will + * reset the device by closing and re-opening it. + */ + kvp_transaction.state = HVUTIL_READY; + return 0; +} + +int hv_kvp_pre_resume(void) +{ + struct vmbus_channel *channel = kvp_transaction.recv_channel; + + tasklet_enable(&channel->callback_event); + + return 0; +} + +void hv_kvp_deinit(void) +{ + kvp_transaction.state = HVUTIL_DEVICE_DYING; + + hv_kvp_cancel_work(); + hvutil_transport_destroy(hvt); } diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c index 03b6454268b3..1c75b38f0d6d 100644 --- a/drivers/hv/hv_snapshot.c +++ b/drivers/hv/hv_snapshot.c @@ -379,10 +379,61 @@ hv_vss_init(struct hv_util_service *srv) return 0; } +static void hv_vss_cancel_work(void) +{ + cancel_delayed_work_sync(&vss_timeout_work); + cancel_work_sync(&vss_handle_request_work); +} + +int hv_vss_pre_suspend(void) +{ + struct vmbus_channel *channel = vss_transaction.recv_channel; + struct hv_vss_msg *vss_msg; + + /* + * Fake a THAW message for the user space daemon in case the daemon + * has frozen the file systems. It doesn't matter if there is already + * a message pending to be delivered to the user space since we force + * vss_transaction.state to be HVUTIL_READY, so the user space daemon's + * write() will fail with EINVAL (see vss_on_msg()), and the daemon + * will reset the device by closing and re-opening it. + */ + vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL); + if (!vss_msg) + return -ENOMEM; + + tasklet_disable(&channel->callback_event); + + vss_msg->vss_hdr.operation = VSS_OP_THAW; + + /* Cancel any possible pending work. */ + hv_vss_cancel_work(); + + /* We don't care about the return value. */ + hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL); + + kfree(vss_msg); + + vss_transaction.state = HVUTIL_READY; + + /* tasklet_enable() will be called in hv_vss_pre_resume(). */ + return 0; +} + +int hv_vss_pre_resume(void) +{ + struct vmbus_channel *channel = vss_transaction.recv_channel; + + tasklet_enable(&channel->callback_event); + + return 0; +} + void hv_vss_deinit(void) { vss_transaction.state = HVUTIL_DEVICE_DYING; - cancel_delayed_work_sync(&vss_timeout_work); - cancel_work_sync(&vss_handle_request_work); + + hv_vss_cancel_work(); + hvutil_transport_destroy(hvt); } diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c index 64fbf4ac80f9..900b8a8af57c 100644 --- a/drivers/hv/hv_util.c +++ b/drivers/hv/hv_util.c @@ -123,12 +123,14 @@ static struct hv_util_service util_shutdown = { }; static int hv_timesync_init(struct hv_util_service *srv); +static int hv_timesync_pre_suspend(void); static void hv_timesync_deinit(void); static void timesync_onchannelcallback(void *context); static struct hv_util_service util_timesynch = { .util_cb = timesync_onchannelcallback, .util_init = hv_timesync_init, + .util_pre_suspend = hv_timesync_pre_suspend, .util_deinit = hv_timesync_deinit, }; @@ -140,18 +142,24 @@ static struct hv_util_service util_heartbeat = { static struct hv_util_service util_kvp = { .util_cb = hv_kvp_onchannelcallback, .util_init = hv_kvp_init, + .util_pre_suspend = hv_kvp_pre_suspend, + .util_pre_resume = hv_kvp_pre_resume, .util_deinit = hv_kvp_deinit, }; static struct hv_util_service util_vss = { .util_cb = hv_vss_onchannelcallback, .util_init = hv_vss_init, + .util_pre_suspend = hv_vss_pre_suspend, + .util_pre_resume = hv_vss_pre_resume, .util_deinit = hv_vss_deinit, }; static struct hv_util_service util_fcopy = { .util_cb = hv_fcopy_onchannelcallback, .util_init = hv_fcopy_init, + .util_pre_suspend = hv_fcopy_pre_suspend, + .util_pre_resume = hv_fcopy_pre_resume, .util_deinit = hv_fcopy_deinit, }; @@ -511,6 +519,44 @@ static int util_remove(struct hv_device *dev) return 0; } +/* + * When we're in util_suspend(), all the userspace processes have been frozen + * (refer to hibernate() -> freeze_processes()). The userspace is thawed only + * after the whole resume procedure, including util_resume(), finishes. + */ +static int util_suspend(struct hv_device *dev) +{ + struct hv_util_service *srv = hv_get_drvdata(dev); + int ret = 0; + + if (srv->util_pre_suspend) { + ret = srv->util_pre_suspend(); + if (ret) + return ret; + } + + vmbus_close(dev->channel); + + return 0; +} + +static int util_resume(struct hv_device *dev) +{ + struct hv_util_service *srv = hv_get_drvdata(dev); + int ret = 0; + + if (srv->util_pre_resume) { + ret = srv->util_pre_resume(); + if (ret) + return ret; + } + + ret = vmbus_open(dev->channel, 4 * HV_HYP_PAGE_SIZE, + 4 * HV_HYP_PAGE_SIZE, NULL, 0, srv->util_cb, + dev->channel); + return ret; +} + static const struct hv_vmbus_device_id id_table[] = { /* Shutdown guid */ { HV_SHUTDOWN_GUID, @@ -547,6 +593,8 @@ static struct hv_driver util_drv = { .id_table = id_table, .probe = util_probe, .remove = util_remove, + .suspend = util_suspend, + .resume = util_resume, .driver = { .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, @@ -616,11 +664,23 @@ static int hv_timesync_init(struct hv_util_service *srv) return 0; } +static void hv_timesync_cancel_work(void) +{ + cancel_work_sync(&adj_time_work); +} + +static int hv_timesync_pre_suspend(void) +{ + hv_timesync_cancel_work(); + return 0; +} + static void hv_timesync_deinit(void) { if (hv_ptp_clock) ptp_clock_unregister(hv_ptp_clock); - cancel_work_sync(&adj_time_work); + + hv_timesync_cancel_work(); } static int __init init_hyperv_utils(void) diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 20edcfd3b96c..f5fa3b3c9baf 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -352,14 +352,20 @@ void vmbus_on_msg_dpc(unsigned long data); int hv_kvp_init(struct hv_util_service *srv); void hv_kvp_deinit(void); +int hv_kvp_pre_suspend(void); +int hv_kvp_pre_resume(void); void hv_kvp_onchannelcallback(void *context); int hv_vss_init(struct hv_util_service *srv); void hv_vss_deinit(void); +int hv_vss_pre_suspend(void); +int hv_vss_pre_resume(void); void hv_vss_onchannelcallback(void *context); int hv_fcopy_init(struct hv_util_service *srv); void hv_fcopy_deinit(void); +int hv_fcopy_pre_suspend(void); +int hv_fcopy_pre_resume(void); void hv_fcopy_onchannelcallback(void *context); void vmbus_initiate_unload(bool crash); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 41c58011431e..692c89ccf5df 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1435,6 +1435,8 @@ struct hv_util_service { void (*util_cb)(void *); int (*util_init)(struct hv_util_service *); void (*util_deinit)(void); + int (*util_pre_suspend)(void); + int (*util_pre_resume)(void); }; struct vmbuspipe_hdr {