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* hv_utils: Add comment about max VMbus packet size in VSS driverMichael Kelley2022-02-181-2/+5
| | | | | | | | | | | | | The VSS driver allocates a VMbus receive buffer significantly larger than sizeof(hv_vss_msg), with no explanation. To help prevent future mistakes, add a #define and comment about why this is done. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1644423070-75125-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
* hv_utils: Set the maximum packet size for VSS driver to the length of the ↵Vitaly Kuznetsov2021-08-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | receive buffer Commit adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer") introduced a notion of maximum packet size and for KVM and FCOPY drivers set it to the length of the receive buffer. VSS driver wasn't updated, this means that the maximum packet size is now VMBUS_DEFAULT_MAX_PKT_SIZE (4k). Apparently, this is not enough. I'm observing a packet of 6304 bytes which is being truncated to 4096. When VSS driver tries to read next packet from ring buffer it starts from the wrong offset and receives garbage. Set the maximum packet size to 'HV_HYP_PAGE_SIZE * 2' in VSS driver. This matches the length of the receive buffer and is in line with other utils drivers. Fixes: adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210825133857.847866-1-vkuznets@redhat.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
* hv_utils: Add validation for untrusted Hyper-V valuesAndres Beltran2021-02-051-37/+52
| | | | | | | | | | | | | | | For additional robustness in the face of Hyper-V errors or malicious behavior, validate all values that originate from packets that Hyper-V has sent to the guest in the host-to-guest ring buffer. Ensure that invalid values cannot cause indexing off the end of the icversion_data array in vmbus_prep_negotiate_resp(). Signed-off-by: Andres Beltran <lkmlabelt@gmail.com> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201109100704.9152-1-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
* hv_utils: Always execute the fcopy and vss callbacks in a taskletAndrea Parri (Microsoft)2020-04-231-1/+1
| | | | | | | | | | | | | | | | | | | | | The fcopy and vss callback functions could be running in a tasklet at the same time they are called in hv_poll_channel(). Current code serializes the invocations of these functions, and their accesses to the channel ring buffer, by sending an IPI to the CPU that is allowed to access the ring buffer, cf. hv_poll_channel(). This IPI mechanism becomes infeasible if we allow changing the CPU that a channel will interrupt. Instead modify the callback wrappers to always execute the fcopy and vss callbacks in a tasklet, thus mirroring the solution for the kvp callback functions adopted since commit a3ade8cc474d8 ("HV: properly delay KVP packets when negotiation is in progress"). This will ensure that the callback function can't run on two CPUs at the same time. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Link: https://lore.kernel.org/r/20200406001514.19876-6-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
* hv_utils: Add the support of hibernationDexuan Cui2020-01-271-2/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | 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 <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* Drivers: hv: Specify receive buffer size using Hyper-V page sizeHimadri Pandya2019-11-221-1/+2
| | | | | | | | | | | | The recv_buffer is used to retrieve data from the VMbus ring buffer. VMbus ring buffers are sized based on the guest page size which Hyper-V assumes to be 4KB. But it may be different on some architectures. So use the Hyper-V page size to allocate the recv_buffer and set the maximum size to receive. Signed-off-by: Himadri Pandya <himadri18.07@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 280Thomas Gleixner2019-06-051-12/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose good title or non infringement see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 9 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141900.459653302@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 4.11-rc4 into char-misc-nextGreg Kroah-Hartman2017-03-271-4/+0
|\ | | | | | | | | | | We want the char-misc fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Drivers: hv: util: move waiting for release to hv_utils_transport itselfVitaly Kuznetsov2017-03-161-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Waiting for release_event in all three drivers introduced issues on release as on_reset() hook is not always called. E.g. if the device was never opened we will never get the completion. Move the waiting code to hvutil_transport_destroy() and make sure it is only called when the device is open. hvt->lock serialization should guarantee the absence of races. Fixes: 5a66fecbf6aa ("Drivers: hv: util: kvp: Fix a rescind processing issue") Fixes: 20951c7535b5 ("Drivers: hv: util: Fcopy: Fix a rescind processing issue") Fixes: d77044d142e9 ("Drivers: hv: util: Backup: Fix a rescind processing issue") Reported-by: Dexuan Cui <decui@microsoft.com> Tested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | vmbus: remove useless return'sStephen Hemminger2017-03-171-2/+0
|/ | | | | | | | No need for empty return at end of void function Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: Log the negotiated IC versions.Alex Ng2017-01-311-3/+8
| | | | | | | | Log the negotiated IC versions. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vmbus: Use all supported IC versions to negotiateAlex Ng2017-01-311-4/+14
| | | | | | | | | | | | | | | | | | | | | Previously, we were assuming that each IC protocol version was tied to a specific host version. For example, some Windows 10 preview hosts only support v3 TimeSync even though driver assumes v4 is supported by all Windows 10 hosts. The guest will stop trying to negotiate even though older supported versions may still be offered by the host. Make IC version negotiation more robust by going through all versions that are supported by the guest. Fixes: 3da0401b4d0e ("Drivers: hv: utils: Fix the mapping between host version and protocol to use") Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: util: Backup: Fix a rescind processing issueK. Y. Srinivasan2017-01-101-0/+4
| | | | | | | | | | | VSS may use a char device to support the communication between the user level daemon and the driver. When the VSS channel is rescinded we need to make sure that the char device is fully cleaned up before we can process a new VSS offer from the host. Implement this logic. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: Operation timeouts should match host expectationAlex Ng2016-11-071-2/+6
| | | | | | | | | | Increase the timeout of backup operations. When system is under I/O load, it needs more time to freeze. These timeout values should also match the host timeout values more closely. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: Improve log messages.Alex Ng2016-11-071-6/+19
| | | | | | | | | Adding log messages to help troubleshoot error cases and transaction handling. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: Check VSS daemon is listening before a hot backupAlex Ng2016-09-021-3/+6
| | | | | | | | | | | | Hyper-V host will send a VSS_OP_HOT_BACKUP request to check if guest is ready for a live backup/snapshot. The driver should respond to the check only if the daemon is running and listening to requests. This allows the host to fallback to standard snapshots in case the VSS daemon is not running. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: Continue to poll VSS channel after handling requests.Alex Ng2016-09-021-47/+43
| | | | | | | | | | | Multiple VSS_OP_HOT_BACKUP requests may arrive in quick succession, even though the host only signals once. The driver wass handling the first request while ignoring the others in the ring buffer. We should poll the VSS channel after handling a request to continue processing other requests. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: fix a race on userspace daemons registrationVitaly Kuznetsov2016-08-311-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Background: userspace daemons registration protocol for Hyper-V utilities drivers has two steps: 1) daemon writes its own version to kernel 2) kernel reads it and replies with module version at this point we consider the handshake procedure being completed and we do hv_poll_channel() transitioning the utility device to HVUTIL_READY state. At this point we're ready to handle messages from kernel. When hvutil_transport is in HVUTIL_TRANSPORT_CHARDEV mode we have a single buffer for outgoing message. hvutil_transport_send() puts to this buffer and till the buffer is cleared with hvt_op_read() returns -EFAULT to all consequent calls. Host<->guest protocol guarantees there is no more than one request at a time and we will not get new requests till we reply to the previous one so this single message buffer is enough. Now to the race. When we finish negotiation procedure and send kernel module version to userspace with hvutil_transport_send() it goes into the above mentioned buffer and if the daemon is slow enough to read it from there we can get a collision when a request from the host comes, we won't be able to put anything to the buffer so the request will be lost. To solve the issue we need to know when the negotiation is really done (when the version message is read by the daemon) and transition to HVUTIL_READY state after this happens. Implement a callback on read to support this. Old style netlink communication is not affected by the change, we don't really know when these messages are delivered but we don't have a single message buffer there. Reported-by: Barry Davis <barry_davis@stormagic.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: util: Pass the channel information during the init callK. Y. Srinivasan2016-03-021-1/+1
| | | | | | | | | | | | | | | | | | Pass the channel information to the util drivers that need to defer reading the channel while they are processing a request. This would address the following issue reported by Vitaly: Commit 3cace4a61610 ("Drivers: hv: utils: run polling callback always in interrupt context") removed direct *_transaction.state = HVUTIL_READY assignments from *_handle_handshake() functions introducing the following race: if a userspace daemon connects before we get first non-negotiation request from the server hv_poll_channel() won't set transaction state to HVUTIL_READY as (!channel) condition will fail, we set it to non-NULL on the first real request from the server. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: Invoke the poll function after handshakeK. Y. Srinivasan2015-12-151-1/+1
| | | | | | | | | | When the handshake with daemon is complete, we should poll the channel since during the handshake, we will not be processing any messages. This is a potential bug if the host is waiting for a response from the guest. I would like to thank Dexuan for pointing this out. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: run only on supported host versionsOlaf Hering2015-12-151-0/+5
| | | | | | | | | | | | | | | | | The Backup integration service on WS2012 has appearently trouble to negotiate with a guest which does not support the provided util version. Currently the VSS driver supports only version 5/0. A WS2012 offers only version 1/x and 3/x, and vmbus_prep_negotiate_resp correctly returns an empty icframe_vercnt/icmsg_vercnt. But the host ignores that and continues to send ICMSGTYPE_NEGOTIATE messages. The result are weird errors during boot and general misbehaviour. Check the Windows version to work around the host bug, skip hv_vss_init on WS2012 and older. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: run polling callback always in interrupt contextOlaf Hering2015-12-151-18/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | All channel interrupts are bound to specific VCPUs in the guest at the point channel is created. While currently, we invoke the polling function on the correct CPU (the CPU to which the channel is bound to) in some cases we may run the polling function in a non-interrupt context. This potentially can cause an issue as the polling function can be interrupted by the channel callback function. Fix the issue by running the polling function on the appropriate CPU at interrupt level. Additional details of the issue being addressed by this patch are given below: Currently hv_fcopy_onchannelcallback is called from interrupts and also via the ->write function of hv_utils. Since the used global variables to maintain state are not thread safe the state can get out of sync. This affects the variable state as well as the channel inbound buffer. As suggested by KY adjust hv_poll_channel to always run the given callback on the cpu which the channel is bound to. This avoids the need for locking because all the util services are single threaded and only one transaction is active at any given point in time. Additionally, remove the context variable, they will always be the same as recv_channel. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: utils: unify driver registration reportingVitaly Kuznetsov2015-05-241-1/+1
| | | | | | | | | | Unify driver registration reporting and move it to debug level as normally daemons write to syslog themselves and these kernel messages are useless. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: full handshake supportVitaly Kuznetsov2015-05-241-12/+37
| | | | | | | | | | Introduce VSS_OP_REGISTER1 to support kernel replying to the negotiation message with its own version. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: convert to hv_utils_transportVitaly Kuznetsov2015-05-241-25/+27
| | | | | | | | | Convert to hv_utils_transport to support both netlink and /dev/vmbus/hv_vss communication methods. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: switch to using the hvutil_device_state state machineVitaly Kuznetsov2015-05-241-29/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | Switch to using the hvutil_device_state state machine from using kvp_transaction.active. State transitions are: -> HVUTIL_DEVICE_INIT when driver loads or on device release -> HVUTIL_READY if the handshake was successful -> HVUTIL_HOSTMSG_RECEIVED when there is a non-negotiation message from the host -> HVUTIL_USERSPACE_REQ after we sent the message to the userspace daemon -> HVUTIL_USERSPACE_RECV after/if the userspace daemon has replied -> HVUTIL_READY after we respond to the host -> HVUTIL_DEVICE_DYING on driver unload In hv_vss_onchannelcallback() process ICMSGTYPE_NEGOTIATE messages even when the userspace daemon is disconnected, otherwise we can make the host think we don't support VSS and disable the service completely. Unfortunately there is no good way we can figure out that the userspace daemon has died (unless we start treating all timeouts as such), add a protection against processing new VSS_OP_REGISTER messages while being in the middle of a transaction (HVUTIL_USERSPACE_REQ or HVUTIL_USERSPACE_RECV state). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: process deferred messages when we complete the transactionVitaly Kuznetsov2015-05-241-5/+9
| | | | | | | | | | | | | | In theory, the host is not supposed to issue any requests before be reply to the previous one. In KVP we, however, support the following scenarios: 1) A message was received before userspace daemon registered; 2) A message was received while the previous one is still being processed. In VSS we support only the former. Add support for the later, use hv_poll_channel() to do the job. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: util: move kvp/vss function declarations to hyperv_vmbus.hVitaly Kuznetsov2015-05-241-0/+2
| | | | | | | | | | These declarations are internal to hv_util module and hv_fcopy_* declarations already reside there. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: kvp,vss: Fast propagation of userspace communication failureVitaly Kuznetsov2014-11-271-1/+7
| | | | | | | | | | | | | | | | | If we fail to send a message to userspace daemon with cn_netlink_send() there is no need to wait for userspace to reply as it is not going to happen. This happens when kvp or vss daemon is stopped after a successful handshake. Report HV_E_FAIL immediately and cancel the timeout job so host won't receive two failures. Use pr_warn() for VSS and pr_debug() for KVP deliberately as VSS request are rare and result in a failed backup. KVP requests are much more frequent after a successful handshake so avoid flooding logs. It would be nice to have an ability to de-negotiate with the host in case userspace daemon gets disconnected so we won't receive new requests. But I'm not sure it is possible. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: vss: Introduce timeout for communication with userspaceVitaly Kuznetsov2014-11-271-2/+18
| | | | | | | | | | | In contrast with KVP there is no timeout when communicating with userspace VSS daemon. In case it gets stuck performing freeze/thaw operation no message will be sent to the host so it will take very long (around 10 minutes) before backup fails. Introduce 10 second timeout using schedule_delayed_work(). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* connector: add portid to unicast in addition to broadcastingDavid Fries2014-02-081-1/+1
| | | | | | | | | This allows replying only to the requestor portid while still supporting broadcasting. Pass 0 to portid for the previous behavior. Signed-off-by: David Fries <David@Fries.net> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: util: Correctly support ws2008R2 and earlierK. Y. Srinivasan2013-09-261-3/+3
| | | | | | | | | | | | | The current code does not correctly negotiate the version numbers for the util driver when hosted on earlier hosts. The version numbers presented by this driver were not compatible with the version numbers supported by Windows Server 2008. Fix this problem. I would like to thank Olaf Hering (ohering@suse.com) for identifying the problem. Reported-by: Olaf Hering <ohering@suse.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: util: Fix a bug in version negotiation code for util servicesK. Y. Srinivasan2013-07-271-12/+6
| | | | | | | | | | | The current code picked the highest version advertised by the host. WS2012 R2 has implemented a protocol version for KVP that is not compatible with prior protocol versions of KVP. Fix the bug in the current code by explicitly specifying the protocol version that the guest can support. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: Add a new driver to support host initiated backupK. Y. Srinivasan2013-03-151-0/+287
This driver supports host initiated backup of the guest. On Windows guests, the host can generate application consistent backups using the Windows VSS framework. On Linux, we ensure that the backup will be file system consistent. This driver allows the host to initiate a "Freeze" operation on all the mounted file systems in the guest. Once the mounted file systems in the guest are frozen, the host snapshots the guest's file systems. Once this is done, the guest's file systems are "thawed". This driver has a user-level component (daemon) that invokes the appropriate operation on all the mounted file systems in response to the requests from the host. The duration for which the guest is frozen is very short - a few seconds. During this interval, the diff disk is comitted. In this version of the patch I have addressed the feedback from Olaf Herring. Also, some of the connector related issues have been fixed. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Cc: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>