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2016-08-31Drivers: hv: vmbus: Reduce the delay between retries in vmbus_post_msg()K. Y. Srinivasan1-4/+4
The current delay between retries is unnecessarily high and is negatively affecting the time it takes to boot the system. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-01Drivers: hv: vmbus: Export the vmbus_set_event() APIK. Y. Srinivasan1-0/+1
In preparation for moving some ring buffer functionality out of the vmbus driver, export the API for signaling the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-02Drivers: hv: vmbus: Support kexec on ws2012 r2 and aboveAlex Ng1-1/+9
WS2012 R2 and above hosts can support kexec in that thay can support reconnecting to the host (as would be needed in the kexec path) on any CPU. Enable this. Pre ws2012 r2 hosts don't have this ability and consequently cannot support kexec. 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>
2016-03-02Drivers: hv: vmbus: avoid wait_for_completion() on crashVitaly Kuznetsov1-1/+1
wait_for_completion() may sleep, it enables interrupts and this is something we really want to avoid on crashes because interrupt handlers can cause other crashes. Switch to the recently introduced vmbus_wait_for_unload() doing busy wait instead. Reported-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Radim Kr.má<rkrcmar@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-08Drivers: hv: vmbus: add an API vmbus_hvsock_device_unregister()Dexuan Cui1-2/+2
The hvsock driver needs this API to release all the resources related to the channel. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-08Drivers: hv: vmbus: Cleanup vmbus_set_event()K. Y. Srinivasan1-2/+2
Cleanup vmbus_set_event() by inlining the hypercall to post the event and since the return value of vmbus_set_event() is not checked, make it void. As part of this cleanup, get rid of the function hv_signal_event() as it is only callled from vmbus_set_event(). Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: vmbus: Force all channel messages to be delivered on CPU 0K. Y. Srinivasan1-4/+7
Force all channel messages to be delivered on CPU0. These messages are not performance critical and are used during the setup and teardown of the channel. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: vmbus: channge vmbus_connection.channel_lock to mutexDexuan Cui1-4/+3
spinlock is unnecessary here. mutex is enough. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-06-01Drivers: hv: vmbus:Update preferred vmbus protocol version to windows 10.Keith Mange1-3/+5
Add support for Windows 10. Signed-off-by: Keith Mange <keith.mange@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24Drivers: hv: vmbus: Implement the protocol for tearing down vmbus stateK. Y. Srinivasan1-0/+5
Implement the protocol for tearing down the monitor state established with the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-04-03hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg()Haiyang Zhang1-2/+5
Most of the retries can be done within a millisecond successfully, so we sleep 1ms before the first retry, then gradually increase the retry interval to 2^n with max value of 2048ms. Doing so, we will have shorter overall delay time, because most of the cases succeed within 1-2 attempts. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-04-03hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind()Dexuan Cui1-5/+1
Since the 2 fucntions can safely run in vmbus_connection.work_queue without hang, we don't need to schedule new work items into the per-channel workqueue. Actally we can even remove the per-channel workqueue now -- we'll do it in the next patch. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-25Drivers: hv: vmbus: Perform device register in the per-channel work elementK. Y. Srinivasan1-1/+5
This patch is a continuation of the rescind handling cleanup work. We cannot block in the global message handling work context especially if we are blocking waiting for the host to wake us up. I would like to thank Dexuan Cui <decui@microsoft.com> for observing this problem. The current char-next branch is broken and this patch fixes the bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: Get rid of some unnecessary messagesK. Y. Srinivasan1-6/+1
Currently we log messages when either we are not able to map an ID to a channel or when the channel does not have a callback associated (in the channel interrupt handling path). These messages don't add any value, get rid of them. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02hv: vmbus_post_msg: retry the hypercall on some transient errorsDexuan Cui1-2/+9
I got HV_STATUS_INVALID_CONNECTION_ID on Hyper-V 2008 R2 when keeping running "rmmod hv_netvsc; modprobe hv_netvsc; rmmod hv_utils; modprobe hv_utils" in a Linux guest. Looks the host has some kind of throttling mechanism if some kinds of hypercalls are sent too frequently. Without the patch, the driver can occasionally fail to load. Also let's retry HV_STATUS_INSUFFICIENT_MEMORY, though we didn't get it before. Removed 'case -ENOMEM', since the hypervisor doesn't return this. CC: "K. Y. Srinivasan" <kys@microsoft.com> Reviewed-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: teardown hv_vmbus_con workqueue and vmbus_connection ↵Vitaly Kuznetsov1-5/+12
pages on shutdown We need to destroy hv_vmbus_con on module shutdown, otherwise the following crash is sometimes observed: [ 76.569845] hv_vmbus: Hyper-V Host Build:9600-6.3-17-0.17039; Vmbus version:3.0 [ 82.598859] BUG: unable to handle kernel paging request at ffffffffa0003480 [ 82.599287] IP: [<ffffffffa0003480>] 0xffffffffa0003480 [ 82.599287] PGD 1f34067 PUD 1f35063 PMD 3f72d067 PTE 0 [ 82.599287] Oops: 0010 [#1] SMP [ 82.599287] Modules linked in: [last unloaded: hv_vmbus] [ 82.599287] CPU: 0 PID: 26 Comm: kworker/0:1 Not tainted 3.19.0-rc5_bug923184+ #488 [ 82.599287] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v1.0 11/26/2012 [ 82.599287] Workqueue: hv_vmbus_con 0xffffffffa0003480 [ 82.599287] task: ffff88007b6ddfa0 ti: ffff88007f8f8000 task.ti: ffff88007f8f8000 [ 82.599287] RIP: 0010:[<ffffffffa0003480>] [<ffffffffa0003480>] 0xffffffffa0003480 [ 82.599287] RSP: 0018:ffff88007f8fbe00 EFLAGS: 00010202 ... To avoid memory leaks we need to free monitor_pages and int_page for vmbus_connection. Implement vmbus_disconnect() function by separating cleanup path from vmbus_connect(). As we use hv_vmbus_con to release channels (see free_channel() in channel_mgmt.c) we need to make sure the work was done before we remove the queue, do that with drain_workqueue(). We also need to avoid handling messages which can (potentially) create new channels, so set vmbus_connection.conn_state = DISCONNECTED at the very beginning of vmbus_exit() and check for that in vmbus_onmessage_work(). 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>
2015-01-12Drivers: hv: vmbus: Use get_cpu() to get the current CPUK. Y. Srinivasan1-2/+4
Replace calls for smp_processor_id() to get_cpu() to get the CPU ID of the current CPU. In these instances, there is no correctness issue with regards to preemption, we just need the current CPU ID. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Cleanup vmbus_post_msg()K. Y. Srinivasan1-3/+14
Posting messages to the host can fail because of transient resource related failures. Correctly deal with these failures and increase the number of attempts to post the message before giving up. In this version of the patch, I have normalized the error code to Linux error code. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-10Drivers: hv: vmbus: Fix a bug in the channel callback dispatch codeK. Y. Srinivasan1-2/+6
Starting with Win8, we have implemented several optimizations to improve the scalability and performance of the VMBUS transport between the Host and the Guest. Some of the non-performance critical services cannot leverage these optimization since they only read and process one message at a time. Make adjustments to the callback dispatch code to account for the way non-performance critical drivers handle reading of the channel. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-29hv: use correct order when freeing monitor_pagesRadim Krčmář1-2/+2
We try to free two pages when only one has been allocated. Cleanup path is unlikely, so I haven't found any trace that would fit, but I hope that free_pages_prepare() does catch it. Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Amos Kong <akong@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-04Drivers: hv: vmbus: Implement per-CPU mapping of relid to channelK. Y. Srinivasan1-1/+23
Currently the mapping of the relID to channel is done under the protection of a single spin lock. Starting with ws2012, each channel is bound to a specific VCPU in the guest. Use this binding to eliminate the spin lock by setting up per-cpu state for mapping relId to the channel. 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>
2014-05-04Drivers: hv: Eliminate the channel spinlock in the callback pathK. Y. Srinivasan1-7/+4
By ensuring that we set the callback handler to NULL in the channel close path on the same CPU that the channel is bound to, we can eliminate this lock acquisition and release in a performance critical path. 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>
2014-04-17Drivers: hv: vmbus: Negotiate version 3.0 when running on ws2012r2 hostsK. Y. Srinivasan1-1/+4
Only ws2012r2 hosts support the ability to reconnect to the host on VMBUS. This functionality is needed by kexec in Linux. To use this functionality we need to negotiate version 3.0 of the VMBUS protocol. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-07Drivers: hv: vmbus: Don't timeout during the initial connection with hostK. Y. Srinivasan1-10/+1
When the guest attempts to connect with the host when there may already be a connection with the host (as would be the case during the kdump/kexec path), it is difficult to guarantee timely response from the host. Starting with WS2012 R2, the host supports this ability to re-connect with the host (explicitly to support kexec). Prior to responding to the guest, the host needs to ensure that device states based on the previous connection to the host have been properly torn down. This may introduce unbounded delays. To deal with this issue, don't do a timed wait during the initial connect with the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-07Drivers: hv: vmbus: Specify the target CPU that should receive notificationK. Y. Srinivasan1-0/+2
During the initial VMBUS connect phase, starting with WS2012 R2, we should specify the VPCU in the guest that should receive the notification. Fix this issue. This fix is required to properly connect to the host in the kexeced kernel. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-30Merge 3.12-rc3 into char-misc-nextGreg Kroah-Hartman1-1/+1
We need/want the mei fixes in here so we can apply other updates that are depending on them. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-27Drivers: hv: vmbus: Terminate vmbus version negotiation on timeoutK. Y. Srinivasan1-1/+1
commit 666b9adc801ef012612c4e43e0f44b2cdc1979cf terminated vmbus version negotiation incorrectly. We need to terminate the version negotiation only if the current negotiation were to timeout. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Olaf Hering <ohering@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-26hv: make "monitor_pages" a "real" pointer arrayGreg Kroah-Hartman1-11/+10
monitor_pages was a void pointer, containing an unknown number of arrays that we just "knew" were a child and parent array of a specific size. Instead of that implicit knowledge, let's make them a real pointer, allowing us to have type safety, and a semblance of sane addressing schemes. Tested-by: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-30Drivers: hv: vmbus: Do not attempt to negoatiate a new version prematurelyK. Y. Srinivasan1-1/+4
The current code would attempt to negotiate a different protocol version if the current negotiation timed out. This triggers an assert in the host (on debug builds). Avoid this by negotiating a newer version only if the host properly rejects the current version being negotiated. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-04Drivers: hv: vmbus: Implement multi-channel supportK. Y. Srinivasan1-0/+14
Starting with Win8, the host supports multiple sub-channels for a given device. As in the past, the initial channel offer specifies the device and is associated with both the type and the instance GUIDs. For performance critical devices, the host may support multiple sub-channels. The sub-channels share the same type and instance GUID as the primary channel. The number of sub-channels offerrred to the guest depends on the number of virtual CPUs assigned to the guest. The guest can request the creation of these sub-channels and once created and opened, the guest can distribute the traffic across all the channels (the primary and the sub-channels). A request sent on a sub-channel will have the response delivered on the same sub-channel. At channel (sub-channel) creation we bind the channel interrupt to a CPU and with this sub-channel support we will be able to spread the interrupt load of a given device across all available CPUs. 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>
2013-01-17Drivers: hv: Cleanup and consolidate reporting of build/version infoK. Y. Srinivasan1-4/+7
Now, cleanup and consolidate reporting of host and vmbus version numbers. 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>
2013-01-17Drivers: hv: Enable protocol negotiation with win8 hostsK. Y. Srinivasan1-1/+1
Now that we have implemented all of the Win8 (WS2012) functionality, negotiate Win8 protocol with the host. 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>
2013-01-17Drivers: hv: Modify the interrupt handling code to support win8 and beyondK. Y. Srinivasan1-2/+24
Starting with Win8 (WS2012), the event page can be used to directly get the channel ID that needs servicing. Modify the channel event handling code to take advantage of this feature. 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>
2013-01-17Drivers: hv: Cleanup vmbus_set_event() to support win7 and beyondK. Y. Srinivasan1-5/+8
On win7 (ws2008 R2) and beyond, we have the notion of having dedicated interrupts on a per-channel basis. When a channel has a dedicated interrupt assigned, there is no need to set the interrupt bit in the shared page. Implement this optimization. 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>
2013-01-17Drivers: hv: Move vmbus version definitions to hyperv.hK. Y. Srinivasan1-15/+0
To support version specific optimization in various vmbus drivers, move the vmbus definitions to the public header file. 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>
2013-01-17Drivers: hv: Change the signature of vmbus_set_event()K. Y. Srinivasan1-1/+2
In preparation for supporting a per-connection signaling mechanism, change the signature of vmbus_set_event(). This change is also needed to implement other aspects of the signaling optimization. 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>
2013-01-17Drivers: hv: Change the signature for hv_signal_event()K. Y. Srinivasan1-1/+1
In preparation for implementing a per-connection signaling framework, change the signature of the function hv_signal_event(). The current code uses a global handle for signaling the host. 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>
2013-01-17Drivers: hv: Save and export negotiated vmbus versionK. Y. Srinivasan1-0/+9
Export the negotiated vmbus version as this may be useful for individual drivers. 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>
2013-01-17Drivers: hv: Support handling multiple VMBUS versionsK. Y. Srinivasan1-54/+111
The current code hard coded the vmbus version independent of the host it was running on. Add code to dynamically negotiate the most appropriate version. 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>
2013-01-17Drivers: hv: Optimize signaling in the read pathK. Y. Srinivasan1-3/+25
Now that we have the infratructure for correctly determining when we should signal the host; optimize the signaling on the read side - signaling the guest from the host. 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>
2011-10-11Staging: hv: remove unneeded asm include file in hyperv.hGreg Kroah-Hartman1-1/+1
No one outside of the hyperv core needs to include the asm/hyperv.h file, so don't put it in the "global" include/linux/hyperv.h file. Cc: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-10-11Staging: hv: move hyperv code out of staging directoryGreg Kroah-Hartman1-0/+318
After many years wandering the desert, it is finally time for the Microsoft HyperV code to move out of the staging directory. Or at least the core hyperv bus code, and the utility driver, the rest still have some review to get through by the various subsystem maintainers. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>