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2018-12-17Drivers: hv: vmbus: Use get/put_cpu() in vmbus_connect()Dexuan Cui1-2/+6
commit 41e270f6898e7502be9fd6920ee0a108ca259d36 upstream. With CONFIG_DEBUG_PREEMPT=y, I always see this warning: BUG: using smp_processor_id() in preemptible [00000000] Fix the false warning by using get/put_cpu(). Here vmbus_connect() sends a message to the host and waits for the host's response. The host will deliver the response message and an interrupt on CPU msg->target_vcpu, and later the interrupt handler will wake up vmbus_connect(). vmbus_connect() doesn't really have to run on the same cpu as CPU msg->target_vcpu, so it's safe to call put_cpu() just here. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.16: - smp_processor_id() is only used once here - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2017-06-05Drivers: hv: vmbus: Raise retry/wait limits in vmbus_post_msg()Vitaly Kuznetsov1-5/+12
commit c0bb03924f1a80e7f65900e36c8e6b3dc167c5f8 upstream. DoS protection conditions were altered in WS2016 and now it's easy to get -EAGAIN returned from vmbus_post_msg() (e.g. when we try changing MTU on a netvsc device in a loop). All vmbus_post_msg() callers don't retry the operation and we usually end up with a non-functional device or crash. While host's DoS protection conditions are unknown to me my tests show that it can take up to 10 seconds before the message is sent so doing udelay() is not an option, we really need to sleep. Almost all vmbus_post_msg() callers are ready to sleep but there is one special case: vmbus_initiate_unload() which can be called from interrupt/NMI context and we can't sleep there. I'm also not sure about the lonely vmbus_send_tl_connect_request() which has no in-tree users but its external users are most likely waiting for the host to reply so sleeping there is also appropriate. 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> [bwh: Backported to 3.16: - Drop changes in vmbus_send_tl_connect_request(), vmbus_initiate_unload() - Adjust context, indentation] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2017-06-05Drivers: hv: vmbus: Reduce the delay between retries in vmbus_post_msg()K. Y. Srinivasan1-4/+4
commit 8de0d7e951826d7592e0ba1da655b175c4aa0923 upstream. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2017-06-05hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg()Haiyang Zhang1-2/+5
commit e1c0d82dab4a4605d3bd1968436f030dfed4a829 upstream. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2017-06-05hv: vmbus_post_msg: retry the hypercall on some transient errorsDexuan Cui1-2/+9
commit 89f9f6796d41e10e224b0cb0027ddd78cb881f65 upstream. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-10-30Drivers: hv: vmbus: Cleanup vmbus_post_msg()K. Y. Srinivasan1-3/+14
commit fdeebcc62279119dbeafbc1a2e39e773839025fd upstream. 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> 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>