linux-toradex.git/drivers/hv/hyperv_vmbus.h, branch v4.8-rc1 Linux kernel for Apalis and Colibri modules Drivers: hv: vmbus: handle various crash scenarios 2016-05-01T16:23:14+00:00 Vitaly Kuznetsov vkuznets@redhat.com 2016-05-01T02:21:34+00:00 cd95aad5579371ac332507fc946008217fc37e6c Kdump keeps biting. Turns out CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was used for initial contact or to CPU0 depending on host version. vmbus_wait_for_unload() doesn't account for the fact that in case we're crashing on some other CPU we won't get the CHANNELMSG_UNLOAD_RESPONSE message and our wait on the current CPU will never end. Do the following: 1) Check for completion_done() in the loop. In case interrupt handler is still alive we'll get the confirmation we need. 2) Read message pages for all CPUs message page as we're unsure where CHANNELMSG_UNLOAD_RESPONSE is going to be delivered to. We can race with still-alive interrupt handler doing the same, add cmpxchg() to vmbus_signal_eom() to not lose CHANNELMSG_UNLOAD_RESPONSE message. 3) Cleanup message pages on all CPUs. This is required (at least for the current CPU as we're clearing CPU0 messages now but we may want to bring up additional CPUs on crash) as new messages won't be delivered till we consume what's pending. On boot we'll place message pages somewhere else and we won't be able to read stale messages. 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> 
Kdump keeps biting. Turns out CHANNELMSG_UNLOAD_RESPONSE is always
delivered to the CPU which was used for initial contact or to CPU0
depending on host version. vmbus_wait_for_unload() doesn't account for
the fact that in case we're crashing on some other CPU we won't get the
CHANNELMSG_UNLOAD_RESPONSE message and our wait on the current CPU will
never end.

Do the following:
1) Check for completion_done() in the loop. In case interrupt handler is
   still alive we'll get the confirmation we need.

2) Read message pages for all CPUs message page as we're unsure where
   CHANNELMSG_UNLOAD_RESPONSE is going to be delivered to. We can race with
   still-alive interrupt handler doing the same, add cmpxchg() to
   vmbus_signal_eom() to not lose CHANNELMSG_UNLOAD_RESPONSE message.

3) Cleanup message pages on all CPUs. This is required (at least for the
   current CPU as we're clearing CPU0 messages now but we may want to bring
   up additional CPUs on crash) as new messages won't be delivered till we
   consume what's pending. On boot we'll place message pages somewhere else
   and we won't be able to read stale messages.

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: kvp: fix IP Failover 2016-05-01T16:23:14+00:00 Vitaly Kuznetsov vkuznets@redhat.com 2016-05-01T02:21:33+00:00 4dbfc2e68004c60edab7e8fd26784383dd3ee9bc Hyper-V VMs can be replicated to another hosts and there is a feature to set different IP for replicas, it is called 'Failover TCP/IP'. When such guest starts Hyper-V host sends it KVP_OP_SET_IP_INFO message as soon as we finish negotiation procedure. The problem is that it can happen (and it actually happens) before userspace daemon connects and we reply with HV_E_FAIL to the message. As there are no repetitions we fail to set the requested IP. Solve the issue by postponing our reply to the negotiation message till userspace daemon is connected. We can't wait too long as there is a host-side timeout (cca. 75 seconds) and if we fail to reply in this time frame the whole KVP service will become inactive. The solution is not ideal - if it takes userspace daemon more than 60 seconds to connect IP Failover will still fail but I don't see a solution with our current separation between kernel and userspace parts. Other two modules (VSS and FCOPY) don't require such delay, leave them untouched. 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> 
Hyper-V VMs can be replicated to another hosts and there is a feature to
set different IP for replicas, it is called 'Failover TCP/IP'. When
such guest starts Hyper-V host sends it KVP_OP_SET_IP_INFO message as soon
as we finish negotiation procedure. The problem is that it can happen (and
it actually happens) before userspace daemon connects and we reply with
HV_E_FAIL to the message. As there are no repetitions we fail to set the
requested IP.

Solve the issue by postponing our reply to the negotiation message till
userspace daemon is connected. We can't wait too long as there is a
host-side timeout (cca. 75 seconds) and if we fail to reply in this time
frame the whole KVP service will become inactive. The solution is not
ideal - if it takes userspace daemon more than 60 seconds to connect
IP Failover will still fail but I don't see a solution with our current
separation between kernel and userspace parts.

Other two modules (VSS and FCOPY) don't require such delay, leave them
untouched.

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: vmbus: Export the vmbus_set_event() API 2016-04-30T21:00:19+00:00 K. Y. Srinivasan kys@microsoft.com 2016-04-03T00:59:49+00:00 5cc472477f928fb8584eb8e08245c9cf9002d74a 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> 
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>
Merge tag 'char-misc-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc 2016-03-17T20:47:50+00:00 Linus Torvalds torvalds@linux-foundation.org 2016-03-17T20:47:50+00:00 8eee93e2576c303b6071368456dcd6c9a5a021c9 Pull char/misc updates from Greg KH: "Here is the big char/misc driver update for 4.6-rc1. The majority of the patches here is hwtracing and some new mic drivers, but there's a lot of other driver updates as well. Full details in the shortlog. All have been in linux-next for a while with no reported issues" * tag 'char-misc-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (238 commits) goldfish: Fix build error of missing ioremap on UM nvmem: mediatek: Fix later provider initialization nvmem: imx-ocotp: Fix return value of imx_ocotp_read nvmem: Fix dependencies for !HAS_IOMEM archs char: genrtc: replace blacklist with whitelist drivers/hwtracing: make coresight-etm-perf.c explicitly non-modular drivers: char: mem: fix IS_ERROR_VALUE usage char: xillybus: Fix internal data structure initialization pch_phub: return -ENODATA if ROM can't be mapped Drivers: hv: vmbus: Support kexec on ws2012 r2 and above Drivers: hv: vmbus: Support handling messages on multiple CPUs Drivers: hv: utils: Remove util transport handler from list if registration fails Drivers: hv: util: Pass the channel information during the init call Drivers: hv: vmbus: avoid unneeded compiler optimizations in vmbus_wait_for_unload() Drivers: hv: vmbus: remove code duplication in message handling Drivers: hv: vmbus: avoid wait_for_completion() on crash Drivers: hv: vmbus: don't loose HVMSG_TIMER_EXPIRED messages misc: at24: replace memory_accessor with nvmem_device_read eeprom: 93xx46: extend driver to plug into the NVMEM framework eeprom: at25: extend driver to plug into the NVMEM framework ... 
Pull char/misc updates from Greg KH:
 "Here is the big char/misc driver update for 4.6-rc1.

  The majority of the patches here is hwtracing and some new mic
  drivers, but there's a lot of other driver updates as well.  Full
  details in the shortlog.

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (238 commits)
  goldfish: Fix build error of missing ioremap on UM
  nvmem: mediatek: Fix later provider initialization
  nvmem: imx-ocotp: Fix return value of imx_ocotp_read
  nvmem: Fix dependencies for !HAS_IOMEM archs
  char: genrtc: replace blacklist with whitelist
  drivers/hwtracing: make coresight-etm-perf.c explicitly non-modular
  drivers: char: mem: fix IS_ERROR_VALUE usage
  char: xillybus: Fix internal data structure initialization
  pch_phub: return -ENODATA if ROM can't be mapped
  Drivers: hv: vmbus: Support kexec on ws2012 r2 and above
  Drivers: hv: vmbus: Support handling messages on multiple CPUs
  Drivers: hv: utils: Remove util transport handler from list if registration fails
  Drivers: hv: util: Pass the channel information during the init call
  Drivers: hv: vmbus: avoid unneeded compiler optimizations in vmbus_wait_for_unload()
  Drivers: hv: vmbus: remove code duplication in message handling
  Drivers: hv: vmbus: avoid wait_for_completion() on crash
  Drivers: hv: vmbus: don't loose HVMSG_TIMER_EXPIRED messages
  misc: at24: replace memory_accessor with nvmem_device_read
  eeprom: 93xx46: extend driver to plug into the NVMEM framework
  eeprom: at25: extend driver to plug into the NVMEM framework
  ...
Drivers: hv: vmbus: Support handling messages on multiple CPUs 2016-03-02T00:57:20+00:00 K. Y. Srinivasan kys@microsoft.com 2016-02-26T23:13:21+00:00 d81274aae61c0a045cd0f34191c51fa64ba58bc4 Starting with Windows 2012 R2, message inteerupts can be delivered on any VCPU in the guest. Support this functionality. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Starting with Windows 2012 R2, message inteerupts can be delivered
on any VCPU in the guest. Support this functionality.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: vmbus: remove code duplication in message handling 2016-03-02T00:57:20+00:00 Vitaly Kuznetsov vkuznets@redhat.com 2016-02-26T23:13:17+00:00 0f70b66975ce4331e9002b792d5aa6787a110181 We have 3 functions dealing with messages and they all implement the same logic to finalize reads, move it to vmbus_signal_eom(). Suggested-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> 
We have 3 functions dealing with messages and they all implement
the same logic to finalize reads, move it to vmbus_signal_eom().

Suggested-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>
Drivers: hv: vmbus: avoid wait_for_completion() on crash 2016-03-02T00:57:20+00:00 Vitaly Kuznetsov vkuznets@redhat.com 2016-02-26T23:13:16+00:00 75ff3a8a9168df750b5bd0589e897a6c0517a9f1 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> 
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>
drivers/hv: Move VMBus hypercall codes into Hyper-V UAPI header 2016-02-16T17:48:40+00:00 Andrey Smetanin asmetanin@virtuozzo.com 2016-02-11T13:44:58+00:00 18f098618aa031f4c8a907c550fcd6785280c977 VMBus hypercall codes inside Hyper-V UAPI header will be used by QEMU to implement VMBus host devices support. Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com> Acked-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> CC: Gleb Natapov <gleb@kernel.org> CC: Paolo Bonzini <pbonzini@redhat.com> CC: Joerg Roedel <joro@8bytes.org> CC: "K. Y. Srinivasan" <kys@microsoft.com> CC: Haiyang Zhang <haiyangz@microsoft.com> CC: Roman Kagan <rkagan@virtuozzo.com> CC: Denis V. Lunev <den@openvz.org> CC: qemu-devel@nongnu.org [Do not rename the constant at the same time as moving it, as that would cause semantic conflicts with the Hyper-V tree. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
VMBus hypercall codes inside Hyper-V UAPI header will
be used by QEMU to implement VMBus host devices support.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Joerg Roedel <joro@8bytes.org>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
[Do not rename the constant at the same time as moving it, as that
 would cause semantic conflicts with the Hyper-V tree. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drivers: hv: vmbus: Give control over how the ring access is serialized 2016-02-08T05:34:12+00:00 K. Y. Srinivasan kys@microsoft.com 2016-01-28T06:29:45+00:00 fe760e4d64fe5c17c39e86c410d41f6587ee88bc On the channel send side, many of the VMBUS device drivers explicity serialize access to the outgoing ring buffer. Give more control to the VMBUS device drivers in terms how to serialize accesss to the outgoing ring buffer. The default behavior will be to aquire the ring lock to preserve the current behavior. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
On the channel send side, many of the VMBUS
device drivers explicity serialize access to the
outgoing ring buffer. Give more control to the
VMBUS device drivers in terms how to serialize
accesss to the outgoing ring buffer.
The default behavior will be to aquire the
ring lock to preserve the current behavior.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: vmbus: Cleanup vmbus_set_event() 2016-02-08T05:32:57+00:00 K. Y. Srinivasan kys@microsoft.com 2015-12-21T23:12:20+00:00 1b807e1011af46a595ba46c75ad5e20ad7177af7 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> 
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>