MFC r215818, r216405, r216437, r216448, r216956, r221827, r222975, r223059,

MFC r215818, r216405, r216437, r216448, r216956, r221827, r222975, r223059,
r225343, r225704, r225705, r225706, r225707, r225709, r226029, r220647,
r230183, r230587, r230916, r228526, r230879:

Bring Xen support in stable/8 up to parity with head.  Almost all
outstanding Xen support differences between head and stable/8 are included,
except for the just added r231743.

  r215818 | cperciva | 2010-11-25 08:05:21 -0700 (Thu, 25 Nov 2010) | 5 lines

  Rename HYPERVISOR_multicall (which performs the multicall hypercall) to
  _HYPERVISOR_multicall, and create a new HYPERVISOR_multicall function which
  invokes _HYPERVISOR_multicall and checks that the individual hypercalls all
  succeeded.

  r216405 | rwatson | 2010-12-13 05:15:46 -0700 (Mon, 13 Dec 2010) | 7 lines

  Add options NO_ADAPTIVE_SX to the XENHVM kernel configuration, matching
  its similar disabling of adaptive mutexes and rwlocks.  The existing
  comment on why this is the case also applies to sx locks.

  MFC after:	3 days
  Discussed with:	attilio

  r216437 | gibbs | 2010-12-14 10:23:49 -0700 (Tue, 14 Dec 2010) | 2 lines

  Remove spurious printf left over from debugging our XenStore support.

  r216448 | gibbs | 2010-12-14 13:57:40 -0700 (Tue, 14 Dec 2010) | 4 lines

  Fix a typo in a comment.

  Noticed by:	Attila Nagy <bra@fsn.hu>

  r216956 | rwatson | 2011-01-04 07:49:54 -0700 (Tue, 04 Jan 2011) | 8 lines

  Make "options XENHVM" compile for i386, not just amd64 -- a largely
  mechanical change.  This opens the door for using PV device drivers
  under Xen HVM on i386, as well as more general harmonisation of i386
  and amd64 Xen support in FreeBSD.

  Reviewed by:	cperciva
  MFC after:	3 weeks

  r221827 | mav | 2011-05-12 21:40:16 -0600 (Thu, 12 May 2011) | 2 lines

  Fix msleep() usage in Xen balloon driver to not wake up on every HZ tick.

  r222975 | gibbs | 2011-06-10 22:59:01 -0600 (Fri, 10 Jun 2011) | 63 lines

  Monitor and emit events for XenStore changes to XenBus trees
  of the devices we manage.  These changes can be due to writes
  we make ourselves or due to changes made by the control domain.
  The goal of these changes is to insure that all state transitions
  can be detected regardless of their source and to allow common
  device policies (e.g. "onlined" backend devices) to be centralized
  in the XenBus bus code.

  sys/xen/xenbus/xenbusvar.h:
  sys/xen/xenbus/xenbus.c:
  sys/xen/xenbus/xenbus_if.m:
  	Add a new method for XenBus drivers "localend_changed".
  	This method is invoked whenever a write is detected to
  	a device's XenBus tree.  The default implementation of
  	this method is a no-op.

  sys/xen/xenbus/xenbus_if.m:
  sys/dev/xen/netfront/netfront.c:
  sys/dev/xen/blkfront/blkfront.c:
  sys/dev/xen/blkback/blkback.c:
  	Change the signature of the "otherend_changed" method.
  	This notification cannot fail, so it should return void.

  sys/xen/xenbus/xenbusb_back.c:
  	Add "online" device handling to the XenBus Back Bus
  	support code.  An online backend device remains active
  	after a front-end detaches as a reconnect is expected
  	to occur in the near future.

  sys/xen/interface/io/xenbus.h:
  	Add comment block further explaining the meaning and
  	driver responsibilities associated with the XenBus
  	Closed state.

  sys/xen/xenbus/xenbusb.c:
  sys/xen/xenbus/xenbusb.h:
  sys/xen/xenbus/xenbusb_back.c:
  sys/xen/xenbus/xenbusb_front.c:
  sys/xen/xenbus/xenbusb_if.m:
  	o Register a XenStore watch against the local XenBus tree
  	  for all devices.
  	o Cache the string length of the path to our local tree.
  	o Allow the xenbus front and back drivers to hook/filter both
  	  local and otherend watch processing.
  	o Update the device ivar version of "state" when we detect
  	  a XenStore update of that node.

  sys/dev/xen/control/control.c:
  sys/xen/xenbus/xenbus.c:
  sys/xen/xenbus/xenbusb.c:
  sys/xen/xenbus/xenbusb.h:
  sys/xen/xenbus/xenbusvar.h:
  sys/xen/xenstore/xenstorevar.h:
  	Allow clients of the XenStore watch mechanism to attach
  	a single uintptr_t worth of client data to the watch.
  	This removes the need to carefully place client watch
  	data within enclosing objects so that a cast or offsetof
  	calculation can be used to convert from watch to enclosing
  	object.

  Sponsored by:	Spectra Logic Corporation
  MFC after:	1 week

  r223059 | gibbs | 2011-06-13 14:36:29 -0600 (Mon, 13 Jun 2011) | 36 lines

  Several enhancements to the Xen block back driver.

  sys/dev/xen/blkback/blkback.c:
  	o Implement front-end request coalescing.  This greatly improves the
  	  performance of front-end clients that are unaware of the dynamic
  	  request-size/number of requests negotiation available in the
  	  FreeBSD backend driver.  This required a large restructuring
  	  in how this driver records in-flight transactions and how those
  	  transactions are mapped into kernel KVA.  For example, the driver
  	  now includes a mini "KVA manager" that allocates ranges of
  	  contiguous KVA to patches of requests that are physically
  	  contiguous in the backing store so that a single bio or UIO
  	  segment can be used to represent the I/O.

  	o Refuse to open any backend files or devices if the system
  	  has yet to mount root.  This avoids a panic.

  	o Properly handle "onlined" devices.  An "onlined" backend
  	  device stays attached to its backing store across front-end
  	  disconnections.  This feature is intended to reduce latency
  	  when a front-end does a hand-off to another driver (e.g.
  	  PV aware bootloader to OS kernel) or during a VM reboot.

  	o Harden the driver against a pathological/buggy front-end
  	  by carefully vetting front-end XenStore data such as the
  	  front-end state.

  	o Add sysctls that report the negotiated number of
  	  segments per-request and the number of requests that
  	  can be concurrently in flight.

  Submitted by:	kdm
  Reviewed by:	gibbs
  Sponsored by:	Spectra Logic Corporation
  MFC after:	1 week

  r225343 | rwatson | 2011-09-02 11:36:01 -0600 (Fri, 02 Sep 2011) | 7 lines

  Add support for alternative break-to-debugger support on the Xen console.
  This should help debug boot-time hangs experienced in 9.0-BETA.

  MFC after:	3 weeks
  Tested by:	sbruno
  Approved by:	re (kib)

  r225704 | gibbs | 2011-09-20 17:44:34 -0600 (Tue, 20 Sep 2011) | 29 lines

  Properly handle suspend/resume events in the Xen device framework.

  Sponsored by:	BQ Internet

  sys/xen/xenbus/xenbusb.c:
  	o In xenbusb_resume(), publish the state transition of the
  	  resuming device into XenbusStateIntiailising so that the
  	  remote peer can see it.  Recording the state locally is
  	  not sufficient to trigger a re-connect sequence.
  	o In xenbusb_resume(), defer new-bus resume processing until
  	  after the remote peer's XenStore address has been updated.
  	  The drivers may need to refer to this information during
  	  resume processing.

  sys/xen/xenbus/xenbusb_back.c:
  sys/xen/xenbus/xenbusb_front.c:
  	Register xenbusb_resume() rather than bus_generic_resume()
  	as the handler for device_resume events.

  sys/xen/xenstore/xenstore.c:
  	o Fix grammer in a comment.
  	o In xs_suspend(), pass suspend events on to the child
  	  devices (e.g. xenbusb_front/back, that are attached
  	  to the XenStore.

  Approved by:	re
  MFC after:	1 week

  r225705 | gibbs | 2011-09-20 18:02:44 -0600 (Tue, 20 Sep 2011) | 35 lines

  Add suspend/resume support to the Xen blkfront driver.

  Sponsored by:	BQ Internet

  sys/dev/xen/blkfront/block.h:
  sys/dev/xen/blkfront/blkfront.c:
  	Remove now unused blkif_vdev_t from the blkfront soft.

  sys/dev/xen/blkfront/blkfront.c:
  	o In blkfront_suspend(), indicate the desire to suspend
  	  by changing the softc connected state to SUSPENDED, and
  	  then wait for any I/O pending on the remote peer to
  	  drain.  Cancel suspend processing if I/O does not
  	  drain within 30 seconds.
  	o Enable and update blkfront_resume().  Since I/O is
  	  drained prior to the suspension of the VM, the complicated
  	  recovery process performed by other Xen blkfront
  	  implementations is avoided.  We simply tear down the
  	  connection to our old peer, and then re-connect.
  	o In blkif_initialize(), fix a resource leak and botched
  	  return if we cannot allocate shadow memory for our
  	  requests.
  	o In blkfront_backend_changed(), correct our response to
  	  the XenbusStateInitialised state.  This state indicates
  	  that our backend peer has published sufficient data for
  	  blkfront to publish ring information and other XenStore
  	  data, not that a connection can occur.  Blkfront now
  	  will only perform connection processing in response to
  	  the XenbusStateConnected state.  This corrects an issue
  	  where blkfront connected before the backend was ready
  	  during resume processing.

  Approved by:	re
  MFC after:	1 week

  r225706 | gibbs | 2011-09-20 18:06:02 -0600 (Tue, 20 Sep 2011) | 11 lines

  [ Forced commit.  Actual changes accidentally included in r225704 ]

  sys/dev/xen/control/control.c:
  	Fix locking violations in Xen HVM suspend processing
  	and have it perform similar actions to those performed
  	during an ACPI triggered suspend.

  Sponsored by:	BQ Internet
  Approved by:	re
  MFC after:	1 week

  r225707 | gibbs | 2011-09-20 18:08:25 -0600 (Tue, 20 Sep 2011) | 21 lines

  Correct suspend/resume support in the Netfront driver.

  Sponsored by:	BQ Internet

  sys/dev/xen/netfront/netfront.c:
  	o Implement netfront_suspend(), a specialized suspend
  	  handler for the netfront driver.  This routine simply
  	  disables the carrier so the driver is idle during
  	  system suspend processing.
  	o Fix a leak when re-initializing LRO during a link reset.
  	o In netif_release_tx_bufs(), when cleaning up the grant
  	  references for our TX ring, use gnttab_end_foreign_access_ref
  	  instead of attempting to grant the page again.
  	o In netif_release_tx_bufs(), we do not track mbufs associated
  	  with mbuf chains, but instead just free each mbuf directly.
  	  Use m_free(), not m_freem(), to avoid double frees of mbufs.
  	o Refactor some code to enhance clarity.

  Approved by:	re
  MFC after:	1 week

  r225709 | gibbs | 2011-09-20 18:15:29 -0600 (Tue, 20 Sep 2011) | 19 lines

  Update netfront so that it queries and honors published
  back-end features.

  sys/dev/xen/netfront/netfront.c:
  	o Add xn_query_features() which reads the XenStore and
  	  records the TSO, LRO, and chained ring-request support
  	  of the backend.
  	o Rename xn_configure_lro() to xn_configure_features() and
  	  use this routine to manage the setup of TSO, LRO, and
  	  checksum offload.
  	o In create_netdev(), initialize if_capabilities and
  	  if_hwassist to the capabilities found on all backends.
  	  Delegate configuration of if_capenable and the TSO flag
  	  if if_hwassist to xn_configure_features().

  Reported by:	Hugo Silva (fix inspired by patch provided)
  Approved by:	re
  MFC after:	1 week

  r226029 | jkim | 2011-10-04 17:53:47 -0600 (Tue, 04 Oct 2011) | 2 lines

  Add strnlen() to libkern.

  r220647 | jkim | 2011-04-14 16:17:39 -0600 (Thu, 14 Apr 2011) | 4 lines

  Add event handlers for (ACPI) suspend/resume events.  Suspend event handlers
  are invoked right before device drivers go into sleep state and resume event
  handlers are invoked right after all device drivers are waken up.

  r230183 | cperciva | 2012-01-15 19:38:45 -0700 (Sun, 15 Jan 2012) | 3 lines

  Make XENHVM work on i386.  The __ffs() function counts bits starting from
  zero, unlike ffs(3), which starts counting from 1.

  r230587 | ken | 2012-01-26 09:35:09 -0700 (Thu, 26 Jan 2012) | 38 lines

  Xen netback driver rewrite.

  share/man/man4/Makefile,
  share/man/man4/xnb.4,
  sys/dev/xen/netback/netback.c,
  sys/dev/xen/netback/netback_unit_tests.c:

  	Rewrote the netback driver for xen to attach properly via newbus
  	and work properly in both HVM and PVM mode (only HVM is tested).
  	Works with the in-tree FreeBSD netfront driver or the Windows
  	netfront driver from SuSE.  Has not been extensively tested with
  	a Linux netfront driver.  Does not implement LRO, TSO, or
  	polling.  Includes unit tests that may be run through sysctl
  	after compiling with XNB_DEBUG defined.

  sys/dev/xen/blkback/blkback.c,
  sys/xen/interface/io/netif.h:

  	Comment elaboration.

  sys/kern/uipc_mbuf.c:

  	Fix page fault in kernel mode when calling m_print() on a
  	null mbuf.  Since m_print() is only used for debugging, there
  	are no performance concerns for extra error checking code.

  sys/kern/subr_scanf.c:

  	Add the "hh" and "ll" width specifiers from C99 to scanf().
  	A few callers were already using "ll" even though scanf()
  	was handling it as "l".

  Submitted by:	Alan Somers <alans@spectralogic.com>
  Submitted by:	John Suykerbuyk <johns@spectralogic.com>
  Sponsored by:	Spectra Logic
  MFC after:	1 week
  Reviewed by:	ken

  r230916 | ken | 2012-02-02 10:54:35 -0700 (Thu, 02 Feb 2012) | 13 lines

  Fix the netback driver build for i386.

  netback.c:	Add missing VM includes.

  xen/xenvar.h,
  xen/xenpmap.h:	Move some XENHVM macros from <machine/xen/xenpmap.h> to
  		<machine/xen/xenvar.h> on i386 to match the amd64 headers.

  conf/files:	Add netback to the build.

  Submitted by:	jhb
  MFC after:	3 days

  r228526 | kevlo | 2011-12-14 23:29:13 -0700 (Wed, 14 Dec 2011) | 2 lines

  s/timout/timeout

  r230879 | ken | 2012-02-01 13:19:33 -0700 (Wed, 01 Feb 2012) | 4 lines

  Add the GSO prefix descriptor define.

  MFC after:	3 days

git-svn-id: svn://svn.freebsd.org/base/stable/8@231759 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f