- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

[Forced commit to correct checkin comment for r256757]

MFC: r256423

Allow FreeBSD to be booted from CDROM media on XenServer 6.2 and
prior releases.

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D
Reviewed by: gibbs
Approved by: re (gjb)

sys/dev/xen/blkfront/blkfront.c:
On XenServer versions up to an including 6.2, paravirtualized
CDROM support is broken. When running in an HVM domain,
ignore paravirtualized instances of CDROM media, and instead
rely on native drivers attaching to emulated hardware. This
functions correctly on all currently known Xen based
platforms.
------------------------------------------------------------------------

MFC: r256425

Centralize the detection logic for the Hyper-V hypervisor.

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D
Reviewed by: gibbs, grehan
Approved by: re (gjb)

sys/sys/systm.h:
* Add a new VM_GUEST type, VM_GUEST_HV (HyperV guest).

sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c:
sys/dev/hyperv/vmbus/hv_hv.c:
sys/dev/hyperv/stordisengage/hv_ata_pci_disengage.c:
* Set vm_guest to VM_GUEST_HV and use that on other HyperV related
devices instead of cloning the cpuid hypervisor check.
* Cleanup the vmbus_identify function.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

If reading a virtual-device value fails, attempt to read a virtual-device-ext
value. Some hosts do not publish "extended" disk IDs via virtual-device in
an attempt to avoid confusing old blkfront drivers, and without this change
we failed to attach such disks.

In particular, this commit allows all 24 ephemeral disks on EC2 hs1.8xlarge
instances to be used, instead of only the first 15.

MFC after: 3 days

Implement vector callback for PVHVM and unify event channel implementations

Re-structure Xen HVM support so that:
- Xen is detected and hypercalls can be performed very
early in system startup.
- Xen interrupt services are implemented using FreeBSD's native
interrupt delivery infrastructure.
- the Xen interrupt service implementation is shared between PV
and HVM guests.
- Xen interrupt handlers can optionally use a filter handler
in order to avoid the overhead of dispatch to an interrupt
thread.
- interrupt load can be distributed among all available CPUs.
- the overhead of accessing the emulated local and I/O apics
on HVM is removed for event channel port events.
- a similar optimization can eventually, and fairly easily,
be used to optimize MSI.

Early Xen detection, HVM refactoring, PVHVM interrupt infrastructure,
and misc Xen cleanups:

Sponsored by: Spectra Logic Corporation

Unification of PV & HVM interrupt infrastructure, bug fixes,
and misc Xen cleanups:

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D

sys/x86/x86/local_apic.c:
sys/amd64/include/apicvar.h:
sys/i386/include/apicvar.h:
sys/amd64/amd64/apic_vector.S:
sys/i386/i386/apic_vector.s:
sys/amd64/amd64/machdep.c:
sys/i386/i386/machdep.c:
sys/i386/xen/exception.s:
sys/x86/include/segments.h:
Reserve IDT vector 0x93 for the Xen event channel upcall
interrupt handler. On Hypervisors that support the direct
vector callback feature, we can request that this vector be
called directly by an injected HVM interrupt event, instead
of a simulated PCI interrupt on the Xen platform PCI device.
This avoids all of the overhead of dealing with the emulated
I/O APIC and local APIC. It also means that the Hypervisor
can inject these events on any CPU, allowing upcalls for
different ports to be handled in parallel.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
Map Xen per-vcpu area during AP startup.

sys/amd64/include/intr_machdep.h:
sys/i386/include/intr_machdep.h:
Increase the FreeBSD IRQ vector table to include space
for event channel interrupt sources.

sys/amd64/include/pcpu.h:
sys/i386/include/pcpu.h:
Remove Xen HVM per-cpu variable data. These fields are now
allocated via the dynamic per-cpu scheme. See xen_intr.c
for details.

sys/amd64/include/xen/hypercall.h:
sys/dev/xen/blkback/blkback.c:
sys/i386/include/xen/xenvar.h:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/xen/gnttab.c:
Prefer FreeBSD primatives to Linux ones in Xen support code.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
sys/dev/xen/balloon/balloon.c:
sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/console/xencons_ring.c:
sys/dev/xen/control/control.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/xenpci/xenpci.c:
sys/i386/i386/machdep.c:
sys/i386/include/pmap.h:
sys/i386/include/xen/xenfunc.h:
sys/i386/isa/npx.c:
sys/i386/xen/clock.c:
sys/i386/xen/mp_machdep.c:
sys/i386/xen/mptable.c:
sys/i386/xen/xen_clock_util.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/xen_rtc.c:
sys/xen/evtchn/evtchn_dev.c:
sys/xen/features.c:
sys/xen/gnttab.c:
sys/xen/gnttab.h:
sys/xen/hvm.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstore.c:
sys/xen/xenstore/xenstore_dev.c:
sys/xen/xenstore/xenstorevar.h:
Pull common Xen OS support functions/settings into xen/xen-os.h.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
Remove constants, macros, and functions unused in FreeBSD's Xen
support.

sys/xen/xen-os.h:
sys/i386/xen/xen_machdep.c:
sys/x86/xen/hvm.c:
Introduce new functions xen_domain(), xen_pv_domain(), and
xen_hvm_domain(). These are used in favor of #ifdefs so that
FreeBSD can dynamically detect and adapt to the presence of
a hypervisor. The goal is to have an HVM optimized GENERIC,
but more is necessary before this is possible.

sys/amd64/amd64/machdep.c:
sys/dev/xen/xenpci/xenpcivar.h:
sys/dev/xen/xenpci/xenpci.c:
sys/x86/xen/hvm.c:
sys/sys/kernel.h:
Refactor magic ioport, Hypercall table and Hypervisor shared
information page setup, and move it to a dedicated HVM support
module.

HVM mode initialization is now triggered during the
SI_SUB_HYPERVISOR phase of system startup. This currently
occurs just after the kernel VM is fully setup which is
just enough infrastructure to allow the hypercall table
and shared info page to be properly mapped.

sys/xen/hvm.h:
sys/x86/xen/hvm.c:
Add definitions and a method for configuring Hypervisor event
delievery via a direct vector callback.

sys/amd64/include/xen/xen-os.h:
sys/x86/xen/hvm.c:

sys/conf/files:
sys/conf/files.amd64:
sys/conf/files.i386:
Adjust kernel build to reflect the refactoring of early
Xen startup code and Xen interrupt services.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
sys/dev/xen/control/control.c:
sys/dev/xen/evtchn/evtchn_dev.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/xen/xenstore/xenstore.c:
sys/xen/evtchn/evtchn_dev.c:
sys/dev/xen/console/console.c:
sys/dev/xen/console/xencons_ring.c
Adjust drivers to use new xen_intr_*() API.

sys/dev/xen/blkback/blkback.c:
Since blkback defers all event handling to a taskqueue,
convert this task queue to a "fast" taskqueue, and schedule
it via an interrupt filter. This avoids an unnecessary
ithread context switch.

sys/xen/xenstore/xenstore.c:
The xenstore driver is MPSAFE. Indicate as much when
registering its interrupt handler.

sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusvar.h:
Remove unused event channel APIs.

sys/xen/evtchn.h:
Remove all kernel Xen interrupt service API definitions
from this file. It is now only used for structure and
ioctl definitions related to the event channel userland
device driver.

Update the definitions in this file to match those from
NetBSD. Implementing this interface will be necessary for
Dom0 support.

sys/xen/evtchn/evtchnvar.h:
Add a header file for implemenation internal APIs related
to managing event channels event delivery. This is used
to allow, for example, the event channel userland device
driver to access low-level routines that typical kernel
consumers of event channel services should never access.

sys/xen/interface/event_channel.h:
sys/xen/xen_intr.h:
Standardize on the evtchn_port_t type for referring to
an event channel port id. In order to prevent low-level
event channel APIs from leaking to kernel consumers who
should not have access to this data, the type is defined
twice: Once in the Xen provided event_channel.h, and again
in xen/xen_intr.h. The double declaration is protected by
__XEN_EVTCHN_PORT_DEFINED__ to ensure it is never declared
twice within a given compilation unit.

sys/xen/xen_intr.h:
sys/xen/evtchn/evtchn.c:
sys/x86/xen/xen_intr.c:
sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/xenpci/xenpcivar.h:
New implementation of Xen interrupt services. This is
similar in many respects to the i386 PV implementation with
the exception that events for bound to event channel ports
(i.e. not IPI, virtual IRQ, or physical IRQ) are further
optimized to avoid mask/unmask operations that aren't
necessary for these edge triggered events.

Stubs exist for supporting physical IRQ binding, but will
need additional work before this implementation can be
fully shared between PV and HVM.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
sys/i386/xen/mp_machdep.c
sys/x86/xen/hvm.c:
Add support for placing vcpu_info into an arbritary memory
page instead of using HYPERVISOR_shared_info->vcpu_info.
This allows the creation of domains with more than 32 vcpus.

sys/i386/i386/machdep.c:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/exception.s:
Add support for new event channle implementation.

Remove duplicate dev.xbd.*.max_requests sysctl added in r252260.

Approved by: gibbs

In the Xen block front driver, take advantage of backends that
support cache flush and write barrier commands.

sys/dev/xen/blkfront/block.h:
Add per-command flag that specifies that the I/O queue must
be frozen after this command is dispatched. This is used
to implement "single-stepping".

Remove the unused per-command flag that indicates a polled
command.

Add block device instance flags to record backend features.

Add a block device instance flag to indicate the I/O queue
is frozen until all outstanding I/O completes.

Enhance the queue API to allow the number of elements in a
queue to be interrogated.

Prefer "inline" to "__inline".

sys/dev/xen/blkfront/blkfront.c:
Formalize queue freeze semantics by adding methods for both
global and command-associated queue freezing.

Provide mechanism to freeze the I/O queue until all outstanding
I/O completes. Use this to implement barrier semantics
(BIO_ORDERED) when the backend does not support
BLKIF_OP_WRITE_BARRIER commands.

Implement BIO_FLUSH as either a BLKIF_OP_FLUSH_DISKCACHE
command or a 0 byte write barrier. Currently, all publicly
available backends perform a diskcache flush when processing
barrier commands, and this frontend behavior matches what
is done in Linux.

Simplify code by using new queue length API.

Report backend features during device attach and via sysctl.

Submitted by: Roger Pau Monné
Submitted by: gibbs (Merge with new driver queue API, sysctl support)

sys/dev/xen/blkfront/blkfront.c:
In xbd_thaw(), fix inverted logic to verify the queue is frozen
before attempting a thaw.

MFC after: 1 week

Properly track the different reasons new I/O is temporarily disabled, and
only re-enable I/O when all reasons have cleared.

sys/dev/xen/blkfront/block.h:
In the block front driver softc, replace the boolean
XBDF_FROZEN flag with a count of commands and driver global
issues that freeze the I/O queue. So long xbd_qfrozen_cnt
is non-zero, I/O is halted.

Add flags to xbd_flags for tracking grant table entry and
free command resource shortages. Each of these classes can
increment xbd_qfrozen_cnt at most once.

Add a command flag (XBDCF_ASYNC_MAPPING) that is set whenever
the initial mapping attempt of a command fails with EINPROGRESS.

sys/dev/xen/blkfront/blkfront.c:
In xbd_queue_cb(), use new XBDCF_ASYNC_MAPPING flag to definitively
know if an async bus dmamap load has occurred.

Add xbd_freeze() and xbd_thaw() helper methods for managing
xbd_qfrozen_cnt and use them to implement all queue freezing logic.

Add missing "thaw" to restart I/O processing once grant references
become available.

Sponsored by: Spectra Logic Corporation

Improve debugger visibility into queuing functions by removing the macro
scheme for defining inline command queuing functions.

Prefer enums to #defines.

sys/dev/xen/blkfront/block.h
Replace inline function generation performed by the
XBDQ_COMMAND_QUEUE() macro with single instances of each
inline function (init, enqueue, dequeue, remove). This was
made possible by using queue indexes instead of bit flags
in the command structure, and passing the index enum as
an argument to the functions.

Improve panic/assert messages in the queue functions.

Combine queue data and stats into a single data structure
and declare an array of them instead of each queue individually.

Convert command flags, softc state, and softc flags to enums.

sys/dev/xen/blkfront/blkfront.c
Mechanical adjustments for new queue api.

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

sys/dev/xen/blkfront/blkfront.c:
Remove dead code.

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

sys/dev/xen/blkfront/blkfront.c:
Remove local, and incorrect, definition for the value of an invalid
grant reference.

Extract ring cleanup code into xbd_free_ring() function for
symetry with xbd_alloc_ring(). This process also eliminated
an initialized but unused variable.

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

Style changes. No intended functional changes.

o rename flush_requests => xbd_flush_requests
o rename xbd_setup_ring => xbd_alloc_ring

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

Style cleanups. No intended functional changes.

o Group functions by by their functionality.
o Remove superfluous declarations.
o Remove more unused (#ifdef'd out) code.

Sponsored by: Spectra Logic Corporation

Style cleanups. No intended functional changes.

o This driver is the "xbd" driver, not the "blkfront", "blkif", "xbf", or
"xb" driver. Use the "xbd_" naming conventions for all functions,
structures, and constants.
o The prevailing convention for structure fields in this driver is to
prefix them with an abreviation of the structure type. Update
"recently added" fields to match this style.
o Remove unused data structures.
o Remove superfluous casts.
o Make a pass over the whole driver and bring it closer to
style(9) conformance.

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

Apply the ad* => ada* IDE device name transition to the Xen block
front driver.

Submitted by: Bei Guan <gbtju85@gmail.com>
Reviewed by: gibbs
MFC after: 1 week

Fix a bug which causes a panic in daopen(). The panic is caused by
a da(4) instance going away while GEOM is still probing it.

In this case, the GEOM disk class instance has been created by
disk_create(), and the taste of the disk is queued in the GEOM
event queue.

While that event is queued, the da(4) instance goes away. When the
open call comes into the da(4) driver, it dereferences the freed
(but non-NULL) peripheral pointer provided by GEOM, which results
in a panic.

The solution is to add a callback to the GEOM disk code that is
called when all of its resources are cleaned up. This is
implemented inside GEOM by adding an optional callback that is
called when all consumers have detached from a provider, and the
provider is about to be deleted.

scsi_cd.c,
scsi_da.c: In the register routine for the cd(4) and da(4)
routines, acquire a reference to the CAM peripheral
instance just before we call disk_create().

Use the new GEOM disk d_gone() callback to register
a callback (dadiskgonecb()/cddiskgonecb()) that
decrements the peripheral reference count once GEOM
has finished cleaning up its resources.

In the cd(4) driver, clean up open and close
behavior slightly. GEOM makes sure we only get one
open() and one close call, so there is no need to
set an open flag and decrement the reference count
if we are not the first open.

In the cd(4) driver, use cam_periph_release_locked()
in a couple of error scenarios to avoid extra mutex
calls.

geom.h: Add a new, optional, providergone callback that
is called when a provider is about to be deleted.

geom_disk.h: Add a new d_gone() callback to the GEOM disk
interface.

Bump the DISK_VERSION to version 2. This probably
should have been done after a couple of previous
changes, especially the addition of the d_getattr()
callback.

geom_disk.c: Add a providergone callback for the disk class,
g_disk_providergone(), that calls the user's
d_gone() callback if it exists.

Bump the DISK_VERSION to 2.

geom_subr.c: In g_destroy_provider(), call the providergone
callback if it has been provided.

In g_new_geomf(), propagate the class's
providergone callback to the new geom instance.

blkfront.c: Callers of disk_create() are supposed to pass in
DISK_VERSION, not an explicit disk API version
number. Update the blkfront driver to do that.

disk.9: Update the disk(9) man page to include information
on the new d_gone() callback, as well as the
previously added d_getattr() callback, d_descr
field, and HBA PCI ID fields.

MFC after: 5 days

Correct failure to attach the PV block front device on Citrix
XenServer configurations that advertise the multi-page ring extension,
but only allow a single page of ring space.

sys/dev/xen/blkfront/blkfront.c:
If only one page of ring space is being used, do not publish
in the XenStore the number of pages in use (1), via either
of the supported multi-page ring extension schemes.

Single page operation is the same with or without the
ring-page extension being negotiated. Relying on the
legacy behavior avoids an incompatible difference in how
the two ring-page extension schemes that are out in the
wild, deal with the base case of a single page. The
Amazon/Red Hat drivers use the same XenStore variable as
if the extension was not negotiated. The Citrix drivers
assume the new ring reference XenStore variables will be
available

Reported by: Oliver Schonefeld <schonefeld@ids-mannheim.de>
MFC after: 3 days

Final pass at having devices use their bus parent for dma tags. The
remaining drivers that haven't been converted have various problems or
complexities that will be dealt with later. This list includes:

hptrr, hptmv, hpt27xx - device aggregation across multiple parents
drm - want to talk to the maintainer first
tsec, sec - Openfirmware devices, not sure if changes are warranted
fatm - Done except for unused testing code
usb - want to talk to the maintainer first
ce, cp, ctau, cx - Significant driver changes needed to convey parent info

There are also devices tucked into architecture subtrees that I'll leave
for the respective maintainers to deal with.

Fix a bug in the calculation of the maximum I/O request size.
The previous code did not limit the I/O request size based on
the maximum number of segments supported by the back-end. In
current practice, since the only back-end supporting chained
requests is the FreeBSD implementation, this limit was never
exceeded.

sys/dev/xen/blkfront/block.h:
Add two macros, XBF_SEGS_TO_SIZE() and XBF_SIZE_TO_SEGS(),
to centralize the logic of reserving a segment to deal with
non-page-aligned I/Os.

sys/dev/xen/blkfront/blkfront.c:
o When negotiating transfer parameters, limit the
max_request_size we use and publish, if it is greater
than the maximum, unaligned, I/O we can support with
the number of segments advertised by the backend.
o Don't unilaterally reduce the I/O size published to
the disk layer by a single page. max_request_size
is already properly limited in the transfer parameter
negotiation code.
o Fix typos in printf strings:
"max_requests_segments" -> "max_request_segments"
"specificed" -> "specified"

MFC after: 1 day

Enhance documentation, improve interoperability, and fix defects in
FreeBSD's front and back Xen blkif interface drivers.

sys/dev/xen/blkfront/block.h:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkback/blkback.c:
Replace FreeBSD specific multi-page ring impelementation with
support for both the Citrix and Amazon/RedHat versions of this
extension.

sys/dev/xen/blkfront/blkfront.c:
o Add a per-instance sysctl tree that exposes all negotiated
transport parameters (ring pages, max number of requests,
max request size, max number of segments).
o In blkfront_vdevice_to_unit() add a missing return statement
so that we properly identify the unit number for high numbered
xvd devices.

sys/dev/xen/blkback/blkback.c:
o Add static dtrace probes for several events in this driver.
o Defer connection shutdown processing until the front-end
enters the closed state. This avoids prematurely tearing
down the connection when buggy front-ends transition to the
closing state, even though the device is open and they
veto the close request from the tool stack.
o Add nodes for maximum request size and the number of active
ring pages to the exising, per-instance, sysctl tree.
o Miscelaneous style cleanup.

sys/xen/interface/io/blkif.h:
o Add extensive documentation of the XenStore nodes used to
implement the blkif interface.
o Document the startup sequence between a front and back driver.
o Add structures and documenatation for the "discard" feature
(AKA Trim).
o Cleanup some definitions related to FreeBSD's request
number/size/segment-limit extension.

sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkback/blkback.c:
sys/xen/xenbus/xenbusvar.h:
Add the convenience function xenbus_get_otherend_state() and
use it to simplify some logic in both block-front and block-back.

MFC after: 1 day

Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.

This means that their use is restricted to a single C file.

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

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

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

Set correct maximum I/O length. We can only handle I/O of up to
max_request_segments * PAGE_SIZE if the I/O is page-aligned; the
largest I/O we can guarantee will work is PAGE_SIZE less than that.
This unbreaks 'diskinfo -t'.

Improve the Xen para-virtualized device infrastructure of FreeBSD:

o Add support for backend devices (e.g. blkback)
o Implement extensions to the Xen para-virtualized block API to allow
for larger and more outstanding I/Os.
o Import a completely rewritten block back driver with support for fronting
I/O to both raw devices and files.
o General cleanup and documentation of the XenBus and XenStore support code.
o Robustness and performance updates for the block front driver.
o Fixes to the netfront driver.

Sponsored by: Spectra Logic Corporation

sys/xen/xenbus/init.txt:
Deleted: This file explains the Linux method for XenBus device
enumeration and thus does not apply to FreeBSD's NewBus approach.

sys/xen/xenbus/xenbus_probe_backend.c:
Deleted: Linux version of backend XenBus service routines. It
was never ported to FreeBSD. See xenbusb.c, xenbusb_if.m,
xenbusb_front.c xenbusb_back.c for details of FreeBSD's XenBus
support.

sys/xen/xenbus/xenbusvar.h:
sys/xen/xenbus/xenbus_xs.c:
sys/xen/xenbus/xenbus_comms.c:
sys/xen/xenbus/xenbus_comms.h:
sys/xen/xenstore/xenstorevar.h:
sys/xen/xenstore/xenstore.c:
Split XenStore into its own tree. XenBus is a software layer built
on top of XenStore. The old arrangement and the naming of some
structures and functions blurred these lines making it difficult to
discern what services are provided by which layer and at what times
these services are available (e.g. during system startup and shutdown).

sys/xen/xenbus/xenbus_client.c:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_probe.c:
sys/xen/xenbus/xenbusb.c:
sys/xen/xenbus/xenbusb.h:
Split up XenBus code into methods available for use by client
drivers (xenbus.c) and code used by the XenBus "bus code" to
enumerate, attach, detach, and service bus drivers.

sys/xen/reboot.c:
sys/dev/xen/control/control.c:
Add a XenBus front driver for handling shutdown, reboot, suspend, and
resume events published in the XenStore. Move all PV suspend/reboot
support from reboot.c into this driver.

sys/xen/blkif.h:
New file from Xen vendor with macros and structures used by
a block back driver to service requests from a VM running a
different ABI (e.g. amd64 back with i386 front).

sys/conf/files:
Adjust kernel build spec for new XenBus/XenStore layout and added
Xen functionality.

sys/dev/xen/balloon/balloon.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/blkfront/blkfront.c:
sys/xen/xenbus/...
sys/xen/xenstore/...
o Rename XenStore APIs and structures from xenbus_* to xs_*.
o Adjust to use of M_XENBUS and M_XENSTORE malloc types for allocation
of objects returned by these APIs.
o Adjust for changes in the bus interface for Xen drivers.

sys/xen/xenbus/...
sys/xen/xenstore/...
Add Doxygen comments for these interfaces and the code that
implements them.

sys/dev/xen/blkback/blkback.c:
o Rewrite the Block Back driver to attach properly via newbus,
operate correctly in both PV and HVM mode regardless of domain
(e.g. can be in a DOM other than 0), and to deal with the latest
metadata available in XenStore for block devices.

o Allow users to specify a file as a backend to blkback, in addition
to character devices. Use the namei lookup of the backend path
to automatically configure, based on file type, the appropriate
backend method.

The current implementation is limited to a single outstanding I/O
at a time to file backed storage.

sys/dev/xen/blkback/blkback.c:
sys/xen/interface/io/blkif.h:
sys/xen/blkif.h:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
Extend the Xen blkif API: Negotiable request size and number of
requests.

This change extends the information recorded in the XenStore
allowing block front/back devices to negotiate for optimal I/O
parameters. This has been achieved without sacrificing backward
compatibility with drivers that are unaware of these protocol
enhancements. The extensions center around the connection protocol
which now includes these additions:

o The back-end device publishes its maximum supported values for,
request I/O size, the number of page segments that can be
associated with a request, the maximum number of requests that
can be concurrently active, and the maximum number of pages that
can be in the shared request ring. These values are published
before the back-end enters the XenbusStateInitWait state.

o The front-end waits for the back-end to enter either the InitWait
or Initialize state. At this point, the front end limits it's
own capabilities to the lesser of the values it finds published
by the backend, it's own maximums, or, should any back-end data
be missing in the store, the values supported by the original
protocol. It then initializes it's internal data structures
including allocation of the shared ring, publishes its maximum
capabilities to the XenStore and transitions to the Initialized
state.

o The back-end waits for the front-end to enter the Initalized
state. At this point, the back end limits it's own capabilities
to the lesser of the values it finds published by the frontend,
it's own maximums, or, should any front-end data be missing in
the store, the values supported by the original protocol. It
then initializes it's internal data structures, attaches to the
shared ring and transitions to the Connected state.

o The front-end waits for the back-end to enter the Connnected
state, transitions itself to the connected state, and can
commence I/O.

Although an updated front-end driver must be aware of the back-end's
InitWait state, the back-end has been coded such that it can
tolerate a front-end that skips this step and transitions directly
to the Initialized state without waiting for the back-end.

sys/xen/interface/io/blkif.h:
o Increase BLKIF_MAX_SEGMENTS_PER_REQUEST to 255. This is
the maximum number possible without changing the blkif
request header structure (nr_segs is a uint8_t).

o Add two new constants:
BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK, and
BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK. These respectively
indicate the number of segments that can fit in the first
ring-buffer entry of a request, and for each subsequent
(sg element only) ring-buffer entry associated with the
"header" ring-buffer entry of the request.

o Add the blkif_request_segment_t typedef for segment
elements.

o Add the BLKRING_GET_SG_REQUEST() macro which wraps the
RING_GET_REQUEST() macro and returns a properly cast
pointer to an array of blkif_request_segment_ts.

o Add the BLKIF_SEGS_TO_BLOCKS() macro which calculates the
number of ring entries that will be consumed by a blkif
request with the given number of segments.

sys/xen/blkif.h:
o Update for changes in interface/io/blkif.h macros.

o Update the BLKIF_MAX_RING_REQUESTS() macro to take the
ring size as an argument to allow this calculation on
multi-page rings.

o Add a companion macro to BLKIF_MAX_RING_REQUESTS(),
BLKIF_RING_PAGES(). This macro determines the number of
ring pages required in order to support a ring with the
supplied number of request blocks.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
o Negotiate with the other-end with the following limits:
Reqeust Size: MAXPHYS
Max Segments: (MAXPHYS/PAGE_SIZE) + 1
Max Requests: 256
Max Ring Pages: Sufficient to support Max Requests with
Max Segments.

o Dynamically allocate request pools and segemnts-per-request.

o Update ring allocation/attachment code to support a
multi-page shared ring.

o Update routines that access the shared ring to handle
multi-block requests.

sys/dev/xen/blkfront/blkfront.c:
o Track blkfront allocations in a blkfront driver specific
malloc pool.

o Strip out XenStore transaction retry logic in the
connection code. Transactions only need to be used when
the update to multiple XenStore nodes must be atomic.
That is not the case here.

o Fully disable blkif_resume() until it can be fixed
properly (it didn't work before this change).

o Destroy bus-dma objects during device instance tear-down.

o Properly handle backend devices with powef-of-2 sector
sizes larger than 512b.

sys/dev/xen/blkback/blkback.c:
Advertise support for and implement the BLKIF_OP_WRITE_BARRIER
and BLKIF_OP_FLUSH_DISKCACHE blkif opcodes using BIO_FLUSH and
the BIO_ORDERED attribute of bios.

sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
Fix various bugs in blkfront.

o gnttab_alloc_grant_references() returns 0 for success and
non-zero for failure. The check for < 0 is a leftover
Linuxism.

o When we negotiate with blkback and have to reduce some of our
capabilities, print out the original and reduced capability before
changing the local capability. So the user now gets the correct
information.

o Fix blkif_restart_queue_callback() formatting. Make sure we hold
the mutex in that function before calling xb_startio().

o Fix a couple of KASSERT()s.

o Fix a check in the xb_remove_* macro to be a little more specific.

sys/xen/gnttab.h:
sys/xen/gnttab.c:
Define GNTTAB_LIST_END publicly as GRANT_REF_INVALID.

sys/dev/xen/netfront/netfront.c:
Use GRANT_REF_INVALID instead of driver private definitions of the
same constant.

sys/xen/gnttab.h:
sys/xen/gnttab.c:
Add the gnttab_end_foreign_access_references() API.

This API allows a client to batch the release of an array of grant
references, instead of coding a private for loop. The implementation
takes advantage of this batching to reduce lock overhead to one
acquisition and release per-batch instead of per-freed grant reference.

While here, reduce the duration the gnttab_list_lock is held during
gnttab_free_grant_references() operations. The search to find the
tail of the incoming free list does not rely on global state and so
can be performed without holding the lock.

sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/evtchn/evtchn.c:
sys/xen/xen_intr.h:
o Implement the bind_interdomain_evtchn_to_irqhandler API for HVM mode.
This allows an HVM domain to serve back end devices to other domains.
This API is already implemented for PV mode.

o Synchronize the API between HVM and PV.

sys/dev/xen/xenpci/xenpci.c:
o Scan the full region of CPUID space in which the Xen VMM interface
may be implemented. On systems using SuSE as a Dom0 where the
Viridian API is also exported, the VMM interface is above the region
we used to search.

o Pass through bus_alloc_resource() calls so that XenBus drivers
attaching on an HVM system can allocate unused physical address
space from the nexus. The block back driver makes use of this
facility.

sys/i386/xen/xen_machdep.c:
Use the correct type for accessing the statically mapped xenstore
metadata.

sys/xen/interface/hvm/params.h:
sys/xen/xenstore/xenstore.c:
Move hvm_get_parameter() to the correct global header file instead
of as a private method to the XenStore.

sys/xen/interface/io/protocols.h:
Sync with vendor.

sys/xeninterface/io/ring.h:
Add macro for calculating the number of ring pages needed for an N
deep ring.

To avoid duplication within the macros, create and use the new
__RING_HEADER_SIZE() macro. This macro calculates the size of the
ring book keeping struct (producer/consumer indexes, etc.) that
resides at the head of the ring.

Add the __RING_PAGES() macro which calculates the number of shared
ring pages required to support a ring with the given number of
requests.

These APIs are used to support the multi-page ring version of the
Xen block API.

sys/xeninterface/io/xenbus.h:
Add Comments.

sys/xen/xenbus/...
o Refactor the FreeBSD XenBus support code to allow for both front and
backend device attachments.

o Make use of new config_intr_hook capabilities to allow front and back
devices to be probed/attached in parallel.

o Fix bugs in probe/attach state machine that could cause the system to
hang when confronted with a failure either in the local domain or in
a remote domain to which one of our driver instances is attaching.

o Publish all required state to the XenStore on device detach and
failure. The majority of the missing functionality was for serving
as a back end since the typical "hot-plug" scripts in Dom0 don't
handle the case of cleaning up for a "service domain" that is not
itself.

o Add dynamic sysctl nodes exposing the generic ivars of
XenBus devices.

o Add doxygen style comments to the majority of the code.

o Cleanup types, formatting, etc.

sys/xen/xenbus/xenbusb.c:
Common code used by both front and back XenBus busses.

sys/xen/xenbus/xenbusb_if.m:
Method definitions for a XenBus bus.

sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusb_back.c:
XenBus bus specialization for front and back devices.

MFC after: 1 month

In blkif_queue_cb(), test the return value from gnttab_claim_grant_reference()
for >= 0 instead of != ENOSPC.

Correct alignment and boundary constraints in blkfront's bus dma tag. The
blkif interface in Xen requires all I/O to be 512 byte aligned with each
segment bounded by a 4k page.

Note: This submission only documents the proper contraints for blkif I/O.
The alignment code in busdma does not yet handle alignment constraints
correctly in all cases.

Merge Scott Long's latest blkfront now that the licensing issues are resolved

Update license to reflect terms in xen 2.0 as of the time when the driver was ported
to FreeBSD

fixup kernel core dumps on paravirtual guests

add core dump support to blkfront

Obtained from: Frank Suchomel

update backend_changed to reflect .m prototype

Merge in support for Xen HVM on amd64 architecture.

merge 186535, 186537, and 186538 from releng_7_xen

Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep

Log:
unmask evtchn in bind_{virq, ipi}_to_irq

Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic

Integrate 185578 from dfr
Use newbus to managed devices

Update xen/interface includes to the latest in mercurial

MFC after: 1 month

Evidently the block device starts at 767.

MFC after: 1 month

make block devices start at 0

mark blkfront_info as ready

MFC after: 1 month

Make sure that machine addresses are vm_paddr_t

MFC after: 1 month

Import Xen paravirtual drivers.

MFC after: 2 weeks