Commit Graph

41 Commits

Author SHA1 Message Date
Justin T. Gibbs
a371f519da 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.
2013-10-13 02:34:20 +00:00
Colin Percival
48a1ceed53 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  Some hosts do not publish "extended" disk IDs via virtual-device in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
2013-08-30 01:46:56 +00:00
Justin T. Gibbs
76acc41fb7 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.
2013-08-29 19:52:18 +00:00
Colin Percival
d1688fc3f1 Remove duplicate dev.xbd.*.max_requests sysctl added in r252260.
Approved by:	gibbs
2013-08-27 19:10:36 +00:00
Justin T. Gibbs
9985113b61 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)
2013-06-26 20:39:07 +00:00
Justin T. Gibbs
b834eea697 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
2013-06-16 16:01:24 +00:00
Justin T. Gibbs
127a9483ed 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
2013-06-15 04:51:31 +00:00
Justin T. Gibbs
e2c1fe9009 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
2013-06-14 17:00:58 +00:00
Justin T. Gibbs
7283d23698 sys/dev/xen/blkfront/blkfront.c:
Remove dead code.

Sponsored by:	Spectra Logic Corporation
MFC after:	1 week
2013-06-01 04:07:56 +00:00
Justin T. Gibbs
d9fab01d7b 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
2013-06-01 04:02:51 +00:00
Justin T. Gibbs
cdf5d66f2f 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
2013-05-31 22:33:28 +00:00
Justin T. Gibbs
fac3fd8015 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
2013-05-31 22:21:37 +00:00
Justin T. Gibbs
33eebb6a75 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
2013-05-31 21:05:07 +00:00
Justin T. Gibbs
5e58295a1f 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
2013-05-31 04:43:19 +00:00
Kenneth D. Merry
c3fb2891f0 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
2012-06-24 04:29:03 +00:00
Justin T. Gibbs
0d17232400 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
2012-03-25 14:20:43 +00:00
Scott Long
6ac6f295b0 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.
2012-03-12 19:29:35 +00:00
Justin T. Gibbs
443cc4d407 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
2012-02-16 21:58:47 +00:00
Justin T. Gibbs
8b8bfa3567 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
2012-02-15 06:45:49 +00:00
Ed Schouten
d745c852be Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.
This means that their use is restricted to a single C file.
2011-11-07 06:44:47 +00:00
Justin T. Gibbs
06a630f65d 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
2011-09-21 00:02:44 +00:00
Justin T. Gibbs
283d6f7287 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
2011-06-11 04:59:01 +00:00
Robert Watson
2913e88c91 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
2011-01-04 14:49:54 +00:00
Colin Percival
518c824362 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'.
2010-12-06 20:40:15 +00:00
Justin T. Gibbs
ff662b5c98 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
2010-10-19 20:53:30 +00:00
Justin T. Gibbs
491e647805 In blkif_queue_cb(), test the return value from gnttab_claim_grant_reference()
for >= 0 instead of != ENOSPC.
2009-12-29 23:31:21 +00:00
Justin T. Gibbs
a4660d594f 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.
2009-12-28 18:59:13 +00:00
Kip Macy
e4808c4b2d Merge Scott Long's latest blkfront now that the licensing issues are resolved 2009-11-30 04:32:34 +00:00
Kip Macy
9999d2cb72 Update license to reflect terms in xen 2.0 as of the time when the driver was ported
to FreeBSD
2009-11-30 04:20:43 +00:00
Kip Macy
be7747b449 fixup kernel core dumps on paravirtual guests 2009-11-24 07:17:51 +00:00
Kip Macy
8698b76c3d add core dump support to blkfront
Obtained from:	Frank Suchomel
2009-08-30 20:45:24 +00:00
Kip Macy
cfed37836e update backend_changed to reflect .m prototype 2009-06-13 21:55:08 +00:00
Doug Rabson
1267802438 Merge in support for Xen HVM on amd64 architecture. 2009-03-11 15:30:12 +00:00
Kip Macy
3a6d1fcf9c 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
2008-12-29 06:31:03 +00:00
Kip Macy
23dc562170 Integrate 185578 from dfr
Use newbus to managed devices
2008-12-04 07:59:05 +00:00
Kip Macy
920ba15bf9 Update xen/interface includes to the latest in mercurial
MFC after:	1 month
2008-09-26 05:29:39 +00:00
Kip Macy
2be5c100cf Evidently the block device starts at 767.
MFC after:	1 month
2008-08-24 04:42:41 +00:00
Kip Macy
5ce36d5254 make block devices start at 0 2008-08-23 21:30:08 +00:00
Kip Macy
4615bad142 mark blkfront_info as ready
MFC after:	1 month
2008-08-20 09:22:37 +00:00
Kip Macy
5d254c0494 Make sure that machine addresses are vm_paddr_t
MFC after:	1 month
2008-08-17 23:33:33 +00:00
Kip Macy
89e0f4d24c Import Xen paravirtual drivers.
MFC after:	2 weeks
2008-08-12 20:01:57 +00:00