CVS log for src/sys/arch/xen/xen/balloon.c

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smal->small in comment.

Attempts to make MP-safe:
xpmap_ptom_unmap() doens't need to be called at splvm; we own the pa.
Use atomic ops to change pmap_pa_end
Make sure the ptom/mtop are up to date before giving the pages back to the
pool.

No need to run hypercalls at IPL_VM.
XXX still not MP-safe

Merge the bouyer-xenpvh branch, bringing in Xen PV drivers support under HVM
guests in GENERIC.
Xen support can be disabled at runtime with
boot -c
disable hypervisor

Sync with HEAD

Mostly merge changes from HEAD upto 20200411

update to __XEN_INTERFACE_VERSION__ 0x0003020a aka Xen 3.2.10

this brings grant memory v2 support:
- status separated from flags - revoking access needs just memory barrier,
  no need for expensive cmpxchg16 any more
- sub-page hypervisor copy-only grants, to be used by xennet(4)
- 64-bit frame, i.e. support for DomU RAM >16TB

the grant table is now always allocated on boot to maximum size, it's now
never grown in runtime; switch back to regular kmem_alloc()/kmem_free()

code now requires v2 support, no compatibility for grant version 1 retained -
Xen v2 support predates all currently supported Xen versions

also interface for baloon changed slightly, code updated

Sync with HEAD

mark with XXXSMP all remaining spl*() and tsleep() calls

update from HEAD

Sync with HEAD

Sync with HEAD.  (Note that most of these changes are simply $NetBSD$
tag issues.)

balloon(4) can now use uvm_hotplug(9)

Do this.

Sync with HEAD

KNF. Remove extra spaces. No functional change.

sync with head

Use setter to set xenguest_handles.

Extend the xpmap API, as described in [1]. This change is mechanical and
avoids exposing the MD phys_to_machine/machine_to_phys tables directly.
Added:

- xpmap_ptom handles PFN (pseudo physical) to MFN (machine frame number)
translations, and is under control of the domain.
- xpmap_mtop is its counterpart (MFN to PFN), and is under control of
hypervisor.

xpmap_ptom_map()      map a pseudo-phys address to a machine address
xpmap_ptom_unmap()    unmap a pseudo-phys address (invalidation)
xpmap_ptom_isvalid()  check for pseudo-phys address validity

The parameters are physical/machine addresses, like bus_dma/bus_space(9).
As x86 MFNs are tracked by u_long (Xen's choice) while machine addresses
can be 64 bits entities (PAE), use ptoa() to avoid truncation when bit
shifting by PAGE_SHIFT.

I kept the same namespace (xpmap_) to avoid code churn.

[1] http://mail-index.netbsd.org/port-xen/2009/05/09/msg004951.html

XXX will document ptoa/atop/trunc_page separately.

Retire XEN_COMPAT_030001 as detailed on port-xen@:

http://mail-index.netbsd.org/port-xen/2012/06/25/msg007431.html

The xen_p2m API comes next.

ok bouyer@.
Tested on i386 PAE and amd64 (Xen 3.3 on private test bed, and
Xen 3.4 for Amazon EC2).

FWIW, Amazon always reported:

hypervisor0 at mainbus0: Xen version 3.4.3-kaos_t1micro

multiple times for Europe and US West-1, so I guess they are now at
3.4 (32 and 64 bits).

sync with head

merge to -current.

Comment fix.

Properly protect the min/target variables from balloon_sc, not just target.

Use their reference directly instead of going through their opaque
sysctl_data storage. It makes the locking a bit more obvious.

Merge jym-xensuspend branch in -current. ok bouyer@.

Goal: save/restore support in NetBSD domUs, for i386, i386 PAE and amd64.

Executive summary:
- split all Xen drivers (xenbus(4), grant tables, xbd(4), xennet(4))
in two parts: suspend and resume, and hook them to pmf(9).
- modify pmap so that Xen hypervisor does not cry out loud in case
it finds "unexpected" recursive memory mappings
- provide a sysctl(7), machdep.xen.suspend, to command suspend from
userland via powerd(8). Note: a suspend can only be handled correctly
when dom0 requested it, so provide a mechanism that will prevent
kernel to blindly validate user's commands

The code is still in experimental state, use at your own risk: restore
can corrupt backend communications rings; this can completely thrash
dom0 as it will loop at a high interrupt level trying to honor
all domU requests.

XXX PAE suspend does not work in amd64 currently, due to (yet again!)
page validation issues with hypervisor. Will fix.

XXX secondary CPUs are not suspended, I will write the handlers
in sync with cherry's Xen MP work.

Tested under i386 and amd64, bear in mind ring corruption though.

No build break expected, GENERICs and XEN* kernels should be fine.
./build.sh distribution still running. In any case: sorry if it does
break for you, contact me directly for reports.

Sync with HEAD. Most notably: uvm/pmap work done by rmind@, and MP Xen
work of cherry@.

No regression observed on suspend/restore.

Move xen.balloon to machdep in the sysctl(7) tree. It does not really
belong to either kern or hw.

Rename machdep.xen_timepush_ticks to xen.timepush_ticks, so it can live
under the same tree as the balloon node, machdep.xen.

ok bouyer@.

Sync with HEAD.

sync with head

Implement pmf(9) suspend/resume routines for balloon(4). Trivial, heh.

Sync with head.

Silence xenbus_read_target() in ENOENT case (== entry is missing from
Xenstore). The error case does not bring much here; assume that the value
is 0.

Print the error code when writing the ``target'' value fails.

sync with head

balloon_xenbus_attach: use KM_SLEEP for allocation.

Note: please do not use KM_NOSLEEP.

Large rewrite of the balloon driver. This one:

- turns balloon into a driver that attaches to xenbus(4). This allows to
disable the functionality either at compile time or boot time via
userconf(4). Driver can implement detach or pmf(9) hooks if deemed
necessary.

- keeps Cherry's locking model, but simplify it a bit. There is now
only one target value serialized inside balloon, we do not feedback
alternative value to Xenstore (clients are not expected to see its value
evolve behind their back, and can't do much about that either)

- implements min threshold; this is an admin-settable value that tells
driver to "not balloon below this threshold." This can be used by domain
to keep memory reservations, useful if activity is expected in the near
future.

- in addition to min threshold, the driver implements internally a
safeguard value (uvmexp.freemin + 1MiB), so that admin cannot
inadvertently set min to a very low value forcing domain into heavy
memory pressure and swapping.

- create the sysctl(8) kern.xen.balloon tree. 4 nodes are actually present
(values are in KiB):
   - min: (rw) an admin-settable value that prevents ballooning below this
          mark
   - max: (ro) the maximum size for reservation, as set by xm(1) mem-max.
   - current: (ro) the current reservation for domain.
   - target:  (rw) the targetted reservation for domain.

- fix a few limitations here and there, most notably the max_reservation
hypercall, and KiB vs pages representations at interfaces.

The driver is still turned off by default. Enabling it would need more
approval, especially from bouyer@, cherry@ and cegger@.

FWIW: tested it two days long, from amd64 dom0 (with dom0 ballooning
enabled for xend), and bunch of domUs. Did not notice anything suspicious.

XXX it still has one big limitation: it cannot hotplug memory pages in
uvm(9) if they were not present beforehand. Example: ballooning above
physmem will give more pages to domain but it won't use it to serve
allocations, unless we teach uvm(9) how to handle the extra pages.

sync with head

Sync with HEAD

file balloon.c was added on branch rmind-uvmplock on 2011-03-05 20:52:34 +0000

Pull in uvm/uvm.h where UVM's page level interface is used.

Sync with HEAD

sync with head

Sync with HEAD.

sync with head.

file balloon.c was added on branch jym-xensuspend on 2010-10-24 22:48:22 +0000

file balloon.c was added on branch uebayasi-xip on 2010-08-17 06:45:36 +0000

file balloon.c was added on branch yamt-nfs-mp on 2010-08-11 22:53:00 +0000

Keep condvar wmesg within 8-char limit

Provide and accept memory reservation information from the hypervisor
in KiloBytes. This is valid both for the xenbus interface, as well as
the dom0 only sysctl interface.

Thanks cegger@ for testing.

Provide the sysctl(7) interface to the balloon driver only to dom0

make read-only, and return sane values in balloon related sysctl(7)
nodes when  'options XEN_BALLOON' is disabled.

The Xen balloon driver enables growing and shrinking
PV domains on the fly, by collaborating with UVM and the hypervisor