Commit Graph
25589 Commits
Author SHA1 Message Date
Stefano Stabellini 88fccdd11c xen: event channel remapping for emulated MSIs
Linux PV on HVM guests remap all the MSIs onto event channels,
including MSIs corresponding to QEMU's emulated devices.  This patch
makes sure that we handle correctly the case of emulated MSI that have
been remapped, sending a pirq to the guest instead.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Deep Debroy <ddebroy@gmail.com>
Committed-by: Keir Fraser <keir@xen.org>
2012-07-03 13:39:01 +01:00
Andrew Cooper 97d39c5fbf xen: Fix off-by-one error when parsing command line arguments
As Xen currently stands, it will attempt to interpret the first few
bytes of the initcall section as a struct kernel_param.

The reason that this not caused problems is because in the overflow
case, param->name is actually a function pointer to the first
initcall, and intepreting it as string is very unlikely to match an
ASCII command line parameter name.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
2012-07-03 13:38:19 +01:00
Ian Campbell 5dd2cbfba5 xen: add assertion in default_vcpu0_location to protect against broken masks
When setting up the cpu sibling/etc masks on ARM I accidentally and
incorrectly omitted a CPU from it's own sibling mask which caused this
function to return an invalid cpu number which caused errors later when we
tried to access per_cpu data for that invalid cpu.

Add an assert to catch this in the future.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:33 +01:00
Ian Campbell 52c18e15d5 arm: fix typo s/approprately/appropriately/g
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:32 +01:00
Ian Campbell 260ab6de95 arm: move PSR flag definitions into interface, for tools use.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:31 +01:00
Ian Campbell 8f7b70034e arm: unwind allocations etc on arch_domain_create_failure
This involves adding the necessary teardown/free functions for some modules.

Don't initialise full arch domain state for the idle domain, it's not needed.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:30 +01:00
Ian Campbell 20a13e3fb4 arm: the hyp timer seems to work in newer model versions, default to using it.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:29 +01:00
Ian Campbell 9c0f32332e arm: context switch virtual timer registers
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:29 +01:00
Ian Campbell 6c52f2a4b4 arm: gic.lock can be taken in interrupt context, so lock appropriately.
In particular it is taken by gic_set_guest_irq which is called by
vgic_vcpu_inject_irq

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:28 +01:00
Ian Campbell 2632e28f67 arm: Upgrade guest barriers to Outer-Shareable. Enable Protected Table Walk.
Upgrading barriers is conservative and may not be necessary.

Protected Table Walk traps stage 1 page tables which refer to device memory
(per stage 2) using a non-device mapping. This generally indicates a guest
error but trapping it as a fault for now helps us know if something odd is
going on.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:27 +01:00
Ian Campbell 9e8c4fd707 arm: enable data-cache at the same time as enabling the MMU, not before
With enough warnings enabled the model seemed to be complaining that pages
cached before paging was enabled had been mapped with to inconsistent sets of
attributes. I'm not convinced that isn't a model issue, nor am I convinced
this has really fixed anything, but it seems sensible enough.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:26 +01:00
Ian Campbell 48ffc44d64 arm: map GICV in all domains, not just dom0.
This requires that we allocate all p2m pages from domheap without a particular
dom because max pages is not setup yet so there is no allocation available to
us.

At some point we should create a separate p2m allocation (similar to x86's shadow allocation) and use that.

Also we seem to have been calling p2m_alloc_table twice for dom0.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:25 +01:00
Ian Campbell 8fb3fc7693 arm: make vgic lock safe for use in interrupt context.
In particular vgic_vcpu_inject_irq can be called in both interrupt and regular
context.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:25 +01:00
Ian Campbell 11f5bc2f07 arm: split pending SPIs (global) out from pending PPIs and SGIs (per CPU)
This tracks SPIs in struct arch_domain and PPIs+SGIs in struct arch_vcpu which
seems more logical.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:24 +01:00
Ian Campbell 766c36b1b0 arm: use correct attributes for mappings in copy_from_paddr()
The DTB is in RAM (hence bufferable), kernel is in flash and therefor requires
a device type mapping (hence dev shared).

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:23 +01:00
Ian Campbell e7f335238d arm: implement vcpu_show_execution_state
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:22 +01:00
Ian Campbell 7597b978e5 arm: implement vpl011 (UART) emulator.
This is not interended to provide a full emulation, but rather just enough to
satisfy the use made by Linux' boot time decompressor code (which is too early
for DT etc)

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:21 +01:00
Ian Campbell fe4c993f8c arm: allow p2m to be created with specific MATTR.
Rename p2m_create_entry to p2m_create_table since it can now only be used to
insert non-leaf entries into the page table.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-03 10:52:20 +01:00
Anthony PERARD 1efe5e116a x86/hvm: fix BUFIOREQ evtchn init for a stubdom
This is a missing part from the previous patch that add the BUFIOREQ_EVTCHN
parameter. This patch changes the ownership of the buifioreq event channel to
the stubdom (when HVM_PARAM_DM_DOMAIN is set within the stubdom).

This patch introduces an helper to replace a xen port.

This fix the initialization of QEMU inside the stubdomain.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

Add error handling to first invocation of hvm_replace_event_channel().
Adjust type of hvm_replace_event_channel()'s second parameter.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Committed-by: Jan Beulich <jbeulich@suse.com>
2012-07-03 09:48:28 +02:00
Ian Campbell 817dbc6f30 xl: ensure handle_domain & preserve_domain update the global domid not a shadow
xl keeps the current domid in a global variable, however it also has various
functions (including the two above) which take a domid parameter which shadows
this.

This fixes the issue introduced by 25563:dbf54d93ac40 "xl: initialise domid to
an explicitly invalid value" but does not tackle the wider problem.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
2012-07-02 11:40:45 +01:00
Ian Jackson 3a527ed448 QEMU_TAG update 2012-06-29 17:57:07 +01:00
George Dunlap 4586090bbd xl: Clarify 'xend is running' error message
* Give reason for check (unpredictable results)
* Give a better recommendation (shut down xend)
* Make it clear that -f is overriding a safety check.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 17:36:50 +01:00
Zhou Peng 705e756e45 libxl: refactor stdvga opinon support.
Be ready to add and describe new vga interface

Signed-off-by: Zhou Peng <ailvpeng25@gmail.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 17:32:20 +01:00
Ian Jackson 32b854a92c QEMU_TAG update 2012-06-29 17:03:59 +01:00
Andrew Cooper 0056df42b2 MAINTAINTERS: update xen-devel email address
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 15:47:59 +01:00
Ian Campbell f388913f43 xl: initialise domid to an explicitly invalid value
also ensure it is invalid whenever we destroy the domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-29 08:58:22 +01:00
Ian Campbell dfa73b4a9b libxl: log on failure in cpupool_info and libxl__domain_cpupool
Also in cpupool_info propagate the failure value from
libxl_cpumap_alloc.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-29 08:58:19 +01:00
Ian Campbell 904efa0b84 libxl: correct type of cpupool variable.
libxl__domain_cpupool returns int and can return ERROR_* so we need to
use a signed type.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-29 08:57:11 +01:00
Ian Campbell 3b77aadeae libxl: initialise cpupoolinfo in libxl__domain_scheduler
If libxl_cpupool_info fails then we would call
libxl_cpupoolinfo_dispose on an uninitialised struct, and possibly
free an invalid pointer.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-29 08:57:11 +01:00
Matt Wilson 23c74ab2b2 xl: rename "list-vm" command to "vm-list"
All of the other "list" verbs are of the form "$noun-list". For
example: "pci-list", "vcpu-list", "network-list", "block-list", etc.

Additionally, many people have well trained muscle memory from years
of typing "xm li". "xl li" was ambiguous due to "xl list-vm", thus
resulting in "command not implemented".

Finally, this command was missing from the xl man page.

Signed-off-by: Matt Wilson <msw@amazon.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-29 15:42:27 +01:00
Tim Deegan 8c77bfea39 docs: various typos
Signed-off-by: Tim Deegan <tim@xen.org>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
2012-06-28 16:57:26 +01:00
Roger Pau Monne cc6ba55e07 autoconf: correctly parse *_INCLUDES and *_LIB env vars
Parse those options correctly, since the "+=" operator is not valid.
Also added CPPFLAGS, so headers checks don't give strange results.

Please rerun configure after applying.

Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
Cc: Christoph Egger <Christoph.Egger@amd.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 15:31:57 +01:00
Ian Campbell 65f28015b4 libxl: make libxl-save-helper depend on the autogenerated code targets
Fixes this build failure:
  In file included from libxl_save_helper.c:44:
  libxl.h:346:26: error: _libxl_types.h: No such file or directory

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 11:24:10 +01:00
Ian Campbell a79655807b libxl: libxl__xs_transaction_commit should always clear the transaction.
This includes the EAGAIN case.

Users are of the form:

   xs_transaction_t t = 0;

   for (;;) {
        rc = libxl__xs_transaction_start(gc, &t);

	rc = stuff
	if (rc) goto out;
	...more...

        rc = libxl__xs_transaction_commit(gc, &t);
        if (!rc) break;
        if (rc<0) goto out;
    }
  ...
 out:

So in EAGAIN (commit -> +1) we will go round the loop again and call start
which leads to:
    xl: libxl_xshelp.c:174: libxl__xs_transaction_start: Assertion `!*t' failed.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
2012-06-29 11:19:02 +01:00
Ian Jackson 83cc69faaf libxl: further fixups re LIBXL_DOMAIN_TYPE
* Abolish the macro LIBXL__DOMAIN_IS_TYPE which had incorrect error
  handling.  At every call site, replace it with an open-coded call to
  libxl_domain_type and check against LIBXL_DOMAIN_TYPE_INVALID.

* This involves adding an `out:' to libxl_domain_unpause.

* In libxl_domain_destroy and do_pci_add, do not `default: abort();'
  if the domain type cannot be found.  Instead switch on
  LIBXL_DOMAIN_TYPE_INVALID specifically and do some actual error
  handling.

* In libxl__primary_console_find, remove a spurious default clause
  from the domain type switch.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:28 +01:00
Ian Jackson 34d1cced24 libxl: do not leak an event struct on ignored ao progress
On entry to libxl__ao_progress_report, the caller has allocated an
event.  If the progress report is to be ignored, we need to free it.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:28 +01:00
Ian Jackson ac29cf9641 libxl: do not leak spawned middle children
libxl__spawn_spawn would, when libxl__spawn_detach was called, make
the spawn become idle immediately.  However it still has a child
process which needs to be waited for: the `detachable' spawned
child.

This is wrong because the ultimate in-libxl caller may return to the
application, with a child process still forked but not reaped libxl
contrary to the documented behaviour of libxl.

Instead, replace libxl__spawn_detach with libxl__spawn_initiate_detach
which is asynchronous.  The detachable spawned children are abolished;
instead, we defer calling back to the in-libxl user until the middle
child has been reaped.

Also, remove erroneous comment suggesting that `death' callback
parameter to libxl__ev_child_fork may be NULL.  It may not, and there
are no callers which pass NULL.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:27 +01:00
Ian Jackson 89be6c47e3 libxl: do not leak dms->saved_state
This was allocated using asprintf but never freed.  Use GCSPRINTF.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:27 +01:00
Ian Jackson 6d4a664675 xl: Handle return value from libxl_domain_suspend correctly
libxl_domain_suspend returns a libxl error code.  So it must be
wrapped with MUST and not CHK_ERRNO.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:26 +01:00
Ian Jackson 349bdd748c libxl: Get compiler to warn about gc_opt==NULL
Since it used to be legal to pass gc_opt==NULL, and there are various
patches floating about and under development which do so, add a
compiler annotation which makes the build fail when that is done.

This turns a runtime crash into a build failure, and should ensure
that we don't accidentally commit a broken combination of patches.

This is something of an annoying approach because it adds a macro
invocation to the RHS of every declaration of a function taking a
gc_opt.  So it should be reverted after Xen 4.2rc1.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:26 +01:00
Ian Jackson 27e1ccd1db libxl: Do not pass NULL as gc_opt; introduce NOGC
In 25182:6c3345d7e9d9 the practice of passing NULL to gc-using memory
allocation functions was introduced.  However, the arrangements there
were not correct as committed, because the error handling and logging
depends on getting a ctx from the gc - so an allocation error would in
fact result in libxl dereferencing NULL.

Instead, provide a special dummy gc in the ctx, called `nogc_gc'.  It
is marked out specially by having alloc_maxsize==-1, which is
otherwise invalid.

Functions which need to actually look into the gc use the new test
function gc_is_real (whose purpose is mainly clarity of the code) to
check whether the gc is the dummy one, and do nothing if it is.  And
we provide a helper macro NOGC which uses the in-scope real gc to find
the ctx and hence the dummy gc (and which replaces the previous
#define NOGC NULL).

Change all callers which pass 0 or NULL to an allocation function to
use NOGC or &ctx->nogc_gc, as applicable in the context.

We add a comment near the definition of LIBXL_INIT_GC pointing out
that it isn't any more the only place a libxl__gc struct is
initialised, for the benefit of anyone changing the contents of gc's
in the future.

Also, actually document that libxl__ptr_add is legal with ptr==NULL,
and change a couple of calls not to check for NULL argument.

Reported-by: Bamvor Jian Zhang <bjzhang@suse.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Bamvor Jian Zhang <bjzhang@suse.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:25 +01:00
Ian Jackson 145511d2ce libxl: Add a gc to libxl_cpumap_alloc, ..._to_hex_string
In the next patch we are going to change the definition of NOGC to
require a local variable libxl__gc *gc.  And this means that passing 0
to libxl__calloc is going to be wrong.

libxl_cpumap_alloc doesn't have a gc but passes 0 to libxl_calloc
Fix this by:
 - introducing an `out' label and an rc variable
 - replacing the returns with  rc = ERROR_BLAH; goto out;
 - adding uses of GC_INIT and GC_FREE.
 - changing NULL to NOGC in the call to libxl__calloc

Likewise fix libxl_cpumap_to_hex_string by:
 - adding a libxl_ctx* parameter and updating the one call site
 - adding uses of GC_INIT and GC_FREE.
 - changing NULL to NOGC in the call to libxl__zalloc

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Dario Faggioli <raistlin@linux.it>
Acked-by: Roger Pau Monne <roger.pau@entel.upc.edu>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:25 +01:00
Ian Jackson 5e07d87098 libxl: Add a gc to libxl_get_cpu_topology
In the next-but-one patch we are going to change the definition of
NOGC to require a local variable libxl__gc *gc.

libxl_get_cpu_topology doesn't have one but does use NOGC.
Fix this by:
 - introducing an `out' label
 - replacing the only call to `return' with a suitable assignment
   to ret and a `goto out'.
 - adding uses of GC_INIT and GC_FREE.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:25 +01:00
Ian Jackson 9cf80c4479 libxl: Make libxl__domain_save_device_model asynchronous
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:24 +01:00
Ian Jackson 87b978d599 libxl: prepare for asynchronous writing of qemu save file
* Combine the various calls to libxl__device_model_savefile into one
  at the start of libxl__domain_suspend, storing the result in the
  dss.  Consequently a few functions take a dss instead of some or all
  of their other arguments.

* Make libxl__domain_save_device_model's API into an asynchronous
  style which takes a callback.  The function is, however, still
  synchronous; it will be made actually async in the next patch.

* Consequently make libxl__remus_domain_checkpoint_callback into an
  asynchronous callback.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:24 +01:00
Ian Jackson 2602bfcf67 libxl: datacopier: provide "prefix data" facility
This will be used to write the qemu data banner to the save/migration
stream.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:23 +01:00
Ian Jackson 0d176cc716 libxl: wait for qemu to acknowledge logdirty command
The current migration code in libxl instructs qemu to start or stop
logdirty, but it does not wait for an acknowledgement from qemu before
continuing.  This might lead to memory corruption (!)

Fix this by waiting for qemu to acknowledge the command.

Unfortunately the necessary ao arrangements for waiting for this
command are unique because qemu has a special protocol for this
particular operation.

Also, this change means that the switch_qemu_logdirty callback
implementation in libxl can no longer synchronously produce its return
value, as it now needs to wait for xenstore.  So we tell the
marshalling code generator that it is a message which does not need a
reply.  This turns the callback function called by the marshaller into
one which returns void; the callback function arranges to later
explicitly sends the reply to the helper, when the xs watch triggers
and the appropriate value is read from xenstore.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:23 +01:00
Ian Jackson 68c6062f0c libxl: provide libxl__xs_*_checked and libxl__xs_transaction_*
These useful utility functions make dealing with xenstore a little
less painful.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:22 +01:00
Ian Jackson a8b4c682ca libxl: rename libxl_dom:save_helper to physmap_path
"save_helper" isn't very descriptive.  Also it is now confusing
because it reads like it might refer to the libxl-save-helper
executable which runs xc_domain_save and xc_domain_restore.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2012-06-28 18:43:22 +01:00
Ian Jackson ad5f4fe423 libxl: domain save/restore: run in a separate process
libxenctrl expects to be able to simply run the save or restore
operation synchronously.  This won't work well in a process which is
trying to handle multiple domains.

The options are:

 - Block such a whole process (eg, the whole of libvirt) while
   migration completes (or until it fails).

 - Create a thread to run xc_domain_save and xc_domain_restore on.
   This is quite unpalatable.  Multithreaded programming is error
   prone enough without generating threads in libraries, particularly
   if the thread does some very complex operation.

 - Fork and run the operation in the child without execing.  This is
   no good because we would need to negotiate with the caller about
   fds we would inherit (and we might be a very large process).

 - Fork and exec a helper.

Of these options the latter is the most palatable.

Consequently:

 * A new helper program libxl-save-helper (which does both save and
   restore).  It will be installed in /usr/lib/xen/bin.  It does not
   link against libxl, only libxc, and its error handling does not
   need to be very advanced.  It does contain a plumbing through of
   the logging interface into the callback stream.

 * A small ad-hoc protocol between the helper and libxl which allows
   log messages and the libxc callbacks to be passed up and down.
   Protocol doc comment is in libxl_save_helper.c.

 * To avoid a lot of tedium the marshalling boilerplate (stubs for the
   helper and the callback decoder for libxl) is generated with a
   small perl script.

 * Implement new functionality to spawn the helper, monitor its
   output, provide responses, and check on its exit status.

 * The functions libxl__xc_domain_restore_done and
   libxl__xc_domain_save_done now turn out to want be called in the
   same place.  So make their state argument a void* so that the two
   functions are type compatible.

The domain save path still writes the qemu savefile synchronously.
This will need to be fixed in a subsequent patch.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2012-06-28 18:43:21 +01:00