Commit Graph
1085 Commits
Author SHA1 Message Date
bauerchenandPaolo Bonzini 037fb5eb39 mem-prealloc: optimize large guest startup
[desc]:
    Large memory VM starts slowly when using -mem-prealloc, and
    there are some areas to optimize in current method;

    1、mmap will be used to alloc threads stack during create page
    clearing threads, and it will attempt mm->mmap_sem for write
    lock, but clearing threads have hold read lock, this competition
    will cause threads createion very slow;

    2、methods of calcuating pages for per threads is not well;if we use
    64 threads to split 160 hugepage,63 threads clear 2page,1 thread
    clear 34 page,so the entire speed is very slow;

    to solve the first problem,we add a mutex in thread function,and
    start all threads when all threads finished createion;
    and the second problem, we spread remainder to other threads,in
    situation that 160 hugepage and 64 threads, there are 32 threads
    clear 3 pages,and 32 threads clear 2 pages.

[test]:
    320G 84c VM start time can be reduced to 10s
    680G 84c VM start time can be reduced to 18s

Signed-off-by: bauerchen <bauerchen@tencent.com>
Reviewed-by: Pan Rui <ruippan@tencent.com>
Reviewed-by: Ivan Ren <ivanren@tencent.com>
[Simplify computation of the number of pages per thread. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-25 09:18:01 +01:00
Alexander BulekovandStefan Hajnoczi 46a07579eb module: check module wasn't already initialized
The virtual-device fuzzer must initialize QOM, prior to running
vl:qemu_init, so that it can use the qos_graph to identify the arguments
required to initialize a guest for libqos-assisted fuzzing. This change
prevents errors when vl:qemu_init tries to (re)initialize the previously
initialized QOM module.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200220041118.23264-4-alxndr@bu.edu
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi 7391d34c3c aio-posix: make AioHandler dispatch O(1) with epoll
File descriptor monitoring is O(1) with epoll(7), but
aio_dispatch_handlers() still scans all AioHandlers instead of
dispatching just those that are ready.  This makes aio_poll() O(n) with
respect to the total number of registered handlers.

Add a local ready_list to aio_poll() so that each nested aio_poll()
builds a list of handlers ready to be dispatched.  Since file descriptor
polling is level-triggered, nested aio_poll() calls also see fds that
were ready in the parent but not yet dispatched.  This guarantees that
nested aio_poll() invocations will dispatch all fds, even those that
became ready before the nested invocation.

Since only handlers ready to be dispatched are placed onto the
ready_list, the new aio_dispatch_ready_handlers() function provides O(1)
dispatch.

Note that AioContext polling is still O(n) and currently cannot be fully
disabled.  This still needs to be fixed before aio_poll() is fully O(1).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-6-stefanha@redhat.com
[Fix compilation error on macOS where there is no epoll(87).  The
aio_epoll() prototype was out of date and aio_add_ready_list() needed to
be moved outside the ifdef.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi 4749079ce0 aio-posix: make AioHandler deletion O(1)
It is not necessary to scan all AioHandlers for deletion.  Keep a list
of deleted handlers instead of scanning the full list of all handlers.

The AioHandler->deleted field can be dropped.  Let's check if the
handler has been inserted into the deleted list instead.  Add a new
QLIST_IS_INSERTED() API for this check.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi ca8c6b2275 aio-posix: don't pass ns timeout to epoll_wait()
Don't pass the nanosecond timeout into epoll_wait(), which expects
milliseconds.

The epoll_wait() timeout value does not matter if qemu_poll_ns()
determined that the poll fd is ready, but passing a value in the wrong
units is still ugly.  Pass a 0 timeout to epoll_wait() instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi ff29ed3a33 aio-posix: fix use after leaving scope in aio_poll()
epoll_handler is a stack variable and must not be accessed after it goes
out of scope:

      if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
          AioHandler epoll_handler;
          ...
          add_pollfd(&epoll_handler);
          ret = aio_epoll(ctx, pollfds, npfd, timeout);
      } ...

  ...

  /* if we have any readable fds, dispatch event */
  if (ret > 0) {
      for (i = 0; i < npfd; i++) {
          nodes[i]->pfd.revents = pollfds[i].revents;
      }
  }

nodes[0] is &epoll_handler, which has already gone out of scope.

There is no need to use pollfds[] for epoll.  We don't need an
AioHandler for the epoll fd.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi 8c6b0356b5 util/async: make bh_aio_poll() O(1)
The ctx->first_bh list contains all created BHs, including those that
are not scheduled.  The list is iterated by the event loop and therefore
has O(n) time complexity with respected to the number of created BHs.

Rewrite BHs so that only scheduled or deleted BHs are enqueued.
Only BHs that actually require action will be iterated.

One semantic change is required: qemu_bh_delete() enqueues the BH and
therefore invokes aio_notify().  The
tests/test-aio.c:test_source_bh_delete_from_cb() test case assumed that
g_main_context_iteration(NULL, false) returns false after
qemu_bh_delete() but it now returns true for one iteration.  Fix up the
test case.

This patch makes aio_compute_timeout() and aio_bh_poll() drop from a CPU
profile reported by perf-top(1).  Previously they combined to 9% CPU
utilization when AioContext polling is commented out and the guest has 2
virtio-blk,num-queues=1 and 99 virtio-blk,num-queues=32 devices.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200221093951.1414693-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Stefan Hajnoczi f25c0b5479 aio-posix: avoid reacquiring rcu_read_lock() when polling
The first rcu_read_lock/unlock() is expensive.  Nested calls are cheap.

This optimization increases IOPS from 73k to 162k with a Linux guest
that has 2 virtio-blk,num-queues=1 and 99 virtio-blk,num-queues=32
devices.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200218182708.914552-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-02-22 08:26:47 +00:00
Peter Maydell a8c6af67e1 Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-5.0-20200221' into staging
ppc patch queue 2020-02-21

Here's the next patch of ppc target patches.  Highlights are:
  * Some fixes for CAS / unplug interactions
  * Remove some leaks of device trees
  * Some fixes for the PHB3 and PHB4 devices
  * Support for NVDIMMs on the pseries machine type
  * Assorted other fixes and cleanups

# gpg: Signature made Fri 21 Feb 2020 03:35:40 GMT
# gpg:                using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg:                 aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E  87DC 6C38 CACA 20D9 B392

* remotes/dgibson/tags/ppc-for-5.0-20200221:
  hw/ppc/virtex_ml507:fix leak of fdevice tree blob
  spapr: Fix handling of unplugged devices during CAS and migration
  spapr: Don't use spapr_drc_needed() in CAS code
  ppc: free 'fdt' after reset the machine
  target/ppc/cpu.h: Clean up comments in the struct CPUPPCState definition
  target/ppc/cpu.h: Move fpu related members closer in cpu env
  target/ppc: Fix typo in comments
  spapr: Allow changing offset for -kernel image
  pnv/phb3: Add missing break statement
  pnv/phb4: Fix error path in pnv_pec_realize()
  pnv/phb3: Convert 1u to 1ull
  target/ppc/cpu.h: Remove duplicate includes
  spapr: Add Hcalls to support PAPR NVDIMM device
  spapr: Add NVDIMM device support
  nvdimm: add uuid property to nvdimm
  mem: move nvdimm_device_list to utilities
  ppc: function to setup latest class options
  ppc/pnv: Fix PCI_EXPRESS dependency
  qtest: Fix rtas dependencies
  spapr/rtas: Print message from "ibm,os-term"

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-02-21 14:20:42 +00:00
Shivaprasad G BhatandDavid Gibson 3f350f6bb3 mem: move nvdimm_device_list to utilities
nvdimm_device_list is required for parsing the list for devices
in subsequent patches. Move it to common utility area.

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <158131055857.2897.15658377276504711773.stgit@lep8c.aus.stglabs.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2020-02-21 09:15:03 +11:00
Peter Maydell b651b80822 Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-5.0-pull-request' into staging
Implement membarrier, SO_RCVTIMEO and SO_SNDTIMEO
Disable by default build of fdt, slirp and tools with linux-user
Improve strace and use qemu_log to send trace to a file
Add partial ALSA ioctl supports

# gpg: Signature made Thu 20 Feb 2020 09:20:20 GMT
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-5.0-pull-request:
  linux-user: Add support for selected alsa timer instructions using ioctls
  linux-user: Add support for getting/setting selected alsa timer parameters using ioctls
  linux-user: Add support for selecting alsa timer using ioctl
  linux-user: Add support for getting/setting specified alsa timer parameters using ioctls
  linux-user: Add support for getting alsa timer version and id
  linux-user: remove gemu_log from the linux-user tree
  linux-user: Use `qemu_log' for strace
  linux-user: Use `qemu_log' for non-strace logging
  configure: Avoid compiling system tools on user build by default
  linux-user/strace: Improve output of various syscalls
  configure: linux-user doesn't need neither fdt nor slirp
  linux-user: implement getsockopt SO_RCVTIMEO and SO_SNDTIMEO
  linux-user: Implement membarrier syscall

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-02-20 17:35:42 +00:00
Josh KunzandLaurent Vivier 4b25a50674 linux-user: Use `qemu_log' for strace
This change switches linux-user strace logging to use the newer `qemu_log`
logging subsystem rather than the older `gemu_log` (notice the "g")
logger. `qemu_log` has several advantages, namely that it allows logging
to a file, and provides a more unified interface for configuration
of logging (via the QEMU_LOG environment variable or options).

This change introduces a new log mask: `LOG_STRACE` which is used for
logging of user-mode strace messages.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Josh Kunz <jkz@google.com>
Message-Id: <20200204025416.111409-3-jkz@google.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-02-19 11:17:40 +01:00
Michal PrivoznikandLaurent Vivier b09d51c909 Report stringified errno in VFIO related errors
In a few places we report errno formatted as a negative integer.
This is not as user friendly as it can be. Use strerror() and/or
error_setg_errno() instead.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Message-Id: <4949c3ecf1a32189b8a4b5eb4b0fd04c1122501d.1581674006.git.mprivozn@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-02-18 20:20:49 +01:00
Peter MaydellandPaolo Bonzini a284f798f3 Remove support for CLOCK_MONOTONIC not being defined
Some older parts of QEMU's codebase assume that CLOCK_MONOTONIC
might not be defined by the host OS, and have workarounds to
deal with this. However, more recently (notably in commit
50290c002c for qemu-img in mid-2019, but also much
earlier in 2011 in commit 22795174a3 for ui/spice-display.c)
we've written code that assumes CLOCK_MONOTONIC is always
defined. The only host OS anybody's ever noticed this on
is OSX 10.11 and earlier, which we don't support.

So we can assume that all our host OSes have the #define,
and we can remove some now-unnecessary ifdefs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200201172252.6605-1-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12 16:23:01 +01:00
Peter Maydell 28db64fce5 Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging
Pull request

# gpg: Signature made Thu 30 Jan 2020 21:38:06 GMT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  qemu_set_log_filename: filename argument may be NULL
  hw/display/qxl.c: Use trace_event_get_state_backends()
  memory.c: Use trace_event_get_state_backends()
  docs/devel/tracing.txt: Recommend only trace_event_get_state_backends()
  Makefile: Keep trace-events-subdirs ordered

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-01-31 17:37:00 +00:00
Salvador FandinoandStefan Hajnoczi e144a605a6 qemu_set_log_filename: filename argument may be NULL
NULL is a valid log filename used to indicate we want to use stderr
but qemu_set_log_filename (which is called by bsd-user/main.c) was not
handling it correctly.

That also made redundant a couple of NULL checks in calling code which
have been removed.

Signed-off-by: Salvador Fandino <salvador@qindel.com>
Message-Id: <20200123193626.19956-1-salvador@qindel.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-01-30 21:33:50 +00:00
Aarushi MehtaandStefan Hajnoczi fcb7a4a4e8 util/async: add aio interfaces for io_uring
Signed-off-by: Aarushi Mehta <mehta.aaru20@gmail.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200120141858.587874-7-stefanha@redhat.com
Message-Id: <20200120141858.587874-7-stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-01-30 20:59:41 +00:00
Carlos SantosandRichard Henderson 00b5032ead util/cacheinfo: fix crash when compiling with uClibc
uClibc defines _SC_LEVEL1_ICACHE_LINESIZE and _SC_LEVEL1_DCACHE_LINESIZE
but the corresponding sysconf calls returns -1, which is a valid result,
meaning that the limit is indeterminate.

Handle this situation using the fallback values instead of crashing due
to an assertion failure.

Signed-off-by: Carlos Santos <casantos@redhat.com>
Message-Id: <20191017123713.30192-1-casantos@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-01-21 14:18:12 -10:00
Peter Maydell abd5f8bb95 Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-pull-request' into staging
Fix some uninitialized variable warnings,
some memory leak warnings and update MAINTAINERS file.

# gpg: Signature made Wed 08 Jan 2020 16:02:11 GMT
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/trivial-branch-pull-request:
  vl: fix memory leak in configure_accelerators
  arm/translate-a64: fix uninitialized variable warning
  nbd: fix uninitialized variable warning
  util/module: fix a memory leak
  MAINTAINERS: Update Yuval Shaia's email address

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-01-13 09:50:48 +00:00
Peter Maydell b952544fe8 Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging
* Compat machines fix (Denis)
* Command line parsing fixes (Michal, Peter, Xiaoyao)
* Cooperlake CPU model fixes (Xiaoyao)
* i386 gdb fix (mkdolata)
* IOEventHandler cleanup (Philippe)
* icount fix (Pavel)
* RR support for random number sources (Pavel)
* Kconfig fixes (Philippe)

# gpg: Signature made Wed 08 Jan 2020 10:41:00 GMT
# gpg:                using RSA key BFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream: (38 commits)
  chardev: Use QEMUChrEvent enum in IOEventHandler typedef
  chardev: use QEMUChrEvent instead of int
  chardev/char: Explicit we ignore some QEMUChrEvent in IOEventHandler
  monitor/hmp: Explicit we ignore a QEMUChrEvent in IOEventHandler
  monitor/qmp: Explicit we ignore few QEMUChrEvent in IOEventHandler
  virtio-console: Explicit we ignore some QEMUChrEvent in IOEventHandler
  vhost-user-blk: Explicit we ignore few QEMUChrEvent in IOEventHandler
  vhost-user-net: Explicit we ignore few QEMUChrEvent in IOEventHandler
  vhost-user-crypto: Explicit we ignore some QEMUChrEvent in IOEventHandler
  ccid-card-passthru: Explicit we ignore QEMUChrEvent in IOEventHandler
  hw/usb/redirect: Explicit we ignore few QEMUChrEvent in IOEventHandler
  hw/usb/dev-serial: Explicit we ignore few QEMUChrEvent in IOEventHandler
  hw/char/terminal3270: Explicit ignored QEMUChrEvent in IOEventHandler
  hw/ipmi: Explicit we ignore some QEMUChrEvent in IOEventHandler
  hw/ipmi: Remove unnecessary declarations
  target/i386: Add missed features to Cooperlake CPU model
  target/i386: Add new bit definitions of MSR_IA32_ARCH_CAPABILITIES
  target/i386: Fix handling of k_gs_base register in 32-bit mode in gdbstub
  hw/rtc/mc146818: Add missing dependency on ISA Bus
  hw/nvram/Kconfig: Restrict CHRP NVRAM to machines using OpenBIOS or SLOF
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-01-10 17:16:49 +00:00
Pan NengyuanandLaurent Vivier 638be47830 util/module: fix a memory leak
spotted by ASAN

Fixes: 81d8ccb1be
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1576805650-16380-1-git-send-email-pannengyuan@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-01-08 16:01:18 +01:00
Marc-André Lureau 1e419ee68f chardev: generate an internal id when none given
Internally, qemu may create chardev without ID. Those will not be
looked up with qemu_chr_find(), which prevents using qdev_prop_set_chr().

Use id_generate(), to generate an internal name (prefixed with #), so
no conflict exist with user-named chardev.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: xiaoqiang zhao <zxq_yx_007@163.com>
2020-01-07 16:50:09 +04:00
Pavel DovgalyukandPaolo Bonzini 878ec29b9c replay: record and replay random number sources
Record/replay feature of icount allows deterministic running of execution
scenarios. Some CPUs and peripheral devices read random numbers from
external sources making deterministic execution impossible.
This patch adds recording and replaying of random read operations
into guest-random module, which is used by the virtual hardware.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-Id: <157675984852.14505.15709141760677102489.stgit@pasha-Precision-3630-Tower>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-07 12:08:39 +01:00
Peter Maydell c4d1069c25 Merge remote-tracking branch 'remotes/elmarco/tags/dbus-vmstate7-pull-request' into staging
Add dbus-vmstate

Hi,

With external processes or helpers participating to the VM support, it
becomes necessary to handle their migration. Various options exist to
transfer their state:
1) as the VM memory, RAM or devices (we could say that's how
   vhost-user devices can be handled today, they are expected to
   restore from ring state)
2) other "vmstate" (as with TPM emulator state blobs)
3) left to be handled by management layer

1) is not practical, since an external processes may legitimatelly
need arbitrary state date to back a device or a service, or may not
even have an associated device.

2) needs ad-hoc code for each helper, but is simple and working

3) is complicated for management layer, QEMU has the migration timing

The proposed "dbus-vmstate" object will connect to a given D-Bus
address, and save/load from org.qemu.VMState1 owners on migration.

Thus helpers can easily have their state migrated with QEMU, without
implementing ad-hoc support (such as done for TPM emulation)

D-Bus is ubiquitous on Linux (it is systemd IPC), and can be made to
work on various other OSes. There are several implementations and good
bindings for various languages.  (the tests/dbus-vmstate-test.c is a
good example of how simple the implementation of services can be, even
in C)

dbus-vmstate is put into use by the libvirt series "[PATCH 00/23] Use
a slirp helper process".

v2:
 - fix build with broken mingw-glib

# gpg: Signature made Mon 06 Jan 2020 14:43:35 GMT
# gpg:                using RSA key 87A9BD933F87C606D276F62DDAE8E10975969CE5
# gpg:                issuer "marcandre.lureau@redhat.com"
# gpg: Good signature from "Marc-André Lureau <marcandre.lureau@redhat.com>" [full]
# gpg:                 aka "Marc-André Lureau <marcandre.lureau@gmail.com>" [full]
# Primary key fingerprint: 87A9 BD93 3F87 C606 D276  F62D DAE8 E109 7596 9CE5

* remotes/elmarco/tags/dbus-vmstate7-pull-request:
  tests: add dbus-vmstate-test
  tests: add migration-helpers unit
  dockerfiles: add dbus-daemon to some of latest distributions
  configure: add GDBUS_CODEGEN
  Add dbus-vmstate object
  util: add dbus helper unit
  docs: start a document to describe D-Bus usage
  vmstate: replace DeviceState with VMStateIf
  vmstate: add qom interface to get id

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-01-06 18:22:42 +00:00
Marc-André Lureau a5021d6991 util: add dbus helper unit
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2020-01-06 18:41:32 +04:00