Commit Graph

347 Commits

Author SHA1 Message Date
Markus Armbruster 62a830b688 ivshmem: Require master to have ID zero
Migration with ivshmem needs to be carefully orchestrated to work.
Exactly one peer (the "master") migrates to the destination, all other
peers need to unplug (and disconnect), migrate, plug back (and
reconnect).  This is sort of documented in qemu-doc.

If peers connect on the destination before migration completes, the
shared memory can get messed up.  This isn't documented anywhere.  Fix
that in qemu-doc.

To avoid messing up register IVPosition on migration, the server must
assign the same ID on source and destination.  ivshmem-spec.txt leaves
ID assignment unspecified, however.

Amend ivshmem-spec.txt to require the first client to receive ID zero.
The example ivshmem-server complies: it always assigns the first
unused ID.

For a bit of additional safety, enforce ID zero for the master.  This
does nothing when we're not using a server, because the ID is zero for
all peers then.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-40-git-send-email-armbru@redhat.com>
2016-03-21 21:29:03 +01:00
Markus Armbruster 5400c02b90 ivshmem: Split ivshmem-plain, ivshmem-doorbell off ivshmem
ivshmem can be configured with and without interrupt capability
(a.k.a. "doorbell").  The two configurations have largely disjoint
options, which makes for a confusing (and badly checked) user
interface.  Moreover, the device can't tell the guest whether its
doorbell is enabled.

Create two new device models ivshmem-plain and ivshmem-doorbell, and
deprecate the old one.

Changes from ivshmem:

* PCI revision is 1 instead of 0.  The new revision is fully backwards
  compatible for guests.  Guests may elect to require at least
  revision 1 to make sure they're not exposed to the funny "no shared
  memory, yet" state.

* Property "role" replaced by "master".  role=master becomes
  master=on, role=peer becomes master=off.  Default is off instead of
  auto.

* Property "use64" is gone.  The new devices always have 64 bit BARs.

Changes from ivshmem to ivshmem-plain:

* The Interrupt Pin register in PCI config space is zero (does not use
  an interrupt pin) instead of one (uses INTA).

* Property "x-memdev" is renamed to "memdev".

* Properties "shm" and "size" are gone.  Use property "memdev"
  instead.

* Property "msi" is gone.  The new device can't have MSI-X capability.
  It can't interrupt anyway.

* Properties "ioeventfd" and "vectors" are gone.  They're meaningless
  without interrupts anyway.

Changes from ivshmem to ivshmem-doorbell:

* Property "msi" is gone.  The new device always has MSI-X capability.

* Property "ioeventfd" defaults to on instead of off.

* Property "size" is gone.  The new device can only map all the shared
  memory received from the server.

Guests can easily find out whether the device is configured for
interrupts by checking for MSI-X capability.

Note: some code added in sub-optimal places to make the diff easier to
review.  The next commit will move it to more sensible places.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-37-git-send-email-armbru@redhat.com>
2016-03-21 21:29:03 +01:00
Markus Armbruster 1309cf448a ivshmem: Propagate errors through ivshmem_recv_setup()
This kills off the funny state described in the previous commit.

Simplify ivshmem_io_read() accordingly, and update documentation.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1458066895-20632-27-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2016-03-21 21:29:01 +01:00
Markus Armbruster ad4929384b qemu-doc: Fix ivshmem huge page example
Option parameter "share" is missing.  Without it, you get a *private*
mmap(), which defeats ivshmem's purpose pretty thoroughly ;)

While there, switch to the conventional mountpoint of hugetlbfs
/dev/hugepages.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1458066895-20632-5-git-send-email-armbru@redhat.com>
2016-03-18 17:34:55 +01:00
Peter Maydell a40db1b36b qemu-options.hx: Improve documentation of chardev multiplexing mode
The current documentation of chardev mux=on is rather brief and opaque;
expand it to hopefully be a bit more helpful.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1455643738-6068-1-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-19 18:27:56 +01:00
Michael Tokarev e999ee4434 remove libtool support
Libtool support was needed to build shared library for libcacard.
Now there's no need to use libtool, and since the build system is
already complicated enough, we have a way to slightly de-complicate
it.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
2016-02-11 15:15:46 +03:00
Thomas Huth c8c6afa886 qemu-doc: Do not promote deprecated -smb and -redir options
Since -smb and -redir are deprecated options, we should not
use them as examples in the documentation anymore.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2016-02-04 13:22:06 +08:00
Sitsofe Wheeler 8485140fa0 docs: Style the command and its options in the synopsis
Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Message-Id: <1452718226-25001-1-git-send-email-sitsofe@yahoo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-26 15:58:11 +01:00
Corey Minyard 23076bb34b Add a base IPMI interface
Add the basic IPMI types and infrastructure to QEMU.  Low-level
interfaces and simulation interfaces will register with this; it's
kind of the go-between to tie them together.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-22 18:39:19 +02:00
Markus Armbruster 1d649244b3 ivshmem: Rename property memdev to x-memdev for 2.5
The device's guest interface and its QEMU user interface are
flawed^Whotly debated.  We'll resolve that in the next development
cycle, probably by deprecating the device in favour of a cleaned up,
but not quite compatible revision.

To avoid adding more baggage to the soon-to-be-deprecated interface,
mark property "memdev" as experimental, by renaming it to "x-memdev".
It's the only recent user interface change.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1448384789-14830-6-git-send-email-armbru@redhat.com>
[Update of qemu-doc.texi squashed in]
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2015-11-25 10:24:27 +01:00
Markus Armbruster a9282c25a5 qemu-doc: Fix ivshmem usage example with shm=...
The example suggests you can omit "shm".  This isn't true; you must
specify exactly one of "shm", "chardev", "memdev".  Fix it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1448384789-14830-3-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2015-11-25 10:23:52 +01:00
Markus Armbruster 50d34c4e35 qemu-doc: Fix ivshmem example markup
Use @var{foo} like we do everywhere else, not <foo>.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1448384789-14830-2-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2015-11-25 10:23:33 +01:00
Pavel Fedin 8d31d6b65a backends/hostmem-file: Allow to specify full pathname for backing file
This allows to explicitly specify file name to use with the backend. This
is important when using it together with ivshmem in order to make it backed
by hugetlbfs. By default filename is autogenerated using mkstemp(), and the
file is unlink()ed after creation, effectively making it anonymous. This is
not very useful with ivshmem because it ends up in a memory which cannot be
accessed by something else.

Distinction between directory and file name is done by stat() check. If an
existing directory is given, the code keeps old behavior. Otherwise it
creates or opens a file with the given pathname.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Tested-by: Igor Skalkin <i.skalkin@samsung.com>
Message-Id: <004301d11166$9672fe30$c358fa90$@samsung.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04 15:56:05 +01:00
Marc-André Lureau 7d4f4bdaf7 doc: document ivshmem & hugepages
Document and give some examples of hugepages support with ivshmem device
and server.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-10-26 10:19:53 +01:00
David Marchand a75eb03b9f contrib: add ivshmem client and server
When using ivshmem devices, notifications between guests can be sent as
interrupts using a ivshmem-server (typical use described in documentation).
The client is provided as a debug tool.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: David Marchand <david.marchand@6wind.com>
[fix a valgrind warning, option and server_close() segvs, extra server
headers includes, getopt() return type, out-of-tree build, use qemu
event_notifier instead of eventfd, fix x86/osx warnings - Marc-André]
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2015-10-24 18:03:16 +02:00
Pavel Butsykin 2cd8af2d44 monitor: added generation of documentation for hmp-commands-info.hx
It will be easier if you need to add info-commands to edit
only hmp-commands-info.hx, before this had to edit monitor.c and
hmp-commands.hx.

From the build point of view all documentation is saved into
qemu-monitor-info.texi which from now on is used for all user
documentation building.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1441899541-1856-5-git-send-email-den@openvz.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-16 17:33:33 +02:00
Daniel P. Berrange b6af097528 maint: remove / fix many doubled words
Many source files have doubled words (eg "the the", "to to",
and so on). Most of these can simply be removed, but a couple
were actual mis-spellings (eg "to to" instead of "to do").
There was even one triple word score "to to to" :-)

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2015-09-11 10:21:38 +03:00
Marc-André Lureau 665b5d0dff qga: start a man page
Add a simple man page for the qemu agent.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
*squashed in review comments from Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2015-09-01 13:16:26 -05:00
Peter Maydell 6c76ec68f6 qemu-doc.texi: Fix capitalization error in OS X build instructions
Fix a capitalization error in the OS X build instructions;
this was picked up in review of commit b352153f5f and intended to be
corrected before I applied it, but I accidentally didn't include it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-08-28 11:44:53 +01:00
G 3 b352153f5f From: John Arbuckle <programmingkidx@gmail.com>
qemu-doc.texi: Add information on compiling source code on Mac OS X

Add information to the documentation on how to build QEMU
on Mac OS X.

Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: fixed a minor capitalization error]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-08-27 16:51:59 +01:00
Gonglei d274e07c6d qemu-doc: fix typos
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Message-Id: <1435917057-9396-1-git-send-email-arei.gonglei@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-07-24 13:57:45 +02:00
Markus Armbruster 92a539d22e raw-posix: Deprecate host floppy passthrough
Raise your hand if you have a physical floppy drive in a computer
you've powered on in 2015.  Okay, I see we got a few weirdos in the
audience.  That's okay, weirdos are welcome here.

Kidding aside, media change detection doesn't fully work, isn't going
to be fixed, and floppy passthrough just isn't earning its keep
anymore.

Deprecate block driver host_floppy now, so we can drop it after a
grace period.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-03-19 11:43:02 +01:00
Markus Armbruster a1f688f415 block: Deprecate QCOW/QCOW2 encryption
We've steered users away from QCOW/QCOW2 encryption for a while,
because it's a flawed design (commit 136cd19 Describe flaws in
qcow/qcow2 encryption in the docs).

In addition to flawed crypto, we have comically bad usability, and
plain old bugs.  Let me show you.

= Example images =

I'm going to use a raw image as backing file, and two QCOW2 images,
one encrypted, and one not:

    $ qemu-img create -f raw backing.img 4m
    Formatting 'backing.img', fmt=raw size=4194304
    $ qemu-img create -f qcow2 -o encryption,backing_file=backing.img,backing_fmt=raw geheim.qcow2 4m
    Formatting 'geheim.qcow2', fmt=qcow2 size=4194304 backing_file='backing.img' backing_fmt='raw' encryption=on cluster_size=65536 lazy_refcounts=off
    $ qemu-img create -f qcow2 -o backing_file=backing.img,backing_fmt=raw normal.qcow2 4m
    Formatting 'normal.qcow2', fmt=qcow2 size=4194304 backing_file='backing.img' backing_fmt='raw' encryption=off cluster_size=65536 lazy_refcounts=off

= Usability issues =

== Confusing startup ==

When no image is encrypted, and you don't give -S, QEMU starts the
guest immediately:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio normal.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: running

But as soon as there's an encrypted image in play, the guest is *not*
started, with no notification whatsoever:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: paused (prelaunch)

If the user figured out that he needs to type "cont" to enter his
keys, the confusion enters the next level: "cont" asks for at most
*one* key.  If more are needed, it then silently does nothing.  The
user has to type "cont" once per encrypted image:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio -drive if=none,file=geheim.qcow2 -drive if=none,file=geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: paused (prelaunch)
    (qemu) c
    none0 (geheim.qcow2) is encrypted.
    Password: ******
    (qemu) info status
    VM status: paused (prelaunch)
    (qemu) c
    none1 (geheim.qcow2) is encrypted.
    Password: ******
    (qemu) info status
    VM status: running

== Incorrect passwords not caught ==

All existing encryption schemes give you the GIGO treatment: garbage
password in, garbage data out.  Guests usually refuse to mount
garbage, but other usage is prone to data loss.

== Need to stop the guest to add an encrypted image ==

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: running
    (qemu) drive_add "" if=none,file=geheim.qcow2
    Guest must be stopped for opening of encrypted image
    (qemu) stop
    (qemu) drive_add "" if=none,file=geheim.qcow2
    OK

Commit c3adb58 added this restriction.  Before, we could expose images
lacking an encryption key to guests, with potentially catastrophic
results.  See also "Use without key is not always caught".

= Bugs =

== Use without key is not always caught ==

Encrypted images can be in an intermediate state "opened, but no key".
The weird startup behavior and the need to stop the guest are there to
ensure the guest isn't exposed to that state.  But other things still
are!

* drive_backup

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) drive_backup -f ide0-hd0 out.img raw
    Formatting 'out.img', fmt=raw size=4194304

  I guess this writes encrypted data to raw image out.img.  Good luck
  with figuring out how to decrypt that again.

* commit

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) commit ide0-hd0

  I guess this writes encrypted data into the unencrypted raw backing
  image, effectively destroying it.

== QMP device_add of usb-storage fails when it shouldn't ==

When the image is encrypted, device_add creates the device, defers
actually attaching it to when the key becomes available, then fails.
This is wrong.  device_add must either create the device and succeed,
or do nothing and fail.

    $ qemu-system-x86_64 -nodefaults -display none -usb -qmp stdio -drive if=none,id=foo,file=geheim.qcow2
    {"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 2}, "package": ""}, "capabilities": []}}
    { "execute": "qmp_capabilities" }
    {"return": {}}
    { "execute": "device_add", "arguments": { "driver": "usb-storage", "id": "bar", "drive": "foo" } }
    {"error": {"class": "DeviceEncrypted", "desc": "'foo' (geheim.qcow2) is encrypted"}}
    {"execute":"device_del","arguments": { "id": "bar" } }
    {"timestamp": {"seconds": 1426003440, "microseconds": 237181}, "event": "DEVICE_DELETED", "data": {"path": "/machine/peripheral/bar/bar.0/legacy[0]"}}
    {"timestamp": {"seconds": 1426003440, "microseconds": 238231}, "event": "DEVICE_DELETED", "data": {"device": "bar", "path": "/machine/peripheral/bar"}}
    {"return": {}}

This stuff is worse than useless, it's a trap for users.

If people become sufficiently interested in encrypted images to
contribute a cryptographically sane implementation for QCOW2 (or
whatever other format), then rewriting the necessary support around it
from scratch will likely be easier and yield better results than
fixing up the existing mess.

Let's deprecate the mess now, drop it after a grace period, and move
on.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-03-16 17:07:25 +01:00
Mark Cave-Ayland 9bb9f217f5 doc: minor updates to SPARC32 and SPARC64 documentation
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
2015-03-10 09:18:56 +00:00
Jeff Cody 30af51ce7f block: vhdx - change .vhdx_create default block state to ZERO
The VHDX spec specifies that the default new block state is
PAYLOAD_BLOCK_NOT_PRESENT for a dynamic VHDX image, and
PAYLOAD_BLOCK_FULLY_PRESENT for a fixed VHDX image.

However, in order to create space-efficient VHDX images with qemu-img
convert, it is desirable to be able to set has_zero_init to true for
VHDX.

There is currently an option when creating VHDX images, to use block
state ZERO for new blocks.  However, this currently defaults to 'off'.
In order to be able to eventually set has_zero_init to true for VHDX,
this needs to default to 'on'.

This patch changes the default to 'on', and provides some help
information to warn against setting it to 'off' when using qemu-img
convert.

[Max Reitz pointed out that a full stop was missing at the end of the
VHDX_BLOCK_OPT_ZERO option help text.  I have added it.
--Stefan]

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 85164899eacc86e150c3ceba793cf93b398dedd7.1418018421.git.jcody@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-12-12 15:42:49 +00:00
Gonglei 63c693f8d0 qemu-doc.texi: fix typos in x509 examples
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-11-05 09:53:18 +03:00
Stefan Hajnoczi 550830f935 block: delete cow block driver
This patch removes support for the cow file format.

Normally we do not break backwards compatibility but in this case there
is no impact and it is the most logical option.  Extraordinary claims
require extraordinary evidence so I will show why removing the cow block
driver is the right thing to do.

The cow file format is the disk image format for Usermode Linux, a way
of running a Linux system in userspace.  The performance of UML was
never great and it was hacky, but it enjoyed some popularity before
hardware virtualization support became mainstream.

QEMU's block/cow.c is supposed to read this image file format.
Unfortunately the file format was underspecified:

1. Earlier Linux versions used the MAXPATHLEN constant for the backing
   filename field.  The value of MAXPATHLEN can change, so Linux
   switched to a 4096 literal but QEMU has a 1024 literal.

2. Padding was not used on the header struct (both in the Linux kernel
   and in QEMU) so the struct layout varied across architectures.  In
   particular, i386 and x86_64 were different due to int64_t alignment
   differences.  Linux now uses __attribute__((packed)), QEMU does not.

Therefore:

1. QEMU cow images do not conform to the Linux cow image file format.

2. cow images cannot be shared between different host architectures.

This means QEMU cow images are useless and QEMU has not had bug reports
from users actually hitting these issues.

Let's get rid of this thing, it serves no purpose and no one will be
affected.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1410877464-20481-1-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:45 +01:00
Hu Tao 0e4271b711 qcow2: Add falloc and full preallocation option
preallocation=falloc allocates disk space by posix_fallocate(),
preallocation=full allocates disk space by writing zeros to disk.
Both modes imply preallocation=metadata.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-12 15:43:06 +02:00
Hu Tao 06247428be raw-posix: Add falloc and full preallocation option
This patch adds a new option preallocation for raw format, and implements
falloc and full preallocation.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-12 15:43:06 +02:00
Gernot Hillier 37cbfcce14 doc: slirp supports ICMP echo if enabled in Linux
Since QEMU 0.15, slirp (user mode networking) supports ping to the
Internet, see e6d43cfb1f

Signed-off-by: Gernot Hillier <gernot.hillier@siemens.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-07-18 17:45:37 +04:00
Chunyan Liu bc3a7f90ff Fix nocow typos in manpage
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-07 09:15:29 +02:00
Chunyan Liu 4ab1559085 qemu-img create: add 'nocow' option
Add 'nocow' option so that users could have a chance to set NOCOW flag to
newly created files. It's useful on btrfs file system to enhance performance.

Btrfs has low performance when hosting VM images, even more when the guest
in those VM are also using btrfs as file system. One way to mitigate this bad
performance is to turn off COW attributes on VM files. Generally, there are
two ways to turn off NOCOW on btrfs: a) by mounting fs with nodatacow, then
all newly created files will be NOCOW. b) per file. Add the NOCOW file
attribute. It could only be done to empty or new files.

This patch tries the second way, according to the option, it could add NOCOW
per file.

For most block drivers, since the create file step is in raw-posix.c, so we
can do setting NOCOW flag ioctl in raw-posix.c only.

But there are some exceptions, like block/vpc.c and block/vdi.c, they are
creating file by calling qemu_open directly. For them, do the same setting
NOCOW flag ioctl work in them separately.

[Fixed up 082.out due to the new 'nocow' creation option
--Stefan]

Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01 10:15:12 +02:00
Michael Tokarev 9d85d55732 doc: grammify "allows to"
English language grammar does not allow usage
of the word "allows" directly followed by an
infinitive, declaring constructs like "something
allows to do somestuff" un-grammatical.  Often
it is possible to just insert "one" between "allows"
and "to" to make the construct grammatical, but
usually it is better to re-phrase the statement.

This patch tries to fix 4 examples of "allows to"
usage in qemu doc, but does not address comments
in the code with similar constructs.  It also adds
missing "the" in the same line.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-04-18 10:33:36 +04:00
Mark Cave-Ayland 340fb41b31 doc: update default PowerPC framebuffer settings
Since 1.7, the default framebuffer settings for PowerPC are 800x600x32.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
CC: qemu-ppc@nongnu.org
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-03-27 19:22:49 +04:00
Mark Cave-Ayland 3363278808 doc: update sun4m documentation
A few minor tidy-ups, plus add reference to the new -vga tcx and cg3 options.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-03-27 19:22:48 +04:00
Daniel P. Berrange 136cd19d05 Describe flaws in qcow/qcow2 encryption in the docs
The qemu-img.texi / qemu-doc.texi files currently describe the
qcow2/qcow2 encryption thus

  "Encryption uses the AES format which is very secure (128 bit
   keys). Use a long password (16 characters) to get maximum
   protection."

While AES is indeed a strong encryption system, the way that
QCow/QCow2 use it results in a poor/weak encryption system.
Due to the use of predictable IVs, based on the sector number
extended to 128 bits, it is vulnerable to chosen plaintext
attacks which can reveal the existence of encrypted data.

The direct use of the user passphrase as the encryption key
also leads to an inability to change the passphrase of an
image. If passphrase is ever compromised the image data will
all be vulnerable, since it cannot be re-encrypted. The admin
has to clone the image files with a new passphrase and then
use a program like shred to secure erase all the old files.

Recommend against any use of QCow/QCow2 encryption, directing
users to dm-crypt / LUKS which can meet modern cryptography
best practices.

[Changed "Qcow" to "qcow" for consistency.
--Stefan]

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-01-31 22:05:03 +01:00
Stefan Hajnoczi 7fa9e1f941 docs: qcow2 compat=1.1 is now the default
Commit 9117b47717 ("qcow2: Change default
for new images to compat=1.1") changed the default qcow2 image format
version but forgot to update qemu-doc.texi and qemu-img.texi.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:16 +01:00
Jeff Cody 8282db1b2e docs: updated qemu-img man page and qemu-doc to reflect VHDX support.
The man page for qemu-img, and the qemu-doc, did not mention VHDX
as a supported format.  This adds in reference to VHDX in those
documents.

[Stefan Weil <sw@weilnetz.de> suggested s/Block Size/Block size/ for
consistency.  I have made this change.
--Stefan]

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20 09:11:58 +01:00
Michael Tokarev a8ad4159ed doc: we use seabios, not bochs bios
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-06-28 22:10:34 +04:00
Blue Swirl 6a4e177114 Remove Sun4c, Sun4d and a few CPUs
Sun4c and Sun4d architectures and related CPUs are not fully implemented
(especially Sun4c MMU) and there has been no interest for them.

Likewise, a few CPUs (Cypress, Ross etc) are only half implemented.

Remove the machines and CPUs, they can be re-added if needed later.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-05-26 11:37:58 +00:00
Hervé Poussineau 59d8276293 audio: update documentation after removing --audio-card-list option
Commit 98af93fde2 removed the
--audio-card-list option in configure, and commit
8f3b664f6c always compiled in
the adlib, gus and cs4231a audio cards.

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-05-12 13:25:55 +04:00
Thomas Schwinge 48c75f484d qemu-doc: Option -ignore-environment removed.
Has been removed in commit fc9c54124d.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-26 12:44:15 +02:00
Richard W.M. Jones 9a2d462e7b block: ssh: Use libssh2_sftp_fsync (if supported by libssh2) to flush to disk.
libssh2_sftp_fsync is an extension to libssh2 to support fsync(2) over
sftp, which is itself an extension of OpenSSH.

If both libssh2 and the ssh daemon support it, this will allow
bdrv_flush_to_disk to commit changes through to disk on the remote
server.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-15 10:18:05 +02:00
Richard W.M. Jones 0a12ec87a5 block: Add support for Secure Shell (ssh) block device.
qemu-system-x86_64 -drive file=ssh://hostname/some/image

QEMU will ssh into 'hostname' and open '/some/image' which is made
available as a standard block device.

You can specify a username (ssh://user@host/...) and/or a port number
(ssh://host:port/...).  You can also use an alternate syntax using
properties (file.user, file.host, file.port, file.path).

Current limitations:

- Authentication must be done without passwords or passphrases, using
  ssh-agent.  Other authentication methods are not supported.

- Uses a single connection, instead of concurrent AIO with multiple
  SSH connections.

This is implemented using libssh2 on the client side.  The server just
requires a regular ssh daemon with sftp-server support.  Most ssh
daemons on Unix/Linux systems will work out of the box.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-15 10:18:05 +02:00
MORITA Kazutaka 1b8bbb46e7 sheepdog: add support for connecting to unix domain socket
This patch adds support for a unix domain socket for a connection
between qemu and local sheepdog server.  You can use the unix domain
socket with the following syntax:

 $ qemu sheepdog+unix:///<vdiname>?socket=<socket path>[#snapid]

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-04 09:54:17 +01:00
MORITA Kazutaka 5d6768e3b8 sheepdog: accept URIs
The URI syntax is consistent with the NBD and Gluster syntax.  The
syntax is

  sheepdog[+tcp]://[host:port]/vdiname[#snapid|#tag]

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-04 09:54:17 +01:00
Peter Maydell 989b697ddd qemu-log: default to stderr for logging output
Switch the default for qemu_log logging output from "/tmp/qemu.log"
to stderr. This is an incompatible change in some sense, but logging
is mostly used for debugging purposes so it shouldn't affect production
use. The previous behaviour can be obtained by adding "-D /tmp/qemu.log"
to the command line.

This change requires us to:
 * update all the documentation/help text (we take the opportunity
   to smooth out minor inconsistencies between the phrasing in
   linux-user/bsd-user/system help messages)
 * make linux-user and bsd-user defer to qemu-log for the default
   logging destination rather than overriding it themselves
 * ensure that all logfile closing is done via qemu_log_close()
   and that that function doesn't close stderr
as well as the obvious change to the behaviour of do_qemu_set_log()
when no logfile name has been specified.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1361901160-28729-1-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-26 13:31:47 -06:00
Kevin Wolf d3067b020b Documentation: Update image format information
Document new and yet undocumented options and image formats. The
qemu-img man page contains information only for raw and qcow2 now and
references the HTML documentation for a more detailed description of
other formats.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2012-11-30 11:33:24 +01:00
Bharata B Rao 8809e28937 qemu: Document GlusterFS block driver usage
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14 18:19:21 +01:00
Paolo Bonzini 1d7d2a9d21 nbd: accept URIs
The URI syntax is consistent with the Gluster syntax.  Export names
are specified in the path, preceded by one or more (otherwise unused)
slashes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-12 14:38:28 +01:00