Commit Graph

69 Commits

Author SHA1 Message Date
Ján Tomko
ede22e58ff qemu: add capability flag for seccomp sandbox
This series adds support to run QEMU with seccomp sandbox enabled. It can be
configured in qemu.conf to on, off, or the QEMU default, which is off in 1.2.
Default value is the QEMU default.
2012-09-18 15:43:28 +08:00
Osier Yang
331934b296 qemu: Add caps to indentify if setting wwn is supported by qemu
This assumes ide-drive.wwn, ide-hd.wwn, ide-cd.wwn were supported
at the same time, similar for scsi-disk.wwn, scsi-hd.wwn, and
scsi-cd.wwn. So only two new caps (QEMU_CAPS_IDE_DRIVE_WWN,
and QEMU_CAPS_SCSI_DISK_WWN) are introduced.
2012-09-18 14:42:39 +08:00
Daniel P. Berrange
6b07dff012 Introduce a API for creating QEMU capabilities for a binary
Introduce a qemuCapsNewForBinary() API which creates a new
QEMU capabilities object, populated with data relating to
a specific QEMU binary. The qemuCaps object is also given
a timestamp, which makes it possible to detect when the
cached capabilities for a binary are out of date

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-09-14 12:59:29 +01:00
Daniel P. Berrange
9b5c540096 Fix data types used for list sizes in QEMU capabilities
The QEMU capabilities APIs used a misc of 'int' and
'unsigned int' for variables relating to array sizes.
Change all these to use 'size_t'

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-09-13 12:30:23 +01:00
Daniel P. Berrange
4dced75e79 Add API for copying instances of the qemuCapsPtr object
To allow each VM instance to record additional capabilities
without affecting other VMs, there needs to be a way to do
a deep copy of the qemuCapsPtr object
2012-09-13 12:28:01 +01:00
Daniel P. Berrange
116e2facde Add ability to store other metadata in the qemu capabilities object
Add struct fields and APIs to allow the qemu capabilities object
to store version, arch, machines & cpu names, etc

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-09-13 12:26:41 +01:00
Daniel P. Berrange
c29ce35af6 Make qemuCapsProbeCommand static
The qemuCapsProbeCommand API is only used by the capabilities
code, so can be static

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-09-13 12:24:13 +01:00
Daniel P. Berrange
beac09fd68 Turn QEMU capabilities object into a full virObjectPtr
The current qemu capabilities are stored in a virBitmapPtr
object, whose type is exposed to callers. We want to store
more data besides just the flags, so we need to move to a
struct type. This object will also need to be reference
counted, since we'll be maintaining a cache of data per
binary. This change introduces a 'qemuCapsPtr' virObject
class. Most of the change is just renaming types and
variables in all the callers

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-09-13 12:24:12 +01:00
Guannan Ren
16e41ab656 qemu: add usb-redir.filter qemu capability flag
Add a qemu flag for USB redirection filter support.

The output:
usb-redir.chardev=chr
usb-redir.debug=uint8
usb-redir.filter=string
usb-redir.port=string
2012-09-13 15:30:02 +08:00
Viktor Mihajlovski
72f1f2206e Rename iolimit to blockio.
After discussion with DB we decided to rename the new iolimit
element as it creates the impression it would be there to
limit (i.e. throttle) I/O instead of specifying immutable
characteristics of a block device.
This is also backed by the fact that the term I/O Limits has
vanished from newer storage admin documentation.

Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
2012-09-04 09:14:36 -06:00
Martin Kletzander
b8216ec917 qemu: Add support for S3/S4 state configuration
This patch adds support for running qemu guests with the required
parameters to forcefully enable or disable BIOS advertising of S3 and
S4 states.  The support for this is added to capabilities and there is
also a qemu command parameter parsing implemented.
2012-09-03 09:32:39 +02:00
Viktor Mihajlovski
277a49bce7 qemu: Support for Block Device IO Limits.
Implementation of iolimits for the qemu driver with
capability probing for block size attribute and
command line generation for block sizes.
Including testcase for qemuxml2argvtest.

Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
2012-08-31 11:27:47 -07:00
Guannan Ren
8694c716ae qemu: add capabilities flags related to scsi controller
QEMU_CAPS_SCSI_LSI
    set the flag when "lsi53c895a", bus PCI, alias "lsi" in
    the output of "qemu -device ?"
    -device lsi in qemu command line

  QEMU_CAPS_VIRTIO_SCSI_PCI
    set the flag when "name "virtio-scsi-pci", bus PCI" in
    the output of qemu devices query.
    -device virtio-scsi-pci in qemu command line
2012-08-08 14:25:24 +08:00
Richa Marwaha
756fe7868b Add -netdev bridge capabilities
This patch adds the capability in libvirt to check if
-netdev bridge option is supported or not.

Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com>
Signed-off-by: Corey Bryant<coreyb@linux.vnet.ibm.com>
2012-08-06 16:56:59 +02:00
Osier Yang
f9ce7dad60 Desert the FSF address in copyright
Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c
2012-07-23 10:50:50 +08:00
Daniel P. Berrange
3399875965 Only enforce check for YAJL when starting a VM
The previous check for YAJL would have many undesirable
consequences, the most important being that it caused the
capabilities XML to lose all <guest> elements. There is
no user visible feedback as to what is wrong in this respect,
merely a syslog message. The empty capabilities causes
libvirtd to then throw away all guest XML configs that are
stored.

This changes the code so that the check for YAJL is only
performed at the time we attempt to spawn a QEMU process

error: Failed to start domain vm-vnc
error: unsupported configuration: this qemu binary requires libvirt to be compiled with yajl

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-07-20 20:31:46 +01:00
Daniel P. Berrange
1d9d5103b4 Wire up handling for QMP's BALLOON_EVENT
If QEMU supports the BALLOON_EVENT QMP event, then we can
avoid invoking 'query-balloon' when returning XML or the
domain info.

* src/qemu/qemu_capabilities.c, src/qemu/qemu_capabilities.h:
  Add QEMU_CAPS_BALLOON_EVENT
* src/qemu/qemu_driver.c: Skip query-balloon in
  qemudDomainGetInfo and qemuDomainGetXMLDesc if we have
  QEMU_CAPS_BALLOON_EVENT set
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h: Check
  for BALLOON_EVENT at connect to monitor. Add callback
  for balloon change notifications
* src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h:
  Add handling of BALLOON_EVENT and impl 'query-events'
  check

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2012-07-14 16:02:34 +08:00
Viktor Mihajlovski
d0304eaac7 S390: Add support for virtio-s390 devices.
The s390(x) architecture doesn't feature a PCI bus. For the purpose of
supporting virtio devices a virtual bus called virtio-s390 is used.
A new address type VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_S390 is used to
distinguish the virtio devices on s390 from PCI-based virtio devices.

V3 Change: updated QEMU_CAPS_VIRTIO_S390 to fit upstream.

Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
2012-07-11 11:19:05 +02:00
Gerd Hoffmann
fd4fd420b4 qemu: Add xhci support
qemu 1.1 features a xhci controller,
this patch adds support for it.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2012-06-21 16:33:00 +02:00
Wen Congyang
cdef31c562 qemu: allow the client to choose the vmcore's format
This patch updates qemu driver to allow the client to choose the
vmcore's format: memory only or including device state.
2012-06-15 20:36:14 +08:00
Marc-André Lureau
0aaebd7abc qemu: test CAPS_HDA_MICRO 2012-05-17 11:12:40 -06:00
Jiri Denemark
63b4243624 qemu: Add support for -no-user-config
Thanks to this new option we are now able to use modern CPU models (such
as Westmere) defined in external configuration file.

The qemu-1.1{,-device} data files for qemuhelptest are filled in with
qemu-1.1-rc2 output for now. I will update those files with real
qemu-1.1 output once it is released.
2012-05-15 20:29:12 +02:00
Jiri Denemark
2d76fea134 qemu: Use common helper when probing qemu capabilities
QEMU binary is called several times when we probe different kinds of
capabilities the binary supports. This patch introduces new common
helper so that all probes use a consistent way of invoking qemu.
2012-04-27 12:09:32 +02:00
Osier Yang
a4cda054e7 qemu: Split ide-drive into ide-cd and ide-hd
A "ide-drive" device can be either a hard disk or a CD-ROM,
if there is ",media=cdrom" specified for the backend, it's
a CD-ROM, otherwise it's a hard disk.

Upstream qemu splitted "ide-drive" into "ide-hd" and "ide-cd"
since commit 1f56e32, and ",media=cdrom" is not required for
ide-cd anymore. "ide-drive" is still supported for backwards
compatibility, but no doubt we should go foward.
2012-04-17 17:21:48 +08:00
Osier Yang
02e8d0cfdf qemu: Split scsi-disk into into scsi-hd and scsi-cd
A "scsi-disk" device can be either a hard disk or a CD-ROM,
if there is ",media=cdrom" specified for the backend, it's
a CD-ROM, otherwise it's a hard disk.

But upstream qemu splitted "scsi-disk" into "scsi-hd" and
"scsi-cd" since commit b443ae, and ",media=cdrom" is not
required for scsi-cd anymore. "scsi-disk" is still supported
for backwards compatibility, but no doubt we should go
foward.
2012-04-17 17:21:24 +08:00
Eric Blake
2b085f5bc5 blockjob: add qemu capabilities related to block pull jobs
RHEL 6.2 was released with an early version of block jobs, which only
worked on the qed file format, where the commands were spelled with
underscore (contrary to QMP style), and where 'block_job_cancel' was
synchronous and did not trigger an event.

The upcoming qemu 1.1 release has fixed these short-comings [1][2]:
the commands now work on multiple file types, are spelled with dash,
and 'block-job-cancel' is asynchronous and emits an event upon conclusion.

[1]qemu commit 370521a1d6f5537ea7271c119f3fbb7b0fa57063
[2]https://lists.gnu.org/archive/html/qemu-devel/2012-04/msg01248.html

This patch recognizes the new spellings, and fixes virDomainBlockRebase
to give a graceful error when talking to a too-old qemu on a partial
rebase attempt.  Fixes for the new semantics will come later.  This
patch also removes a bogus ATTRIBUTE_NONNULL mistakenly added in
commit 10ec36e2.

* src/qemu/qemu_capabilities.h (QEMU_CAPS_BLOCKJOB_SYNC)
(QEMU_CAPS_BLOCKJOB_ASYNC): New bits.
* src/qemu/qemu_capabilities.c (qemuCaps): Name them.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONCheckCommands): Set
them.
(qemuMonitorJSONBlockJob): Manage both command names.
(qemuMonitorJSONDiskSnapshot): Minor formatting fix.
* src/qemu/qemu_monitor.h (qemuMonitorBlockJob): Alter signature.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONBlockJob): Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorBlockJob): Pass through
capability bit.
* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Update callers.
2012-04-11 20:43:53 -06:00
Eric Blake
311357d9e3 snapshot: add qemu capability for 'transaction' command
We need a capability bit to gracefully error out if some of the
additions in future patches can't be implemented by the running qemu.

* src/qemu/qemu_capabilities.h (QEMU_CAPS_TRANSACTION): New cap.
* src/qemu/qemu_capabilities.c (qemuCaps): Name it.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONCheckCommands): Set
it.
2012-03-23 16:38:19 -06:00
Osier Yang
3165602a55 qemu: Use scsi-block for lun passthrough instead of scsi-disk
And don't allow to hotplug a usb disk with "device == lun". This
is the missed pieces in previous virtio-scsi patchset:

http://www.redhat.com/archives/libvir-list/2012-February/msg01052.html
2012-03-14 23:32:53 +08:00
Osier Yang
05fbe728ee qemu: New cap flag to indicate if channel is supported by scsi-disk 2012-02-28 14:27:13 +08:00
Michal Privoznik
2f1e003939 qemu: Set capabilities based on supported monitor commands
In the future (my next patch in fact) we may want to make
decisions depending on qemu having a monitor command or not.
Therefore, we want to set qemuCaps flag instead of querying
on the monitor each time we are about to make that decision.
2012-02-15 11:37:39 +01:00
Eric Blake
6e769ebadb qemu: require qmp on new enough qemu
The qemu developers have made it clear that modern qemu will no
longer guarantee human monitor command stability; furthermore,
some features, such as async events, are only supported via qmp.
If we are compiled without support for handling JSON, we cannot
expect to sanely interact with modern qemu.

However, things must continue to build on RHEL 5, where qemu
is stuck at 0.10, and where yajl is not available.

Another benefit of this patch: future additions of new monitor
commands need only focus on qemu_monitor_json.c, instead of
also wasting time with qemu_monitor_text.c.

* src/qemu/qemu_capabilities.c (qemuCapsComputeCmdFlags): Report
error if yajl is missing but qemu requires qmp.
(qemuCapsParseHelpStr): Propagate error.
(qemuCapsExtractVersionInfo): Update caller.
* tests/qemuhelptest.c (testHelpStrParsing): Likewise.
2012-01-27 08:45:50 -07:00
Eric Blake
32b57a72de maint: cleanup qemu capabilities
Fix inconsistent whitespace and long lines.

* src/qemu/qemu_capabilities.h (qemuCapsFlags): Improve formatting.
2012-01-20 16:34:29 -07:00
Martin Kletzander
4c82f09ef0 Added capability checking for block <iotune> setting.
There was missing capability for blkiotune and thus specifying these
settings caused libvirt to run qemu with invalid parameters and then
reporting qemu error instead of the standard libvirt one. The support
for blkiotune setting was added in upstream qemu repo under commit
0563e191516289c9d2f282a8c50f2eecef2fa773.
2012-01-18 09:56:00 -07:00
Deepak C Shetty
d9e0d8204b Add new attribute wrpolicy to <driver> element
This introduces new attribute wrpolicy with only supported
value as immediate. This will be an optional
attribute with no defaults. This helps specify whether
to skip the host page cache.

When wrpolicy is specified, meaning when wrpolicy=immediate
a writeback is explicitly initiated for the dirty pages in
the host page cache as part of the guest file write operation.

Usage:
<filesystem type='mount' accessmode='passthrough'>
  <driver type='path' wrpolicy='immediate'/>
  <source dir='/export/to/guest'/>
  <target dir='mount_tag'/>
</filesystem>

Currently this only works with type='mount' for the QEMU/KVM driver.

Signed-off-by: Deepak C Shetty <deepakcs@linux.vnet.ibm.com>
2012-01-17 15:37:42 -07:00
Jiri Denemark
e7201afdf7 qemu: Add support for host CPU modes
This adds support for host-model and host-passthrough CPU modes to qemu
driver. The host-passthrough mode is mapped to -cpu host.
2012-01-17 12:22:19 +01:00
Osier Yang
5edfcaae6f qemu: Support copy on read for disk
The new introduced optional attribute "copy_on_read</code> controls
whether to copy read backing file into the image file. The value can
be either "on" or "off". Copy-on-read avoids accessing the same backing
file sectors repeatedly and is useful when the backing file is over a
slow network. By default copy-on-read is off.
2012-01-13 10:08:15 +08:00
Laine Stump
e8daeeb136 qemu: add capabilities flags related to SG_IO
This patch adds two capabilities flags to deal with various aspects
of supporting SG_IO commands on virtio-blk-pci devices:

  QEMU_CAPS_VIRTIO_BLK_SCSI
    set if -device virtio-blk-pci accepts the scsi="on|off" option
    When present, this is on by default, but can be set to off to disable
    SG_IO functions.

  QEMU_CAPS_VIRTIO_BLK_SG_IO
    set if SG_IO commands are supported in the virtio-blk-pci driver
    (present since qemu 0.11 according to a qemu developer, if I
     understood correctly)
2012-01-09 10:55:44 -05:00
Osier Yang
a1a83c5874 qemu: Support readonly filesystem passthrough
Upstream QEMU starts to support it from commit 2c74c2cb.
2011-12-22 12:29:58 +08:00
Michael Ellerman
5abbe04d68 qemu: Add a capability flag for -no-acpi
Currently non-x86 guests must have <acpi/> defined in <features> to
prevent libvirt from running qemu with -no-acpi. Although it works, it
is a hack.

Instead add a capability flag which indicates whether qemu understands
the -no-acpi option. Use it to control whether libvirt emits -no-acpi.

Current versions of qemu always display -no-acpi in their help output,
so this patch has no effect. However the development version of qemu
has been modified such that -no-acpi is only displayed when it is
actually supported.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
2011-12-20 12:33:55 -07:00
Jim Fehlig
c1bc3d892c Add AHCI support to qemu driver
Tested with multiple AHCI controllers and multiple disks attached
to a controller. E.g.,

    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test/disk0.raw'/>
      <target dev='sda' bus='sata'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test/disk1.raw'/>
      <target dev='sdb' bus='sata'/>
      <address type='drive' controller='0' bus='0' unit='1'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test/disk2.raw'/>
      <target dev='sdc' bus='sata'/>
      <address type='drive' controller='1' bus='0' unit='0'/>
    </disk>
    <controller type='sata' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </controller>
    <controller type='sata' index='1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </controller>
2011-10-17 15:44:21 -06:00
Laine Stump
dc79852af8 qemu: add ability to set PCI device "rombar" on or off
This patch was made in response to:

  https://bugzilla.redhat.com/show_bug.cgi?id=738095

In short, qemu's default for the rombar setting (which makes the
firmware ROM of a PCI device visible/not on the guest) was previously
0 (not visible), but they recently changed the default to 1
(visible). Unfortunately, there are some PCI devices that fail in the
guest when rombar is 1, so the setting must be exposed in libvirt to
prevent a regression in behavior (it will still require explicitly
setting <rom bar='off'/> in the guest XML).

rombar is forced on/off by adding:

  <rom bar='on|off'/>

inside a <hostdev> element that defines a PCI device. It is currently
ignored for all other types of devices.

At the moment there is no clean method to determine whether or not the
rombar option is supported by QEMU - this patch uses the advice of a
QEMU developer to assume support for qemu-0.12+. There is currently a
patch in the works to put this information in the output of "qemu-kvm
-device pci-assign,?", but of course if we switch to keying off that,
we would lose support for setting rombar on all the versions of qemu
between 0.12 and whatever version gets that patch.
2011-09-27 11:23:28 -04:00
Oskari Saarenmaa
f887334dcf Add unsafe cache mode support for disk driver
QEMU 0.13 introduced cache=unsafe for -drive, this patch exposes
it in the libvirt layer.

  * Introduced a new QEMU capability flag ($prefix_CACHE_UNSAFE),
    as even if $prefix_CACHE_V2 is set, we can't know if unsafe
    is supported.

  * Improved the reliability of qemu cache type detection.
2011-09-23 08:29:57 -06:00
Jiri Denemark
f84aedad09 qemu: Fix shutdown regression with buggy qemu
The commit that prevents disk corruption on domain shutdown
(96fc478417) causes regression with QEMU
0.14.* and 0.15.* because of a regression bug in QEMU that was fixed
only recently in QEMU git. The affected versions of QEMU do not quit on
SIGTERM if started with -no-shutdown, which we use to implement fake
reboot. Since -no-shutdown tells QEMU not to quit automatically on guest
shutdown, domains started using the affected QEMU cannot be shutdown
properly and stay in a paused state.

This patch disables fake reboot feature on such QEMU by not using
-no-shutdown, which makes shutdown work as expected. However,
virDomainReboot will not work in this case and it will report "Requested
operation is not valid: Reboot is not supported with this QEMU binary".
2011-09-21 16:53:06 +02:00
Marc-André Lureau
fdabeb3c5f Add USB hub device
domain parsing and serialization code, qemu driver backend and
a couple of test
2011-09-02 23:38:52 +08:00
Marc-André Lureau
329f907b99 Add various USB devices QEMU_CAPS 2011-09-02 23:22:56 +08:00
Osier Yang
6ee52c1b76 Add directsync cache mode support for disk driver
Newer QEMU introduced cache=directsync for -drive, this patchset
is to expose it in libvirt layer.

  * Introduced a new QEMU capability flag ($prefix_CACHE_DIRECTSYNC),
    As even $prefix_CACHE_V2 is set, we can't known if directsync
    is supported.
2011-09-02 21:36:58 +08:00
Laine Stump
73c0a148af qemu: support event_idx parameter for virtio disk and net devices
In some versions of qemu, both virtio-blk-pci and virtio-net-pci
devices can have an event_idx setting that determines some details of
event processing. When it is enabled, it "reduces the number of
interrupts and exits for the guest". qemu will automatically enable
this feature when it is available, but there may be cases where this
new feature could actually make performance worse (NB: no such case
has been found so far).

As a safety switch in case such a situation is encountered in the
field, this patch adds a new attribute "event_idx" to the <driver>
element of both disk and interface devices. event_idx can be set to
"on" (to force event_idx on in case qemu has it disabled by default)
or "off" (for force event_idx off). In the case that event_idx support
isn't present in qemu, the attribute is ignored (this on the advice of
the qemu developer).

docs/formatdomain.html.in: document the new flag (marking it as
   "don't mess with this!"
docs/schemas/domain.rng: add event_idx in appropriate places
src/conf/domain_conf.[ch]: add event_idx to parser and formatter
src/libvirt_private.syms: export
   virDomainVirtioEventIdx(From|To)String
src/qemu/qemu_capabilities.[ch]: detect and report event_idx in
   disk/net
src/qemu/qemu_command.c: add event_idx parameter to qemu commandline
    when appropriate.
tests/qemuxml2argvdata/qemuxml2argv-event_idx.args,
tests/qemuxml2argvdata/qemuxml2argv-event_idx.xml,
tests/qemuxml2argvtest.c,
tests/qemuxml2xmltest.c: test cases for event_idx.
2011-08-15 09:35:42 -04:00
Michal Privoznik
874e65aa15 bios: Add support for SGA
This patch creates new <bios> element which, at this time has only the
attribute useserial='yes|no'. This attribute allow users to use
Serial Graphics Adapter and see BIOS messages from the very first moment
domain boots up. Therefore, users can choose boot medium, set PXE, etc.
2011-07-11 11:47:14 +02:00
Michal Privoznik
017abcbb1a qemu: domain I/O asynchronous handling
For virtio disks and interfaces, qemu allows users to enable or disable
ioeventfd feature. This means, qemu can execute domain code, while
another thread waits for I/O event. Basically, in some cases it is win,
in some loss. This feature is available via 'ioeventfd' attribute in disk
and interface <driver> element. It accepts 'on' and 'off'. Leaving this
attribute out defaults to hypervisor decision.
2011-06-22 09:26:24 +02:00
Wen Congyang
d58c382e93 check whether qemu supports multi function PCI device
qemu supports multi function PCI device at least version 0.13.0.
2011-06-13 09:27:21 +08:00