Commit Graph

3784 Commits

Author SHA1 Message Date
Daniel P. Berrange
4886cba76a Convert audio devices over to -device syntax
The current syntax for audio devices is a horrible multiplexed
arg

    -soundhw sb16,pcspk,ac97

The new syntax is

    -device sb16,id=sound0

or

    -device AC97,id=sound1,addr=<PCI SLOT>

NB, pcspk still uses the old -soundhw syntax
2010-01-18 13:55:56 +00:00
Daniel P. Berrange
38a22fbfaa Convert watchdog to -device
The current syntax for watchdogs is

    -watchdog i6300esb

The new syntax will now be

    -device i6300esb,id=watchdogNN,addr=<PCI-SLOT>
2010-01-18 13:55:56 +00:00
Daniel P. Berrange
7b2f8cdd7c Convert character devices over to use -device
The current character device syntax uses either

  -serial tty,path=/dev/ttyS2

Or

  -chardev tty,id=serial0,path=/dev/ttyS2 -serial chardev:serial0

With the new -device support, we now prefer

  -chardev file,id=serial0,path=/tmp/serial.log -device isa-serial,chardev=serial0

This patch changes the existing -chardev syntax to use this new
scheme, and fallbacks to the old plain -serial syntax for old
QEMU.

The monitor device changes to

  -chardev socket,id=monitor,path=/tmp/test-monitor,server,nowait -mon chardev=monitor

In addition, this patch adds --nodefaults, which kills off the
default serial, parallel, vga and nic devices. THis avoids the
need for us to explicitly turn each off
2010-01-18 13:55:56 +00:00
Daniel P. Berrange
053307175c Assign device aliases for all devices at startup
When starting a guest, give every device a unique alias. This will
be used for the 'id' parameter in -device args in later patches.
It can also be used to uniquely identify devices in the monitor

For old QEMU without -device, assign disk names based on QEMU's
historical naming scheme.

* src/qemu/qemu_conf.c: Assign unique device aliases
* src/qemu/qemu_driver.c: Remove obsolete qemudDiskDeviceName
  and use the device alias in eject & blockstats commands
2010-01-18 13:55:56 +00:00
Jim Meyering
a6e7ba9464 storage_backend_fs.c: do not ignore probe failure
* src/storage/storage_backend_fs.c (virStorageBackendFileSystemRefresh):
Correct parentheses.  The documented intent is to ignore non-regular
files, yet due to a parenthesization error all errors were handled
that way.
2010-01-18 14:46:51 +01:00
Daniel P. Berrange
1ed1bf3a38 Probe for -device and use -nodefaults
Probe for the new -device flag and if available set the -nodefaults
flag, instead of using -net none, -serial none or -parallel none.
Other device types will be converted to use -device in later patches.
The -nodefaults flag will help avoid unwelcome surprises from future
QEMU releases

* src/qemu/qemu_conf.c: Probe for -device. Add -nodefaults flag.
  Remove -net none, -serial none or -parallel none
* src/qemu/qemu_conf.h: Define QEMU_CMD_FLAG_DEVICE
* tests/qemuhelpdata/qemu-0.12.1: New data file for 0.12.1 QEMU
* tests/qemuhelptest.c: Test feature extraction from 0.12.1 QEMU
2010-01-18 13:39:14 +00:00
Daniel P. Berrange
4ac290cc33 Add device info to serial, parallel, channel, input & fs devices
Although the serial, parallel, chanel, input & fs devices do
not have PCI address info, they can all have device aliases.
Thus it neccessary to associate the virDomainDeviceInfo data
with them all.

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add hooks for
  parsing / formatting device info for serial, parallel, channel
  input and fs devices.
* docs/schemas/domain.rng: Associate device info with character
  devices, input & fs device
2010-01-18 13:38:56 +00:00
Daniel P. Berrange
5da9c98067 Introduce device aliases
This patch introduces the support for giving all devices a short,
unique name, henceforth known as a 'device alias'.  These aliases
are not set by the end user, instead being assigned by the hypervisor
if it decides it want to support this concept.

The QEMU driver sets them whenever using the -device arg syntax
and uses them for improved hotplug/hotunplug. it is the intent
that other APIs (block / interface stats & device hotplug) be
able to accept device alias names in the future.

The XML syntax is

   <alias name="video0"/>

This may appear in any type of device that supports device info.

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add a 'alias'
  field to virDomainDeviceInfo struct & parse/format it in XML
* src/libvirt_private.syms: Export virDomainDefClearDeviceAliases
* src/qemu/qemu_conf.c: Replace use of "nic_name" field with the
  standard device alias
* src/qemu/qemu_driver.c: Clear device aliases at shutdown
2010-01-18 13:38:47 +00:00
Daniel P. Berrange
774c757e67 Clear assigned PCI devices at shutdown
The PCI device addresses are only valid while the VM is running,
since they are auto-assigned by QEMU. After shutdown they must
all be cleared. Future QEMU driver enhancement will allow for
persistent PCI address assignment

* src/conf/domain_conf.h, src/conf/domain_conf.c, src/libvirt_private.syms
  Add virDomainDefClearPCIAddresses() method for wiping out auto assigned
  PCI addresses
* src/qemu/qemu_driver.c: Clear PCI addresses at VM shutdown
2010-01-18 13:35:51 +00:00
Daniel P. Berrange
b030084f07 Auto-add disk controllers based on defined disks
Existing applications using libvirt are not aware of the disk
controller concept. Thus, after parsing the <disk> definitions
in the XML, it is neccessary to create <controller> elements
to satisfy all requested disks, as per their defined drive
addresses

* src/conf/domain_conf.c, src/conf/domain_conf.h,
  src/libvirt_private.syms: Add virDomainDefAddDiskControllers()
  method for populating disk controllers, and call it after
  parsing disk definitions.
* src/qemu/qemu_conf.c: Call virDomainDefAddDiskControllers()
  when doing ARGV -> XML conversion
* tests/qemuxml2argvdata/qemuxml2argv*.xml: Add disk controller
  data to all data files which don't have it already
2010-01-18 13:35:40 +00:00
Daniel P. Berrange
2224989c39 Avoid free'ing a constant string in chardev lookup code
* src/qemu/qemu_monitor_text.c: Don't free const string in
   qemuMonitorTextGetPtyPaths()
2010-01-18 13:33:50 +00:00
Daniel P. Berrange
4359900ed1 Remove restriction on duplicated sound devices in parser
It is perfectly acceptable to have multiple sound devices of
same type in guest configuration. If the underlying hypervisor
does not like this, it is its job to complain, not the XML
parser's

* src/conf/domain_conf.c: Remove hack which deleted duplicated
  sound device models.
* tests/xml2sexprdata/xml2sexpr-fv-sound.xml: Remove duplicate
  models
2010-01-18 12:44:50 +00:00
Daniel P. Berrange
989051a85e Detect PCI addresses at QEMU startup
Hotunplug of devices requires that we know their PCI address. Even
hotplug of SCSI drives, required that we know the PCI address of
the SCSI controller to attach the drive to. We can find this out
by running 'info pci' and then correlating the vendor/product IDs
with the devices we booted with.

Although this approach is somewhat fragile, it is the only viable
option with QEMU < 0.12, since there is no way for libvirto set
explicit PCI addresses when creating devices in the first place.
For QEMU > 0.12, this code will not be used.

* src/qemu/qemu_driver.c: Assign all dynamic PCI addresses on
  startup of QEMU VM, matching vendor/product IDs
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h: Add
  API for fetching PCI device address mapping
2010-01-18 12:44:50 +00:00
Daniel P. Berrange
3a6bf1bb78 Properly support SCSI drive hotplug
The current SCSI hotplug support attaches a brand new SCSI controller
for every disk. This is broken because the semantics differ from those
used when starting the VM initially. In the latter case, each SCSI
controller is filled before a new one is added.

If the user specifies an high drive index (sdazz) then at initial
startup, many intermediate SCSI controllers may be added with no
drives.

This patch changes SCSI hotplug so that it exactly matches the
behaviour of initial startup. First the SCSI controller number is
determined for the drive to be hotplugged. If any controller upto
and including that controller number is not yet present, it is
attached. Then finally the drive is attached to the last controller.

NB, this breaks SCSI hotunplug, because there is no 'drive_del'
command in current QEMU. Previous SCSI hotunplug was broken in
any case because it was unplugging the entire controller, not
just the drive in question.

A future QEMU will allow proper SCSI hotunplug of a drive.

This patch is derived from work done by Wolfgang Mauerer on disk
controllers.

* src/qemu/qemu_driver.c: Fix SCSI hotplug to add a drive to
 the correct controller, instead of just attaching a new
  controller.
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h: Add
  support for 'drive_add' command
2010-01-18 12:44:50 +00:00
Wolfgang Mauerer
da9d937b94 Implement SCSI controller hotplug/unplug for QEMU
This patch allows for explicit hotplug/unplug of SCSI controllers.
Ordinarily this is not required, since QEMU/libvirt will attach
a new SCSI controller whenever one is required. Allowing explicit
hotplug of controllers though, enables the caller to specify a
static PCI address, instead of auto-assigning the next available
PCI slot. Or it will when we have static PCI addressing.

This patch is derived from Wolfgang Mauerer's disk controller
patch series.

* src/qemu/qemu_driver.c: Support hotplug & unplug of SCSI
  controllers
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h: Add
  new API for attaching PCI SCSI controllers
2010-01-18 12:44:50 +00:00
Jim Meyering
1867004ed1 vbox_tmpl.c: remove useless array-is-non-NULL comparisons
* src/vbox/vbox_tmpl.c (vboxStorageVolDelete): Remove always-true
array-is-non-NULL test.  git grep 'key\[.*\];'|grep -F .h
src/datatypes.h:    char key[PATH_MAX];
(vboxStorageVolGetInfo): Likewise.
(vboxStorageVolGetXMLDesc): Likewise.
(vboxStorageVolGetPath): Likewise.
(vboxDomainDefineXML): Likewise. (but now with "mac[]")
2010-01-18 13:31:47 +01:00
Jim Meyering
0a6a6f5e61 lxc_driver: remove useless comparison
* src/lxc/lxc_driver.c (lxcSetupInterfaces): Remove always-true
array-is-non-NULL test.  git grep 'mac\[.*\];'|grep -F .h
src/conf/domain_conf.h:    unsigned char mac[VIR_MAC_BUFLEN];
2010-01-18 13:31:41 +01:00
Jim Meyering
8803937b59 build: update gnulib submodule to latest 2010-01-18 09:50:08 +01:00
Jim Meyering
eabb98b0a8 gnulib added a new syntax-check test: use $(VAR), not @VAR@
The latter is not officially "wrong", but *is* terribly anachronistic.
I think automake documentation or comments call that syntax obsolescent.
* cfg.mk (_makefile_at_at_check_exceptions): Exempt @SCHEMADIR@
and @SYSCONFDIR@ uses -- there are no Makefile variables for those.
* docs/Makefile.am: Use $(INSTALL), not @INSTALL@.
* examples/dominfo/Makefile.am: Similar.
* examples/domsuspend/Makefile.am: Similar.
* proxy/Makefile.am: Similar.
* python/Makefile.am: Similar.
* python/tests/Makefile.am: Similar.
* src/Makefile.am: Similar.
* tests/Makefile.am: Similar.
2010-01-18 09:50:08 +01:00
Jim Meyering
d6c99337a9 storage_backend.h: include required headers
* src/storage/storage_backend.h: Include <stdint.h>.
2010-01-18 09:50:08 +01:00
Jim Meyering
61defb6bcc esx_vi_types.c: include required headers
* src/esx/esx_vi_types.c: Include <stdint.h>.
2010-01-18 09:50:08 +01:00
Jim Meyering
73f702ff4a vbox: include required headers
* src/vbox/vbox_driver.c: Include <stdint.h> <unistd.h> <sys/types.h>.
2010-01-18 09:50:08 +01:00
Jim Meyering
3d294a1c03 cpu_x86_data.h: include required header
* src/cpu/cpu_x86_data.h: Include <stdint.h>.
2010-01-18 09:50:08 +01:00
Jim Meyering
30a9329ab1 util.c: include required header, no longer masked by gnulib
Until recently, some gnulib-generated replacement headers
included *other* headers that were not strictly necessary,
thus masking the need in this file for an explicit <stdlib.h>.
* src/util/util.c: Include <stdlib.h> for declarations of e.g.,
strtol, random_r, getenv, etc.
2010-01-18 09:50:08 +01:00
Jiri Denemark
322707ba8a Use closest CPU model when decoding from CPUID
Current implementation of x86Decode() used for CPUID -> model+features
translation does not always select the closest CPU model. When walking
through all models from cpu_map.xml the function considers a new
candidate as a better choice than a previously selected candidate only
if the new one is a superset of the old one. In case the new candidate
is closer to host CPU but lacks some feature comparing to the old
candidate, the function does not choose well.

This patch changes the algorithm so that the closest model is always
selected. That is, the model which requires the lowest number of
additional features to describe host CPU.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2010-01-18 02:40:41 +01:00
Diego Elio Pettenò
3c58896eb7 Change detection of xen so that it's actually automatic rather than forced.
This ensures that ./configure will work fine if xen development packages
are not around, rather than fail. When passing ./configure --with-xen, the
lack of xen development packages become fatal.
2010-01-18 02:12:48 +01:00
Diego Elio Pettenò
4d434da34c Standardise ./configure --help options reporting.
Always use AC_HELP_STRING for the help text for options at ./configure,
so that the output is properly aligned.

Use proper quadrigraphs for outputting the brackets.

Always use autoconf-style [default=$foo] output to state the default, both
where it was stated before and where it wasn't.

This time, include Matthias Bolte notes regarding defaults, and removing
PFX specification from phyp.
2010-01-18 02:10:46 +01:00
Matthias Bolte
a0356bcc41 qemu: Use log output for pty assignment if 'info chardev' is unavailable
qemudFindCharDevicePTYsMonitor reports an error if 'info chardev' didn't
provide information for a requested device, even if the log output parsing
had found the pty path for that device. This makes pty assignment fail for
older QEMU/KVM versions. For example KVM 72 on Debian doesn't support
'info chardev', so qemuMonitorTextGetPtyPaths cannot parse any useful
information and the hash for device-id-to-pty-path mapping stays empty.

Make qemudFindCharDevicePTYsMonitor report an error only if the log output
parsing and the 'info chardev' parsing failed to provide the pty path.
2010-01-18 01:54:40 +01:00
Matthias Bolte
c2c4d51b2f esx: Add VNC support
* src/conf/domain_conf.c: add defaults for the video device
* src/esx/esx_vmx.[ch]: add VNC support to the VMX handling
* tests/vmx2xmltest.c, tests/xml2vmxtest.c: add tests for the VNC support
2010-01-18 01:44:20 +01:00
Matthias Bolte
58fe995e50 esx: Make the domain part of the hostname optional
Before the driver assumed that there is always a domain part. That's
not true. Now the domain part is handled as optional.
2010-01-18 01:21:37 +01:00
Matthias Bolte
d6c40aaec8 esx: Add stubs for secondary driver types
This stops libvirt from probing for a libvirtd on the ESX server and
sets the base for the implementation of the secondary drivers.
2010-01-18 01:15:11 +01:00
David Jorm
9bca7a7e2e BZs 528709 548485 2010-01-18 09:48:39 +10:00
Matthias Bolte
cebc4b8921 Fix validation of news.html 2010-01-15 19:29:50 +01:00
Daniel P. Berrange
ad4f092443 Fix build of Xen proxy daemon
* src/conf/domain_conf.c: Allow virDomainDeviceInfoIsSet,
  virDomainDeviceInfoClear & virDomainDeviceInfoFormat when
  building Xen proxy
2010-01-15 17:55:59 +00:00
Daniel P. Berrange
8a73fe5936 Remove obsolete comment in QEMU JSON code
* src/qemu/qemu_monitor_json.c: We fill in the PCI function number
   now, so remove obsolete XXX comment
2010-01-15 17:55:59 +00:00
Daniel P. Berrange
d78554d884 Specify bus/unit instead of index for disks with QEMU
The current code for using -drive simply sets the -drive 'index'
parameter. QEMU internally converts this to bus/unit depending
on the type of drive. This does not give us precise control over
the bus/unit assignment though. This change switches over to make
libvirt explicitly calculate the bus/unit number.

In addition bus/unit/index are actually irrelevant for VirtIO
disks, since each virtio disk is a separate PCI device. No disk
controller is involved.

Doing the conversion to bus/unit in libvirt allows us to correctly
attach SCSI controllers when required.

* src/qemu/qemu_conf.c: Specify bus/unit instead of index for
  disks
* tests/qemuxml2argvdata/qemuxml2argv-disk*.args: Switch over from
  using index=NNNN, to bus=NN, unit=NN for SCSI/IDE/Floppy disks
2010-01-15 17:55:59 +00:00
Daniel P. Berrange
2982d73a11 Split code for building QEMU -drive arg in separate method
To enable it to be called from multiple locations, split out
the code for building the -drive arg string. This will be needed
by later patches which do drive hotplug, the conversion to use
-device, and the conversion to controller/bus/unit addressing

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Add qemuBuildDriveStr
  for building -drive arg string
2010-01-15 17:55:58 +00:00
Daniel P. Berrange
ab0da52b43 Convert monitor over to use virDomainDeviceAddress
Convert the QEMU monitor APIs over to use virDomainDeviceAddress
structs for passing addresses in/out, instead of individual bits.
This makes the number of parameters smaller & easier to deal with.
No functional change

* src/qemu/qemu_driver.c, src/qemu/qemu_monitor.c,
  src/qemu/qemu_monitor.h, src/qemu/qemu_monitor_text.c,
  src/qemu/qemu_monitor_text.h: Change monitor hotplug APIs to
  take an explicit address ptr for all host/guest addresses
2010-01-15 17:55:58 +00:00
Jim Fehlig
8d6af63a8a Minor fixes for API extension doc
Update the API Extensions doc to reflect new source directory layout.
2010-01-15 10:45:18 -07:00
Wolfgang Mauerer
74ec5e65ce Add new domain device: "controller"
This augments virDomainDevice with a <controller> element
that is used to represent disk controllers (e.g., scsi
controllers). The XML format is given by

  <controller type="scsi" index="<num>">
     <address type="pci" domain="0xNUM" bus="0xNUM" slot="0xNUM"/>
  </controller>

where type denotes the disk interface (scsi, ide,...), index
is an integer that identifies the controller for association
with disks, and the <address> element specifies the controller
address on the PCI bus as described in previous commits
The address element can be omitted; in this case, an address
will be assigned automatically.

Most of the code in this patch is from Wolfgang Mauerer's
previous disk controller series

 * docs/schemas/domain.rng: Define syntax for <controller>
   XML element
 * src/conf/domain_conf.c, src/conf/domain_conf.h: Define
   virDomainControllerDef struct, and routines for parsing
   and formatting XML
* src/libvirt_private.syms: Add virDomainControllerInsert
   and virDomainControllerDefFree
2010-01-15 16:38:59 +00:00
Daniel P. Berrange
776e37e1eb Set default disk controller/bus/unit props
When parsing the <disk> element specification, if no <address>
is provided for the disk, then automatically assign one based on
the <target dev='sdXX'/> device name. This provides for backwards
compatability with existing applications using libvirt, while also
allowing new apps to have complete fine grained control.

* src/conf/domain_conf.h, src/conf/domain_conf.c,
  src/libvirt_private.syms: Add virDomainDiskDefAssignAddress()
  for assigning a controller/bus/unit address based on disk target
* src/qemu/qemu_conf.c: Call virDomainDiskDefAssignAddress() after
  generating XML from ARGV
* tests/qemuxml2argvdata/*.xml: Add in drive address information
  to all XML files
2010-01-15 16:38:29 +00:00
Daniel P. Berrange
a9e4ea94f1 Add address info to sound, video and watchdog devices
Add the virDomainDeviceAddress information to the sound, video
and watchdog devices. This means all of them gain the new XML
element

  <address .... />

This brings them upto par with disk/net/hostdev devices which
already have address info

* src/conf/domain_conf.h: Add virDomainDeviceAddress to sound,
  video & watchdog device struts.
* src/conf/domain_conf.c: Hook up parsing/formatting for
  virDomainDeviceAddress in sound, video & watchdog devices
* docs/schemas/domain.rng: Associate device address info
  with sound, video & watchdog
2010-01-15 16:38:08 +00:00
Daniel P. Berrange
d812e7aeb8 Extend the virDomainDeviceAddress struture to allow disk controller addresses
Introduce a new structure

      struct _virDomainDeviceDriveAddress {
        unsigned int controller;
        unsigned int bus;
        unsigned int unit;
      };

and plug that into virDomainDeviceAddress and generates XML that
looks like

  <address type='drive' controller='1' bus='0' unit='5'/>

This syntax will be used by the QEMU driver to explicitly control
how drives are attached to the bus

* src/conf/domain_conf.h, src/conf/domain_conf.c: Parsing and
  formatting of drive addresses
* docs/schemas/domain.rng: Define new address format for drives
2010-01-15 16:37:57 +00:00
Daniel P. Berrange
1b0cce7d3a Introduce a standardized data structure for device addresses
All guest devices now use a common device address structure
summarized by:

  enum virDomainDeviceAddressType {
    VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE,
    VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI,
  };

  struct _virDomainDevicePCIAddress {
    unsigned int domain;
    unsigned int bus;
    unsigned int slot;
    unsigned int function;
  };

  struct _virDomainDeviceInfo {
    int type;
    union {
        virDomainDevicePCIAddress pci;
    } addr;
  };

This replaces the anonymous structs in Disk/Net/Hostdev data
structures. Where available, the address is *always* printed
in the XML file, instead of being hidden in the internal state
file.

  <address type='pci' domain='0x0000' bus='0x1e' slot='0x07' function='0x0'/>

The structure definition is based on Wolfgang Mauerer's disk
controller patch series.

* docs/schemas/domain.rng: Define the <address> syntax and
  associate it with disk/net/hostdev devices
* src/conf/domain_conf.h, src/conf/domain_conf.c,
  src/libvirt_private.syms: APIs for parsing/formatting address
  information. Also remove the QEMU specific 'pci_addr' attributes
* src/qemu/qemu_driver.c: Replace use of 'pci_addr' attrs with
  new standardized format.
2010-01-15 16:37:44 +00:00
Daniel P. Berrange
e8ac4a79f1 Make test suite output less verbose
Only print out '.' for each test case, full test output can be
re-enabled with VIR_TEST_VERBOSE=1, or VIR_TEST_DEBUG=XXXX

Sample output now looks like

  TEST: statstest
        ........................................ 40
        ...................................      75  OK
  PASS: statstest
  TEST: qparamtest
        ................................         32  OK
  PASS: qparamtest
  TEST:
        ............                             12  OK
2010-01-15 16:28:05 +00:00
Matthias Bolte
cfe49446d3 Fix compilation of virt-aa-helper.c
Commit 5073aa994a added an additional
'}' to a case block that messed up the block structure of the get_files
function.
2010-01-15 12:06:03 +01:00
Jim Meyering
0276587287 xen: do not report a write-to-Xen-daemon failure as a read failure
* src/xen/xend_internal.c (wr_sync): Correct the diagnostic.
2010-01-15 10:22:18 +01:00
Matthias Bolte
9933c4f2f6 Fix linkage of virt-aa-helper to libgnu.a 2010-01-14 21:50:21 +01:00
Cole Robinson
522776ed4c util: Make sure virExec hook failures are raised
With the introduction virDispatchError, hook function errors are
never sent through the error callback, so users will never see
these messages.

Fix this by calling virDispatchError after hook failure.
2010-01-14 09:19:39 -05:00
Cole Robinson
5073aa994a Implement path lookup for USB by vendor:product
Based off how QEMU does it, look through /sys/bus/usb/devices/* for
matching vendor:product info, and if found, use info from the surrounding
files to build the device's /dev/bus/usb path.

This fixes USB device assignment by vendor:product when running qemu
as non-root (well, it should, but for some reason I couldn't reproduce
the failure people are seeing in [1], but it appears to work properly)

[1] https://bugzilla.redhat.com/show_bug.cgi?id=542450
2010-01-13 15:24:41 -05:00