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  1. May 03, 2022
  3. Apr 06, 2022
  5. Jun 04, 2021
  7. May 27, 2021
  9. Jul 15, 2020
    • Daniel P. Berrangé's avatar
      net: detect errors from probing vnet hdr flag for TAP devices · e7b347d0
      Daniel P. Berrangé authored 
      
When QEMU sets up a tap based network device backend, it mostly ignores errors
reported from various ioctl() calls it makes, assuming the TAP file descriptor
is valid. This assumption can easily be violated when the user is passing in a
pre-opened file descriptor. At best, the ioctls may fail with a -EBADF, but if
the user passes in a bogus FD number that happens to clash with a FD number that
QEMU has opened internally for another reason, a wide variety of errnos may
result, as the TUNGETIFF ioctl number may map to a completely different command
on a different type of file.

By ignoring all these errors, QEMU sets up a zombie network backend that will
never pass any data. Even worse, when QEMU shuts down, or that network backend
is hot-removed, it will close this bogus file descriptor, which could belong to
another QEMU device backend.

There's no obvious guaranteed reliable way to detect that a FD genuinely is a
TAP device, as opposed to a UNIX socket, or pipe, or something else. Checking
the errno from probing vnet hdr flag though, does catch the big common cases.
ie calling TUNGETIFF will return EBADF for an invalid FD, and ENOTTY when FD is
a UNIX socket, or pipe which catches accidental collisions with FDs used for
stdio, or monitor socket.

Previously the example below where bogus fd 9 collides with the FD used for the
chardev saw:

$ ./x86_64-softmmu/qemu-system-x86_64 -netdev tap,id=hostnet0,fd=9 \
  -chardev socket,id=charchannel0,path=/tmp/qga,server,nowait \
  -monitor stdio -vnc :0
qemu-system-x86_64: -netdev tap,id=hostnet0,fd=9: TUNGETIFF ioctl() failed: Inappropriate ioctl for device
TUNSETOFFLOAD ioctl() failed: Bad address
QEMU 2.9.1 monitor - type 'help' for more information
(qemu) Warning: netdev hostnet0 has no peer

which gives a running QEMU with a zombie network backend.

With this change applied we get an error message and QEMU immediately exits
before carrying on and making a bigger disaster:

$ ./x86_64-softmmu/qemu-system-x86_64 -netdev tap,id=hostnet0,fd=9 \
  -chardev socket,id=charchannel0,path=/tmp/qga,server,nowait \
  -monitor stdio -vnc :0
qemu-system-x86_64: -netdev tap,id=hostnet0,vhost=on,fd=9: Unable to query TUNGETIFF on FD 9: Inappropriate ioctl for device

Reported-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Tested-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 20171027085548.3472-1-berrange@redhat.com
[lv: to simplify, don't check on EINVAL with TUNGETIFF as it exists since v2.6.27]
Signed-off-by: default avatarLaurent Vivier <lvivier@redhat.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
      e7b347d0
  11. Aug 16, 2019
    • Markus Armbruster's avatar
      Clean up inclusion of sysemu/sysemu.h · d5938f29
      Markus Armbruster authored 
      
In my "build everything" tree, changing sysemu/sysemu.h triggers a
recompile of some 5400 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h).

Almost a third of its inclusions are actually superfluous.  Delete
them.  Downgrade two more to qapi/qapi-types-run-state.h, and move one
from char/serial.h to char/serial.c.

hw/semihosting/config.c, monitor/monitor.c, qdev-monitor.c, and
stubs/semihost.c define variables declared in sysemu/sysemu.h without
including it.  The compiler is cool with that, but include it anyway.

This doesn't reduce actual use much, as it's still included into
widely included headers.  The next commit will tackle that.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarAlistair Francis <alistair.francis@wdc.com>
Message-Id: <20190812052359.30071-27-armbru@redhat.com>
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
      d5938f29
  13. Jun 12, 2019
    • Markus Armbruster's avatar
      Include qemu-common.h exactly where needed · a8d25326
      Markus Armbruster authored 
      
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
      a8d25326
  15. Oct 26, 2016
  17. Mar 22, 2016
    • Veronia Bahaa's avatar
      util: move declarations out of qemu-common.h · f348b6d1
      Veronia Bahaa authored 
      
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)

Signed-off-by: default avatarVeronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      f348b6d1
    • Markus Armbruster's avatar
      include/qemu/osdep.h: Don't include qapi/error.h · da34e65c
      Markus Armbruster authored 
      
Commit 57cb38b3 included qapi/error.h into qemu/osdep.h to get the
Error typedef.  Since then, we've moved to include qemu/osdep.h
everywhere.  Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h.  That's in excess of
100KiB of crap most .c files don't actually need.

Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h.  Include qapi/error.h in .c files that need it and don't
get it now.  Include qapi-types.h in qom/object.h for uint16List.

Update scripts/clean-includes accordingly.  Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h.  Update the list of includes in the qemu/osdep.h
comment quoted above similarly.

This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third.  Unfortunately, the number depending on
qapi-types.h shrinks only a little.  More work is needed for that one.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      da34e65c
  19. Feb 04, 2016
    • Peter Maydell's avatar
      net: Clean up includes · 2744d920
      Peter Maydell authored 
      
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-id: 1454089805-5470-11-git-send-email-peter.maydell@linaro.org
      2744d920
  21. Nov 06, 2015
  23. Jun 19, 2015
  25. May 27, 2015
  27. Aug 01, 2014
  29. Sep 06, 2013
  31. May 24, 2013
  33. Feb 01, 2013
    • Jason Wang's avatar
      tap: multiqueue support · 264986e2
      Jason Wang authored 
      
Recently, linux support multiqueue tap which could let userspace call TUNSETIFF
for a signle device many times to create multiple file descriptors as
independent queues. User could also enable/disabe a specific queue through
TUNSETQUEUE.

The patch adds the generic infrastructure to create multiqueue taps. To achieve
this a new parameter "queues" were introduced to specify how many queues were
expected to be created for tap by qemu itself. Alternatively, management could
also pass multiple pre-created tap file descriptors separated with ':' through a
new parameter fds like -netdev tap,id=hn0,fds="X:Y:..:Z". Multiple vhost file
descriptors could also be passed in this way.

Each TAPState were still associated to a tap fd, which mean multiple TAPStates
were created when user needs multiqueue taps. Since each TAPState contains one
NetClientState, with the multiqueue nic support, an N peers of NetClientState
were built up.

A new parameter, mq_required were introduce in tap_open() to create multiqueue
tap fds.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
      264986e2
    • Jason Wang's avatar
      tap: introduce a helper to get the name of an interface · e5dc0b40
      Jason Wang authored 
      
This patch introduces a helper tap_get_ifname() to get the device name of tap
device. This is needed when ifname is unspecified in the command line and qemu
were asked to create tap device by itself. In this situation, the name were
allocated by kernel, so if multiqueue is asked, we need to fetch its name after
creating the first queue.

Only linux has this support since it's the only platform that supports
multiqueue tap.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
      e5dc0b40
    • Jason Wang's avatar
      tap: add Linux multiqueue support · 94fdc6d0
      Jason Wang authored 
      
This patch add basic multiqueue support for Linux. When multiqueue is needed, we
will first check whether kernel support multiqueue tap before creating more
queues. Two new functions tap_fd_enable() and tap_fd_disable() were introduced
to enable and disable a specific queue. Since the multiqueue is only supported
in Linux, return error on other platforms.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
      94fdc6d0
  35. Dec 19, 2012
  37. Jul 23, 2012
  39. Jun 09, 2012
    • Michael Tokarev's avatar
      do not include <libutil.h> needlessly or if it doesn't exist · 3294ce18
      Michael Tokarev authored 
      
<libutil.h> and <util.h> on *BSD (some have one, some another)
were #included just for openpty() declaration.  The only file
where this function is actually used is qemu-char.c.

In vl.c and net/tap-bsd.c, none of functions declared in libutil.h
(login logout logwtmp timdomain openpty forkpty uu_lock realhostname
fparseln and a few others depending on version) are used.

Initially the code which is currently in qemu-char.c was in vl.c,
it has been removed into separate file in commit 0e82f34d
Fri Oct 31 18:44:40 2008, but the #includes were left in vl.c.
So with vl.c, we just remove includes - libutil.h, util.h and
pty.h (which declares only openpty() and forkpty()) from there.

The code in net/tap-bsd.c, which come from net/tap.c, had this

commit 5281d757
Author: Mark McLoughlin <markmc@redhat.com>
Date:   Thu Oct 22 17:49:07 2009 +0100

    net: split all the tap code out into net/tap.c

Note this commit not only moved stuff out of net.c to net/tap.c,
but also rewrote large portions of the tap code, and added these
completely unnecessary #includes -- as usual, I question why such
a misleading commit messages are allowed.

Again, no functions defined in libutil.h or util.h on *BSD are
used by neither net/tap.c nor net/tap-bsd.c.  Removing them.

And finally, the only real user for these #includes, qemu-char.c,
which actually uses openpty().  There, the #ifdef logic is wrong.
A GLIBC-based system has <pty.h>, even if it is a variant of *BSD.
So __GLIBC__ should be checked first, and instead of trying to
include <libutil.h> or <util.h>, we include <pty.h>.  If it is not
GLIBC-based, we check for variations between <*util.h> as before.

This patch fixes build of qemu 1.1 on Debian/kFreebsd (well, one
of the two problems): it is a distribution with a FreeBSD kernel,
so it #defines at least __FreeBSD_kernel__, but since it is based
on GLIBC, it has <pty.h>, but current version does not have neither
<util.h> nor <libutil.h>, which the code tries to include 3 times
but uses only once.

Signed-off-By: default avatarMichael Tokarev <mjt@tls.msk.ru>
Cc: Aurelien Jarno <aurelien@aurel32.net>

Signed-off-by: default avatarBlue Swirl <blauwirbel@gmail.com>
      3294ce18
  41. Aug 07, 2011
  43. Dec 21, 2010
  45. Sep 29, 2010
  47. Sep 07, 2010
  49. Mar 27, 2010
    • Blue Swirl's avatar
      Fix BSD and win32 builds · 73d96e29
      Blue Swirl authored 
      
  CC    net/tap-bsd.o
/src/qemu/net/tap-bsd.c: In function `tap_open':
/src/qemu/net/tap-bsd.c:93: warning: implicit declaration of function `error_report'

  CC    sparc-softmmu/../net/tap-win32.o
cc1: warnings being treated as errors
/src/qemu/target-sparc/../net/tap-win32.c: In function 'net_init_tap':
/src/qemu/target-sparc/../net/tap-win32.c:709: warning: implicit declaration of function 'error_report'

Signed-off-by: default avatarBlue Swirl <blauwirbel@gmail.com>
      73d96e29
  51. Mar 16, 2010
    • Markus Armbruster's avatar
      error: Replace qemu_error() by error_report() · 1ecda02b
      Markus Armbruster authored 
      error_report() terminates the message with a newline.  Strip it it
from its arguments.

This fixes a few error messages lacking a newline:
net_handle_fd_param()'s "No file descriptor named %s found", and
tap_open()'s "vnet_hdr=1 requested, but no kernel support for
IFF_VNET_HDR available" (all three versions).

There's one place that passes arguments without newlines
intentionally: load_vmstate().  Fix it up.
      1ecda02b
  53. Nov 29, 2009
  55. Nov 21, 2009
  57. Oct 30, 2009