This is the QEMU backend code for the SCLP console support.
It includes SCLP capability detection, QEMU command line generation
and a test case.
Signed-off-by: NJ.B. Joret <jb@linux.vnet.ibm.com>
Signed-off-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

Since we daemonized QEMU for capabilities probing there is a long
time if QEMU fails to launch. This is because we're not passing in
any virDomainObjPtr instance and thus the monitor code can not
check to see if the PID is still alive.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The current code is initializing capabilities before setting
directory permissions. Thus the QEMU binaries being run may
not have the ability to create the UNIX monitor socket on
the first run of libvirtd.

This prevents domain starting and disk attaching if the shared disk's
setting conflicts with other active domain(s), E.g. A domain with
"sgio" set as "filtered", however, another active domain is using
it set as "unfiltered".

This ignores the default "filtered" if unpriv_sgio is not supported
by kernel, but for explicit request "filtered", it error out for
domain starting.

This introduces a hash table for qemu driver, to store the shared
disk's info as (@major:minor, @ref_count). @ref_count is the number
of domains which shares the disk.

Since we only care about if the disk support unprivileged SG_IO
commands, and the SG_IO commands only make sense for block disk,
this patch only manages (add/remove hash entry) the shared disk for
block disk.

* src/qemu/qemu_conf.h: (Add member 'sharedDisks' of type
                         virHashTablePtr; Declare helpers
                         qemuGetSharedDiskKey, qemuAddSharedDisk
                         and qemuRemoveSharedDisk)
* src/qemu/qemu_conf.c (Implement the 3 helpers)
* src/qemu/qemu_process.c (Update 'sharedDisks' when domain
                           starting and shutdown)
* src/qemu/qemu_driver.c (Update 'sharedDisks' when attaching
                          or detaching disk).

A redefinition of an external inactive snapshot/checkpoint wasn't
possible without this change.

When the disk alignment check done while redefining an existing snapshot
failed, the qemu driver attempted to free the existing snapshot. As in
the cleanup path the definition of the snapshot wasn't assigned, the
cleanup code dereferenced a NULL pointer.

This patch changes the behavior on error paths while redefining snapshot
in two ways:

1) On failure, modifications done on the snapshot definition object are
rolled back.

2) The previous definition of the data isn't freed until it's certain it
won't be needed any more.

This change avoids the segfault and additionally the snapshot doesn't
vanish if redefinition fails for some reason.

This also changes the function signature to take a
virDomainChrSourceDefPtr instead of just a path, since it needs to
differentiate behavior based on source->type.

The functionality provided in virchrdev.c (previously virconsole.c) is
applicable to other types of character devices besides consoles, such
as channels.  This patch is just code motion, renaming things such as
"console" or "pty", instead using more general terms such as
"character device" or "device path".

This is just code motion, in preparation to rename identifiers to be
less console-specific.

Since 4c993d8a we failed to set this important capability, which
allows starting a domain with QXL video card. We set DEVICE_QXL
capability bit instead, which is not necessary wrong. Anyway, if
qemu supports the new '-device qxl' it supports older '-vga qxl'
as well. The latter is used for the primary (the first) qxl video
card, the former for other video cards.

Commit b3f2b4ca left buf unallocated in
the case of QMP capability probing being used, leading to a segfault in
strlen in the cleanup path.

This patch opens the log and allocates the buffer if QMP probing was
used, so we can display the helpful error message.

Despite our great effort we still parsed qemu log output.
We wouldn't notice unless upcoming qemu 1.4 changed the
format of the logs slightly. Anyway, now we should gather
all interesting knobs like pty paths from monitor. Moreover,
since for historical reasons the first console can be just
an alias to the first serial port, we need to check this and
copy the pty path if that's the case to the first console.

This reverts commit 28224c4d
which shouldn't be needed at all because with current qemu
we obtain all paths from 'query-chardev' output. We ought
not parse log output at all anymore.

Since 586502189edf9fd0f89a83de96717a2ea826fdb0 qemu commit, the log
lines reporting chardev's path has changed from:

$ ./x86_64-softmmu/qemu-system-x86_64 -serial pty -serial pty -monitor pty
char device redirected to /dev/pts/5
char device redirected to /dev/pts/6
char device redirected to /dev/pts/7

to:

$ ./x86_64-softmmu/qemu-system-x86_64 -serial pty -serial pty -monitor pty
char device compat_monitor0 redirected to /dev/pts/5
char device serial0 redirected to /dev/pts/6
char device serial1 redirected to /dev/pts/7

However, with current code we are not prepared for such change, which
results in us being unable to start any domain.

Many internal qemu APIs must find domain object from passed
virDomainPtr. And with function Peter's introduced, we can use it
instead of copying multiple lines among code.

There is no need to hold qemu lock during the whole execution
of these two APIs.

Since we switched to QMP probing, the object types are spelled out
explicitly, i.e. virtio-net-pci. This has effectively disabled
the capability detection of s390 virtio devices. The trivial fix
is to add the s390 virtio types explicitly to qemuCapsObjectProps.
Signed-off-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

https://bugzilla.redhat.com/show_bug.cgi?id=888426

The code for doing a block-copy was supposed to track the destination
file in drive->mirror, but was set up to do all mallocs prior to
starting the copy so that OOM wouldn't leave things partially started.
However, the wrong variable was being written; later in the code we
silently did 'disk->mirror = mirror' which was still NULL, and thus
leaking memory and leaving libvirt to think that the mirror job was
never started, which prevented a pivot operation after a copy.
Problem introduced in commit 35c7701c.

* src/qemu/qemu_driver.c (qemuDomainBlockCopy): Initialize correct
variable.