The MRS instruction requires that bits [19..16] are all 1s, and for
A/R profile also that bits [7..0] are all 0s.  At this point in the
decode tree we have checked all of the rest of the instruction but
were allowing these to be any value.  If these bits are not set then
the result is architecturally UNPREDICTABLE, but choosing to UNDEF is
more helpful to the user and avoids unexpected odd behaviour if the
encodings are used for some purpose in future architecture versions.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Message-id: 1487616072-9226-4-git-send-email-peter.maydell@linaro.org

M profile doesn't have the MSR(banked) and MRS(banked) instructions
and uses the encodings for different kinds of M-profile MRS/MSR.
Guard the relevant bits of the decode logic to make sure we don't
accidentally fall into them by accident on M-profile.

(The bit being checked for this (bit 5) is part of the SYSm field on
M-profile, but since no currently allocated system registers have
encodings with bit 5 of SYSm set, this hasn't been a problem in
practice.)
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Message-id: 1487616072-9226-3-git-send-email-peter.maydell@linaro.org

M profile doesn't have the HVC or SMC encodings, so make them always
UNDEF rather than generating calls to helper functions that assume
A/R profile.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Message-id: 1487616072-9226-2-git-send-email-peter.maydell@linaro.org

One bugfix for device plug/unplug and migration in the
channel subsystem code.

# gpg: Signature made Mon 20 Mar 2017 08:45:59 GMT
# gpg:                using RSA key 0xDECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20170320:
  s390x/css: reassign subchannel if schid is changed after migration
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

fixes for 2.9: vnc, cirrus, tcg display updates.

# gpg: Signature made Mon 20 Mar 2017 08:52:34 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/pull-fixes-20170320-1:
  vnc: fix a qio-channel leak
  cirrus: fix off-by-one in cirrus_bitblt_rop_bkwd_transp_*_16
  ui/console: ensure graphic updates don't race with TCG vCPUs
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The subchannel is a means to access a device. While the device number is
assigned by the administrator, the subchannel number is assigned by
the channel subsystem in an ascending order on cold and hot plug.
When doing unplug and replug operations, the same device may end up on
a different subchannel; for example

- We start with a device fe.1.2222, which ends up at subchannel
  fe.1.0000.
- Now we detach the device, attach a device fe.1.3333 (which would get
  the now-free subchannel fe.1.0000), re-attach fe.1.2222 (which ends
  up at subchannel fe.1.0001) and detach fe.1.3333.
- We now have the same device (fe.1.2222) available to the guest; it
  just shows up on a different subchannel.

In such a case, the subchannel numbers are different from what a
QEMU would create during cold plug when parsing the command line.

As this would cause a guest visible change on migration, we do restore
the source system's value of the subchannel number on load.

So we are now fine from the guest perspective. From the host
perspective this will cause an inconsistent state in our internal data
structures, though.

For example, the subchannel 0 might not be at array position 0. This will
lead to problems when we continue doing hot (un/re) plug operations.

Let's fix this by cleaning up our internal data structures.
Reported-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Spotted by ASAN.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20170317092802.17973-1-marcandre.lureau@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add a const qom link between the CPU and the IIC instead
of passing the CPU link through a qom property.
Signed-off-by: NMarek Vasut <marex@denx.de>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-id: 20170317210627.23532-1-marex@denx.de
Cc: Alexander Graf <agraf@suse.de>
Cc: Chris Wulff <crwulff@gmail.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jeff Da Silva <jdasilva@altera.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Sandra Loosemore <sandra@codesourcery.com>
Cc: Yves Vandervennet <yvanderv@altera.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target/xtensa fixes for 2.9:

- fix build failure when FDT support is not enabled;
- correctly pass command line arguments to semihosting guests.

# gpg: Signature made Fri 17 Mar 2017 18:14:01 GMT
# gpg:                using RSA key 0x51F9CC91F83FA044
# gpg: Good signature from "Max Filippov <filippov@cadence.com>"
# gpg:                 aka "Max Filippov <max.filippov@cogentembedded.com>"
# gpg:                 aka "Max Filippov <jcmvbkbc@gmail.com>"
# Primary key fingerprint: 2B67 854B 98E5 327D CDEB  17D8 51F9 CC91 F83F A044

* remotes/xtensa/tags/20170317-xtensa:
  target/xtensa: fix semihosting argc/argv implementation
  target/xtensa: xtfpga: load DTB only when FDT support is enabled
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

si_band is not found in OpenBSD.   It is marked as obsolescent in
POSIX, so we can delete it without any remorse.
Reported-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170317152214.6148-1-pbonzini@redhat.com
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

EPROTO is not found in OpenBSD.   We usually use EIO when no better
errno is available, do that here too.
Reported-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170317152412.8472-1-pbonzini@redhat.com
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Block layer fixes for 2.9.0-rc1

# gpg: Signature made Fri 17 Mar 2017 12:06:04 GMT
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  block: quiesce AioContext when detaching from it
  thread-pool: add missing qemu_bh_cancel in completion function
  block: Propagate error in bdrv_open_backing_file
  blockdev: fix bitmap clear undo
  block: Always call bdrv_child_check_perm first
  file-posix: Don't leak fd in hdev_get_max_segments
  replication: clarify permissions
  file-posix: clean up max_segments buffer termination
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Block patches for 2.9-rc1

# gpg: Signature made Fri Mar 17 12:59:20 2017 CET
# gpg:                using RSA key 0xF407DB0061D5CF40
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* mreitz/tags/pull-block-2017-03-17:
  block: quiesce AioContext when detaching from it
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

While it is true that bdrv_set_aio_context only works on a single
BlockDriverState subtree (see commit message for 53ec73e2, "block: Use
bdrv_drain to replace uncessary bdrv_drain_all", 2015-07-07), it works
at the AioContext level rather than the BlockDriverState level.

Therefore, it is also necessary to trigger pending bottom halves too,
even if no requests are pending.

For NBD this ensures that the aio_co_schedule of a previous call to
nbd_attach_aio_context is completed before detaching from the old
AioContext; it fixes qemu-iotest 094.  Another similar bug happens
when the VM is stopped and the virtio-blk dataplane irqfd is torn down.
In this case it's possible that guest I/O gets stuck if notify_guest_bh
was scheduled but doesn't run.

Calling aio_poll from another AioContext is safe if non-blocking; races
such as the one mentioned in the commit message for c9d1a561 ("block:
only call aio_poll on the current thread's AioContext", 2016-10-28)
are a concern for blocking calls.

I considered other options, including:

- moving the bs->wakeup mechanism to AioContext, and letting the caller
check.  This might work for virtio which has a clear place to wakeup
(notify_place_bh) and check the condition (virtio_blk_data_plane_stop).
For aio_co_schedule I couldn't find a clear place to check the condition.

- adding a dummy oneshot bottom half and waiting for it to trigger.
This has the complication that bottom half list is LIFO for historical
reasons.  There were performance issues caused by bottom half ordering
in the past, so I decided against it for 2.9.

Fixes: 99723548Reported-by: NMax Reitz <mreitz@redhat.com>
Reported-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Tested-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170314111157.14464-2-pbonzini@redhat.com
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

commit 3c80ca15 fixed a deadlock scenarion with nested aio_poll invocations.

However, the rescheduling of the completion BH introcuded unnecessary spinning
in the main-loop. On very fast file backends this can even lead to the
"WARNING: I/O thread spun for 1000 iterations" message popping up.

Callgrind reports about 3-4% less instructions with this patch running
qemu-img bench on a ramdisk based VMDK file.

Fixes: 3c80ca15
Cc: qemu-stable@nongnu.org
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Only undo the action if we actually prepared the action.
Signed-off-by: NJohn Snow <jsnow@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

bdrv_child_set_perm alone is not very usable because the caller must
call bdrv_child_check_perm first. This is already encapsulated
conveniently in bdrv_child_try_set_perm, so remove the other prototypes
from the header and fix the one wrong caller, block/mirror.c.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This fixes a leaked fd introduced in commit 9103f1ce.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Even if hidden_disk, secondary_disk are backing files, they all need
write permissions in replication scenario. Otherwise we will encouter
below exceptions on secondary side during adding nbd server:

{'execute': 'nbd-server-add', 'arguments': {'device': 'colo-disk', 'writable': true } }
{"error": {"class": "GenericError", "desc": "Conflicts with use by hidden-qcow2-driver as 'backing', which does not allow 'write' on sec-qcow2-driver-for-nbd"}}

CC: Zhang Hailiang <zhang.zhanghailiang@huawei.com>
CC: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
CC: Wen Congyang <wencongyang2@huawei.com>
Signed-off-by: NChanglong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The following pattern is unsafe:

  char buf[32];
  ret = read(fd, buf, sizeof(buf));
  ...
  buf[ret] = 0;

If read(2) returns 32 then a byte beyond the end of the buffer is
zeroed.

In practice this buffer overflow does not occur because the sysfs
max_segments file only contains an unsigned short + '\n'.  The string is
always shorter than 32 bytes.

Regardless, avoid this pattern because static analysis tools might
complain and it could lead to real buffer overflows if copy-pasted
elsewhere in the codebase.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The switch from pointers to addresses (commit
026aeffc and
ffaf8577) added
a off-by-one bug to 16bit backward blits.  Fix.
Reported-by: N李强 <liqiang6-s@360.cn>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NLi Qiang <liqiang6-s@360.cn>
Message-id: 1489735296-19047-1-git-send-email-kraxel@redhat.com

Commit 8d04fb55..

  tcg: drop global lock during TCG code execution

..broke the assumption that updates to the GUI couldn't happen at the
same time as TCG vCPUs where running. As a result the TCG vCPU could
still be updating a directly mapped frame-buffer while the display
side was updating. This would cause artefacts to appear when the
update code assumed that memory block hadn't changed.

The simplest solution is to ensure the two things can't happen at the
same time like the old BQL locking scheme. Here we use the solution
introduced for MTTCG and schedule the update as async_safe_work when
we know no vCPUs can be running.
Reported-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>
Message-id: 20170315144825.3108-1-alex.bennee@linaro.org
Cc: BALATON Zoltan <balaton@eik.bme.hu>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>

[ kraxel: updated comment clarifying the display adapters are buggy
          and this is a temporary workaround ]
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

cirrus: blitter fixes.

# gpg: Signature made Thu 16 Mar 2017 09:05:22 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/pull-cirrus-20170316-1:
  cirrus: stop passing around src pointers in the blitter
  cirrus: stop passing around dst pointers in the blitter
  cirrus: fix cirrus_invalidate_region
  cirrus: add option to disable blitter
  cirrus: switch to 4 MB video memory by default
  cirrus/vnc: zap bitblit support from console code.
  fix :cirrus_vga fix OOB read case qemu Segmentation fault

# Conflicts:
#	include/hw/compat.h
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

migration/next for 20170316

# gpg: Signature made Thu 16 Mar 2017 08:21:51 GMT
# gpg:                using RSA key 0xF487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* remotes/juanquintela/tags/migration/20170316:
  postcopy: Check for shared memory
  RAMBlocks: qemu_ram_is_shared
  vmstate: fix failed iotests case 68 and 91
  migration/block: Avoid invoking blk_drain too frequently
  migration: use "" as the default for tls-creds/hostname
  Change the method to calculate dirty-pages-rate
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Pull request

Tracing makefile fixes for QEMU 2.9.

# gpg: Signature made Thu 16 Mar 2017 06:56:10 GMT
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: ensure $(tracetool-y) is defined in top level makefile
  makefile: generate trace-events-all upfront
  makefile: merge GENERATED_HEADERS & GENERATED_SOURCES variables
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Commit c2cabb34 inadvertently downgraded the 'dtc' submodule,
undoing the increments added in earlier commits. Revert this,
returning the submodule state to where we should be.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

QAPI patches for 2017-03-16

# gpg: Signature made Thu 16 Mar 2017 06:18:38 GMT
# gpg:                using RSA key 0x3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2017-03-16: (49 commits)
  qapi: Fix a misleading parser error message
  qapi: Make pylint a bit happier
  qapi: Drop unused .check_clash() parameter schema
  qapi: union_types is a list used like a dict, make it one
  qapi: struct_types is a list used like a dict, make it one
  qapi: enum_types is a list used like a dict, make it one
  qapi: Factor add_name() calls out of the meta conditional
  qapi: Simplify what gets stored in enum_types
  qapi: Drop unused variable events
  qapi: Eliminate check_docs() and drop QAPIDoc.expr
  qapi: Fix detection of bogus member documentation
  tests/qapi-schema: Improve coverage of bogus member docs
  tests/qapi-schema: Rename doc-bad-args to doc-bad-command-arg
  qapi: Move empty doc section checking to doc parser
  qapi: Improve error message on @NAME: in free-form doc
  qapi: Move detection of doc / expression name mismatch
  qapi: Fix detection of doc / expression mismatch
  tests/qapi-schema: Improve doc / expression mismatch coverage
  qapi2texi: Use category "Object" for all object types
  qapi2texi: Generate descriptions for simple union tags
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

virtio, pci: fixes

More fixes missed in the previous pull request.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Thu 16 Mar 2017 02:29:49 GMT
# gpg:                using RSA key 0x281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17  0970 C350 3912 AFBE 8E67
#      Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA  8A0D 281F 0DB8 D28D 5469

* remotes/mst/tags/for_upstream:
  virtio-serial-bus: Delete timer from list before free it
  hw/virtio: fix Power Management Control Register for PCI Express virtio devices
  hw/virtio: fix Link Control Register for PCI Express virtio devices
  hw/virtio: fix error enabling flags in Device Control register
  hw/pcie: fix Extended Configuration Space for devices with no Extended Capabilities
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

# gpg: Signature made Thu 16 Mar 2017 00:52:41 GMT
# gpg:                using RSA key 0x7DEF8106AAFC390E
# gpg: Good signature from "John Snow (John Huston) <jsnow@redhat.com>"
# Primary key fingerprint: FAEB 9711 A12C F475 812F  18F2 88A9 064D 1835 61EB
#      Subkey fingerprint: F9B7 ABDB BCAC DF95 BE76  CBD0 7DEF 8106 AAFC 390E

* remotes/jnsnow/tags/ide-pull-request:
  ide: ahci: call cleanup function in ahci unit
  ide: core: add cleanup function
  ide: qdev: register ide bus unrealize function
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Postcopy doesn't support migration of RAM shared with another process
yet (we've got a bunch of things to understand).
Check for the case and don't allow postcopy to be enabled.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Provide a helper to say whether a RAMBlock was created as a
shared mapping.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

This problem affects s390x only if we are running without KVM.
Basically, S390CPU.irqstate is unused if we do not use KVM,
and thus no buffer is allocated.
This causes size=0, first_elem=NULL and n_elems=1 in
vmstate_load_state and vmstate_save_state. And the assert fails.
With this fix we can go back to the old behavior and support
VMS_VBUFFER with size 0 and nullptr.
Signed-off-by: NQingFeng Hao <haoqf@linux.vnet.ibm.com>
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Increase bmds->cur_dirty after submit io, so reduce the frequency
involve into blk_drain, and improve the performance obviously
when block migration.

The performance test result of this patch:

During the block dirty save phase, this patch improve guest os IOPS
from 4.0K to 9.5K. and improve the migration speed from
505856 rsec/s to 855756 rsec/s.
Signed-off-by: NLidong Chen <jemmy858585@gmail.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Does basically the same as "cirrus: stop passing around dst pointers in
the blitter", just for the src pointer instead of the dst pointer.

For the src we have to care about cputovideo blits though and fetch the
data from s->cirrus_bltbuf instead of vga memory.  The cirrus_src*()
helper functions handle that.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489584487-3489-1-git-send-email-kraxel@redhat.com

Instead pass around the address (aka offset into vga memory).  Calculate
the pointer in the rop_* functions, after applying the mask to the
address, to make sure the address stays within the valid range.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489574872-8679-1-git-send-email-kraxel@redhat.com

off_cur_end is exclusive, so off_cur_end == cirrus_addr_mask is valid.
Fix calculation to make sure to allow that, otherwise the assert added
by commit f153b563 can trigger for valid
blits.

Test case: boot windows nt 4.0
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489579606-26020-1-git-send-email-kraxel@redhat.com

Ok, we have this beast in the cirrus code which is not used at all by
modern guests, except when you try to find security holes in qemu.  So,
add an option to disable blitter altogether.  Guests released within
the last ten years should not show any rendering issues if you turn off
blitter support.

There are no known bugs in the cirrus blitter code.  But in the past we
hoped a few times already that we've finally nailed the last issue.  So
having some easy way to mitigate in case yet another blitter issue shows
up certainly makes me sleep a bit better at night.

For completeness:  The by far better way to mitigate is to switch away
from cirrus and use stdvga instead.  Or something more modern like
virtio-vga in case your guest has support for it.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489494540-15745-1-git-send-email-kraxel@redhat.com

Quoting cirrus source code:
   Follow real hardware, cirrus card emulated has 4 MB video memory.
   Also accept 8 MB/16 MB for backward compatibility.

So just use 4MB by default.  We decided to leave that at 8MB by default
a while ago, for live migration compatibility reasons.  But we have
compat properties to handle that, so that isn't a compeling reason.

This also removes some sanity check inconsistencies in the cirrus code.
Some places check against the allocated video memory, some places check
against the 4MB physical hardware has.  Guest code can trigger asserts
because of that.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489494514-15606-1-git-send-email-kraxel@redhat.com

There is a special code path (dpy_gfx_copy) to allow graphic emulation
notify user interface code about bitblit operations carryed out by
guests.  It is supported by cirrus and vnc server.  The intended purpose
is to optimize display scrolls and just send over the scroll op instead
of a full display update.

This is rarely used these days though because modern guests simply don't
use the cirrus blitter any more.  Any linux guest using the cirrus drm
driver doesn't.  Any windows guest newer than winxp doesn't ship with a
cirrus driver any more and thus uses the cirrus as simple framebuffer.

So this code tends to bitrot and bugs can go unnoticed for a long time.
See for example commit "3e10c3ec vnc: fix qemu crash because of SIGSEGV"
which fixes a bug lingering in the code for almost a year, added by
commit "c7628bff vnc: only alloc server surface with clients connected".

Also the vnc server will throttle the frame rate in case it figures the
network can't keep up (send buffers are full).  This doesn't work with
dpy_gfx_copy, for any copy operation sent to the vnc client we have to
send all outstanding updates beforehand, otherwise the vnc client might
run the client side blit on outdated data and thereby corrupt the
display.  So this dpy_gfx_copy "optimization" might even make things
worse on slow network links.

Lets kill it once for all.

Oh, and one more reason: Turns out (after writing the patch) we have a
security bug in that code path ...

Fixes: CVE-2016-9603
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489494419-14340-1-git-send-email-kraxel@redhat.com