target-arm: handle address translations that start at level 3

The ARMv8 address translation system defines that a page table walk
starts at a level which depends on the translation granule size
and the number of bits of virtual address that need to be resolved.
Where the translation granule is 64KB and the guest sets the
TCR.TxSZ field to between 35 and 39, it's actually possible to
start at level 3 (the final level). QEMU's implementation failed
to handle this case, and so we would set level to 2 and behave
incorrectly (including invoking the C undefined behaviour of
shifting left by a negative number). Correct the code that
determines the starting level to deal with the start-at-3 case,
by replacing the if-else ladder with an expression derived from
the ARM ARM pseudocode version.

This error was detected by the Coverity scan, which spotted
the potential shift by a negative number.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1415890569-7454-1-git-send-email-peter.maydell@linaro.org
raw-posix: Fix comment for raw_co_get_block_status()

Missed in commit 705be72.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
raw-posix: SEEK_HOLE suffices, get rid of FIEMAP

Commit 5500316 (May 2012) implemented raw_co_is_allocated() as
follows:

1. If defined(CONFIG_FIEMAP), use the FS_IOC_FIEMAP ioctl

2. Else if defined(SEEK_HOLE) && defined(SEEK_DATA), use lseek()

3. Else pretend there are no holes

Later on, raw_co_is_allocated() was generalized to
raw_co_get_block_status().

Commit 4f11aa8 (May 2014) changed it to try the three methods in order
until success, because "there may be implementations which support
[SEEK_HOLE/SEEK_DATA] but not [FIEMAP] (e.g., NFSv4.2) as well as vice
versa."

Unfortunately, we used FIEMAP incorrectly: we lacked FIEMAP_FLAG_SYNC.
Commit 38c4d0a (Sep 2014) added it.  Because that's a significant
speed hit, the next commit 7c159037 put SEEK_HOLE/SEEK_DATA first.

As you see, the obvious use of FIEMAP is wrong, and the correct use is
slow.  I guess this puts it somewhere between -7 "The obvious use is
wrong" and -10 "It's impossible to get right" on Rusty Russel's Hard
to Misuse scale[*].

"Fortunately", the FIEMAP code is used only when

* SEEK_HOLE/SEEK_DATA aren't defined, but CONFIG_FIEMAP is

  Uncommon.  SEEK_HOLE had no XFS implementation between 2011 (when it
  was introduced for ext4 and btrfs) and 2012.

* SEEK_HOLE/SEEK_DATA and CONFIG_FIEMAP are defined, but lseek() fails

  Unlikely.

Thus, the FIEMAP code executes rarely.  Makes it a nice hidey-hole for
bugs.  Worse, bugs hiding there can theoretically bite even on a host
that has SEEK_HOLE/SEEK_DATA.

I don't want to worry about this crap, not even theoretically.  Get
rid of it.

[*] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
raw-posix: The SEEK_HOLE code is flawed, rewrite it

On systems where SEEK_HOLE in a trailing hole seeks to EOF (Solaris,
but not Linux), try_seek_hole() reports trailing data instead.

Additionally, unlikely lseek() failures are treated badly:

* When SEEK_HOLE fails, try_seek_hole() reports trailing data.  For
  -ENXIO, there's in fact a trailing hole.  Can happen only when
  something truncated the file since we opened it.

* When SEEK_HOLE succeeds, SEEK_DATA fails, and SEEK_END succeeds,
  then try_seek_hole() reports a trailing hole.  This is okay only
  when SEEK_DATA failed with -ENXIO (which means the non-trailing hole
  found by SEEK_HOLE has since become trailing somehow).  For other
  failures (unlikely), it's wrong.

* When SEEK_HOLE succeeds, SEEK_DATA fails, SEEK_END fails (unlikely),
  then try_seek_hole() reports bogus data [-1,start), which its caller
  raw_co_get_block_status() turns into zero sectors of data.  Could
  theoretically lead to infinite loops in code that attempts to scan
  data vs. hole forward.

Rewrite from scratch, with very careful comments.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Merge remote-tracking branch 'mreitz/block' into queue-block

* mreitz/block:
  raw-posix: The SEEK_HOLE code is flawed, rewrite it
  raw-posix: SEEK_HOLE suffices, get rid of FIEMAP
  raw-posix: Fix comment for raw_co_get_block_status()
exec: Handle multipage ranges in invalidate_and_set_dirty()

The code in invalidate_and_set_dirty() needs to handle addr/length
combinations which cross guest physical page boundaries. This can happen,
for example, when disk I/O reads large blocks into guest RAM which previously
held code that we have cached translations for. Unfortunately we were only
checking the clean/dirty status of the first page in the range, and then
were calling a tb_invalidate function which only handles ranges that don't
cross page boundaries. Fix the function to deal with multipage ranges.

The symptoms of this bug were that guest code would misbehave (eg segfault),
in particular after a guest reboot but potentially any time the guest
reused a page of its physical RAM for new code.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1416167061-13203-1-git-send-email-peter.maydell@linaro.org
block/raw-posix: Fix preallocating write() loop

write() may write less bytes than requested; in this case, the number of
bytes written is returned. This is the byte count we should be
subtracting from the number of bytes still to be written, and not the
byte count we requested to write.

Reported-by: László Érsek <lersek@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/raw-posix: Only sync after successful preallocation

The loop which filled the file with zeroes may have been left early due
to an error. In that case, the fsync() should be skipped.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/raw-posix: Catch fsync() errors

fsync() may fail, and that case should be handled.

Reported-by: László Érsek <lersek@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
migration: fix parameter validation on ram load

During migration, the values read from migration stream during ram load
are not validated. Especially offset in host_from_stream_offset() and
also the length of the writes in the callers of said function.

To fix this, we need to make sure that the [offset, offset + length]
range fits into one of the allocated memory regions.

Validating addr < len should be sufficient since data seems to always be
managed in TARGET_PAGE_SIZE chunks.

Fixes: CVE-2014-7840

Note: follow-up patches add extra checks on each block->host access.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
linux-headers: update to 3.18-rc5

This updates the Linux header to version 3.18-rc5, adding support for
(among other things) read-only memslots on ARM and arm64.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Message-id: 1416248898-6302-1-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Merge remote-tracking branch 'remotes/amit-migration/tags/for-2.2' into staging

Fix for CVE-2014-7840, avoiding arbitrary qemu memory overwrite for
migration by Michael S. Tsirkin.

# gpg: Signature made Tue 18 Nov 2014 11:23:00 GMT using RSA key ID 854083B6
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"

* remotes/amit-migration/tags/for-2.2:
  migration: fix parameter validation on ram load

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block patches for 2.2.0-rc2

# gpg: Signature made Tue 18 Nov 2014 11:32:55 GMT using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream:
  block/raw-posix: Catch fsync() errors
  block/raw-posix: Only sync after successful preallocation
  block/raw-posix: Fix preallocating write() loop
  raw-posix: The SEEK_HOLE code is flawed, rewrite it
  raw-posix: SEEK_HOLE suffices, get rid of FIEMAP
  raw-posix: Fix comment for raw_co_get_block_status()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Tracing docs fix configure option and description

Fix the example trace configure option.
Update the text to say that multiple backends are allowed and what
happens when multiple backends are enabled.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 1412691161-31785-1-git-send-email-dgilbert@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tracing: Fix simpletrace.py error on tcg enabled binary traces

simpletrace.py does not recognize the tcg option while reading trace-events  file. In result simpletrace does not work on binary traces and tcg enabled events. Moved transformation of tcg enabled events to _read_events() which is used by simpletrace.

Signed-off-by: Christoph Seifert <christoph.seifert@posteo.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

# gpg: Signature made Tue 18 Nov 2014 15:04:14 GMT using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/tracing-pull-request:
  Tracing: Fix simpletrace.py error on tcg enabled binary traces
  Tracing docs fix configure option and description

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Merge remote-tracking branch 'remotes/stefanha/tags/net-pull-request' into staging

# gpg: Signature made Tue 18 Nov 2014 15:04:53 GMT using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/net-pull-request:
  net: The third parameter of getsockname should be initialized

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
hw/ide/core.c: Prevent SIGSEGV during migration

The other callers to blk_set_enable_write_cache() in this file
already check for s->blk == NULL.

Signed-off-by: Don Slutz <dslutz@verizon.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1416259239-13281-1-git-send-email-dslutz@verizon.com
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Update version for v2.2.0-rc2 release

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
migration: static variables will not be reset at second migration

The static variables in migration_bitmap_sync will not be reset in
the case of a second attempted migration.

Signed-off-by: ChenLiang <chenliang88@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>