Note that this code is generally not running in coroutine context, so
this is an actual blocking synchronous operation. We'll fix this in a
moment.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

Note that this code is generally not running in coroutine context, so
this is an actual blocking synchronous operation. We'll fix this in a
moment.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

Instead of passing the return value to a callback, return it to the
caller so that the callback can be inlined there.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

Note that this code is generally not running in coroutine context, so
this is an actual blocking synchronous operation. We'll fix this in a
moment.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

The qed driver serialises allocating write requests. When the active
allocation is finished, the AIO callback is called, but after this, the
next allocating request is immediately processed instead of leaving the
coroutine. Resuming another allocation request in the same request
coroutine means that the request now runs in the wrong coroutine.

The following is one of the possible effects of this: The completed
request will generally reenter its request coroutine in a bottom half,
expecting that it completes the request in bdrv_driver_pwritev().
However, if the second request actually yielded before leaving the
coroutine, the reused request coroutine is in an entirely different
place and is reentered prematurely. Not a good idea.

Let's make sure that we exit the coroutine after completing the first
request by resuming the next allocating request only with a bottom
half.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

We already have functions for doing these calculations, so let's use
them instead of doing everything by hand. This makes the code a bit
more readable.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

If the guest tries to write data that results on the allocation of a
new cluster, instead of writing the guest data first and then the data
from the COW regions, write everything together using one single I/O
operation.

This can improve the write performance by 25% or more, depending on
several factors such as the media type, the cluster size and the I/O
request size.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Instead of passing a single buffer pointer to do_perform_cow_write(),
pass a QEMUIOVector. This will allow us to merge the write requests
for the COW regions and the actual data into a single one.

Although do_perform_cow_read() does not strictly need to change its
API, we're doing it here as well for consistency.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Reading both COW regions requires two separate requests, but it's
perfectly possible to merge them and perform only one. This generally
improves performance, particularly on rotating disk drives. The
downside is that the data in the middle region is read but discarded.

This patch takes a conservative approach and only merges reads when
the size of the middle region is <= 16KB.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch splits do_perform_cow() into three separate functions to
read, encrypt and write the COW regions.

perform_cow() can now read both regions first, then encrypt them and
finally write them to disk. The memory allocation is also done in
this function now, using one single buffer large enough to hold both
regions.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Instead of calling perform_cow() twice with a different COW region
each time, call it just once and make perform_cow() handle both
regions.

This patch simply moves code around. The next one will do the actual
reordering of the COW operations.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Qcow2COWRegion has two attributes:

- The offset of the COW region from the start of the first cluster
  touched by the I/O request. Since it's always going to be positive
  and the maximum request size is at most INT_MAX, we can use a
  regular unsigned int to store this offset.

- The size of the COW region in bytes. This is guaranteed to be >= 0,
  so we should use an unsigned type instead.

In x86_64 this reduces the size of Qcow2COWRegion from 16 to 8 bytes.
It will also help keep some assertions simpler now that we know that
there are no negative numbers.

The prototype of do_perform_cow() is also updated to reflect these
changes.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We are using the return value of qcow2_encrypt_sectors() to detect
problems but we are throwing away the returned Error since we have no
way to report it to the user. Therefore we can simply get rid of the
local Error variable and pass NULL instead.

Alternatively we could try to figure out a way to pass the original
error instead of simply returning -EIO, but that would be more
invasive, so let's keep the current approach.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Add the ability for the NVMe model to support both the RDS and WDS
modes in the Controller Memory Buffer.

Although not currently supported in the upstreamed Linux kernel a fork
with support exists [1] and user-space test programs that build on
this also exist [2].

Useful for testing CMB functionality in preperation for real CMB
enabled NVMe devices (coming soon).

[1] https://github.com/sbates130272/linux-p2pmem
[2] https://github.com/sbates130272/p2pmem-testSigned-off-by: NStephen Bates <sbates@raithlin.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Perform the savevm/loadvm test with both iothread on and off.  This
covers the recently found savevm/loadvm hang when iothread is enabled.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The legacy -hda option does not support -drive/-device parameters.  They
will be required by the next patch that extends this test case.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Avoid duplicating the QEMU command-line.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

migration_incoming_state_destroy() uses qemu_fclose() on the vmstate
file.  Make sure to call it inside an AioContext acquire/release region.

This fixes an 'qemu: qemu_mutex_unlock: Operation not permitted' abort
in loadvm.

This patch closes the vmstate file before ending the drained region.
Previously we closed the vmstate file after ending the drained region.
The order does not matter.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

There used to be throttle_timers_{detach,attach}_aio_context() calls
in bdrv_set_aio_context(), but since 7ca7f0f6
they are now in blk_set_aio_context().
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This documents the driver-specific options for the raw, qcow2 and file
block drivers for the man page. For everything else, we refer to the
QAPI documentation.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

This adds documentation for the -blockdev options that apply to all
nodes independent of the block driver used.

All options that are shared by -blockdev and -drive are now explained in
the section for -blockdev. The documentation of -drive mentions that all
-blockdev options are accepted as well.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

blk/bdrv_drain_all() only takes effect for a single instant and then
resumes block jobs, guest devices, and other external clients like the
NBD server.  This can be handy when performing a synchronous drain
before terminating the program, for example.

Monitor commands usually need to quiesce I/O across an entire code
region so blk/bdrv_drain_all() is not suitable.  They must use
bdrv_drain_all_begin/end() to mark the region.  This prevents new I/O
requests from slipping in or worse - block jobs completing and modifying
the graph.

I audited other blk/bdrv_drain_all() callers but did not find anything
that needs a similar fix.  This patch fixes the savevm/loadvm commands.
Although I haven't encountered a read world issue this makes the code
safer.
Suggested-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

AioContext was designed to allow nested acquire/release calls.  It uses
a recursive mutex so callers don't need to worry about nesting...or so
we thought.

BDRV_POLL_WHILE() is used to wait for block I/O requests.  It releases
the AioContext temporarily around aio_poll().  This gives IOThreads a
chance to acquire the AioContext to process I/O completions.

It turns out that recursive locking and BDRV_POLL_WHILE() don't mix.
BDRV_POLL_WHILE() only releases the AioContext once, so the IOThread
will not be able to acquire the AioContext if it was acquired
multiple times.

Instead of trying to release AioContext n times in BDRV_POLL_WHILE(),
this patch simply avoids nested locking in save_vmstate().  It's the
simplest fix and we should step back to consider the big picture with
all the recent changes to block layer threading.

This patch is the final fix to solve 'savevm' hanging with -object
iothread.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Calling aio_poll() directly may have been fine previously, but this is
the future, man!  The difference between an aio_poll() loop and
BDRV_POLL_WHILE() is that BDRV_POLL_WHILE() releases the AioContext
around aio_poll().

This allows the IOThread to run fd handlers or BHs to complete the
request.  Failure to release the AioContext causes deadlocks.

Using BDRV_POLL_WHILE() partially fixes a 'savevm' hang with -object
iothread.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Call bdrv_inc/dec_in_flight() for vmstate reads/writes.  This seems
unnecessary at first glance because vmstate reads/writes are done
synchronously while the guest is stopped.  But we need the bdrv_wakeup()
in bdrv_dec_in_flight() so the main loop sees request completion.
Besides, it's cleaner to count vmstate reads/writes like ordinary
read/write requests.

The bdrv_wakeup() partially fixes a 'savevm' hang with -object iothread.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

When qemu is exited, all running jobs should be cancelled successfully.
This adds a test for this for all types of block jobs that currently
exist in qemu.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

After _cleanup_qemu(), test cases should be able to start the next qemu
process and call _cleanup_qemu() for that one as well. For this to work
cleanly, we need to improve the cleanup so that the second invocation
doesn't try to kill the qemu instances from the first invocation a
second time (which would result in error messages).
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

commit_complete() can't assume that after its block_job_completed() the
job is actually immediately freed; someone else may still be holding
references. In this case, the op blockers on the intermediate nodes make
the graph reconfiguration in the completion code fail.

Call block_job_remove_all_bdrv() manually so that we know for sure that
any blockers on intermediate nodes are given up.

Cc: qemu-stable@nongnu.org
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Queued target/s390x patches

# gpg: Signature made Fri 23 Jun 2017 17:18:24 BST
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-s390-20170623:
  target/s390x: Implement idte instruction
  target/s390x: Improve heuristic for ipte
  target/s390x: Indicate and check for local tlb clearing
  target/s390x: Clean up TB flag bits
  target/s390x: Finish implementing ETF2-ENH
  target/s390x: Mark STFLE_49 facility as available
  target/s390x: Implement processor-assist insn
  target/s390x: Implement execution-hint insns
  target/s390x: Mark STFLE_53 facility as available
  target/s390x: Implement load-and-zero-rightmost-byte insns
  target/s390x: Implement load-on-condition-2 insns
  target/s390x: Mark FPSEH facility as available
  target/s390x: implement mvcos instruction
  target/s390x: change PSW_SHIFT_KEY
  target/s390x: Map existing FAC_* names to S390_FEAT_* names
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Let's keep it very simple for now and flush the complete tlb,
we currently can't find the right entries in our tlb, we would have
to store the used tables for each element.

As we now fully implement the DAT-enhancement facility, we can allow to
enable it for the qemu CPU model.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170622094151.28633-4-david@redhat.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

If only the page index is set, most likely we don't have a valid
virtual address. Let's do a full tlb flush for that case.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170622094151.28633-3-david@redhat.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

Let's allow to enable it for the qemu cpu model and correctly emulate
it.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Message-Id: <20170622094151.28633-2-david@redhat.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

Most of the PSW bits that were being copied into TB->flags
are not relevant to translation.  Removing those that are
unnecessary reduces the amount of translation required.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

Missed the proper alignment in TRTO/TRTT, and ignoring the M3
field for all TRXX insns without ETF2-ENH.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

This facility bit includes execution-hint, load-and-trap,
miscellaneous-instruction-extensions and processor-assist.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

This facility bit includes load-on-condition-2 and
load-and-zero-rightmost-byte.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>