Aurelien Jarno [Tue, 9 Oct 2012 19:53:08 +0000 (21:53 +0200)]
tcg: rework TCG helper flags
The current helper flags, TCG_CALL_CONST and TCG_CALL_PURE might be
confusing and doesn't provide enough granularity for some helpers (FP
helpers for example).
This patch changes them into the following helpers flags:
- TCG_CALL_NO_READ_GLOBALS means that the helper does not read globals,
either directly or via an exception. They will not be saved to their
canonical location before calling the helper.
- TCG_CALL_NO_WRITE_GLOBALS means that the helper does not modify any
globals. They will only be saved to their canonical locations before
calling helpers, but they won't be reloaded afterwise.
- TCG_CALL_NO_SIDE_EFFECTS means that the call to the function is
removed if the return value is not used.
It provides convenience flags, to avoid helper definitions longer than
80 characters. It also provides compatibility flags, and updates the
documentation.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:08 +0000 (21:53 +0200)]
tcg: synchronize globals for ops with side effects
Operations with side effects (in practice qemu_ld/st ops), only need to
synchronize globals to make sure the CPU state is consistent in case of
exception.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:08 +0000 (21:53 +0200)]
tcg: forbid ld/st function to modify globals
Mapping a memory address using a global and accessing it through
ld/st operations is currently broken. As it doesn't make any sense
to do that performance wise, let's forbid that.
Update the TCG documentation, and remove partial support for that.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:08 +0000 (21:53 +0200)]
tcg: fix some op flags
Some branch related ops are marked with TCG_OPF_SIDE_EFFECTS, some other
not. In practice they don't need to, as they are all marked with
TCG_OPF_BB_END, which is handled specifically in all the code.
The call op is marked as TCG_OPF_SIDE_EFFECTS, which might be not true
as there is are specific flags (TCG_CALL_CONST and TCG_CALL_PURE) for
specifying that. On the other hand it always clobber arguments, so mark
it as such even if the call op is handled in a different code path.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:07 +0000 (21:53 +0200)]
tcg: don't explicitly save globals and temps
The liveness analysis ensures that globals and temps are at the correct
state at a basic block end or with an op with side effects. Avoid
looping on all temps, this can be time consuming on targets with a lot
of globals. Keep an assert in debug mode.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:07 +0000 (21:53 +0200)]
tcg: rewrite tcg_reg_alloc_mov()
Now that the liveness analysis provides more information, rewrite
tcg_reg_alloc_mov(). This changes the behaviour about propagating
constants and memory accesses. We now take the assumption that once
a value is loaded into a register (from memory or from a constant),
it's better to keep it there than to reload it later. This assumption
is now always almost correct given that we are now sure the
corresponding temp is going to be used later (otherwise it would have
been synchronized and marked as dead already). The assumption is wrong
if one of the op after clobbers some registers including the one
of the holding the temp (this can be avoided by allocating clobbered
registers last, which is what most TCG target do), or in case of lack
of available register.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:07 +0000 (21:53 +0200)]
tcg: rework liveness analysis
Rework the liveness analysis by tracking temps that need to go back to
memory in addition to dead temps tracking. This allows to mark output
arguments as "need sync", and to synchronize them back to memory as soon
as they are not written anymore. This way even arguments mapping to
globals can be marked as "dead", avoiding moves to a new register when
input and outputs are aliased.
In addition it means that registers are freed as soon as temps are not
used anymore, instead of waiting for a basic block end or an op with side
effects. This reduces register spilling especially on CPUs with few
registers, and spread the mov over all the TB, increasing the
performances on in-order CPUs.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:07 +0000 (21:53 +0200)]
tcg: sync output arguments on liveness request
Synchronize an output argument when requested by the liveness analysis.
This is needed so that the temp can be declared dead later.
For that, add a new op_sync_args table in which each bit tells if the
corresponding output argument needs to be synchronized with the memory.
Pass it to the tcg_reg_alloc_* functions, and honor this bit. We need to
synchronize the argument before marking it as dead, and we have to make
sure all the infos about the temp are correctly filled.
At the same time change some types from unsigned int to uint16_t when
passing op_dead_args.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:06 +0000 (21:53 +0200)]
tcg: add temp_sync()
Add a new function temp_sync() to synchronize the canonical location
of a temp with the value in the corresponding register, but without
freeing the associated register. Rewrite temp_save() to call
temp_sync() followed by temp_dead().
Aurelien Jarno [Tue, 9 Oct 2012 19:53:06 +0000 (21:53 +0200)]
tcg: add tcg_reg_sync()
Add a new function tcg_reg_sync() to synchronize the canonical location
of a temp with the value in the associated register, but without freeing
it. Rewrite tcg_reg_free() to first call tcg_reg_sync() and then to free
the register.
Aurelien Jarno [Tue, 9 Oct 2012 19:53:06 +0000 (21:53 +0200)]
tcg: add temp_dead()
A lot of code is duplicated to mark a temporary as dead. Replace it
by temp_dead(), which in addition marks the temp as saved in memory
for globals and local temps, instead of doing this a posteriori in
temp_save().
Aurelien Jarno [Sat, 20 Oct 2012 15:31:44 +0000 (17:31 +0200)]
tcg/i386: remove ld/st third argument register constraint
On x86_64, remove the constraint on the third argument register which
is not needed:
- For loads the helper arguments are env, addr, mem_idx. The addr
value should not be in the two first argument registers as they are
used in tcg_out_tlb_load().
- For stores the helper arguments are env, addr, data, mem_idx.
The addr and data values should not be in the two first argument
registers as they are used in tcg_out_tlb_load(). The data value
should also not be in the two first argument registers, but could
be in the third argument register in which case it would be already
loaded at the right location.
Aurelien Jarno [Sat, 20 Oct 2012 15:31:44 +0000 (17:31 +0200)]
tcg/i386: remove suboptimal register shifting
Now that CONFIG_TCG_PASS_AREG0 has been removed, it's easier to get
an optimal code for the load/store functions.
First swap the two registers used in tcg_out_tlb_load() so that the
address end-up in the second register instead of the first one. Adjust
tcg_out_qemu_ld() and tcg_out_qemu_st() to respectively call
tcg_out_qemu_ld_direct() and tcg_out_qemu_st_direct() with the correct
registers. Then replace the register shifting by direct load of the
arguments.
Peter Maydell [Fri, 19 Oct 2012 13:54:23 +0000 (14:54 +0100)]
Makefile: Forbid out-of-tree build from a source tree that has been built in
If we try to do an out-of-tree build but the source tree we're building from
has been used in the past for an in-tree build then things will go
confusingly wrong. Specifically, some parts of the build process will pull
in generated files from the old in-tree build (because SRC_PATH is on
the vpath). Diagnose this situation so we can produce a useful error
message and tell the user how to fix it (run distclean in the source tree).
Blue Swirl [Sat, 27 Oct 2012 14:21:37 +0000 (14:21 +0000)]
Merge branch 'target-arm.for-upstream' of git://git.linaro.org/people/pmaydell/qemu-arm
* 'target-arm.for-upstream' of git://git.linaro.org/people/pmaydell/qemu-arm:
target-arm: Remove out of date FIXME regarding saturating arithmetic
target-arm: Implement abs_i32 inline rather than as a helper
target-arm: Use TCG operation for Neon 64 bit negation
arm-semi.c: Handle get/put_user() failure accessing arguments
Bruce Rogers [Mon, 20 Aug 2012 18:45:08 +0000 (12:45 -0600)]
configure: avoid compiler warning in pipe2 detection
When building qemu-kvm for openSUSE:Factory, I am getting a
warning in the pipe2 detection performed by configure, which
prevents using --enable-werror.
Change detection code to use return value of pipe2.
Disable clang's initializer-overrides warnings, as QEMU makes significant
use of the pattern of initializing an array with a range-based default
entry like
[0 ... 0x1ff] = { GPIO_NONE, 0 }
followed by specific entries which override that default, and clang
would otherwise warn "initializer overrides prior initialization of
this subobject" when it encountered the specific entry.
Gerd Hoffmann [Wed, 24 Oct 2012 07:38:08 +0000 (09:38 +0200)]
xhci: allow disabling interrupters
For secondary interrupters this is explicitly allowed in the specs.
For the primary interrupter behavior is undefined, lets be friendly
and allow disabling too.
Gerd Hoffmann [Wed, 24 Oct 2012 08:14:16 +0000 (10:14 +0200)]
xhci: flush endpoint context unconditinally
Not updating the endpoint context in case the state didn't change is
wrong. Other context fields might have changed, for example the
dequeue pointer in response to a CR_SET_TR_DEQUEUE command.
Hans de Goede [Wed, 24 Oct 2012 16:31:19 +0000 (18:31 +0200)]
uhci: Retry to fill the queue while waiting for td completion
If the guest is using multiple transfers to try and keep the usb bus busy /
used at maximum efficiency, currently we would see / do the following:
1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) report transfer 2 completion to guest
5) submit transfer 1 to the device
6) report transfer 1 completion to guest
7) submit transfer 2 to the device
8) report transfer 2 completion to guest
etc.
So after the initial submission we would effectively only have 1 transfer
in flight, rather then 2. This is caused by us not checking the queue for
addition of new transfers by the guest (ie the resubmission of a recently
finished transfer), while waiting for a pending transfer to complete.
This patch does add a check for this, changing the sequence to:
1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) submit transfer 1 to the device
5) report transfer 2 completion to guest
6) submit transfer 2 to the device
etc.
Thus keeping 2 transfers in flight (most of the time, and always 1),
as intended by the guest.
Hans de Goede [Wed, 24 Oct 2012 16:31:18 +0000 (18:31 +0200)]
uhci: Always mark a queue valid when we encounter it
Before this patch we would not mark a queue valid when its head was a
non-active td. This causes us to misbehave in the following scenario:
1) queue with multiple input transfers queued
2) We hit some latency issue, causing qemu to get behind processing frames
3) When qemu gets to run again, it notices the first transfer ends short,
marking the head td non-active
4) It now processes 32+ frames in a row without giving the guest a chance
to run since it is behind
5) valid is decreased to 0, causing the queue to get cancelled also cancelling
already queued up further input transfers
6) guest gets to run, notices the inactive td, cleanups up further tds
from the short transfer, and lets the queue continue at the first td of
the next input transfer
7) we re-start the queue, issuing the second input transfer for the *second*
time, and any data read by the first time we issued it has been lost
Hans de Goede [Wed, 24 Oct 2012 16:31:16 +0000 (18:31 +0200)]
uhci: Detect guest td re-use
A td can be reused by the guest in a different queue, before we notice
the original queue has been unlinked. So search for tds by addr only, detect
guest td reuse, and cancel the original queue, this is necessary to keep our
packet ids unique.
Hans de Goede [Wed, 24 Oct 2012 16:31:15 +0000 (18:31 +0200)]
uhci: Verify queue has not been changed by guest
According to the spec a guest can unlink a qh, and then as soon as frindex
has changed by 1 since the unlink, assume it is idle and re-use it. However
for various reasons, we cannot simply consider a qh as unlinked if we've not
seen it for 1 frame. This means that it is possible for a guest to re-use /
restart the queue while we still see its old state. This patch adds a safety
check for this, and "early" retires queues when they were changed by the guest.
Hans de Goede [Wed, 24 Oct 2012 16:31:14 +0000 (18:31 +0200)]
uhci: Immediately free queues on device disconnect
There is no need to just cancel any in-flight packets, and then wait
for validate-end to clean things up, we can simply clean things up
immediately on device removal.
Hans de Goede [Wed, 24 Oct 2012 16:31:12 +0000 (18:31 +0200)]
uhci: Make uhci_fill_queue() actually operate on an UHCIQueue
And move its calling point to handle_td, this removes the ep_ret ugliness,
and prepates the way for further cleanups in the follow-up patches in this
patch-set.
Hans de Goede [Wed, 24 Oct 2012 16:31:10 +0000 (18:31 +0200)]
uhci: Rename UHCIAsync->td to UHCIAsync->td_addr
We use the name td both to refer to a UHCI_TD read from guest memory as
well as to refer to the guest address where a td is stored, switch over
to always use td_addr in the second case for consistency.
Hans de Goede [Wed, 24 Oct 2012 16:31:07 +0000 (18:31 +0200)]
uhci: Don't retry on error
Since we are either dealing with emulated devices, where retrying is
not going to help, or with redirected devices where the host OS will
have already retried, don't bother retrying on failed transfers.
Also move some common/indentical code out of all the error cases
into the generic error path.
Hans de Goede [Wed, 24 Oct 2012 16:14:09 +0000 (18:14 +0200)]
usb: Move short-not-ok handling to the core
After a short-not-ok packet ending short, we should not advance the queue.
Move enforcing this to the core, rather then handling it in the hcd code.
This may result in the queue now actually containing multiple input packets
(which would not happen before), and this requires special handling in
combination with pipelining, so disable pipleining for input endpoints
(for now).
Hans de Goede [Wed, 24 Oct 2012 16:14:08 +0000 (18:14 +0200)]
usb: Move clearing of queue on halt to the core
hcds which queue up more then one packet at once (uhci, ehci and xhci),
must clear the queue after an error which has caused the queue to halt.
Currently this is handled as a special case inside the hcd code, this
patch instead adds an USB_RET_REMOVE_FROM_QUEUE packet result code, teaches
the 3 hcds about this and moves the clearing of the queue on a halt into
the USB core.
Hans de Goede [Wed, 24 Oct 2012 16:14:07 +0000 (18:14 +0200)]
usb: Add USB_RET_ADD_TO_QUEUE packet result code
This can be used by usb-device code which wishes to process an entire endpoint
queue at once, to do this the usb-device code returns USB_RET_ADD_TO_QUEUE
from its handle_data class method and defines a flush_ep_queue class method
to call when the hcd is done queuing up packets.
Hans de Goede [Wed, 24 Oct 2012 16:14:04 +0000 (18:14 +0200)]
ehci: Retry to fill the queue while waiting for td completion
If the guest is using multiple transfers to try and keep the usb bus busy /
used at maximum efficiency, currently we would see / do the following:
1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) report transfer 2 completion to guest
5) submit transfer 1 to the device
6) report transfer 1 completion to guest
7) submit transfer 2 to the device
8) report transfer 2 completion to guest
etc.
So after the initial submission we would effectively only have 1 transfer
in flight, rather then 2. This is caused by us not checking the queue for
addition of new transfers by the guest (ie the resubmission of a recently
finished transfer), while waiting for a pending transfer to complete.
This patch does add a check for this, changing the sequence to:
1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) submit transfer 1 to the device
5) report transfer 2 completion to guest
6) submit transfer 2 to the device
etc.
Thus keeping 2 transfers in flight (most of the time, and always 1),
as intended by the guest.
Hans de Goede [Wed, 24 Oct 2012 16:14:03 +0000 (18:14 +0200)]
ehci: Detect going in circles when filling the queue
For ctrl endpoints Windows (atleast Win7) creates circular td lists, so far
these were not a problem because we would stop filling the queue if altnext
was set. Since further patches in this patchset remove the altnext check this
does become a problem and we need detection for going in circles.
Hans de Goede [Wed, 24 Oct 2012 16:14:02 +0000 (18:14 +0200)]
ehci: Speed up the timer of raising int from the async schedule
Often the guest will queue up new packets in response to a packet, in the
async schedule with its IOC flag set, completing. By speeding up the
frame-timer, we notice these new packets earlier. This increases the
speed (MB/s) of a Linux guest reading from a USB mass storage device by a
factor of 1.15 on top of the "Improve latency of interrupt delivery"
speed-ups, both with and without input pipelining enabled.
I've not tested the speed-up of this patch without the
"Improve latency of interrupt delivery" patch.
Hans de Goede [Wed, 24 Oct 2012 16:14:01 +0000 (18:14 +0200)]
ehci: Improve latency of interrupt delivery and async schedule scanning
While doing various performance tests of reading from USB mass storage devices
I noticed the following::
1) When an async handled packet completes, we don't immediately report an
interrupt to the guest, instead we wait for the frame-timer to run and
report it from there
2) If 1) has been fixed and an async handled packet takes a while to complete,
then async_stepdown will become a high value, which means that there
will be a large latency before any new packets queued by the guest in
response to the interrupt get seen
1) was done deliberately as part of commit f0ad01f92:
http://www.kraxel.org/cgit/qemu/commit/?h=usb.57&id=f0ad01f92ca02eee7cadbfd225c5de753ebd5fce
Since setting the interrupt immediately on async packet completion was causing
issues with Linux guests, I believe this recently fixed Linux bug explains
why this is happening:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=361aabf395e4a23cf554cf4ec0c0c6963b8beb01
Note that we can *not* count on this fix being present in all Linux guests!
I was hoping that the recently added support for Interrupt Threshold Control
would fix the issues with Linux guests, but adding a simple ehci_commit_irq()
call to ehci_async_bh() still caused problems with Linux guests.
The problem is, that when doing ehci_commit_irq() from ehci_async_bh(),
the "old" frindex value is used to calculate usbsts_frindex, and when
the frame-timer then runs possibly very shortly after ehci_async_bh(),
it increases the frame-timer, and thus any interrupts raised from that
frame-timer run, will also get reported to the guest immediately, rather
then being delayed to the next frame-timer run.
Luckily the solution for this is simple, this means that we need to
increase frindex before calling ehci_commit_irq() from ehci_async_bh(),
which in the end boils down to simple calling ehci_frame_timer() instead
of ehci_async_bh() from the bh.
This may seem like it causes a lot of extra work to be done, but this
is not true. Any work done from the frame-timer processing the periodic
schedule is work which then does not need to be done the next time the
frame timer runs, also the frame-timer will re-arm itself at (possibly)
a later time then it was armed for saving a vmexit at that time.
As an additional advantage moving to simply calling the frame-timer also
fixes 2) as the packet completion will set async_stepdown to 0, and the
re-arming of the timer with an async_stepdown of 0 ensures that any
newly queued up packets get seen in a reasonable amount of time.
This improves the speed (MB/s) of a Linux guest reading from a USB mass
storage device by a factor of 1.5 - 1.7 with input pipelining disabled,
and by a factor of 1.8 with input pipelining enabled.
Hans de Goede [Wed, 24 Oct 2012 16:14:00 +0000 (18:14 +0200)]
ehci: Set int flag on a short input packet
According to 4.15.1.2 an interrupt must be raised when a short packet
is received. If we don't do this it may take a significant time for
the guest to notice a short trasnfer has completed, since only the last td
will have its IOC flag set, and a short transfer may complete in an earlier
packet.
Hans de Goede [Wed, 24 Oct 2012 16:13:59 +0000 (18:13 +0200)]
ehci: Get rid of packet tbytes field
This field is used in some places to track the tbytes field of the token, but
in other places the field is used directly, use it directly everywhere for
consistency.
Hans de Goede [Wed, 24 Oct 2012 16:13:58 +0000 (18:13 +0200)]
uhci: Move checks to continue queuing to uhci_fill_queue()
Rather then having a special check to start queuing after the first packet,
and then another check for the other packets in uhci_fill_queue(), simply
check the previous packet beforehand in uhci_fill_queue()
Luiz Capitulino [Wed, 24 Oct 2012 16:12:15 +0000 (14:12 -0200)]
win32: fix broken build due to missing QEMU_MADV_HUGEPAGE
Commit ad0b5321f1f797274603ebbe20108b0750baee94 forgot to add
QEMU_MADV_HUGEPAGE macros for when CONFIG_MADVISE is not defined.
This broke the build for Windows. Fix it.
Anthony Liguori [Wed, 24 Oct 2012 14:39:49 +0000 (09:39 -0500)]
Merge remote-tracking branch 'bonzini/nbd-next' into staging
* bonzini/nbd-next: (30 commits)
qmp: add NBD server commands
block: add close notifiers
block: prepare code for adding block notifiers
qemu-sockets: add socket_listen, socket_connect, socket_parse
tests: do not include tools-obj-y Signed-off-by: Paolo Bonzini <[email protected]>
qemu-sockets: return InetSocketAddress from inet_parse
qapi: add socket address types
build: add QAPI files to the tools
vnc: drop QERR_VNC_SERVER_FAILED
qemu-sockets: add error propagation to Unix socket functions
qemu-sockets: add error propagation to inet_parse
qemu-sockets: add error propagation to inet_dgram_opts
qemu-sockets: add error propagation to inet_connect_addr
qemu-sockets: include strerror or gai_strerror output in error messages
vnc: add error propagation to vnc_display_open
vnc: reorganize code for reverse mode
vnc: introduce a single label for error returns
vnc: avoid Yoda conditionals
qemu-ga: ask and print error information from qemu-sockets
nbd: ask and print error information from qemu-sockets
...
Paolo Bonzini [Fri, 19 Oct 2012 14:45:24 +0000 (16:45 +0200)]
migration: go to paused state after finishing incoming migration with -S
At the end of migration the machine has started already, and cannot be
destroyed without losing the guest's data. Hence, prelaunch is the
wrong state. Go to the paused state instead. QEMU would reach that
state anyway (after running the guest for the blink of an eye) if the
"stop" command had been received after the start of migration.
Paolo Bonzini [Tue, 23 Oct 2012 12:54:21 +0000 (14:54 +0200)]
qmp: handle stop/cont in INMIGRATE state
Right now, stop followed by an incoming migration will let the
virtual machine start. cont before an incoming migration instead
will fail.
This is bad because the actual behavior is not predictable; it is
racy with respect to the start of the incoming migration. That's
because incoming migration is blocking, and thus will delay the
processing of stop/cont until the end of the migration.
In addition, there's nothing that really prevents the user from
typing the block device's passwords before incoming migration is
done, so returning the DeviceEncrypted error is also helpful in
the QMP case.
Both things can be fixed by just toggling the autostart variable when
stop/cont are called in INMIGRATE state.
Note that libvirt is currently working around the race by looping
if the MigrationExpected answer is returned. After this patch, the
command will return right away without ever raising an error.
Aurelien Jarno [Fri, 19 Oct 2012 21:19:19 +0000 (23:19 +0200)]
hmp: fix info cpus for sparc targets
On sparc targets, info cpus returns this kind of output:
| info cpus
| * CPU #0: pc=0x0000000000424d18pc=0x0000000000424d18npc=0x0000000000424d1c thread_id=19460
pc is printed twice, there is no space between pc, pc and npc.
With this patch, pc is not printed anymore when has_npc is set. In addition
the space is printed before pc/nip/npc/PC instead of after the colon so that
multiple prints are possible. This result on the following kind of input on
sparc targets:
| info cpus
| * CPU #0: pc=0x0000000000424d18 npc=0x0000000000424d1c thread_id=19460
Peter Maydell [Fri, 19 Oct 2012 04:23:05 +0000 (04:23 +0000)]
target-arm: Remove out of date FIXME regarding saturating arithmetic
Remove an out of date FIXME regarding the saturating arithmetic helpers:
we now do pass a pointer to CPUARMState to these helpers, and since
the AREG0 changes went in there is no difference between helper.c
and op_helper.c and therefore no point in moving the functions.
Rework the handling of arguments to ARM semihosting calls so that we
handle a possible failure return from get_user_ual() or put_user_ual().
(This incidentally silences a lot of warnings from clang about
"expression result unused").
Corey Bryant [Thu, 18 Oct 2012 20:41:04 +0000 (16:41 -0400)]
osdep: Less restrictive F_SEFL in qemu_dup_flags()
qemu_dup_flags() currently limits the flags that can be set on the
fcntl() F_SETFL call to those that we currently know can be set with
fcntl() F_SETFL. The problem with this is that it will prevent use
of new flags in the future without a code update.
This patch relaxes the checking and lets fcntl() determine the flags
it can set.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:29 +0000 (16:49 +0200)]
qmp: add pull_event function
This function is unlike get_events in that it makes it easy to process
one event at a time. This is useful in the mirroring test cases, where
we want to process just one event (BLOCK_JOB_ERROR) and leave the others
to a helper function.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:28 +0000 (16:49 +0200)]
mirror: add support for on-source-error/on-target-error
Error management is important for mirroring; otherwise, an error on the
target (even something as "innocent" as ENOSPC) requires to start again
with a full copy. Similar to on_read_error/on_write_error, two separate
knobs are provided for on_source_error (reads) and on_target_error (writes).
The default is 'report' for both.
The 'ignore' policy will leave the sector dirty, so that it will be
retried later. Thus, it will not cause corruption.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:25 +0000 (16:49 +0200)]
mirror: implement completion
Switching to the target of the migration is done mostly asynchronously,
and reported to management via the BLOCK_JOB_COMPLETED event; the only
synchronous phase is opening the backing files. bdrv_open_backing_file
can always be done, even for migration of the full image (aka sync:
'full'). In this case, qmp_drive_mirror will create the target disk
with no backing file at all, and bdrv_open_backing_file will be a no-op.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:23 +0000 (16:49 +0200)]
mirror: introduce mirror job
This patch adds the implementation of a new job that mirrors a disk to
a new image while letting the guest continue using the old image.
The target is treated as a "black box" and data is copied from the
source to the target in the background. This can be used for several
purposes, including storage migration, continuous replication, and
observation of the guest I/O in an external program. It is also a
first step in replacing the inefficient block migration code that is
part of QEMU.
The job is possibly never-ending, but it is logically structured into
two phases: 1) copy all data as fast as possible until the target
first gets in sync with the source; 2) keep target in sync and
ensure that reopening to the target gets a correct (full) copy
of the source data.
The second phase is indicated by the progress in "info block-jobs"
reporting the current offset to be equal to the length of the file.
When the job is cancelled in the second phase, QEMU will run the
job until the source is clean and quiescent, then it will report
successful completion of the job.
In other words, the BLOCK_JOB_CANCELLED event means that the target
may _not_ be consistent with a past state of the source; the
BLOCK_JOB_COMPLETED event means that the target is consistent with
a past state of the source. (Note that it could already happen
that management lost the race against QEMU and got a completion
event instead of cancellation).
It is not yet possible to complete the job and switch over to the target
disk. The next patches will fix this and add many refinements to the
basic idea introduced here. These include improved error management,
some tunable knobs and performance optimizations.
Paolo Bonzini [Mon, 23 Jul 2012 13:15:47 +0000 (15:15 +0200)]
block: introduce BLOCK_JOB_READY event
Even for jobs that need to be manually completed, management may want
to take care itself of the completion, not requiring the user to issue
a command to terminate the job. In this case we want to avoid that
they poll us continuously, waiting for completion to become available.
Thus, add a new event that signals the phase switch and the availability
of the block-job-complete command.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:21 +0000 (16:49 +0200)]
block: add block-job-complete
While streaming can be dropped as soon as it progressed through the whole
image, mirroring needs to be completed manually for two reasons: 1) so that
management knows exactly when the VM switches to the target; 2) because
for other use cases such as replication, we may leave the operation running
for the whole life of the virtual machine.
Add a new block job command that manually completes background operations.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:18 +0000 (16:49 +0200)]
block: introduce new dirty bitmap functionality
Assert that write_compressed is never used with the dirty bitmap.
Setting the bits early is wrong, because a coroutine might concurrently
examine them and copy incomplete data from the source.
Paolo Bonzini [Thu, 18 Oct 2012 14:49:17 +0000 (16:49 +0200)]
block: add bdrv_open_backing_file
Mirroring runs without the backing file so that it can be copied outside
QEMU. However, we need to add it at the time the job is completed and
QEMU switches to the target. Factor out the common bits of opening an
image and completing a mirroring operation.
The new function does not assume that the file is closed immediately after
it returns failure, so it keeps the BDRV_O_NO_BACKING flag up-to-date.
Corey Bryant [Thu, 18 Oct 2012 19:19:34 +0000 (15:19 -0400)]
qemu-config: Add new -add-fd command line option
This option can be used for passing file descriptors on the
command line. It mirrors the existing add-fd QMP command which
allows an fd to be passed to QEMU via SCM_RIGHTS and added to an
fd set.
This can be combined with commands such as -drive to link file
descriptors in an fd set to a drive:
This example adds dups of fds 3 and 4, and the accompanying opaque
strings to the fd set with ID=2. qemu_open() already knows how
to handle a filename of this format. qemu_open() searches the
corresponding fd set for an fd and when it finds a match, QEMU
goes on to use a dup of that fd just like it would have used an
fd that it opened itself.
Corey Bryant [Thu, 18 Oct 2012 19:19:33 +0000 (15:19 -0400)]
monitor: Prevent removing fd from set during init
If an fd is added to an fd set via the command line, and it is not
referenced by another command line option (ie. -drive), then clean
it up after QEMU initialization is complete.
Corey Bryant [Thu, 18 Oct 2012 19:19:32 +0000 (15:19 -0400)]
monitor: Enable adding an inherited fd to an fd set
qmp_add_fd() gets an fd that was received over a socket with
SCM_RIGHTS and adds it to an fd set. This patch adds support
that will enable adding an fd that was inherited on the
command line to an fd set.
Note: All of the code added to monitor_fdset_add_fd(), with the
exception of the error path for non-valid fdset-id, is code motion
from qmp_add_fd().
Corey Bryant [Thu, 18 Oct 2012 19:19:31 +0000 (15:19 -0400)]
monitor: Allow add-fd to any specified fd set
The first call to add an fd to an fd set was previously not
allowed to choose the fd set ID. The ID was generated as
the first available and ensuing calls could add more fds by
specifying the fd set ID. This change allows users to
choose the fd set ID on the first call.
Stefan Hajnoczi [Wed, 17 Oct 2012 12:02:31 +0000 (14:02 +0200)]
qemu-img: Add --backing-chain option to info command
The qemu-img info --backing-chain option enumerates the backing file
chain. For example, for base.qcow2 <- snap1.qcow2 <- snap2.qcow2 the
output becomes:
$ qemu-img info --backing-chain snap2.qcow2
image: snap2.qcow2
file format: qcow2
virtual size: 100M (104857600 bytes)
disk size: 196K
cluster_size: 65536
backing file: snap1.qcow2
backing file format: qcow2
Jeff Cody [Tue, 16 Oct 2012 19:49:10 +0000 (15:49 -0400)]
block: in commit, determine base image from the top image
This simplifies some code and error checking, and also fixes a bug.
bdrv_find_backing_image() should only be passed absolute filenames,
or filenames relative to the chain. In the QMP message handler for
block commit, when looking up the base do so from the determined top
image, so we know it is reachable from top.
Some of the error messages put out by block-commit have changed
slightly, which causes 2 tests cases for block-commit to fail.
This patch updates the test cases to look for the correct error
output.
Jeff Cody [Tue, 16 Oct 2012 19:49:09 +0000 (15:49 -0400)]
block: make bdrv_find_backing_image compare canonical filenames
Currently, bdrv_find_backing_image compares bs->backing_file with
what is passed in as a backing_file name. Mismatches may occur,
however, when bs->backing_file and backing_file are not both
absolute or relative.
Use path_combine() to make sure any relative backing filenames are
relative to the current image filename being searched, and then use
realpath() to make all comparisons based on absolute filenames.
If either backing_file or bs->backing_file is determine to be a
protocol, then no filename normalization is performed.
This also changes bdrv_find_backing_image to no longer be recursive,
but iterative.
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