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2017-06-22Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20170619' into stagingPeter Maydell
Queued TCG patches # gpg: Signature made Mon 19 Jun 2017 19:12:06 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-tcg-20170619: target/arm: Exit after clearing aarch64 interrupt mask target/s390x: Exit after changing PSW mask target/alpha: Use tcg_gen_lookup_and_goto_ptr tcg: Increase hit rate of lookup_tb_ptr tcg/arm: Use ldr (literal) for goto_tb tcg/arm: Try pc-relative addresses for movi tcg/arm: Remove limit on code buffer size tcg/arm: Use indirect branch for goto_tb tcg/aarch64: Use ADR in tcg_out_movi translate-all: consolidate tb init in tb_gen_code tcg: allocate TB structs before the corresponding translated code util: add cacheinfo Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-06-19util: add cacheinfoEmilio G. Cota
Add helpers to gather cache info from the host at init-time. For now, only export the host's I/D cache line sizes, which we will use to improve cache locality to avoid false sharing. Suggested-by: Richard Henderson <rth@twiddle.net> Suggested-by: Geert Martin Ijewski <gm.ijewski@web.de> Tested-by: Geert Martin Ijewski <gm.ijewski@web.de> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1496794624-4083-1-git-send-email-cota@braap.org> [rth: Move all implementations from tcg/ppc/] Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-06-16util: add stats64 modulePaolo Bonzini
This module provides fast paths for 64-bit atomic operations on machines that only have 32-bit atomic access. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <20170605123908.18777-11-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2017-03-19qemu-ga: obey LISTEN_PID when using systemd socket activationPaolo Bonzini
qemu-ga's socket activation support was not obeying the LISTEN_PID environment variable, which avoids that a process uses a socket-activation file descriptor meant for its parent. Mess can for example ensue if a process forks a children before consuming the socket-activation file descriptor and therefore setting O_CLOEXEC on it. Luckily, qemu-nbd also got socket activation code, and its copy does support LISTEN_PID. Some extra fixups are needed to ensure that the code can be used for both, but that's what this patch does. The main change is to replace get_listen_fds's "consume" argument with the FIRST_SOCKET_ACTIVATION_FD macro from the qemu-nbd code. Cc: "Richard W.M. Jones" <rjones@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-03-07keyval: New keyval_parse()Markus Armbruster
keyval_parse() parses KEY=VALUE,... into a QDict. Works like qemu_opts_parse(), except: * Returns a QDict instead of a QemuOpts (d'oh). * Supports nesting, unlike QemuOpts: a KEY is split into key fragments at '.' (dotted key convention; the block layer does something similar on top of QemuOpts). The key fragments are QDict keys, and the last one's value is updated to VALUE. * Each key fragment may be up to 127 bytes long. qemu_opts_parse() limits the entire key to 127 bytes. * Overlong key fragments are rejected. qemu_opts_parse() silently truncates them. * Empty key fragments are rejected. qemu_opts_parse() happily accepts empty keys. * It does not store the returned value. qemu_opts_parse() stores it in the QemuOptsList. * It does not treat parameter "id" specially. qemu_opts_parse() ignores all but the first "id", and fails when its value isn't id_wellformed(), or duplicate (a QemuOpts with the same ID is already stored). It also screws up when a value contains ",id=". * Implied value is not supported. qemu_opts_parse() desugars "foo" to "foo=on", and "nofoo" to "foo=off". * An implied key's value can't be empty, and can't contain ','. I intend to grow this into a saner replacement for QemuOpts. It'll take time, though. Note: keyval_parse() provides no way to do lists, and its key syntax is incompatible with the __RFQDN_ prefix convention for downstream extensions, because it blindly splits at '.', even in __RFQDN_. Both issues will be addressed later in the series. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1488317230-26248-4-git-send-email-armbru@redhat.com>
2017-02-21block: move AioContext, QEMUTimer, main-loop to libqemuutilPaolo Bonzini
AioContext is fairly self contained, the only dependency is QEMUTimer but that in turn doesn't need anything else. So move them out of block-obj-y to avoid introducing a dependency from io/ to block-obj-y. main-loop and its dependency iohandler also need to be moved, because later in this series io/ will call iohandler_get_aio_context. [Changed copyright "the QEMU team" to "other QEMU contributors" as suggested by Daniel Berrange and agreed by Paolo. --Stefan] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170213135235.12274-2-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-31host-utils: Move 128-bit guard macro to .c fileJose Ricardo Ziviani
It is not possible to implement functions in host-utils.c for architectures with quadwords because the guard is implemented in the Makefile. This patch move the guard out of the Makefile to the implementation file. Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-01-16qemu-thread: introduce QemuLockCntPaolo Bonzini
A QemuLockCnt comprises a counter and a mutex, with primitives to increment and decrement the counter, and to take and release the mutex. It can be used to do lock-free visits to a data structure whenever mutexes would be too heavy-weight and the critical section is too long for RCU. This could be implemented simply by protecting the counter with the mutex, but QemuLockCnt is harder to misuse and more efficient. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170112180800.21085-3-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-28aio: convert from RFifoLock to QemuRecMutexPaolo Bonzini
It is simpler and a bit faster, and QEMU does not need the contention callbacks (and thus the fairness) anymore. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-21-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2016-09-23util: Add UUID APIFam Zheng
A number of different places across the code base use CONFIG_UUID. Some of them are soft dependency, some are not built if libuuid is not available, some come with dummy fallback, some throws runtime error. It is hard to maintain, and hard to reason for users. Since UUID is a simple standard with only a small number of operations, it is cleaner to have a central support in libqemuutil. This patch adds qemu_uuid_* functions that all uuid users in the code base can rely on. Except for qemu_uuid_generate which is new code, all other functions are just copy from existing fallbacks from other files. Note that qemu_uuid_parse is moved without updating the function signature to use QemuUUID, to keep this patch simple. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Message-Id: <1474432046-325-2-git-send-email-famz@redhat.com>
2016-09-13cutils: Move buffer_is_zero and subroutines to a new fileRichard Henderson
Signed-off-by: Richard Henderson <rth@twiddle.net> Message-Id: <1472496380-19706-2-git-send-email-rth@twiddle.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-30range: Create range.c for code that should not be inlineEric Blake
g_list_insert_sorted_merged() is rather large to be an inline function; move it to its own file. range_merge() and ranges_can_merge() can likewise move, as they are only used internally. Also, it becomes obvious that the condition within range_merge() is already satisfied by its caller, and that the return value is not used. The diffstat is misleading, because of the copyright boilerplate. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1464712890-14262-2-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-06-11qht: QEMU's fast, resizable and scalable Hash TableEmilio G. Cota
This is a fast, scalable chained hash table with optional auto-resizing, allowing reads that are concurrent with reads, and reads/writes that are concurrent with writes to separate buckets. A hash table with these features will be necessary for the scalability of the ongoing MTTCG work; before those changes arrive we can already benefit from the single-threaded speedup that qht also provides. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1465412133-3029-11-git-send-email-cota@braap.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11qdist: add module to represent frequency distributions of dataEmilio G. Cota
Sometimes it is useful to have a quick histogram to represent a certain distribution -- for example, when investigating a performance regression in a hash table due to inadequate hashing. The appended allows us to easily represent a distribution using Unicode characters. Further, the data structure keeping track of the distribution is so simple that obtaining its values for off-line processing is trivial. Example, taking the last 10 commits to QEMU: Characters in commit title Count ----------------------------------- 39 1 48 1 53 1 54 2 57 1 61 1 67 1 78 1 80 1 qdist_init(&dist); qdist_inc(&dist, 39); [...] qdist_inc(&dist, 80); char *str = qdist_pr(&dist, 9, QDIST_PR_LABELS); // -> [39.0,43.6)▂▂ █▂ ▂ ▄[75.4,80.0] g_free(str); char *str = qdist_pr(&dist, 4, QDIST_PR_LABELS); // -> [39.0,49.2)▁█▁▁[69.8,80.0] g_free(str); Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1465412133-3029-9-git-send-email-cota@braap.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-02-03log: move qemu-log.c into util/ directoryDenis V. Lunev
log will become common facility with tracepoints support in next step. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1452174932-28657-9-git-send-email-den@openvz.org Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-12-18util: add base64 decoding functionDaniel P. Berrange
The standard glib provided g_base64_decode doesn't provide any kind of sensible error checking on its input. Add a QEMU custom wrapper qbase64_decode which can be used with untrustworthy input that can contain invalid base64 characters, embedded NUL characters, or not be NUL terminated at all. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-11-12util: Infrastructure for computing recent averagesAlberto Garcia
This module computes the average of a set of values within a time window, keeping also track of the minimum and maximum values. In order to produce more accurate results it works internally by creating two time windows of the same period, offsetted by half of that period. Values are accounted on both windows and the data is always returned from the oldest one. [Add missing util/replay.o to test-timed-average dependencies to fix the build. --Stefan] Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 201b09c21bbc9c329779d2b2365ee2b9c80dceeb.1446044837.git.berto@igalia.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-22Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into stagingPeter Maydell
vhost, pc, virtio features, fixes, cleanups New features: VT-d support for devices behind a bridge vhost-user migration support Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Thu 22 Oct 2015 12:39:19 BST using RSA key ID D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" * remotes/mst/tags/for_upstream: (37 commits) hw/isa/lpc_ich9: inject the SMI on the VCPU that is writing to APM_CNT i386: keep cpu_model field in MachineState uptodate vhost: set the correct queue index in case of migration with multiqueue piix: fix resource leak reported by Coverity seccomp: add memfd_create to whitelist vhost-user-test: check ownership during migration vhost-user-test: add live-migration test vhost-user-test: learn to tweak various qemu arguments vhost-user-test: wrap server in TestServer struct vhost-user-test: remove useless static check vhost-user-test: move wait_for_fds() out vhost: add migration block if memfd failed vhost-user: use an enum helper for features mask vhost user: add rarp sending after live migration for legacy guest vhost user: add support of live migration net: add trace_vhost_user_event vhost-user: document migration log vhost: use a function for each call vhost-user: add a migration blocker vhost-user: send log shm fd along with log_base ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-10-22util: add linux-only memfd fallbackMarc-André Lureau
Implement memfd_create() fallback if not available in system libc. memfd_create() is still not included in glibc today, atlhough it's been available since Linux 3.17 in Oct 2014. memfd has numerous advantages over traditional shm/mmap for ipc memory sharing with fd handler, which we are going to make use of for vhost-user logging memory in following patches. The next patches are going to introduce helpers to use best practices of memfd usage and provide some compatibility fallback. memfd.c is thus temporarily useless and eventually empty if memfd_create() is provided by the system. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Thibaut Collet <thibaut.collet@6wind.com>
2015-10-22build-sys: split util-obj- on multi-linesMarc-André Lureau
Make it easier to add new unrelated units with shorter lines. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Thibaut Collet <thibaut.collet@6wind.com>
2015-10-21exec: factor out duplicate mmap codeMichael S. Tsirkin
Anonymous and file-backed RAM allocation are now almost exactly the same. Reduce code duplication by moving RAM mmap code out of oslib-posix.c and exec.c. Reported-by: Marc-André Lureau <mlureau@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Tested-by: Thibaut Collet <thibaut.collet@6wind.com>
2015-10-20util: pull Buffer code out of VNC moduleDaniel P. Berrange
The Buffer code in the VNC server is useful for the IO channel code, so pull it out into a shared module, QIOBuffer. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-10-20coroutine: move into libqemuutil.a libraryDaniel P. Berrange
The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-07-07crypto: move built-in AES implementation into crypto/Daniel P. Berrange
To prepare for a generic internal cipher API, move the built-in AES implementation into the crypto/ directory Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1435770638-25715-3-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-02rcu: add rcu libraryPaolo Bonzini
This includes a (mangled) copy of the liburcu code. The main changes are: 1) removing dependencies on many other header files in liburcu; 2) removing for simplicity the tentative busy waiting in synchronize_rcu, which has limited performance effects; 3) replacing futexes in synchronize_rcu with QemuEvents for Win32 portability. The API is the same as liburcu, so it should be possible in the future to require liburcu on POSIX systems for example and use our copy only on Windows. Among the various versions available I chose urcu-mb, which is the least invasive implementation even though it does not have the fastest rcu_read_{lock,unlock} implementation. The urcu flavor can be changed later, after benchmarking. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-03util: Emancipate id_wellformed() from QemuOptsMarkus Armbruster
IDs have long spread beyond QemuOpts: not everything with an ID necessarily goes through QemuOpts. Commit 9aebf3b is about such a case: block layer names are meant to be well-formed IDs, but some of them don't go through QemuOpts, and thus weren't checked. The commit fixed that the straightforward way: rename the internal QemuOpts helper id_wellformed() to qemu_opts_id_wellformed() and give it external linkage. Instead of using it directly in block.c, the commit adds wrapper bdrv_is_valid_name(), probably to hide the connection to QemuOpts. Go one logical step further: emancipate IDs from QemuOpts. Rename the function back to id_wellformed(), and put it in another file. While there, clean up its value to bool. Peel off the bdrv_is_valid_name() wrapper. [Replaced stray return 0 with return false to match bool returns used elsewhere in id_wellformed(). --Stefan] Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-09util: Don't link host-utils.o if it's emptyFam Zheng
Reported-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-06-23tcg-ppc: Merge cache-utils into the backendRichard Henderson
As a "utility", it only supported ppc, and in a way that other tcg backends provided directly in tcg-target.h. Removing this disparity is easier now that the two ppc backends are merged. Tested-by: Tom Musta <tommusta@gmail.com> Signed-off-by: Richard Henderson <rth@twiddle.net>
2014-03-13rfifolock: add recursive FIFO lockStefan Hajnoczi
QemuMutex does not guarantee fairness and cannot be acquired recursively: Fairness means each locker gets a turn and the scheduler cannot cause starvation. Recursive locking is useful for composition, it allows a sequence of locking operations to be invoked atomically by acquiring the lock around them. This patch adds RFifoLock, a recursive lock that guarantees FIFO order. Its first user is added in the next patch. RFifoLock has one additional feature: it can be initialized with an optional contention callback. The callback is invoked whenever a thread must wait for the lock. For example, it can be used to poke the current owner so that they release the lock soon. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-01-22readline: move readline to a generic locationStefan Hajnoczi
Now that the monitor and readline are decoupled, readline.h no longer belongs in include/monitor/. Put the header into include/qemu/. Move the source file into util/ so it can be linked as part of libqemuutil.a. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-30osdep: Create qemu_getauxval and qemu_init_auxvalRichard Henderson
Abstract away dependence on a system implementation of getauxval. Signed-off-by: Richard Henderson <rth@twiddle.net>
2013-09-06throttle: Add a new throttling API implementing continuous leaky bucket.Benoît Canet
Implement the continuous leaky bucket algorithm devised on IRC as a separate module. Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-06-14create qemu_openpty_raw() helper function and move it to a separate fileMichael Tokarev
In two places qemu uses openpty() which is very system-dependent, and in both places the pty is switched to raw mode as well. Make a wrapper function which does both steps, and move all the system-dependent complexity into a separate file, together with static/local implementations of openpty() and cfmakeraw() from qemu-char.c. It is in a separate file, not part of oslib-posix.c, because openpty() often resides in -lutil which is not linked to every program qemu builds. This change removes #including of <pty.h>, <termios.h> and other rather specific system headers out of qemu-common.h, which isn't a place for such specific headers really. This version has been verified to build correctly on Linux, OpenBSD, FreeBSD and OpenIndiana. On the latter it lets qemu to be built with gtk gui which were not possible there due to missing openpty() and cfmakeraw(). Signed-off-by: Michael Tokarev <mjt@tls.msk.ru> Tested-by: Andreas Färber <andreas.faerber@web.de>
2013-05-03qemu: add castagnoli crc32c checksum algorithmJeff Cody
This adds the Castagnoli CRC32C algorithm, using the 0x11EDC6F41 polynomial. This is extracted from the linux kernel cryptographic crc32.c module. The algorithm is based on: Castagnoli93: Guy Castagnoli and Stefan Braeuer and Martin Herrman "Optimization of Cyclic Redundancy-Check Codes with 24 and 32 Parity Bits", IEEE Transactions on Communication, Volume 41, Number 6, June 1993 Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-13unicode: New mod_utf8_codepoint()Markus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-03-15iov: Factor out hexdumperPeter Crosthwaite
Factor out the hexdumper functionality from iov for all to use. Useful for creating verbose debug printfery that dumps packet data. Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Message-id: faaac219c55ea586d3f748befaf5a2788fd271b8.1361853677.git.peter.crosthwaite@xilinx.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2013-03-01hw: move fifo.[ch] to libqemuutilPaolo Bonzini
fifo.c is generic code that can be easily unit tested. So it belongs in libqemuutil. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-25add hierarchical bitmap data type and test casesPaolo Bonzini
HBitmaps provides an array of bits. The bits are stored as usual in an array of unsigned longs, but HBitmap is also optimized to provide fast iteration over set bits; going from one bit to the next is O(logB n) worst case, with B = sizeof(long) * CHAR_BIT: the result is low enough that the number of levels is in fact fixed. In order to do this, it stacks multiple bitmaps with progressively coarser granularity; in all levels except the last, bit N is set iff the N-th unsigned long is nonzero in the immediately next level. When iteration completes on the last level it can examine the 2nd-last level to quickly skip entire words, and even do so recursively to skip blocks of 64 words or powers thereof (32 on 32-bit machines). Given an index in the bitmap, it can be split in group of bits like this (for the 64-bit case): bits 0-57 => word in the last bitmap | bits 58-63 => bit in the word bits 0-51 => word in the 2nd-last bitmap | bits 52-57 => bit in the word bits 0-45 => word in the 3rd-last bitmap | bits 46-51 => bit in the word So it is easy to move up simply by shifting the index right by log2(BITS_PER_LONG) bits. To move down, you shift the index left similarly, and add the word index within the group. Iteration uses ffs (find first set bit) to find the next word to examine; this operation can be done in constant time in most current architectures. Setting or clearing a range of m bits on all levels, the work to perform is O(m + m/W + m/W^2 + ...), which is O(m) like on a regular bitmap. When iterating on a bitmap, each bit (on any level) is only visited once. Hence, The total cost of visiting a bitmap with m bits in it is the number of bits that are set in all bitmaps. Unless the bitmap is extremely sparse, this is also O(m + m/W + m/W^2 + ...), so the amortized cost of advancing from one bit to the next is usually constant. Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-01-12build: move libqemuutil.a components to util/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>