...contains block layer and storage features that have been proposed. These features may not be in active development and questions about them should be address
== Core block layer ==
1 KB (196 words) - 10:51, 11 November 2020
Supporting asynchronous I/O in the NBD block device and qemu-nbd server makes it easier to use high-performance remote s
...for using remote storage within QEMU. NBD can also be coupled with other features such as streaming or copy-on-read. However, the NBD implementation in QEMU
932 bytes (132 words) - 14:56, 11 October 2016
..., Ceph). On Linux the cgroups blkio-controller supports I/O throttling on block devices but is a relatively recent feature. More importantly, there is no
The disk I/O limits feature introduces QEMU block layer I/O limits together with command-line and QMP interfaces for configur
1 KB (211 words) - 14:54, 11 October 2016
=== Removed features and incompatible changes ===
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
2 KB (214 words) - 15:30, 15 April 2024
...scales to several hundreds nodes, and supports advanced volume management features such as snapshot, cloning, and thin provisioning.
...no central node such as a meta-data server. This design enables following features.
2 KB (247 words) - 14:55, 11 October 2016
'''ICH9 block diagram'''
'''Intel Edison block diagram'''
2 KB (269 words) - 14:56, 9 July 2020
...arushi Mehta is working on the project for Outreachy. Project status is [[Features/IOUring|here]].
* Extending block/file-posix.c to use io_uring
2 KB (365 words) - 15:12, 17 May 2019
Block jobs, and other QAPI operations, may modify and impact the
operations safely, we need a mechanism to block and gate operations,
4 KB (709 words) - 18:15, 14 September 2016
| '''1 - Extend block/file-posix.c to use io_uring.'''
| '''6 - Add a fast path when QEMU block layer features are not in use .'''
2 KB (234 words) - 18:17, 23 May 2019
...out how much coverage of library functions you are doing. As QEMU's basic block boundaries are naturally at branch points you could do all of this pretty e
* See [[Features/TCGPlugins]]
891 bytes (140 words) - 22:19, 17 February 2021
==== Block devices ====
...and can be used by firmware directly. This will in the future enable new features without modifications of all firmware components (SeaBIOS, OVMF, CoreBoot)
4 KB (563 words) - 11:31, 10 December 2013
* Both to be solved by block-queue
...when the old one is full - and that one we don't even read, but write, so block-queue will help
4 KB (552 words) - 08:57, 12 October 2016
..., and the bit is 1 if the block is in the FVD image. The default size of a block is 64KB, same as the cluster size of QCOW2. To represent the state of a 1TB
=Important Features=
4 KB (688 words) - 14:45, 11 October 2016
...ts/qemu-iotests/. It contains test for disk image formats and block layer features.
...lative to the build directory) is the script to run tests. Tests exercise block I/O operations using qemu-img(1), qemu-io(1), and sometimes by running QEMU
2 KB (298 words) - 10:00, 12 October 2016
* Various minor bugfixes; no new features in this release.
=== Block devices ===
4 KB (589 words) - 12:24, 19 February 2013
| [[Planning/SoftFeatureFreeze|Soft feature freeze]]. All features
should have patches on the list by this date; major features should
4 KB (636 words) - 08:31, 12 October 2016
...or Mode Execution Prevention) and SMAP (Supervisor Mode Access Prevention) features of newer x86 processors.
...se, bmi1, hle, avx2, smep, bmi2, erms, invpcid, rtm) and "Opteron_G5" (new features: tbm, f16c, fma)
6 KB (951 words) - 16:38, 15 January 2013
* snowridge cpu name/features
* coverity issue in block/nvme
3 KB (488 words) - 20:51, 5 November 2019
To record and replay block operations the drive must be configured
==Features to add==
4 KB (568 words) - 08:17, 2 March 2017
...l future writes will be redirected into a separate location. The previous block device has a consistent state whereas it represents a point-in-time snapsho
The merge_disk command will copy the allocated block content into the backing file and once the image is empty, reopen the backi
4 KB (663 words) - 14:43, 11 October 2016
...different patch series posted on the mailing list sparked a discussion on block device operations
One is Jeff Cody's multiple-device snapshot series, documented [[Features/SnapshotsMultipleDevices|here]].
5 KB (591 words) - 08:39, 12 October 2016
* the new block-copy feature can assert on unaligned images [https://lists.gnu.org/archive/
== Targeted Features ==
3 KB (468 words) - 08:45, 20 August 2020
features that change the format in an incompatible way, so that older
increase in order to introduce some incompatible features, however it's
9 KB (1,281 words) - 10:12, 9 September 2016
=== New deprecated options and features ===
* Parsing of key,value pair filenames for the RBD block device
7 KB (1,028 words) - 16:56, 21 February 2019
...QAPI/GuestAgent Guest Agent]. Please check the guest [http://wiki.qemu.org/Features/QAPI/GuestAgent Guest Agent] page for design and implementation details.
The two main guest agent features of interest to live snapshots are:
21 KB (3,274 words) - 14:58, 11 October 2016
...ing to I/O errors; patch proposed: https://lists.gnu.org/archive/html/qemu-block/2022-08/msg00375.html
== Targeted Features ==
2 KB (273 words) - 13:20, 22 August 2022
...host-user-blk device backend although the QEMU block layer has a number of features that make QEMU desirable as a software-defined storage appliance in its own
2 KB (342 words) - 07:49, 11 March 2019
uint64_t features; /* format feature bits */
/* if (features & QED_F_BACKING_FILE) */
9 KB (1,374 words) - 14:45, 11 October 2016
...It should integrate into the existing build system. Currently, we allow features to be specified in for inclusion in a boolean fashion (either 'y' or 'n' to
...mechanism to support third party extensions to QEMU or out of tree drivers/features
9 KB (1,464 words) - 19:33, 11 August 2016
* The "autoload" parameter of the "block-dirty-bitmap-add" QMP command has been removed (it's no longer needed).
=== New deprecated options and features ===
11 KB (1,631 words) - 11:24, 3 December 2019
Future qemu is expected to support these features (some already implemented):
= Live features =
21 KB (3,397 words) - 15:04, 11 October 2016
* mps3-an524: Fix MPC setting for SRAM block
== Targeted Features ==
4 KB (610 words) - 14:09, 19 October 2021
...s without a native code generator can use the TCG interpreter (TCI). See [[Features/TCI]] for more information.
== Block devices (disks) ==
6 KB (908 words) - 20:51, 17 February 2012
...cpu-add QMP command. More details [[Features/CPUHotplug#cpu-add_interface|Features/CPUHotplug]].
...ltered-features" to allow introspection of supported and not supported CPU features.
7 KB (1,120 words) - 18:28, 27 May 2013
...registers mean we can boot more recent Linux kernels that probe for these features
* Removed dependency on external kernel headers, all supported KVM features are now built into the binary
8 KB (1,151 words) - 06:40, 13 October 2011
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features' ] page for details of suggested replacement functionality
=== New deprecated options and features ===
8 KB (1,060 words) - 18:28, 9 December 2021
* Fixed block load instructions regression happened in 1.0 release.
...g a pflash drive. This feature is not supported when KVM is enabled. See [[Features/PC System Flash]] for more information.
8 KB (1,276 words) - 05:38, 3 June 2012
== Block subsystem ==
* Tested all 9p file system ( security models, features like mmap, locking, posixacl, zerocopy) using the basic fs tests, I/O and s
7 KB (1,052 words) - 16:41, 29 November 2011
* Host floppy device pass-through (block driver “host_floppy”) has been removed; it is still possible to use the
* Block device parameter aio=native has no effect without cache.direct=on. It will
13 KB (2,001 words) - 11:33, 17 December 2015
...size configurations, with the logical block size smaller than the physical block size, are rejected.
...eprecated Features"] appendix for the full list of historically deprecated features/options.
10 KB (1,457 words) - 01:21, 12 June 2018
=== New deprecated options and features ===
...eprecated Features"] appendix for the full list of historically deprecated features/options.
12 KB (1,748 words) - 09:55, 28 April 2019
...ockdev setup). Fix is on the list: https://lists.gnu.org/archive/html/qemu-block/2018-11/msg00759.html
== Targeted Features ==
3 KB (531 words) - 15:15, 4 September 2019
easy to understand and implement. The fine-grained features are marked
Requests that exceed the current limit must be queued since block I/O is
4 KB (631 words) - 15:41, 11 October 2016
...MODEL'',enforce", of course as long as TCG or KVM support the CPU's set of features. Previously, a few CPUs included extraneous CPUID flags that cause "-cpu ''
=== Block devices in system emulation ===
7 KB (980 words) - 15:30, 14 December 2014
=== [[Features/VNC_Tight_PNG|Tight PNG]] ===
...the queue will be threaded and (hopefully) send_framebuffer_update() won't block the guest execution anymore.
4 KB (662 words) - 07:54, 13 October 2016
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
==== Other removed features ====
11 KB (1,553 words) - 14:27, 3 February 2023
[[Features/QED | QED]] is another new QEMU image format. Below is the FVD developer’
.../ext4, reiserFS, Reiser4, XFS, JFS, VMFS, ZFS, etc) provide many different features and are optimized for different objectives (flash wear leveling, seek dista
8 KB (1,278 words) - 14:45, 11 October 2016
* A thin layer sits between device emulation and net/block layer
|Storage replication QEMU's block migration or others
4 KB (636 words) - 14:45, 11 October 2016
=== New deprecated options and features ===
...System Emulation User's Guide for the full list of historically deprecated features/options.
14 KB (2,072 words) - 20:38, 28 April 2020
=== New deprecated options and features ===
...eprecated Features"] appendix for the full list of historically deprecated features/options.
11 KB (1,707 words) - 08:58, 24 October 2019
* Removed support for tftp:// in the block layer, since this has been broken forever for files bigger than 256KB.
...command blockdev-add is still a work in progress. It doesn't support all block drivers, it lacks a matching blockdev-del, and more. It might change incom
9 KB (1,253 words) - 11:05, 21 December 2016
=== New deprecated options and features ===
...System Emulation User's Guide for the full list of historically deprecated features/options.
12 KB (1,689 words) - 16:12, 14 May 2021
...n a VM writes to a data block, the lower layers decide where to store that block. Traditionally, storage allocation is done twice, first by an image format
.../ext4, reiserFS, Reiser4, XFS, JFS, VMFS, ZFS, etc) provide many different features and are optimized for different objectives (flash wear leveling, seek dista
5 KB (875 words) - 14:45, 11 October 2016
* New "invtsc" (Invariant TSC) CPU feature. When enabled, this will block migration and savevm, so it is not enabled by default on any CPU model. To
=== Block devices in system emulation ===
10 KB (1,454 words) - 10:42, 29 July 2014
* Initial support for KVM on AArch64 systems (some features such as migration are not yet implemented)
...5420 is needed. In particular hotplug, pvpanic device and other ACPI based features now work for OVMF.
10 KB (1,572 words) - 19:24, 16 April 2014
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features' ] page for details of suggested replacement functionality
...maintained. Users are recommended to switch to an alternative distributed block device driver such as RBD.
12 KB (1,665 words) - 16:02, 24 August 2021
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features' ] page for details of suggested replacement functionality
=== New deprecated options and features ===
13 KB (1,888 words) - 07:16, 11 April 2022
==Outstanding features==
* Block device support (i.e. QED on LVM volumes)
3 KB (397 words) - 14:45, 11 October 2016
=== Removed features and incompatible changes ===
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
12 KB (1,752 words) - 14:51, 19 April 2023
...nected to the Ardunio. Each widget is defined as a block that can have two features:
3 KB (533 words) - 11:47, 9 March 2020
=== Removed features and incompatible changes ===
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
14 KB (2,029 words) - 10:59, 17 April 2024
; QEMU User-mode Emulation User's Guide (docs/user, [[Features/Documentation/user]])
; QEMU System Emulation User's Guide (docs/system, [[Features/Documentation/system]])
11 KB (1,827 words) - 15:38, 31 March 2020
...are needed to make reporting of block job error events robust (otherwise, block jobs just disappear and, if management misses BLOCK_JOB_COMPLETED events, i
* QEMUMachine has been replaced with a QOM hierarchy, details on [[Features/QOM/Machine]].
6 KB (988 words) - 06:57, 17 March 2022
=== Removed features and incompatible changes ===
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
15 KB (2,193 words) - 13:57, 18 December 2023
* COLO Block Replication (Please refer to [http://wiki.qemu.org/Features/BlockReplication BlockReplication])
: The following is the image of block replication workflow:
16 KB (1,321 words) - 18:38, 30 January 2023
* Don't allow multiwrites against a block device without underlying medium {{git|a0af597d00c27741a0bf99720209def055f4
* Various bug fixes, no new features.
16 KB (2,781 words) - 08:34, 12 October 2016
=== Removed features and incompatible changes ===
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features'] page for details of suggested replacement functionality.
14 KB (2,074 words) - 14:12, 15 August 2023
...[https://qemu-project.gitlab.io/qemu/about/removed-features.html 'Removed features' ] page for details of suggested replacement functionality.
=== New deprecated options and features ===
13 KB (1,895 words) - 13:55, 20 August 2022
...the internal implementation of QMP to simplify maintainability and enable features such as asynchronous command completion and rich error reporting. Minimize
# @device: This is normally the name of a block device but it may also be 'vnc'.
16 KB (2,377 words) - 18:10, 2 April 2015
'''Summary:''' The [[Features/tcg-multithread|MTTCG Project]] is a project
* Place TranslationBlock structures into the same memory block as code_gen_buffer
6 KB (983 words) - 13:44, 30 March 2017
* Host floppy device pass-through (block driver "host_floppy") is deprecated, and will be dropped in a future releas
* Block device parameter aio=native has no effect without cache.direct=on. It will
13 KB (2,067 words) - 17:11, 2 December 2015
* [[Features/QTest|QTest]]-based tests, which inject predefined stimuli into the device
* [[Testing/QemuIoTests|qemu-iotests]], a regression test suite for the block layer code.
9 KB (1,420 words) - 12:16, 12 July 2021
...[https://qemu-project.gitlab.io/qemu/system/removed-features.html 'Removed features' ] page for details of suggested replacement functionality
* The ''encryption_key_missing'' field has been removed from block device info data
19 KB (2,811 words) - 07:39, 16 April 2021
.../master/system/deprecated.html#recently-removed-features "Recently removed features"] chapter of the QEMU System Emulation User's Guide.
=== New deprecated options and features ===
18 KB (2,670 words) - 01:26, 7 May 2022
This page lists areas in the implementation of [[Features/Channel_I/O_Passthrough|vfio-ccw for channel I/O passthrough]] that still n
== Missing architecture features ==
9 KB (1,396 words) - 11:18, 11 December 2019
...e. Only x3270 is supported as client. See https://wiki.qemu.org/index.php/Features/3270 for details.
...vfio-ccw (channel device passthrough). See https://wiki.qemu.org/index.php/Features/Channel_I/O_Passthrough for details.
11 KB (1,614 words) - 18:24, 24 August 2017
* Support for network boot, see http://wiki.qemu-project.org/Features/S390xNetworkBoot
==== Block devices ====
13 KB (1,919 words) - 09:03, 19 April 2017
====Coroutines in the block layer [Kevin]====
* Programming model to simplify block drivers without blocking QEMU threads
21 KB (3,159 words) - 10:43, 11 November 2020
=== New deprecated options and features ===
...eprecated Features"] appendix for the full list of historically deprecated features/options.
25 KB (3,731 words) - 14:03, 23 October 2019
** fix: https://lists.gnu.org/archive/html/qemu-block/2020-11/msg00674.html
...already registered) - not a recent regression, thus this should likely not block the release
5 KB (755 words) - 10:12, 3 December 2020
There are several features still pending:
Persistence is the ability to save dirty block information to persistent storage in order to completely shut down QEMU wit
26 KB (4,022 words) - 16:28, 16 July 2019
...command blockdev-add is still a work in progress. It doesn't support all block drivers, it lacks a matching blockdev-del, and more. It might change incom
==== Block devices ====
12 KB (1,746 words) - 15:53, 1 September 2016
=== Deprecated options and features ===
...eprecated Features"] appendix for the full list of historically deprecated features/options.
18 KB (2,730 words) - 10:02, 26 April 2018
* Specifying block device parameter aio=native is now an error on POSIX systems if qemu is com
...command blockdev-add is still a work in progress. It doesn't support all block drivers, it lacks a matching blockdev-del, and more. It might change incom
20 KB (2,998 words) - 09:09, 19 July 2016
...than q35 does (e.g. interrupt remapping). As time permits, some additional features could already be added so that q35 could be manually configured to expose t
Minimally required VT-d features for q35 are:
19 KB (3,009 words) - 15:08, 16 February 2016
More detail: [[Features/Real rng device]]
...e amount of entropy the host has to give. Doing mouse, keyboard, network, block activity on the host will accelerate the speed with which the host can give
6 KB (994 words) - 16:08, 17 October 2016
For booting an s390x guest via network, see the dedicated page [[Features/S390xNetworkBoot]].
In this case I was using a block device via a ZFS pool, but a normal qcow2 device would work just as well.
7 KB (1,146 words) - 08:11, 30 September 2019
...ill in the configuration files, and no way to express dependencies between features. The project seeks to adopt Linux's Kconfig in QEMU, and possibly to impro
Useful features which can be added:
17 KB (2,629 words) - 15:07, 16 February 2016
- block: Handle multiwrite errors only when all requests have completed
- block: Fix early failure in multiwrite
42 KB (6,720 words) - 12:21, 18 February 2011
...er which means the fs driver needs to call file I/O syscall(s) which might block for a long time. Therefore the 9P server leaves the Coroutine at that point
* <b>Features</b>:
29 KB (4,827 words) - 12:39, 10 January 2024
