While we do mention some of this stuff in the various daemons and
manuals the subtleties of the socket and memory sharing are sometimes
missed. This document attempts to give some background on vhost-user
daemons in general terms.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210720232703.10650-4-alex.bennee@linaro.org>
Since the top-level subsections aren't self-contained manuals
any more, the "Contents:" lines at the top of each of their
index pages look a bit odd; remove them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20210705095547.15790-4-peter.maydell@linaro.org
We merged our previous multiple-manual setup into a single Sphinx
manual, but we left some text in the various index.rst lines that
still calls the top level subsections separate 'manuals'. Update
them to talk about "this section of the manual" instead, and remove
now-obsolete comments about how the index.rst files are the "top
level page for the 'foo' manual".
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20210705095547.15790-3-peter.maydell@linaro.org
In downstream, we want to use a different name for the QEMU binary,
and some people might also use the docs for non-x86 binaries, that's
why we already created the |qemu_system| placeholder in the past.
Use it now in the live-block-operations doc, too.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210607172311.915385-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Create an enum definition, '@amd-sev-es', for SEV-ES and add documention
for the new enum. Add an example that shows some of the requirements for
SEV-ES, including not having SMM support and the requirement for an
X64-only build.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Message-Id: <b941a7ee105dfeb67607cf2d24dafcb82658b212.1619208498.git.thomas.lendacky@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
The QAPI reference docs for the guest agent, storage daemon and QMP are
all rather long and hard to navigate unless you already know the name of
the command and can do full text search for it.
A table of contents in each doc will help people locate stuff much more
easily.
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The default "alabaster" sphinx theme has a couple shortcomings:
- the navbar moves along the page
- the search bar is not always at the same place
- it lacks some contrast and colours
The "rtd" theme from readthedocs.org is a popular third party theme used
notably by the kernel, with a custom style sheet. I like it better,
perhaps others do too. It also simplifies the "Edit on Gitlab" links.
Tweak a bit the custom theme to match qemu.org style, use the
QEMU logo, and favicon etc.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20210323115328.4146052-1-marcandre.lureau@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Now that we merged into one doc, it makes the nav looks nicer.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210323074704.4078381-1-marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Actually L1 table entry offset is in 512 bytes sectors. Fix the spec.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210224104707.88430-3-vsementsov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This has the following visible changes:
- GBM is required only for OpenGL dma-buf.
- X11 is explicitly required by gtk-egl.
- EGL is now mandatory for the OpenGL displays.
The last one needs some detailed description. Before this change,
EGL was tested only for OpenGL dma-buf with the check of
EGL_MESA_image_dma_buf_export. However, all of the OpenGL
displays depend on EGL and EGL_MESA_image_dma_buf_export is always
defined by epoxy's EGL interface.
Therefore, it makes more sense to always check the presence of EGL
and say the OpenGL displays are available along with OpenGL dma-buf
if it is present.
Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Message-Id: <20210223060307.87736-1-akihiko.odaki@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The preferred syntax is to use "foo=on|off", rather than a bare
"+foo" or "-foo"
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210216191027.595031-10-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The preferred syntax is to use "foo=on|off", rather than a bare
"foo" or "nofoo".
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210216191027.595031-8-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Original specification says that l1 table size if 64 * l1_size, which
is obviously wrong. The size of the l1 entry is 64 _bits_, not bytes.
Thus 64 is to be replaces with 8 as specification says about bytes.
There is also minor tweak, field name is renamed from l1 to l1_table,
which matches with the later text.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20210128171313.2210947-1-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[Replace the original commit message "docs: fix mistake in dirty bitmap
feature description" as suggested by Eric Blake.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210127144734.2367693-1-armbru@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
When we first converted our documentation to Sphinx, we split it into
multiple manuals (system, interop, tools, etc), which are all built
separately. The primary driver for this was wanting to be able to
avoid shipping the 'devel' manual to end-users. However, this is
working against the grain of the way Sphinx wants to be used and
causes some annoyances:
* Cross-references between documents become much harder or
possibly impossible
* There is no single index to the whole documentation
* Within one manual there's no links or table-of-contents info
that lets you easily navigate to the others
* The devel manual doesn't get published on the QEMU website
(it would be nice to able to refer to it there)
Merely hiding our developer documentation from end users seems like
it's not enough benefit for these costs. Combine all the
documentation into a single manual (the same way that the readthedocs
site builds it) and install the whole thing. The previous manual
divisions remain as the new top level sections in the manual.
* The per-manual conf.py files are no longer needed
* The man_pages[] specifications previously in each per-manual
conf.py move to the top level conf.py
* docs/meson.build logic is simplified as we now only need to run
Sphinx once for the HTML and then once for the manpages5B
* The old index.html.in that produced the top-level page with
links to each manual is no longer needed
Unfortunately this means that we now have to build the HTML
documentation into docs/manual in the build tree rather than directly
into docs/; otherwise it is too awkward to ensure we install only the
built manual and not also the dependency info, stamp file, etc. The
manual still ends up in the same place in the final installed
directory, but anybody who was consulting documentation from within
the build tree will have to adjust where they're looking.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210115154449.4801-1-peter.maydell@linaro.org
Although individual qemu-storage-daemon QMP commands are identical to
QEMU QMP commands, qemu-storage-daemon only supports a subset of QEMU's
QMP commands. Generate a manual page of just the commands supported by
qemu-storage-daemon so that users know exactly what is available in
qemu-storage-daemon.
Add an h1 heading in storage-daemon/qapi/qapi-schema.json so that
block-core.json is at the h2 heading level.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201209103802.350848-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fix also a similar typo in a code comment.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Message-Id: <20201117193448.393472-1-sw@weilnetz.de>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
QEMU currently truncates the mmap_offset field when sending
VHOST_USER_ADD_MEM_REG and VHOST_USER_REM_MEM_REG messages. The struct
layout looks like this:
typedef struct VhostUserMemoryRegion {
uint64_t guest_phys_addr;
uint64_t memory_size;
uint64_t userspace_addr;
uint64_t mmap_offset;
} VhostUserMemoryRegion;
typedef struct VhostUserMemRegMsg {
uint32_t padding;
/* WARNING: there is a 32-bit hole here! */
VhostUserMemoryRegion region;
} VhostUserMemRegMsg;
The payload size is calculated as follows when sending the message in
hw/virtio/vhost-user.c:
msg->hdr.size = sizeof(msg->payload.mem_reg.padding) +
sizeof(VhostUserMemoryRegion);
This calculation produces an incorrect result of only 36 bytes.
sizeof(VhostUserMemRegMsg) is actually 40 bytes.
The consequence of this is that the final field, mmap_offset, is
truncated. This breaks x86_64 TCG guests on s390 hosts. Other guest/host
combinations may get lucky if either of the following holds:
1. The guest memory layout does not need mmap_offset != 0.
2. The host is little-endian and mmap_offset <= 0xffffffff so the
truncation has no effect.
Fix this by extending the existing 32-bit padding field to 64-bit. Now
the padding reflects the actual compiler padding. This can be verified
using pahole(1).
Also document the layout properly in the vhost-user specification. The
vhost-user spec did not document the exact layout. It would be
impossible to implement the spec without looking at the QEMU source
code.
Existing vhost-user frontends and device backends continue to work after
this fix has been applied. The only change in the wire protocol is that
QEMU now sets hdr.size to 40 instead of 36. If a vhost-user
implementation has a hardcoded size check for 36 bytes, then it will
fail with new QEMUs. Both QEMU and DPDK/SPDK don't check the exact
payload size, so they continue to work.
Fixes: f1aeb14b08 ("Transmit vhost-user memory regions individually")
Cc: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201109174355.1069147-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: f1aeb14b08 ("Transmit vhost-user memory regions individually")
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Add a link to the top of the sidebar in every docs page that takes the
user back to the source code in gitlab.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20201102130926.161183-5-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
'qemu-img map' provides a way to determine which extents of an image
come from the top layer vs. inherited from a backing chain. This is
useful information worth exposing over NBD. There is a proposal to
add a QMP command block-dirty-bitmap-populate which can create a dirty
bitmap that reflects allocation information, at which point the
qemu:dirty-bitmap:NAME metadata context can expose that information
via the creation of a temporary bitmap, but we can shorten the effort
by adding a new qemu:allocation-depth metadata context that does the
same thing without an intermediate bitmap (this patch does not
eliminate the need for that proposal, as it will have other uses as
well).
While documenting things, remember that although the NBD protocol has
NBD_OPT_SET_META_CONTEXT, the rest of its documentation refers to
'metadata context', which is a more apt description of what is
actually being used by NBD_CMD_BLOCK_STATUS: the user is requesting
metadata by passing one or more context names. So I also touched up
some existing wording to prefer the term 'metadata context' where it
makes sense.
Note that this patch does not actually enable any way to request a
server to enable this context; that will come in the next patch.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20201027050556.269064-10-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This patch introduces the icount field for saving within the snapshot.
It is required for navigation between the snapshots in record/replay mode.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Kevin Wolf <kwolf@redhat.com>
--
v7 changes:
- also fix the test which checks qcow2 snapshot extra data
Message-Id: <160174518284.12451.2301137308458777398.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Convert qemu-qmp-ref to rST format. This includes dropping
the plain-text, pdf and info format outputs for this document;
as with all our other Sphinx-based documentation, we provide
HTML and manpage only.
The qemu-qmp-ref.rst is somewhat more stripped down than
the .texi was, because we do not (currently) attempt to
generate indexes for the commands, events and data types
being documented.
Again, we drop the direct link from index.html.in now that
the QMP ref is part of the interop manual.
This commit removes the code from the root meson.build file that
handled the various Texinfo-based outputs, because we no longer
generate any documentation except for the Sphinx HTML manuals and the
manpages, and the code can't handle having an empty list of files
to process.. We'll do further cleanup of the remainders of
Texinfo support in subsequent commits.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-10-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Unicode legacy literal dumbed down to plain string literal, TODO
comment on displaying QEMU version added, "make html" fixed,
storage-daemon/qapi/meson.build updated]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Convert qemu-ga-ref to rST format. This includes dropping
the plain-text, pdf and info format outputs for this document;
as with all our other Sphinx-based documentation, we provide
HTML and manpage only.
The qemu-ga-ref.rst is somewhat more stripped down than
the .texi was, because we do not (currently) attempt to
generate indexes for the commands, events and data types
being documented.
As the GA ref is now part of the Sphinx 'interop' manual,
we can delete the direct link from index.html.in.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-9-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Unicode legacy literal dumbed down to plain string literal, TODO
comment on displaying QEMU version added]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
I found that there are many spelling errors in the comments of qemu,
so I used the spellcheck tool to check the spelling errors
and finally found some spelling errors in the docs folder.
Signed-off-by: zhaolichang <zhaolichang@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200917075029.313-4-zhaolichang@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Commit 4d8bb958fa0..231aaf3a821 integrated the contents of
docs/qmp-events.txt into QAPI schema doc comments. It left dangling
references to qmp-events.txt behind. Fix to point to the QEMU QMP
reference manual generated from the QAPI schema.
Add a similar reference for commands.
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200806081147.3123652-2-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Subcluster allocation in qcow2 is implemented by extending the
existing L2 table entries and adding additional information to
indicate the allocation status of each subcluster.
This patch documents the changes to the qcow2 format and how they
affect the calculation of the L2 cache size.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <5199f2e1c717bcaa58b48142c9062b803145ff7f.1594396418.git.berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
The binaries move to the root directory, e.g. qemu-system-i386 or
qemu-arm. This requires changes to qtests, CI, etc.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The various schemas included in QEMU use a JSON-based format which
is, however, strictly speaking not valid JSON.
As a consequence, when vim tries to apply syntax highlight rules
for JSON (as guessed from the file name), the result is an unreadable
mess which mostly consist of red markers pointing out supposed errors
in, well, pretty much everything.
Using Python syntax highlighting produces much better results, and
in fact these files already start with specially-formatted comments
that instruct Emacs to process them as if they were Python files.
This commit adds the equivalent special comments for vim.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Message-Id: <20200729185024.121766-1-abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Make the capitalization of the hexadecimal numbers consistent for the
QCOW2 header extension constants in docs/interop/qcow2.txt.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <1594973699-781898-2-git-send-email-andrey.shinkevich@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Currently we have 2 types of vhost backends in QEMU: vhost kernel and
vhost-user. The above patch provides a generic device for vDPA purpose,
this vDPA device exposes to user space a non-vendor-specific configuration
interface for setting up a vhost HW accelerator, this patch set introduces
a third vhost backend called vhost-vdpa based on the vDPA interface.
Vhost-vdpa usage:
qemu-system-x86_64 -cpu host -enable-kvm \
......
-netdev type=vhost-vdpa,vhostdev=/dev/vhost-vdpa-id,id=vhost-vdpa0 \
-device virtio-net-pci,netdev=vhost-vdpa0,page-per-vq=on \
Signed-off-by: Lingshan zhu <lingshan.zhu@intel.com>
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Signed-off-by: Cindy Lu <lulu@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20200701145538.22333-14-lulu@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
This patch specifies the VHOST_USER_SET_STATUS and
VHOST_USER_GET_STATUS requests, which are sent by
the master to update and query the Virtio status
in the backend.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Message-Id: <20200618134501.145747-1-maxime.coquelin@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Historically, sending all memory regions to vhost-user backends in a
single message imposed a limitation on the number of times memory
could be hot-added to a VM with a vhost-user device. Now that backends
which support the VHOST_USER_PROTOCOL_F_CONFIGURE_SLOTS send memory
regions individually, we no longer need to impose this limitation on
devices which support this feature.
With this change, VMs with a vhost-user device which supports the
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS can support a configurable
number of memory slots, up to the maximum allowed by the target
platform.
Existing backends which do not support
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS are unaffected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Suggested-by: Mike Cui <cui@nutanix.com>
Message-Id: <1588533678-23450-6-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
With this change, when the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS
protocol feature has been negotiated, Qemu no longer sends the backend
all the memory regions in a single message. Rather, when the memory
tables are set or updated, a series of VHOST_USER_ADD_MEM_REG and
VHOST_USER_REM_MEM_REG messages are sent to transmit the regions to map
and/or unmap instead of sending send all the regions in one fixed size
VHOST_USER_SET_MEM_TABLE message.
The vhost_user struct maintains a shadow state of the VM’s memory
regions. When the memory tables are modified, the
vhost_user_set_mem_table() function compares the new device memory state
to the shadow state and only sends regions which need to be unmapped or
mapped in. The regions which must be unmapped are sent first, followed
by the new regions to be mapped in. After all the messages have been
sent, the shadow state is set to the current virtual device state.
Existing backends which do not support
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS are unaffected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Swapnil Ingle <swapnil.ingle@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Suggested-by: Mike Cui <cui@nutanix.com>
Message-Id: <1588533678-23450-5-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This change introduces a new feature to the vhost-user protocol allowing
a backend device to specify the maximum number of ram slots it supports.
At this point, the value returned by the backend will be capped at the
maximum number of ram slots which can be supported by vhost-user, which
is currently set to 8 because of underlying protocol limitations.
The returned value will be stored inside the VhostUserState struct so
that on device reconnect we can verify that the ram slot limitation
has not decreased since the last time the device connected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Message-Id: <1588533678-23450-4-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
zstd significantly reduces cluster compression time.
It provides better compression performance maintaining
the same level of the compression ratio in comparison with
zlib, which, at the moment, is the only compression
method available.
The performance test results:
Test compresses and decompresses qemu qcow2 image with just
installed rhel-7.6 guest.
Image cluster size: 64K. Image on disk size: 2.2G
The test was conducted with brd disk to reduce the influence
of disk subsystem to the test results.
The results is given in seconds.
compress cmd:
time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
src.img [zlib|zstd]_compressed.img
decompress cmd
time ./qemu-img convert -O qcow2
[zlib|zstd]_compressed.img uncompressed.img
compression decompression
zlib zstd zlib zstd
------------------------------------------------------------
real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
user 65.0 15.8 5.3 2.5
sys 3.3 0.2 2.0 2.0
Both ZLIB and ZSTD gave the same compression ratio: 1.57
compressed image size in both cases: 1.4G
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
QAPI part:
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200507082521.29210-4-dplotnikov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Backing files and raw external data files are mutually exclusive.
The documentation of the raw external data bit (in autoclear_features)
already indicates that, but we should also mention it on the other
side.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200410121816.8334-1-berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The feature table is supposed to advertise the name of all feature
bits that we support; however, we forgot to update the table for
autoclear bits. While at it, move the table to read-only memory in
code, and tweak the qcow2 spec to name the second autoclear bit.
Update iotests that are affected by the longer header length.
Fixes: 88ddffae
Fixes: 93c24936
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200324174233.1622067-3-eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Although qemu-ga has supported vsock since 2016 it was not documented on
the man page.
Also add the socket address representation to the qga --help output.
Fixes: 586ef5dee7
("qga: add vsock-listen method")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Description copied from Linux kernel commit from Gustavo A. R. Silva
(see [3]):
--v-- description start --v--
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to
declare variable-length types such as these ones is a flexible
array member [1], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler
warning in case the flexible array does not occur last in the
structure, which will help us prevent some kind of undefined
behavior bugs from being unadvertenly introduced [2] to the
Linux codebase from now on.
--^-- description end --^--
Do the similar housekeeping in the QEMU codebase (which uses
C99 since commit 7be41675f7).
All these instances of code were found with the help of the
following command (then manual analysis, without modifying
structures only having a single flexible array member, such
QEDTable in block/qed.h):
git grep -F '[0];'
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76497732932f
[3] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=17642a2fbd2c1
Inspired-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For good reason, vhost-user is currently built asynchronously, that
way better performance can be obtained. However, for certain use
cases such as simulation, this is problematic.
Consider an event-based simulation in which both the device and CPU
have scheduled according to a simulation "calendar". Now, consider
the CPU sending I/O to the device, over a vring in the vhost-user
protocol. In this case, the CPU must wait for the vring interrupt
to have been processed by the device, so that the device is able to
put an entry onto the simulation calendar to obtain time to handle
the interrupt. Note that this doesn't mean the I/O is actually done
at this time, it just means that the handling of it is scheduled
before the CPU can continue running.
This cannot be done with the asynchronous eventfd based vring kick
and call design.
Extend the protocol slightly, so that a message can be used for kick
and call instead, if VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS is
negotiated. This in itself doesn't guarantee synchronisation, but both
sides can also negotiate VHOST_USER_PROTOCOL_F_REPLY_ACK and thus get
a reply to this message by setting the need_reply flag, and ensure
synchronisation this way.
To really use it in both directions, VHOST_USER_PROTOCOL_F_SLAVE_REQ
is also needed.
Since it is used for simulation purposes and too many messages on
the socket can lock up the virtual machine, document that this should
only be used together with the mentioned features.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Message-Id: <20200123081708.7817-6-johannes@sipsolutions.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Move the following tools documentation files to the new tools manual:
docs/interop/qemu-img.rst
docs/interop/qemu-nbd.rst
docs/interop/virtfs-proxy-helper.rst
docs/interop/qemu-trace-stap.rst
docs/interop/virtiofsd.rst
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200217155415.30949-4-peter.maydell@linaro.org
The qemu-option-trace.rst.inc file contains a rST documentation
fragment which describes trace options common to qemu-nbd and
qemu-img. We put this file into interop/, but we'd like to move the
qemu-nbd and qemu-img files into the tools/ manual. We could move
the .rst.inc file along with them, but we're eventually going to want
to use it for the main QEMU binary options documentation too, and
that will be in system/. So move qemu-option-trace.rst.inc to the
top-level docs/ directory, where all these files can include it via
.. include:: ../qemu-option-trace.rst.inc
This does have the slight downside that we now need to explicitly
tell Make which manuals use this file rather than relying on
a wildcard for all .rst.inc in the manual.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200217155415.30949-3-peter.maydell@linaro.org
In many cases the target of a convert operation is a newly provisioned
target that the user knows is blank (reads as zero). In this situation
there is no requirement for qemu-img to wastefully zero out the entire
device.
Add a new option, --target-is-zero, allowing the user to indicate that
an existing target device will return zeros for all reads.
Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20200205110248.2009589-2-david.edmondson@oracle.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
The patch adds a new additional field to the qcow2 header: compression_type,
which specifies compression type. If field is absent or zero, default
compression type is set: ZLIB, which corresponds to current behavior.
New compression type (ZSTD) is to be added in further commit.
Suggested-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200131142219.3264-3-vsementsov@virtuozzo.com>
[mreitz: s/Bits 3-63: Reserved/Bits 4-63: Reserved/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Make it more obvious how to add new fields to the version 3 header and
how to interpret them.
The specification is adjusted so that for new defined optional fields:
1. Software may support some of these optional fields and ignore the
others, which means that features may be backported to downstream
Qemu independently.
2. If we want to add incompatible field (or a field, for which some of
its values would be incompatible), it must be accompanied by
incompatible feature bit.
Also the concept of "default is zero" is clarified, as it's strange to
say that the value of the field is assumed to be zero for the software
version which don't know about the field at all and don't know how to
treat it be it zero or not.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200131142219.3264-2-vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
[mreitz: s/some its/some of its/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Document the virtiofsd(1) program and its command-line options. This
man page is a rST conversion of the original texi documentation that I
wrote.
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
