This driver is like virtio-balloon on steroids: it allows both changing the
guest memory allocation via ballooning and (in the next patch) inserting
pieces of extra RAM into it on demand from a provided memory backend.
The actual resizing is done via ballooning interface (for example, via
the "balloon" HMP command).
This includes resizing the guest past its boot size - that is, hot-adding
additional memory in granularity limited only by the guest alignment
requirements, as provided by the next patch.
In contrast with ACPI DIMM hotplug where one can only request to unplug a
whole DIMM stick this driver allows removing memory from guest in single
page (4k) units via ballooning.
After a VM reboot the guest is back to its original (boot) size.
In the future, the guest boot memory size might be changed on reboot
instead, taking into account the effective size that VM had before that
reboot (much like Hyper-V does).
For performance reasons, the guest-released memory is tracked in a few
range trees, as a series of (start, count) ranges.
Each time a new page range is inserted into such tree its neighbors are
checked as candidates for possible merging with it.
Besides performance reasons, the Dynamic Memory protocol itself uses page
ranges as the data structure in its messages, so relevant pages need to be
merged into such ranges anyway.
One has to be careful when tracking the guest-released pages, since the
guest can maliciously report returning pages outside its current address
space, which later clash with the address range of newly added memory.
Similarly, the guest can report freeing the same page twice.
The above design results in much better ballooning performance than when
using virtio-balloon with the same guest: 230 GB / minute with this driver
versus 70 GB / minute with virtio-balloon.
During a ballooning operation most of time is spent waiting for the guest
to come up with newly freed page ranges, processing the received ranges on
the host side (in QEMU and KVM) is nearly instantaneous.
The unballoon operation is also pretty much instantaneous:
thanks to the merging of the ballooned out page ranges 200 GB of memory can
be returned to the guest in about 1 second.
With virtio-balloon this operation takes about 2.5 minutes.
These tests were done against a Windows Server 2019 guest running on a
Xeon E5-2699, after dirtying the whole memory inside guest before each
balloon operation.
Using a range tree instead of a bitmap to track the removed memory also
means that the solution scales well with the guest size: even a 1 TB range
takes just a few bytes of such metadata.
Since the required GTree operations aren't present in every Glib version
a check for them was added to the meson build script, together with new
"--enable-hv-balloon" and "--disable-hv-balloon" configure arguments.
If these GTree operations are missing in the system's Glib version this
driver will be skipped during QEMU build.
An optional "status-report=on" device parameter requests memory status
events from the guest (typically sent every second), which allow the host
to learn both the guest memory available and the guest memory in use
counts.
Following commits will add support for their external emission as
"HV_BALLOON_STATUS_REPORT" QMP events.
The driver is named hv-balloon since the Linux kernel client driver for
the Dynamic Memory Protocol is named as such and to follow the naming
pattern established by the virtio-balloon driver.
The whole protocol runs over Hyper-V VMBus.
The driver was tested against Windows Server 2012 R2, Windows Server 2016
and Windows Server 2019 guests and obeys the guest alignment requirements
reported to the host via DM_CAPABILITIES_REPORT message.
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
add the libvfio-user library as a submodule. build it as a meson
subproject.
libvfio-user is distributed with BSD 3-Clause license and
json-c with MIT (Expat) license
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: c2adec87958b081d1dc8775d4aa05c897912f025.1655151679.git.jag.raman@oracle.com
[Changed submodule URL to QEMU's libvfio-user mirror on GitLab. The QEMU
project mirrors its dependencies so that it can provide full source code
even in the event that its dependencies become unavailable. Note that
the mirror repo is manually updated, so please contact me to make newer
libvfio-user commits available. If I become a bottleneck we can set up a
cronjob.
Updated scripts/meson-buildoptions.sh to match the meson_options.txt
change. Failure to do so can result in scripts/meson-buildoptions.sh
being modified by the build system later on and you end up with a dirty
working tree.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Pass CONFIG_FUZZ via host_kconfig, and use it to select the
sparse-mem device.
Cc: Alexander Oleinik <alxndr@bu.edu>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20211007130829.632254-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add configuration options to enable or disable multiprocess QEMU code
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 6cc37253e35418ebd7b675a31a3df6e3c7a12dc1.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Following the same logic as for vhost-net-user and vhost-kernel,
enable vhost-net if vhost-net-vdpa is enabled and vhost-net is not
explicitly disabled.
See 299e6f19b3 ("vhost-net: revamp configure logic")
Autoselect VHOST if VHOST_VDPA is set
See 21c6b0c87e ("configure: simplify vhost condition with Kconfig")
See 2becc36a3e ("meson: infrastructure for building emulators"
Problems can be triggered using;
... --enable-vhost-vdpa --disable-vhost-user --disable-vhost-kernel ...
Fixes: 108a64818e ("vhost-vdpa: introduce vhost-vdpa backend")
Cc: lulu@redhat.com
Cc: pbonzini@redhat.com
Cc: marcandre.lureau@redhat.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20200924210023.160679-1-lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Move the accel selectors from the global Kconfig.host to their
own Kconfig file.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Express the complex conditions in Kconfig rather than Makefiles, since Kconfig
is better suited at expressing dependencies and detecting contradictions.
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For devices that require msi_init/msix_init to succeed, add a
dependency on CONFIG_MSI_NONBROKEN. This will prevent those devices
from appearing in a binary that cannot instantiate them.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The make_device_config.sh script is replaced by minikconf, which
is modified to support the same command line as its predecessor.
The roots of the parsing are default-configs/*.mak, Kconfig.host and
hw/Kconfig. One difference with make_device_config.sh is that all symbols
have to be defined in a Kconfig file, including those coming from the
configure script. This is the reason for the Kconfig.host file introduced
in the previous patch. Whenever a file in default-configs/*.mak used
$(...) to refer to a config-host.mak symbol, this is replaced by a
Kconfig dependency; this part must be done already in this patch
for bisectability.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190123065618.3520-28-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The Kconfig files were generated mostly with this script:
for i in `grep -ho CONFIG_[A-Z0-9_]* default-configs/* | sort -u`; do
set fnord `git grep -lw $i -- 'hw/*/Makefile.objs' `
shift
if test $# = 1; then
cat >> $(dirname $1)/Kconfig << EOF
config ${i#CONFIG_}
bool
EOF
git add $(dirname $1)/Kconfig
else
echo $i $*
fi
done
sed -i '$d' hw/*/Kconfig
for i in hw/*; do
if test -d $i && ! test -f $i/Kconfig; then
touch $i/Kconfig
git add $i/Kconfig
fi
done
Whenever a symbol is referenced from multiple subdirectories, the
script prints the list of directories that reference the symbol.
These symbols have to be added manually to the Kconfig files.
Kconfig.host and hw/Kconfig were created manually.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20190123065618.3520-27-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maciej S. Szmigiero