Add missing WCE (write-cache enable) property support. This not only
an enhancement, but also a fix for a bug.
Right now, when vhost_user_blk uses a qcow2 image, it doesn't write
the QCOW2 metadata until the guest explicitly requests a flush. In
practice, this is equivalent to the write back semantic.
Without WCE, the guest assumes write through for the virtio_blk
device, and doesn't send those flush requests. Adding support for WCE,
and enabling it by default, we ensure the guest does send said
requests.
Supporting "WCE = false" would require updating our qcow2
implementation to ensure that, when required, it honors the write
through semantics by not deferring the updates to QCOW2 metadata.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Add support for opening the disk images with O_DIRECT. This allows
bypassing the host's file system cache, which is useful to avoid
polluting its cache and for better data integrity.
This mode of operation can be enabled by adding the "direct=<bool>"
parameter to the "backend" argument:
./target/debug/vhost_user_blk --backend image=test.raw,sock=/tmp/vhostblk,direct=true
The "direct" parameter defaults to "false", to preserve the original
behavior.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Use RawFile as backend instead of File. This allows us to abstract
the access to the actual image with a specialized layer, so we have a
place where we can deal with the low-level peculiarities.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Doing I/O on an image opened with O_DIRECT requires to adhere to
certain restrictions, requiring the following elements to be aligned:
- Address of the source/destination memory buffer.
- File offset.
- Length of the data to be read/written.
The actual alignment value depends on various elements, and according
to open(2) "(...) there is currently no filesystem-independent
interface for an application to discover these restrictions (...)".
To discover such value, we iterate through a list of alignments
(currently, 512 and 4096) calling pread() with each one and checking
if the operation succeeded.
We also extend RawFile so it can be used as a backend for QcowFile,
so the later can be easily adapted to support O_DIRECT too.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Update the common part in net_util.rs under vm-virtio to add mq
support, meanwhile enable mq for virtio-net device, vhost-user-net
device and vhost-user-net backend. Multiple threads will be created,
one thread will be responsible to handle one queue pair separately.
To gain the better performance, it requires to have the same amount
of vcpus as queue pair numbers defined for the net device, due to
the cpu affinity.
Multiple thread support is not added for vhost-user-net backend
currently, it will be added in future.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Since the common parts are put into net_util.rs under vm-virtio,
refactoring code for virtio-net device, vhost-user-net device
and backend to shrink the code size and improve readability
meanwhile.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
The current backend only support rw, and we also need
add readonly support.
The new command:
vhost_user_blk \
--backend "image=/home/test.img, \
sock=/home/path/vhost.socket, \
readonly=true"
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Because the vhost_user_backend crate needs some changes to support
moving the process to a different mount namespace and perform a pivot
root, it is not possible to change '/' to the given shared directory.
This commit, as a temporary measure, let the code point at the given
shared directory.
The long term solution is to perform the mount namespace change and the
pivot root as this will provide greater security.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This patch implements a vhost-user-fs daemon based on Rust. It only
supports communicating through the virtqueues. The support for the
shared memory region associated with DAX will be added later.
It relies on all the code copied over from the crosvm repository, based
on the commit 961461350c0b6824e5f20655031bf6c6bf6b7c30.
It also relies on the vhost_user_backend crate, limiting the amount of
code needed to get this daemon up and running.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Create a vhost-user-blk backend using vhost-user-backend and following
the conventions established by the existing vhost-user-net
implementation.
This backend is based on https://github.com/slp/vhost-user-backend,
but a bit simplified, making it closer to the original implementation
in Firecracker. The main features missing are EVENT_IDX, support for
asynchronous I/O and multiqueue, but it's still fully functional and
provides a good starting point for evolving it into a more complete
implementation.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Extend VhostUserBackend trait with protocol_features(), so device
backend implementations can freely define which protocol features they
want to support.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Clean up the error handling and ensure that where possible errors are
propagated. Make use of std::convert::From in order to translate error
types.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Simplify the check for the unusual situation where the memory is not
configured by using .ok_or() on the option to convert it to a result.
This cleans up a bunch of extra indentation.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Remove messages that are left over from the development of the project
that represent normal operation for the backend. This cleans up the
console output and improves performance.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Create vhost-user-net backend with Tap interface, to offload network
transaction from cloud-hypervisor. The goal is to provide flexibility
about the backend being in use, but also more security as it will allow
users to isolate the backend with different security profiles since it
will run as a dedicated process on the host.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
