On the restore path, using the available and used indexes read from
memory to fill the Queue structure was a mistake. Indeed, the available
index is written from the guest and it reflects the last available index
in the descriptor table. But the driver might have queued a lot of
buffers which have not yet been used by the device. This leads to a
situation where the next_avail from Queue is completely different from
the one we can read from memory.
Instead, the right way to determine the next_avail index that should be
used by the device is by relying on the used index from the memory. This
index represents the correct information we're looking for as it has
been updated before the snapshot to let the guest know the next index to
process.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
First, this modifies the existing helpers on how to get indexes for
available and used rings from memory. Instead of updating the queue
through each helper, they are now used as simple getters.
Based on these new getters, we could create a new helper to determine if
the queue has some available descriptors already queued from the driver
side. This helper is going to be particularly helpful when trying to
determine from a virtio thread if a queue is already loaded with some
available buffers that can be used to send information to the guest.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
When a virtio device is dynamically removed from the VM through the
hot-unplug mechanism, every mapping associated with it must be properly
removed.
Based on the previous patches letting a VirtioDevice expose the list of
userspace mappings associated with it, this patch can now remove all the
KVM userspace memory regions through the MemoryManager.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The same way we added a helper for creating userspace memory mappings
from the MemoryManager, this patch adds a new helper to remove some
previously added mappings.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Since the virtio-fs device is backed by a vhost-user process, it is
important to implement the proper shutdown() function from the
VirtioDevice trait, as vhost-user-blk and vhost-user-net do.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
When hot-unplugging the virtio-pmem from the VM, we don't remove the
associated userspace mapping. This patch will let us fix this in a
following patch. For now, it simply adapts the code so that the Pmem
device knows about the mapping associated with it. By knowing about it,
it can expose it to the caller through the new userspace_mappings()
function.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This will help when we will implement the hot-unplug of the virtio-fs
device, as we will have to remove correctly the userspace mappings
associated with the device.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Introduce new getter function to the VirtioDevice trait, as it will
allow the caller to retrieve the list of userspace mappings associated
with the device.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
There is some duplication between regular and hotplug virtio-fs tests
that can be factorized by adding a simple hotplug flag to choose if each
test should run with or without hotplugging the device.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The hotplugged virtio devices were not added to the list of virtio
devices from the DeviceManager. This patch fixes it, as it was causing
hotplugged virtio-fs devices from not supporting memory hotplug, since
they were never getting the update as they were not part of the list of
virtio devices held by the DeviceManager.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Adds DeviceManager method `make_virtio_fs_device` which creates a single
device, and modifies `make_virtio_fs_devices` to use this method.
Implements the new `vm.add-fs route`.
Signed-off-by: Dean Sheather <dean@coder.com>
Currently unimplemented. Once implemented, this API will allow for
creating virtio-fs devices in the VM after it has booted.
Signed-off-by: Dean Sheather <dean@coder.com>
In the context of the shared memory region used by virtio-fs in order to
support DAX feature, the shared region is exposed as a dedicated PCI
BAR, and it is backed by a KVM userspace mapping.
Upon BAR remapping, the BAR is moved to a different location in the
guest address space, and the KVM mapping must be updated accordingly.
Additionally, we need the VirtioDevice to report the updated guest
address through the shared memory region returned by get_shm_regions().
That's why a new setter is added to the VirtioDevice trait, so that
after the mapping has been updated for KVM, we can tell the VirtioDevice
the new guest address the shared region is located at.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
By adding the shared memory regions to the list of BARs, we make sure
the DeviceManager will register it as a BAR on the PCI bus. Without
this, when PCI BAR reprogramming happens, the PCI bus errors since it
does not know about any BAR at the specified address.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The order the elements are pushed into the list is important to restore
them in the right order. This is particularly important for MmioDevice
(or VirtioPciDevice) and their VirtioDevice counterpart.
A device must be fully ready before its associated transport layer
management can trigger its restoration, which will end up activating the
device in most cases.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Any virtio device relying on the mmio transport layer can be snapshotted
and restored thanks to this new patch. From the MmioDevice perspective,
it is mainly a matter of saving the information about the virtqueues as
the restore path will need them to activate the device (if needed
because it has been activated before being snapshotted).
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In anticipation for adding snapshot/restore support to virtio devices,
this commit introduces two new helpers updating the available and used
indexes of a queue, relying on the guest memory.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit relies on serde to serialize and deserialize the content of
a Queue structure. This will be useful information to store when
implementing snapshot/restore feature for virtio devices.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Add the WRITE_KILL_PRIV write flag, corresponding to
FUSE_WRITE_KILL_PRIV introduced in 7.31, and use to only remove the
setuid and setgid bits (by switching credentials) conditionally.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Add support for MAX_PAGES, corresonding to FUSE_MAX_PAGES introduced
in FUSE 7.28.
This allows us to negotiate with the kernel the maximum number of
pages that we support to transfer in a single request.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Add support for FOPEN_CACHE_DIR, a flag that allows us to tell the
guest that it's safe to cache a directory, introduced in FUSE 7.28.
Signed-off-by: Sergio Lopez <slp@redhat.com>
When reporting the BAR size it is necessary to return a value that is
encoded such that all the bits are set that represent the mask of the
natural alignment of the field.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Add support for specifying the PCI revision in the PCI configuration and
populate this with the value of 1 for virtio-pci devices.
The virtio-pci specification is slightly ambiguous only saying that
transitional (i.e. devices that support legacy and virtio 1.0) should
set this to 0. In practice it seems that software expects the revision
to be set to 1 for modern only devices.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
OVMF and other standard firmwares use I/O port 0x402 as a simple debug
port by writing ASCII characters to it. This is gated under a feature
that is not enabled by default.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
After all the previous refactoring patches, we can finally create
multiple threads under the same backend. This is directly combined with
multiqueues so that it will create one thread per queue.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Anticipating the follow up patches to run multiple threads for the same
backend, we need the initialization of the disk to happen in the high
level structure VhostUserBlkBackend.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The DiskFile will need to be shared across multiple threads when running
multiple queues across these threads. That's why it needs to be put
inside an Arc. The reason for the Mutex is because execute() expects a
mutable object implementing Read + Write + Seek. Unfortunately, this
create a contention point as the object needs to be locked from each
thread, reducing the performance gain we will get with multiple threads.
The need for an immutable object would solve this problem, and it will
be addressed later through follow up patches.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
There is no need for retrieving the VringWorker since we don't need to
register some extra file descriptors to the epoll loop.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
We now support assigning device ids for VFIO and virtio-pci devices so
this error can be generalised.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Extend the eject_device() method on DeviceManager to also support
virtio-pci devices being unplugged.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Add an accessor to return the underlying VirtioDevice. This is useful
for managing the removal of the device from internal datastructures when
handling virtio-pci device unplug.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
In order to support hotplugging there is a map of human readable device
id to PCI BDF map.
As the device id is part of the specific device configuration (e.g.
NetConfig) it is necessary to return the id through from the helper
functions that create the devices through to the functions that add
those devices to the bus. This necessitates changing a great deal of
function prototypes but otherwise has little impact.
Currently only if an id is supplied by the user as part of the device
configuration is it populated into this map. A later commit will
populate with an autogenerated name where none is supplied by the user.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
