By implementing this virtio feature, we let the virtio-iommu driver call
the device backend so that it can probe each device that gets attached.
Through this probing, the device provides a range of reserved memory
related to MSI. This is mandatory for x86 architecture as we want to
avoid the default MSI range assigned by the virtio-iommu driver if no
range is provided at all. The default range is 0x8000000-0x80FFFFF but
it only makes sense for ARM architectures.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This allows us to change the memory map that is being used by the
devices via an atomic swap (by replacing the map with another one). The
ArcSwap provides the mechanism for atomically swapping from to another
whilst still giving good read performace. It is inside an Arc so that we
can use a single ArcSwap for all users.
Not covered by this change is replacing the GuestMemoryMmap itself.
This change also removes some vertical whitespace from use blocks in the
files that this commit also changed. Vertical whitespace was being used
inconsistently and broke rustfmt's behaviour of ordering the imports as
it would only do it within the block.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Due to the amount of code currently duplicated across virtio devices,
the stats for this commit is on the large side but it's mostly more
duplicated code, unfortunately.
Migratable and Snapshotable placeholder implementations are provided as
well, making all virtio devices Migratable.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In order to speed up the boot time and reduce the amount of mappings,
this patch exposes the virtio-iommu device as supporting both 2M and 4k
page sizes.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This patch relies on the trait implementation provided for each device
which requires some sort of external update based on a map or unmap.
Whenever a MAP or UNMAP request comes through the virtqueues, it
triggers a call to the external mapping trait with map()/unmap()
functions being invoked.
Those external mappings are meant to be used from VFIO and vhost-user
devices as they need to update their own mappings. In case of VFIO, the
goal is to update the DMAR table in the physical IOMMU, while vhost-user
devices needs to update their internal representation of the virtqueues.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This patch introduces the first implementation of the virtio-iommu
device. This device emulates an IOMMU for the guest, which allows
special use cases like nesting passed through devices, or even using
IOVAs from the guest.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
