With the per handler needs_reset() gates removed from net and
block, nothing reads DEVICE_NEEDS_RESET anymore. Drop the
device_needs_reset helper and refresh the doc comment on
mark_device_needs_reset to reflect the central call site in
spawn_virtio_thread, where it runs after the worker has already
exited.
No functional change.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
With virtqueue iterator errors now killing the worker and
spawn_virtio_thread marking NEEDS_RESET centrally, the per
handler needs_reset() gate on process_queue_submit and
process_queue_complete is unreachable.
Drop needs_reset(), the two early returns, the unused
device_status field on BlockEpollHandler and its initializer,
and the device_needs_reset import.
No functional change.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
queue.iter() errors used to be swallowed by
handle_queue_iterator_error(), which marked the device as
NEEDS_RESET and returned Ok so the worker kept running while
disabled. spawn_virtio_thread now does the NEEDS_RESET marking
when the worker exits with an error.
Propagate the iterator error as Error::QueueIterator and escalate
it to EpollHelperError::HandleEvent in
process_queue_submit_and_signal so the worker exits. Per request
errors stay logged. Drop the now unused
handle_queue_iterator_error helper.
No functional change for the guest. NEEDS_RESET is still set and
the config interrupt is still raised on virtqueue corruption.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
spawn_virtio_thread now marks the device as NEEDS_RESET and notifies
the guest whenever the worker thread exits with an error, so the
per handler needs_reset() gate and the handle_queue_iterator_error()
helper in net are redundant.
Let virtqueue iterator errors propagate out of the worker thread
through DeviceError::NetQueuePair. Drop the unused device_status
field and the device_needs_reset and mark_device_needs_reset
imports.
No functional change for the guest. NEEDS_RESET is still set and
the config interrupt is still raised on virtqueue corruption.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Request::parse rejected unknown request types with an error, causing
process_queue to report the chain as used with no response written.
The device should write an error response so the driver knows the
request was handled. Move type validation out of parse into
process_queue where a proper response can be constructed.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Address translation, guest memory read, write, and flush failures on
the transmitq propagated errors that killed the console device thread.
A host-side I/O error such as a PTY disconnect would permanently
disable the console. Log warnings and continue processing instead.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Address translation or guest memory write failures on the receiveq
propagated errors that killed the console device thread. Log a
warning and break out of the descriptor loop instead.
Also fix a data-loss bug: bytes were drained from the input buffer
before the write to guest memory, so a failed write would silently
discard the data. Copy first, write, then drain only on success.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
The output queue handler read data from every descriptor without
checking the write-only flag. The driver must not put device-writable
buffers in the transmitq. Skip them with a warning.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
The input queue handler wrote data to every descriptor without
checking the write-only flag. The device must not write to
device-readable buffers. Skip them with a warning.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Remove UnknownRequestType (no longer returned after responding with
ERROR), EventFdWriteFail, EventFdTryCloneFail, MpscRecvFail, and
NotActivatedByGuest which have no call sites. Drop the now-unused
mpsc import.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
A malformed descriptor chain — wrong read/write flags, missing
descriptors, or undersized buffers — caused Request::parse to return
an error that killed the device thread. Log a warning, report the
chain as used with zero length, and continue processing.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
is_range_state() and set_range() took nb_blocks as u16 to match the
wire format, but unplug_all() computed the total block count from
region_size / block_size and cast to u16, silently truncating for
regions larger than 128 GiB. Widen the internal parameter to usize
so unplug_all() resets the full bitmap.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
When is_valid_range() returns false, the handler still computed
offset = addr - config.addr which can underflow if addr is below the
region base, then queried the bitmap at a meaningless index. Return
(ERROR, 0) immediately so no arithmetic runs on invalid input.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
An unknown request type caused process_queue to return an error that
killed the device thread. The request/response descriptors are already
parsed at this point, so respond with VIRTIO_MEM_RESP_ERROR and
continue processing.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Address translation or memory release errors on the free page
reporting queue propagated up and killed the balloon device thread.
Log a warning and skip the offending descriptor so the device
continues operating.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
A single malformed descriptor — device-writable where device-readable
is expected, non-aligned length, overflowed address, unmapped PFN, or
a failed fallocate/madvise — propagated an error that killed the
balloon device thread. Skip bad descriptors and PFNs with a warning
so the device keeps operating.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Only the first descriptor in each chain was processed. If the PFN
array spanned multiple chained descriptors the remaining PFNs were
silently dropped. Iterate the full chain so every descriptor is
validated and its PFNs are acted on.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
The inflate and deflate queues carry device-readable PFN arrays: the
driver writes them and the device only reads. The device never writes
to the descriptor buffers, so the used ring entry should report 0
bytes written rather than the descriptor length.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Fix "Fail tp signal" typo, replace copy-pasted "entropy" comment
with "balloon", and remove EventFdWriteFail and QueueIterator error
variants that have no call sites.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
When address translation or the entropy read fails mid-chain the
handler reset total_len to zero before breaking out of the loop.
If earlier descriptors in the same chain were already filled, the
used ring entry under-reports the bytes actually written to guest
memory. Drop the reset so the used length reflects reality.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
A device-readable descriptor anywhere in the chain caused the handler
to reset the byte count to zero and abandon the rest of the chain.
This discards valid device-writable descriptors that follow and
misreports bytes already written to earlier descriptors.
Skip device-readable and zero-length descriptors individually so
the remaining device-writable buffers still get filled with entropy.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-6
Worker threads spawned through spawn_virtio_thread previously wrote to
exit_evt on any clean Err return, taking the whole VMM down on a single
failed device worker. A guest induced fault in any virtio device thus
propagated into a host wide failure.
Route the Err return through the shared mark_device_needs_reset helper
instead. The helper sets the DEVICE_NEEDS_RESET bit on device_status
and triggers a config change interrupt, so the device goes idle and
the guest is informed. The thread exits cleanly without killing the
rest of the VMM.
The panic and the seccomp filter apply paths keep writing to exit_evt.
A panicked worker may have left poisoned locks or partially mutated
state, so a hard exit remains the right policy there.
spawn_virtio_thread now takes the device_status and the interrupt
callback. Every native virtio and vhost-user call site is updated to
pass them in.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Both block and net implement the same DEVICE_NEEDS_RESET bookkeeping
when a corrupted virtqueue request is detected. They set the bit,
trigger a config change interrupt and log a warning. Move that logic
into shared device_needs_reset and mark_device_needs_reset helpers in
lib.rs and update both call sites to use them.
No functional change.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
The per-domain mapping cap bounds memory inside one domain, but a
guest can still grow the domains map indefinitely with ATTACH
requests for distinct domain IDs. Reject ATTACH with
VIRTIO_IOMMU_S_NOMEM at 64K domains.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The virtio spec says the device must never present a value other
than 0 or 1 for bypass. Mask off the upper bits on write so a
later read does not return whatever the driver wrote.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The device offers VIRTIO_IOMMU_F_INPUT_RANGE when the address
width is constrained, but never validates that guest MAP requests
fall inside the advertised range. The virtio spec requires such
requests to fail with VIRTIO_IOMMU_S_RANGE.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The virtio spec mandates VIRTIO_IOMMU_S_NOENT, not S_INVAL, when
the target domain does not exist.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The handler accepted unknown flag bits, unaligned ranges, and
overlapping mappings, and returned the wrong status code when the
target domain did not exist. The virtio spec requires explicit
rejections for each of these.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The virtio spec requires the device to reject ATTACH with a
non-zero reserved field, an unknown flag bit, or a bypass flag
that conflicts with an existing domain. The current handler
silently accepts all three.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The virtio spec requires the device to leave the reply buffer
untouched and report a used length of zero for an unrecognised
request type, so the driver can tell the request was not handled.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
Domain::mappings only shrinks on UNMAP. Without a bound a guest can
issue MAP for arbitrarily many distinct virt_start values and drive
the VMM heap until the host runs out.
Reject MAP with VIRTIO_IOMMU_S_NOMEM at 1M entries per domain.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
A concurrent DETACH between the read-lock check and the write-lock
get_mut().unwrap() in MAP/UNMAP would panic the worker. Replace the
unwrap with a let-else.
A failure on a later endpoint in the per-endpoint MAP loop, or a
DETACH that races the missing-domain branch, must roll back the
external mappings already installed; otherwise domain.mappings
diverges from VFIO state.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
An UNMAP that would split an existing mapping must be rejected with
VIRTIO_IOMMU_S_RANGE without removing anything. The previous start-only
retain silently left mappings that started outside the unmap range but
overlapped it.
Walk bookkeeping under a read lock and reject before touching VFIO so a
rejection cannot leave VFIO and bookkeeping out of sync.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The DmaRemapping translate_gva and translate_gpa entry points discarded
the size argument that AccessPlatform's signature already carries and
only checked the base address. A buffer beginning inside a mapping but
extending past it was treated as fully translated, allowing reads or
writes outside the IOMMU-authorized window.
Add `size` to the trait, validate the full span fits in a single
mapping, and propagate it through AccessPlatformMapping.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
The reply length was `hdr_len + size_of::<tail>()`, computed twice.
Make it explicit via checked_add and reuse the result.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Assisted-by: Claude:claude-opus-4-7
Verify that firing a config change interrupt with msix_config
vector beyond the table size returns Ok without panicking.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Verify that a valid in bounds vector with MSI-X enabled
successfully triggers the interrupt source group.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Verify that requesting a notifier with an out-of-bounds MSI-X
vector returns None instead of panicking.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Verify that triggering an interrupt when the vector is set to
VIRTQ_MSI_NO_VECTOR short-circuits and returns Ok.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Verify that firing an interrupt with a queue vector beyond the
MSI-X table size returns Ok without panicking.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
A malicious or buggy guest can write an out-of-bounds value to
queue_msix_vector or msix_config. When the device later triggers
an interrupt, it indexes into table_entries with the unchecked
vector, causing a panic.
Validate the vector against the MSI-X table size in both trigger()
and notifier() paths, logging a warning and returning early when
the vector exceeds the table bounds.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Follow the same pattern as other virtio devices using a bool to check if
it needs notification and propagating its own Error enum.
Sadly this does still use `anyhow!()` but this does match with the
behaviour of the other devices in their implementations.
As a side effect we can now remove two errors from the top-level Error
enum in virtio-devices as these were only used by this module and those
errors had mangled descriptions.
Signed-off-by: Rob Bradford <rbradford@meta.com>
`get_host_address_range` used `check_range(addr, size)` as a guard then
unwrapped `get_slice(addr, size)`. This allowed a span across two
regions to hit the unwrap (get_slice limits to one range).
If `size` were zero, then the checks were all skipped. Causing a panic
later on for an invalid address.
Make get_slice the sole authority and reject size==0 explicitly.
Callers already handle None.
Signed-off-by: Dylan Reid <dgreid@fb.com>
The guest can cause submit and completion failures with malformed chains
or invalid addresses. However, this shouldn't permanently stall the
device and terminate the worker.
Genuine reset-worthy failures set needs_reset and return `Ok` anyways
and will more cleanly reset the worker.
Signed-off-by: Dylan Reid <dgreid@fb.com>
process_queue_submit's drain loop builds a fresh queue.iter() per
iteration, which re-reads the guest avail index on every call and has
no per-call cap (the per-iter gap check in virtio-queue only protects
against avail_idx jumping more than queue_size between two reads).
In theory, a malicous or buggy guest could keep adding descriptors and
cause this loop to overflow the iouring submit queue.
Cap a single drain at queue_size. A spec-compliant driver never
produces more than queue_size outstanding entries simultaneously, so
the cap is invisible to well-behaved guests.
Signed-off-by: Dylan Reid <dgreid@fb.com>
If querying the fd's MTU fails (because it was from a different network
namespace). Degrade gracefully by not advertising the VIRTIO_NET_F_MTU
feature and instead let the guest kernel use the default 1500 Ethernet
MTU.
Signed-off-by: Rob Bradford <rbradford@meta.com>
The TX path's inline-data branch didn't check the inline buffer length
against the guest-supplied pkt.len() field. The worker will later panic
when it tries to index the packet.
Add the missing check, mirroring the other TX branches.
Signed-off-by: Dylan Reid <dgreid@fb.com>
dma_unmap computed `iova + size - 1` unchecked while the sibling dma_map
already used checked_add/checked_sub. A guest reaching dma_unmap via
VIRTIO_IOMMU_T_UNMAP could cause a panic.
Signed-off-by: Dylan Reid <dgreid@fb.com>
