submit_batch_requests pushed each BatchRequest into the io_uring SQ in
turn and used `?` to bail on the first push failure.
Leaving the initial SQEs visible to the kernel — but submitter.submit()
was never called, and every other call site in this file gates submit()
behind a preceding sq.push() that now also fails on the full ring.
This could allow a guest to DoS it's own queue or worse if the buffer is
freed early.
Signed-off-by: Dylan Reid <dgreid@fb.com>
(cherry picked from commit ee315d2e7c)
The bounce buffer for an unaligned descriptor was allocated in
execute_async and leaked on error paths, even though, for the sync
case the kernel already had a pointer to the buffer.
Clean this up by moving ownership of the buffer to the
AlignedOperation type. To make it actually safe, stop stashing a
guest memory pointer for the duration of the op. Instead, save the
guest address and pass guest memory back to the complete function.
Signed-off-by: Dylan Reid <dgreid@fb.com>
(cherry picked from commit 1b8c92dd5e3c0c58316826486ce5ee30eeb71407))
[backport: adapted to stable/v51.x; v51.x has no block/src/request.rs
split, so the new aligned_operation module is added next to
block/src/lib.rs and the in tree struct, alloc, free path is
replaced in place.]
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
For non-batch backends execute_async submits the kernel I/O inline
before returning. An early return while processing before inserting in
inflight_requests, meant the request went untracked, the local batch
list was never appended to inflight_requests, even though the request is
pending in the kernel.
To track it, insert into self.inflight_requests as soon as execute_async
returns Ok. The completion path's find_inflight_request now matches the
orphan and the bounce buffer is freed only after the kernel signals it
is done.
Signed-off-by: Dylan Reid <dgreid@fb.com>
(cherry picked from commit fa8acbd712)
A malicious or buggy guest can violate virtio by making the same
descriptor head available twice before the first chain has been placed
on the used ring. The submit path pushed both chains onto the
VecDeque-backed inflight_requests keyed by head_index, and on completion
find_inflight_request() returned the first linear match. That Request's
complete_async() freed its bounce buffer while the other chain's
io_uring op was still targeting it, producing a use-after-free the
kernel could then scribble into.
Signed-off-by: Dylan Reid <dgreid@fb.com>
(cherry picked from commit 544fa4aa76)
A buggy or malicious guest may write an inappropriate value into
virtqueue's next_avail field. This will result in an error
when iterating over the queue:
863837ef86/virtio-queue/src/queue.rs (L708)
but this error is (logged and) ignored if pop_descriptor_chain()
is used:
863837ef86/virtio-queue/src/queue.rs (L583)
A reasonable approach, implemented here, is to mark the device as
NEEDS_RESET and ignore further queue events until the guest
reinitializes the device.
How this patch was tested:
Linux kernel was patched to trigger a bad next_avail when the
virtqueue queue counter reaches 5000:
--------------- START OF LINUX KERNEL PATCH ----------
$ git diff
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index b784aab668670..989f2a0c64a77 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -15,6 +15,9 @@
#include <linux/spinlock.h>
#include <xen/xen.h>
+
+void virtqueue_kick_always(struct virtqueue *vq);
+
#ifdef DEBUG
/* For development, we want to crash whenever the ring is screwed. */
#define BAD_RING(_vq, fmt, args...) \
@@ -677,6 +680,12 @@ static inline int virtqueue_add_split(
struct virtqueue *_vq,
* new available array entries. */
virtio_wmb(vq->weak_barriers);
vq->split.avail_idx_shadow++;
+ {
+ if ((vq->split.avail_idx_shadow % 100) == 0)
+ printk(KERN_ERR "avail idx: %d",
+ (int)vq->split.avail_idx_shadow);
+ if (vq->split.avail_idx_shadow == 5000)
+ vq->split.avail_idx_shadow = 0;
+ }
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
vq->split.avail_idx_shadow);
vq->num_added++;
@@ -689,6 +698,11 @@ static inline int virtqueue_add_split(
struct virtqueue *_vq,
if (unlikely(vq->num_added == (1 << 16) - 1))
virtqueue_kick(_vq);
+ {
+ if (unlikely(vq->split.avail_idx_shadow == 0))
+ virtqueue_kick_always(_vq);
+ }
+
return 0;
unmap_release:
@@ -2515,6 +2529,11 @@ bool virtqueue_kick(struct virtqueue *vq)
}
EXPORT_SYMBOL_GPL(virtqueue_kick);
+void virtqueue_kick_always(struct virtqueue *vq)
+{
+ virtqueue_kick_prepare(vq);
+ virtqueue_notify(vq);
+}
/**
* virtqueue_get_buf_ctx - get the next used buffer
* @_vq: the struct virtqueue we're talking about.
--------------- END OF LINUX KERNEL PATCH ----------
Then the kernel was booted, and the host pinged until the
nic became unresponsive:
ping -i 0.002 192.168.4.1
Device status was confirmed using
cat /sys/class/net/eth0/device/status
(it was 0x4f).
Then the device was re-initialized:
DEV_NAME=$(basename $(readlink -f /sys/class/net/eth0/device))
echo $DEV_NAME | tee /sys/bus/virtio/drivers/virtio_net/unbind
echo $DEV_NAME | tee /sys/bus/virtio/drivers/virtio_net/bind
ip link set eth0 up
At this point networking became healthly again.
Signed-off-by: Peter Oskolkov <posk@google.com>
(cherry picked from commit 563303b50a)
As well as rejecting writes to sector 0 in the case of raw files where
the user hasn't specified the image_type also reject virtio requests of
type discard and write_zeroes.
Signed-off-by: Rob Bradford <rbradford@meta.com>
If the disk image was autodetected to raw (not specified with image_type
= 0) then in the virtio-block subsystem generate errors for writes to
block 0 (treat as if read-only). This gives an immediate error vs using
the image implementations in the block subsystem.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Add an image_type to DiskConfig to specify the image type. If none is
specified autodetect the image type but disable potentially unsafe
behaviour in the QCOW2 backend by disabling the backing file support.
If the image type is autodetected then fix it in the config so that it
will be persistant across reboots and migrations/snapshot & restores.
This also handles the case where the image type was not specified as
part of the disk configuration.
Signed-off-by: Rob Bradford <rbradford@meta.com>
Verify that opening a QCOW2 image with a backing file reference
through QcowDiskSync with backing_files=off produces the user-facing
BackingFilesDisabled error rather than MaxNestingDepthExceeded.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
When a QCOW2 image has a backing file but backing_files=on is not set,
the error was MaxNestingDepthExceeded which gives no indication that
this is a policy decision or how to resolve it.
Add a BackingFilesDisabled error variant whose message indicates that
backing file support is disabled and references the backing_files
option. The translation from MaxNestingDepthExceeded to
BackingFilesDisabled happens at the QcowDiskSync boundary where the
policy decision is made, preserving the original error for genuine
recursive depth exhaustion.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
The 0.6.7 version of the mshv crates introduced a new version of
make_default_partition_create_arg inside `struct Mshv`. This version
queries the available processor features on the host and gives the same
feature set to the guests.
Move Cloud Hypervisor to this new function.
Signed-off-by: Anirudh Rayabharam <anrayabh@microsoft.com>
test_guest_numa_generic_initiator was missing the #[test] attribute and
did not match the VFIO CI filter pattern "vfio::test_nvidia"
Add #[test] and rename to test_nvidia_guest_numa_generic_initiator so
the existing CI infrastructure picks it up on the vfio-nvidia runner.
Fixes: #7718
Signed-off-by: Saravanan D <saravanand@crusoe.ai>
The device_id field was added to both NumaConfig and NumaNode as part
of the Generic Initiator support, but create_numa_nodes() change
was missed when the commits were reorganized.
As a result, node.device_id is never propogated from the config to
the runtime node and the ACPI SRAT Type 5 (Generic Initiator Affinity)
entries were never emitted.
Add the missing propogation so that create_srat_table() can resolve
the device and emit the correct affinity structure
Fixes: #7717
Signed-off-by: Saravanan D <saravanand@crusoe.ai>
Add performance tests for standalone qcow2 images without backing
files - uncompressed, zlib and zstd compressed. Each variant
includes single queue and multiqueue tests for sequential
read, random read and warmed up sequential read.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add multiqueue num_queues=4 performance tests for qcow2 overlay
images with both qcow2 and raw backing files - sequential read,
random read, and warm read variants.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
The backing_files option defaults to false, so qcow2 overlay
tests fail with MaxNestingDepthExceeded. Pass backing_files=on
when the test file is an overlay.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
The focal image checksums have been moved in the -common
sha1sums file. Use the correct file for metrics.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Unlike most virtio feature bits, VIRTIO_BLK_F_RO is not optional.
It indicates that the host is refusing to permit write operations, and
the guest must not be allowed to override it.
However, the block device currently does not enforce this. If the guest
does not negotiate VIRTIO_BLK_F_RO, the block device will think the
device is writable and forward write requests to the backend.
This is not a security problem right now because the backing device of a
read-only device is always opened read-only. The kernel will thus
reject the write operations with EBADF. If support is added for
receiving the backing device file descriptor via SCM_RIGHTS (#7704),
it will be possible to have a read-only block device backed by a
writable file descriptor. This would make the bug a genuine security
vulnerability.
Fix the bug by explicitly checking if VIRTIO_BLK_F_RO was offered but
not negotiated. In this case, log a warning and proceed as if the guest
did acknowledge the feature. This always indicates a guest driver bug.
Fixes: #7697
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
OVMF sends FLUSH requests to read-only virtio-block devices. Refusing
these requests prevents OVMF from accessing the EFI System Partition and
therefore makes VMs unable to boot. Accept these requests instead.
them.
Ignoring these requests is possible, but inconsistent with fsync(2)
which honors them.
Fixes: #7698
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
Add handling for GHCB_INFO_SPECIAL_DBGPRINT VMG exit in the SEV-SNP
guest exit handler. This exit occurs when the guest sends debug print
requests through the GHCB interface.
Without this handler, SEV-SNP guests fail to boot when debug output
is triggered, such as when a debugger is attached to the guest image.
The handler acknowledges the exit without printing to avoid performance
degradation from frequent debug print requests.
Signed-off-by: Muminul Islam <muislam@microsoft.com>
The --net help text documented fd as fd=<fd1,fd2...>, but
comma-separated FD lists in option values must be bracketed to avoid
top-level option splitting.
Update NetConfig::SYNTAX to use fd=<[fd1,fd2,...]>, matching parser
behavior and existing net parsing tests:
`cargo test -p vmm test_net_parsing`
On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>
Add comprehensive integration tests for DISCARD and WRITE_ZEROES:
Multiqueue stress tests verify concurrent operations across queues,
testing scattered writes with simultaneous fstrim, and write/discard
races that stress refcount table locking.
Format specific tests verify QCOW2 deallocates clusters after DISCARD,
raw files create holes using fallocate, and unsupported formats VHD
and VHDX correctly reject DISCARD requests.
Tests for sparse=off verify raw files preallocate full disk size and
QCOW2 uses zero flag instead of deallocating clusters.
Add helper functions to verify sparse files, count QCOW2 zero flagged
regions using qemu-img map, and verify guest reads zeros from
discarded regions.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add comprehensive tests for DISCARD and WRITE_ZEROES operations:
QCOW2 zero flag test validates the complete workflow: allocate
cluster, DISCARD it, verify reads return zeros, write new data,
verify cluster reallocated.
QcowSync tests verify punch_hole and write_zeroes with Arc<Mutex<>>
sharing, including tests for cache consistency with multiple async
I/O operations.
RawFileSync tests verify punch_hole and write_zeroes using
fallocate.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Implement punch_hole() and write_zeroes() for raw file backends using
io_uring and fallocate.
punch_hole() uses FALLOC_FL_PUNCH_HOLE to deallocate storage.
write_zeroes() uses FALLOC_FL_ZERO_RANGE to write zeros efficiently.
Both use FALLOC_FL_KEEP_SIZE to maintain file size.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Implement punch_hole and write_zeroes for QcowSync backend by
delegating to QcowFile::punch_hole which triggers cluster
deallocation. write_zeroes delegates to punch_hole as unallocated
clusters read as zeros in QCOW2.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add VIRTIO_BLK_T_DISCARD and VIRTIO_BLK_T_WRITE_ZEROES request types.
Parse discard/write_zeroes descriptors (sector, num_sectors, flags),
convert to byte offsets, and call punch_hole/write_zeroes on the disk
backend. Mark as unsupported in sync mode.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Implement DISCARD using QCOW2 zero flag (bit 0 of L2 entries) with
sparse aware behavior.
When sparse=true - fully deallocate clusters by decrementing
refcount, clearing L2 entry, and reclaiming storage via punch_hole
when refcount reaches zero.
When sparse=false - use zero flag to keep storage allocated while
marking as reading zeros. Only works when cluster is not shared.
Shared clusters are fully deallocated.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
When sparse=false is configured, preallocate the entire raw disk file
at startup using fallocate(). This provides space reservation and
reduces fragmentation.
Only applies to raw disks. QCOW2/VHD/VHDX formats manage their own
allocation.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add sparse parameter to QcowFile constructors and propagate it from
device_manager through QcowDiskSync. This makes the sparse configuration
available throughout the QCOW2 implementation for controlling allocation
and deallocation behavior.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add supports_zero_flag() to DiskFile trait to indicate whether a disk
format can mark clusters/blocks as reading zeros without deallocating
storage.
QCOW2 supports this via the zero flag in L2 entries. VHDX also has
PAYLOAD_BLOCK_ZERO state for this, though it's not yet implemented in
cloud-hypervisor.
This enables DISCARD to be advertised even with sparse=false for formats
with zero-flag support, since they can mark regions as zeros (keeps
storage allocated) instead of requiring full deallocation.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add sparse boolean configuration option to DiskConfig with a default
value of true to control disk space allocation behavior.
When sparse is true, the disk uses sparse allocation where deallocated
blocks are returned to the filesystem, and the DISCARD feature is
advertised to the guest.
When sparse is false, disk space is kept fully allocated and DISCARD
is not advertised.
WRITE_ZEROES is always advertised when the backend supports it,
regardless of the sparse setting.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add capability query to DiskFile trait to check backend
support for sparse operations (punch hole, write zeroes,
discard). Only advertise VIRTIO_BLK_F_DISCARD and
VIRTIO_BLK_F_WRITE_ZEROES when the backend supports these
operations.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
