Commit Graph

112 Commits

Author SHA1 Message Date
Henry Hrvoje Tonkovac
ae7c0dd9f1 build: exempt arch from clippy::absolute_paths, use full paths
Suggested by phip1611 on #8446.

This adds the repo's first clippy.toml, carving arch out of the
absolute_paths deny from #7670. Glob imports and trait imports that
must be in scope for method-call resolution (e.g. DeviceInfoForFdt for
.irq()) are left as-is.

Signed-off-by: Henry Hrvoje Tonkovac <htonkovac@gmail.com>
Assisted-by: Claude:Opus-4.8
2026-07-01 16:27:46 +00:00
Henry Hrvoje Tonkovac
025e782e50 vmm: trim qualified paths
Import the modules used in the crate instead of spelling the full paths
at every use site, and drop the now-unnecessary crate-level

Signed-off-by: Henry Hrvoje Tonkovac <htonkovac@gmail.com>
Assisted-by: Claude:Opus-4.8
2026-06-24 15:12:32 +00:00
Bo Chen
867b5796a5 vmm: Accept an externally-opened iommufd FD
The CLI `--platform` option now accepts `iommufd_fd=<n>` alongside the
existing `iommufd=on|off`.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
Assisted-by: Claude:Opus-4.7
2026-06-17 08:39:43 +00:00
Bo Chen
c315d5fd96 vmm: Enable FD-based VFIO devices
Signed-off-by: Bo Chen <bchen@crusoe.ai>
Assisted-by: Claude:Opus-4.7
2026-06-17 08:39:43 +00:00
Bo Chen
0e4b98ae8e vmm: DeviceConfig: Add fd field for an externally-opened vfio cdev
Add a new `fd: Option<i32>` field to DeviceConfig so a caller can
supply a pre-opened vfio cdev FD (e.g. /dev/vfio/devices/vfioN) in
addition to the existing sysfs path. The CLI `--device` option now
accepts `fd=<n>`, parsed alongside the existing options.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
Assisted-by: Claude:Opus-4.7
2026-06-17 08:39:43 +00:00
Bo Chen
bc5363823a vmm: DeviceConfig: Store path as Option<PathBuf>
Relax DeviceConfig::path from PathBuf to Option<PathBuf> in preparation
to accept an externally-opened vfio cdev FD. The parser and OpenAPI spec
still enforces that `path` is set, so callers see no behavior change.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
Assisted-by: Claude:Opus-4.7
2026-06-17 08:39:43 +00:00
Ian Klemm
8d05407799 vmm: add memory reserve option to opt out of MAP_NORESERVE
Cloud Hypervisor maps guest RAM with MAP_NORESERVE, so the kernel never
reserves the backing pages at mmap time. On a host whose hugepage pool
cannot satisfy every guest, a VM is created successfully and then takes
a SIGBUS when the guest faults a page the pool can no longer back. This
is the failure mode reported in #5730 and #7387. As noted on #5730,
checking free pool headroom up front is not a reliable fix: another
process can consume pages between the check and the fault.

Add a reserve=on parameter to --memory and --memory-zone (default off,
preserving the current MAP_NORESERVE behaviour). When set, the region
is mapped without MAP_NORESERVE, so the kernel reserves the backing
pages (swap, or huge pages for hugepage-backed memory) at mmap time,
atomically with the mapping. An over-committed configuration then
fails cleanly at VM creation with an mmap ENOMEM instead of crashing
the guest later. Unlike prefault it does not fault the memory in, so
it does not slow down boot.

This mirrors QEMU's memory-backend reserve property, which has the same
name and meaning (reserve=off maps with MAP_NORESERVE). reserve is
threaded through the same mmap paths as the existing prefault option,
and is exposed in the OpenAPI schema, CLI help and docs. The top-level
--memory reserve=on path is unchanged: the default zone is synthesised
from MemoryConfig and inherits its reserve value.

Assisted-by: Claude Code (Opus 4.8)
Signed-off-by: Ian Klemm <hi@ianklemm.de>
2026-06-10 12:30:25 +00:00
Ruben Hakobyan
b1d33ec9aa vmm: vm_config: apply serde defaults to FwCfgConfig
FwCfgConfig already has a Default impl (e820/kernel/cmdline/initramfs/
acpi_tables = true, items = None), but deserialization did not use it:
without serde default every field was mandatory, so any caller building
a payload config over the API had to spell out the whole object even to
flip a single flag.

Add a container-level #[serde(default)] so missing fields fall back to
FwCfgConfig::default(). The container form is required here because the
defaults are all true; a per-field #[serde(default)] would resolve bool
to false and contradict the Default impl.

This lets callers send only the fields that differ from the defaults.

Assisted-by: Claude:Opus-4.8
Signed-off-by: Ruben Hakobyan <hruben@meta.com>
2026-06-09 15:49:42 +00:00
Ruben Hakobyan
dc6a56a0db vmm: vm_config: allow opening /dev/sev after landlock
On KVM, an SEV-SNP guest opens /dev/sev at VM creation and passes
its fd as kvm_sev_cmd.sev_fd. KVM uses it to issue the SNP_LAUNCH_*
commands. The open happens after the landlock ruleset is applied,
so grant rw access to /dev/sev when the sev_snp platform feature
is enabled.

Assisted-by: Claude:Opus-4.8
Signed-off-by: Ruben Hakobyan <hruben@meta.com>
2026-06-09 15:49:42 +00:00
Philipp Schuster
212986f013 vmm, docs: make PCI BDF configurable for ivshmem
Add shared PCI config to ivshmem.

On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-06-03 13:54:56 +00:00
Philipp Schuster
5aa0587f2a vmm: make PCI BDF configurable for balloon
Add shared PCI config to virtio-balloon.

On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-06-03 13:54:56 +00:00
Max Makarov
08bd7727ff vmm: omit unset Option fields from API responses
VmConfig and its nested configuration structs, the VmInfoResponse
wrapper and DeviceNode serialize their Option<T> fields as JSON null
when unset. The OpenAPI specification types these fields as
non-nullable, so strict client generators (for example ogen for Go)
reject /vm.info responses and cannot generate a working API client.

Apply serde_with's skip_serializing_none to the affected structs so
that unset optional fields are omitted from the serialized JSON instead
of being emitted as null. API responses now validate against the
existing specification unchanged; no nullable annotations are required.

Fixes: #7775

Signed-off-by: Max Makarov <maxpain@linux.com>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]
2026-06-03 15:47:38 +01:00
Leander Kohler
063caca4a8 vmm: platform: add structured SMBIOS config
Extend SMBIOS System Information with manufacturer, product,
version, family, sku, serial, and uuid fields, add a chassis
asset tag, and pass a structured SMBIOS config from --platform
into arch setup. Keep OEM strings and legacy serial_number/uuid
options working for compatibility. The platform option naming
follows `dmidecode -s <field>`.

Fields:
  - system_manufacturer
  - system_product_name
  - system_version
  - system_family
  - system_serial_number
  - system_uuid
  - chassis_asset_tag

On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>
2026-05-28 16:32:41 +00:00
Leander Kohler
e097d7d495 vmm: plumb legacy SMBIOS config
Add a small SMBIOS config that carries serial_number, uuid,
and OEM strings, and pass it from platform config into
x86_64 setup.

On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>
2026-05-28 16:32:41 +00:00
Oliver Anderson
549f3d6c04 misc: Make CPU profile part of various configs
We integrate the CPU profile into the various configs that
ultimately get set by the user.

This quickly ends up involving multiple files, luckily Rust
helps us find which ones via compilation errors.

Signed-off-by: Oliver Anderson <oliver.anderson@cyberus-technology.de>
On-behalf-of: SAP oliver.anderson@sap.com
2026-05-28 15:19:15 +00:00
Cameron Baird
b452440f6c virtio-devices: Implement virtio-device rtc
This change will allow us to get accurate time over ptp in guests
started from a MSHV-virtualized Linux host. Implementing it as a
virtio device is preferable to using the existing kvm_ptp because:

kvm_ptp relies on hypercalls that only exist on host kernels running
kvm. Virtio-rtc gives us more flexibility in what clock types we want
to provide. We can later extend the device to implement multiple clocks
(smeared UTC, TAI, monotonic, etc.). Virtio-rtc protocol supports
alarms. Alarms may later enable usecases where the guests can do their
own VM lifecycle management without relying on a host-side
orchestrator.

Implement device backend for virtio-rtc. Currently this implementation
encompasses:

1. CONFIG, CAP, READ, CROSSCAP (returns false)
2. One PTP clock is presented of type
VIRTIO_RTC_CLOCK_UTC_MAYBE_SMEARED with leap_second_smearing
VIRTIO_RTC_SMEAR_UNSPECIFIED

The device is disabled by default, requiring --rtc to be passed

Not implemented but theoretically supported by virtio-rtc is:

1. Cross-timestamping support
2. The alarm queue

Fixes #7730

Signed-off-by: Cameron Baird <cameronbaird@microsoft.com>
2026-05-26 20:00:24 +00:00
Bo Chen
8fd8224ee3 vmm: Use HashSet for VmConfig::preserved_fds
Each VM reboot re-entered the VFIO/virtio-net add paths and re-appended
the same originating fds, leaving duplicates in preserved_fds and a
double-close hazard at final teardown. Switching to HashSet makes
add_preserved_fds idempotent.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
Assisted-by: Claude:Opus-4.7
2026-05-23 07:29:10 +00:00
Philipp Schuster
ba04c4f318 virtio-devices, vmm: replace Vec<T> with Box<[T]> in config structs
I started by looking at all `Option<Vec<T>>` values in config.rs and
vm_config.rs, and replaced them with `Option<Box<[T]>>`. This has the
advantage that one now can see at a glance if this field will ever
resize during operation or not, reducing cognitive load and increasing
maintainability. All fields that need the properties of a Ver or where
this change was not trivial are kept intact.

On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-15 16:05:01 +00:00
Philipp Schuster
29e2319247 vmm: store CPU affinity lists as slices
Each affinity host CPU list is copied from configuration.
It is only iterated afterwards, so a boxed slice is enough.

On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-15 16:05:01 +00:00
Philipp Schuster
e793353bfb vmm, main: make PCI BDF configurable for ConsoleConfig
Add common PCI device configuration to the virtio-console device
configuration. This allows setting the device ID (the name), ID, the
PCI segment, and the PCI device ID (BDF), which were previously not
configurable for the virtio-console device.

This gives management software, such as libvirt, more control over PCI
resource assignment and aligns virtio-console with other devices that
already support this functionality [0].

[0] https://github.com/cloud-hypervisor/cloud-hypervisor/issues/8175

On-behalf-of: Philipp Schuster <philipp.schuster@sap.com>
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-11 20:18:03 +00:00
Philipp Schuster
36a3369802 vmm: drop misleading iommu option from serial config
`--serial` still accepted `iommu=on|off` from the shared serial/console
configuration shape, even though only virtio-console has a meaningful
IOMMU connection.

Cloud Hypervisor wires virtio-iommu support through DMA-capable
virtio/VFIO PCI endpoints. The serial devices are legacy UARTs accessed
through PIO or MMIO registers, so exposing an IOMMU option there is
misleading.

On-behalf-of: Philipp Schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-11 20:18:03 +00:00
Philipp Schuster
04bc6b3ccc vmm, main: split ConsoleConfig and SerialConfig into separate structs
This commit introduces a new struct `CommonConsoleConfig` which is the
base for the split into `ConsoleConfig` and `SerialConfig`. This is a
pre-requisite for allowing more configurable PCI options for the
virtio-console device.

The commit doesn't change or add any functionality.

On-behalf-of: Philipp Schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-11 20:18:03 +00:00
Philipp Schuster
bad10f3026 main, vmm: add explicit PCI BDF support for Rng device
This was missing in [0] but is required for proper explicit PCI BDF
management, e.g., when a VM is created via libvirt and each device has
an explicit BDF.

[0] https://github.com/cloud-hypervisor/cloud-hypervisor/pull/7965

On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
2026-05-08 19:39:18 +00:00
Damian Barabonkov
41e12e9d6a vmm, pci, openapi: Add VFIO mmap BAR exclusion
Allow VFIO devices to list BAR indices that should not be
mmapped into the guest. This lets operators skip large BARs that
are known not to be used by their workload.

When a BAR is skipped, the log also calls out that P2P DMA
mapping is skipped because the VFIO DMA map path uses the same
mmap backing.

Signed-off-by: Damian Barabonkov <dbctl@pm.me>
Assisted-by: OpenCode:gpt-5.5
2026-05-06 14:15:41 +00:00
Keith Adler
926dd1e141 vmm, devices: Add fw_cfg string item support
QEMU supports passing inline string values to the guest via fw_cfg
(-fw_cfg name=...,string=...). Cloud Hypervisor previously only
supported file-backed fw_cfg items. This adds the 'string' option
so users can pass values like OVMF's X-PciMmio64Mb without creating
a temporary file on the host.

Each fw_cfg item now accepts exactly one of 'file' or 'string'.
The FwCfgInvalidItem invariant is validated in PayloadConfig::validate()
(via FwCfgConfig::validate()), covering both CLI and JSON API paths.
The populate_fw_cfg match arm uses unreachable!() since validation
guarantees the invariant holds at that point.

CLI syntax:
  --fw-cfg-config items=[name=opt/ovmf/X-PciMmio64Mb,string=262144]

Signed-off-by: Keith Adler <kadler@cloudflare.com>
2026-04-20 09:39:56 +00:00
Keith Adler
e4e3375a8d vmm: move fw_cfg validation into PayloadConfig::validate()
Move FwCfgMissingKernel/Cmdline/Initramfs error variants from
ValidationError into PayloadConfigError. Change FwCfgConfig::validate()
to take &PayloadConfig instead of &VmConfig and return
PayloadConfigError. Wire the call through PayloadConfig::validate()
so both CLI and JSON API paths are covered.

Signed-off-by: Keith Adler <kadler@cloudflare.com>
2026-04-20 09:39:56 +00:00
Ruben Hakobyan
c31f5d4998 vmm: allow IGVM payload alongside a kernel
Previously, the payload validation rejected an IGVM file combined with
a kernel or firmware.

Relax this constraint to allow an IGVM carrying a firmware (e.g Oak
stage0) to be paired with a separate kernel image.

This enables fw_cfg-style boot where stage0 loads a kernel provided
through fw_cfg rather than embedded in the IGVM file itself.

Signed-off-by: Ruben Hakobyan <hruben@meta.com>
2026-04-17 12:28:55 +00:00
Rob Bradford
c3ec804a44 vmm: config: Add pci_device_id to PciDeviceCommonConfig
This adds it to all device types that use the common PCI device
configuration.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-17 07:45:22 +00:00
Rob Bradford
37b1ed1b84 vmm: config: Switch VsockConfig to use PciDeviceCommonConfig
Switch VsockConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
ece77c3c52 vmm: config: Switch VdpaConfig to use PciDeviceCommonConfig
Switch VdpaConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
2c50be4753 vmm: config: Switch UserDeviceConfig to use PciDeviceCommonConfig
Switch UserDeviceConfig over to using the newly extracted struct members
as used by all PCI based devices. The use of #[serde(flatten)] means
that this change has no impact on the JSON format that the data is
stored as.

As VFIO user devices do not support being placed behind an IOMMU an
error is now raised if iommu is set. This can't happen via the CLI but
could via the JSON/API.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
47182201f9 vmm: config: Switch DeviceConfig to use PciDeviceCommonConfig
Switch DeviceConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
c9082570b0 vmm: config: Switch PmemConfig to use PciDeviceCommonConfig
Switch PmemConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
0d3080e036 vmm: config: Switch GenericVhostUserConfig to use PciDeviceCommonConfig
Switch GenericVhostUserConfig over to using the newly extracted struct
members as used by all PCI based devices. The use of #[serde(flatten)]
means that this change has no impact on the JSON format that the data is
stored as.

As generic vhost-user devices do not support being placed behind an
IOMMU an error is now raised if iommu is set. This can't happen via the
CLI but could via the JSON/API.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
40150dd72d vmm: config: Switch FsConfig to use PciDeviceCommonConfig
Switch FsConfig over to using the newly extracted struct members as used
by all PCI based devices. The use of #[serde(flatten)] means that this
change has no impact on the JSON format that the data is stored as.

As virtio-fs does not support being placed behind an IOMMU an error is
now raised if iommu is set. This option is not exposed via the CLI but
could happen with a miscontructed JSON/API call.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
92c2cf0103 vmm: config: Switch NetConfig to use PciDeviceCommonConfig
Switch NetConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
d2ce7667bc vmm: config: Switch DiskConfig to use PciDeviceCommonConfig
Switch DiskConfig over to using the newly extracted struct members as
used by all PCI based devices. The use of #[serde(flatten)] means that
this change has no impact on the JSON format that the data is stored as.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
Rob Bradford
4f7ff8fe48 vmm: Introduce a PciDeviceCommonConfig struct
Introduce a common struct that can encompass all the config fields
used by devices that are PCI based. The use of `skip_serializing_if`
means that the iommu field will only be included if set (otherwise
falling back to default false). This neatly handles the devices that
don't support an iommu.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-04-14 14:19:34 +00:00
JP Kobryn
bdc7a6947d vmm: add per-zone mergeable option to --memory-zone
Add a `mergeable` field to `MemoryZoneConfig` so that KSM page merging
can be enabled selectively per memory zone rather than globally for all
guest RAM.

Previously, `MADV_MERGEABLE` was only controllable via the top-level
`--memory mergeable=on` flag, which applied uniformly to all regions.
With this change, users can leave boot memory unmerged while enabling
KSM only on hotplug zones:

  --memory size=0,hotplug_method=virtio-mem
  --memory-zone id=boot,size=512M,shared=on,mergeable=off
  --memory-zone id=hotplug,size=256M,hotplug_size=1G,shared=off,mergeable=on

The `MemoryZone` runtime struct now carries the `mergeable` flag so
that both `allocate_address_space` and `add_ram_region` can apply
per-zone `MADV_MERGEABLE` instead of the global `self.mergeable`.
The top-level `--memory mergeable=on` path continues to work unchanged:
the default zone is synthesised from `MemoryConfig` and inherits its
`mergeable` value.

AI/LLM disclosure: this patch was co-authored with
GitHub Copilot and Claude Code (Opus 4.6).

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
2026-04-11 09:01:57 +00:00
Bo Chen
87992c77c1 vmm: Introduce option --platform vfio_p2p_dma=on|off
Add a user-configurable option to control whether VFIO device MMIO BAR
regions are DMA-mapped into the host IOMMU address space.

This mapping is required for peer-to-peer DMA between devices (e.g.
NVLink, RDMA NIC accessing GPU VRAM). However, iommufd on upstream
kernels does not support mapping device MMIO pages (VM_PFNMAP), causing
IOMMU_IOAS_MAP to fail with -EFAULT. Kernels with the NVIDIA PFNMAP
workaround or future kernels with DMABUF-based mapping
(IOMMU_IOAS_MAP_FILE) handle this correctly.

The option defaults to `on` to preserve existing behavior. Users on
vanilla kernels using iommufd should set `vfio_p2p_dma=off` to skip
MMIO BAR DMA mapping.

A validation check ensures that `x_nv_gpudirect_clique` (which depends
on P2P DMA) cannot be used when `vfio_p2p_dma=off`.

Signed-off-by: Bo Chen <bchen@crusoe.ai>
2026-04-10 22:55:38 +00:00
Bo Chen
13972a0edf vmm: Introduce option --platform iommufd=on|off
This option allows user to configure VFIO device pass-through with
iommufd (e.g. vfio cdev mode) or not (e.g. vfio legacy mode).

Signed-off-by: Bo Chen <bchen@crusoe.ai>
2026-04-10 22:55:38 +00:00
Alyssa Ross
e1e6d0a25b vmm: fix rebooting with landlock and pty console
When landlock support was added, creation of file descriptors was
moved out into a function called pre_create_console_devices, with the
idea being that this could be run before Landlock rules are applied
and access to all the necessary paths are dropped.

This idea didn't take reboots into account, though.  When a VM is
rebooted, pre_create_console_devices is called again, but now the
Landlock rules have been applied, so they need to allow access to all
those paths anyway.

I imagine the way this was intended to work was that file descriptors
would be preserved across reboot, but that's not currently the case,
and it's not a trivial change to make because they get dropped when
the VM is destroyed.  Longer term it would be ideal if Cloud
Hypervisor's implementation was more focused on file descriptors than
paths[1], and if created VMs only took references to file descriptors,
so they were easily preserved across reboots.

Fixes: b3e5738b4 ("vmm: Introduce ApplyLandlock trait")
Closes: https://github.com/cloud-hypervisor/cloud-hypervisor/issues/7547
Link: https://github.com/cloud-hypervisor/cloud-hypervisor/issues/7704 [1]
Signed-off-by: Alyssa Ross <hi@alyssa.is>
2026-03-27 11:11:26 +00:00
Victor Vieux
7c690ffec0 vmm: config: Expose disk lock granularity option
Add a per-disk lock_granularity parameter that lets users choose
between byte-range OFD locks and whole-file OFD locks:

  --disk path=/foo.img,lock_granularity=byte-range
  --disk path=/bar.img,lock_granularity=full

Byte-range is the default and matches QEMU behavior, working
best with storage backends where whole-file OFD locks are treated
as mandatory. The full option restores the original whole-file
locking for environments that depend on it.

The LockGranularityChoice enum and its FromStr impl live in the
block crate alongside the existing LockGranularity type. The
Block device converts the user-facing choice to the internal
LockGranularity at lock time, keeping device_manager.rs simple.

Closes: #7553

Signed-off-by: Victor Vieux <vieux@repl.it>
2026-03-08 10:07:03 +00:00
Rob Bradford
3f800d2bb4 vmm: Add core scheduling support for vCPU threads
Add a core_scheduling option to --cpus with three modes of operation.
This feature takes advantage of a kernel feature that restricts
scheduling of processes on the SMT threads on the same core. This is
useful for mitigating certain classes of side-channel attacks and has
better performance that disabling SMT on the CPU.

- vm (default): All vCPU threads share one core scheduling cookie.
  They may be co-scheduled on SMT siblings while host threads are
  excluded - this has minimal performance impact and can even
  potentially improve performance from co-location.
- vcpu: Each vCPU gets a unique cookie preventing any two vCPUs from
  sharing SMT siblings. This has the strongest isolation but at some
  compromise of performance.
- off: No core scheduling applied (old behaviour).

This isolation is done by the kernel maintaining a "cookie" - threads
with the same cookie can share the same core.

In vCPU mode each vCPU thread the cookie is created when the thread
starts and each gets a unique cookie. For VM mode the first vCPU thread
(the leader) will create the cookie. All other vCPU threads started (via
hotplug or during boot) will have that cookie shared to it.

EINVAL/ENODEV from prctl is silently ignored so this works transparently
on kernels older than 5.14 that lack PR_SCHED_CORE or when SMT disabled.

Full details of this kernel feature can be found at:
https://docs.kernel.org/admin-guide/hw-vuln/core-scheduling.html

This implementation was inspired by crosvm's implementation - in
particular the enable_core_scheduling() function.

This is challenging to test via integration testing but the logging of
the received cookie shows it working:

VM case:

cloud-hypervisor:   0.243102s: <vcpu1> INFO:vmm/src/cpu.rs:1247 -- vCPU 1: core scheduling cookie = 0x33e4c167
cloud-hypervisor:   0.243102s: <vcpu0> INFO:vmm/src/cpu.rs:1247 -- vCPU 0: core scheduling cookie = 0x33e4c167

vCPU case:

cloud-hypervisor:   0.089356s: <vcpu0> INFO:vmm/src/cpu.rs:1247 -- vCPU 0: core scheduling cookie = 0x13993ad6
cloud-hypervisor:   0.089380s: <vcpu1> INFO:vmm/src/cpu.rs:1247 -- vCPU 1: core scheduling cookie = 0xd48e86e

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-02-26 11:57:39 +00:00
Demi Marie Obenour
085a7a49fa vmm: generic vhost-user: add support
Add VMM support for generic vhost-user devices.

Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
2026-02-24 07:53:53 +00:00
Rob Bradford
6f2357c14e vmm: Improve resiliency of image type handling
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>
2026-02-19 22:43:15 +00:00
Anatol Belski
7dfcbff309 vmm: config: Add sparse flag to control disk space allocation
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>
2026-02-13 18:44:30 +00:00
Saravanan D
6d4827b5ff vmm: Add device_id field to NUMA configuration
Add an optional device_id string field to NumaConfig for identifying
PCI devices associated with a NUMA node. This is used by the Generic
Initiator support to map devices to their proximity domain.

Update OpenAPI spec (cloud-hypervisor.yaml) to include the
new device_id field in the NumaConfig schema.

The device_id is optional and parsed from the --numa parameter:
  --numa "device_id=<device_id>,distances=[...],..."

The optional field is accepted but not used.

Signed-off-by: Saravanan D <saravanand@crusoe.ai>
2026-02-12 22:54:54 +00:00
Saravanan D
231bbe2d5d vmm: Enforce guest_numa_id on NUMA nodes
The documentation says guest_numa_id is required to be unique and
therefore the parser() giving default value for non-existing
guest_numa_id with .unwrap_or(0) is dangerous.

Return a validation error if guest_numa_id is not provided instead
of silently defaulting to 0.

Signed-off-by: Saravanan D <saravanand@crusoe.ai>
2026-02-12 22:54:54 +00:00
Rob Bradford
509832298b vmm: Add option to control backing files
Backing files (e.g. for QCOW2) interact badly with landlock since they
are not obvious from the initial VM configuration. Only enable their use
with an explicit option.

Signed-off-by: Rob Bradford <rbradford@meta.com>
2026-02-10 17:41:42 +00:00