v0.12.0

This release brings feature additions including foundational support for Intel Trust Domain Extensions (TDX), new emulated devices for firmware boot, and bug fixes and refactorings.

New Features

• Intel TDX Support: Alioth now provides basic support for booting Intel TDX confidential virtual machines.
  • Added userspace emulation for the IOAPIC, required by TDX guests to enable KVM_CAP_SPLIT_IRQCHIP.
• Preparation for supporting UEFI boot on x86:
  • Added an emulated CMOS and an ACPI power management timer for x86.
  • Added a fw_dbg device to capture firmware logs.
  • Included CPU count and memory size in fw_cfg.
  • Corrected fw_cfg ACPI table checksum calculation by clearing checksum fields before computation.
  • MMIO reads from unmapped addresses now correctly return all-ones.

Bug Fixes and Refactorings

• VFIO:
  • Dynamically allocate buffers for PCI configuration space, resolving an EFAULT error when reading device configs.
  • Conditionally reset devices based on device flags.
• Confidential Computing (AMD SEV-SNP):
  • Verified the firmware's SEV metadata signature.
  • Explicitly enabled the MAP_GPA_RANGE hypercall for SNP.
  • Added unknown descriptors as zero pages for SNP and removed unsupported CPUID features.
  • Filtered out empty KVM CPUID entries and checked the SEV error code in kvm_memory_encrypt_op.
• Console: Abstracted the I/O backend using a new Console trait, decoupling the console worker from hardcoded stdio logic.
• Others:
  • Added tests for PL031 RTC and PL011 UART.
  • Prevented log spam originating from virtio split queues
  • Preserved the lower bits of addr_hi during MSI address translation in KVM.

Documentation & Infrastructure

• Documentation: Added instructions for running Intel-TDX.
• Dependencies & Tooling:
  • Upgraded workspace Cargo.toml resolver to V3 and removed deprecated authors fields.
  • Bumped various dependencies.

v0.11.0

This release introduces support for booting from cloud images, a new command to convert Qcow2 images, and a host of other new features, bug fixes, and improvements.

New Features

• Boot from Cloud Images: Alioth now supports booting guest Linux systems from cloud images, using a minimal Linux kernel and an initramfs with u-root as a bootloader.
  • PR #3492 merged to u-root enables booting Fedora on aarch64.
• Qcow2 Image Conversion: A new img command has been added to the CLI to convert Qcow2 images to raw format.
• Vsock Vhost-User Backend: The UdsVsock (Unix Domain Socket based Vsock) can now be run as a vhost-user backend.
• PSCI (AArch64): Implemented PSCI calls for CPU_OFF and AFFINITY_INFO, which are prerequisites for kexec support in guests on aarch64.

Bug Fixes

• HVF (macOS):
  • The zero register (X31) is now correctly handled for MMIO on aarch64.
  • VCPUs are now interrupted on stop requests instead of being shut down immediately.
• Networking:
  • Removed INDIRECT_DESC from the virtio-net feature set.
  • vmnet: Fixed incorrect handling of zero-length buffers.
• Devicetree (AArch64): Removed the msi-parent property from the PCI bridge node to resolve a guest kernel warning.
• Vsock:
  • Guest-initiated connections are now set to non-blocking to prevent indefinite blocking.
  • Fixed socket listener deregistration on reset.
• Block Device: Added file locking to disk images to prevent corruption from concurrent access.
• Vhost-User:
  • Enforced a limit to serve only one VMM connection at a time.
  • Fixed handling of 128-bit device features in the vhost-user protocol by truncating to 64-bit.

Documentation & Infrastructure

• Added documentation for booting cloud images.
• Added macOS entitlements and signing documentation.
• Added workflows for release automation.

v0.10.0

What's Changed

New

• aarch64: emulated PL031 RTC for aarch64 #285
• HVF/aarch64: vmnet-based virtio-net device on macOS #299
• New command line flag --cpu for specifying CPU topology #331
• KVM/x86_64: enable x2APIC by default, allow booting up to 32768 VCPUs (theoretical value) #344

Fixes

• HVF/aarch64: handle OSDLR_EL1 and OSLAR_EL1 #284
• HVF/aarch64: fix system reboot #298
• x86_64: fix CPU topology encoded in CPUID #331

Other

• Many unit tests added
• Dependency bumps by @dependabot[bot]

Full Changelog: v0.9.0...v0.10.0

v0.9.0

What's Changed

New

• VirtIO packed queue #273
• Unix domain socket based vsock device #277
• Alioth now can boot Linux on macOS with Hypervisor framework #281

Chore

• Dependency bumps
• Code coverage report

Full Changelog: v0.8.0...v0.9.0

v0.8.0

What's Changed

New

• vhost-user devices in #243
• Built-in VirtIO FS device in #244
• virtio-fs: handle opcodes CREATE and WRITE in #246
• Run virtio-fs as a vhost-user backend in #247
• virtio-fs: DAX support in #252

Fixes

• fix(vu): avoid socket pair fd leak in #235
• fix(kvm): handle IO string operations in #255

Refactors

• refactor(virtio): remove generic paramter D from VirtioDevice in #237
• refactor(virtio): move Register to VirtioPciDevice in #238
• refactor: replace boxed_debug_trace with trait BoxTrace in #242

Full Changelog: v0.7.0...v0.8.0

v0.7.0

What's Changed

• fix(vfio): calculate MSI cap size from msg control by @Lencerf in #184
• fix(vfio): clear the multi-function device bit by @Lencerf in #185
• feat(help): implement Help for array types by @Lencerf in #186
• feat(vfio)!: add parameter types for Ioas and Container by @Lencerf in #188
• fix(vm): let device builders take immutable self by @Lencerf in #190
• docs: update README by @Lencerf in #193
• perf(pci): remove Arc from PCI configs by @Lencerf in #194
• clippy fix by @Lencerf in #199
• Add MSI capability support for VFIO devices by @Lencerf in #191
• docs: fix README format by @Lencerf in #201
• style: format imports by @Lencerf in #202
• fix(vfio): implement reset() for MsiCapMmio by @Lencerf in #203
• refactor(vfio): get MSIX count from capability by @Lencerf in #204
• fix: avoid infinite wait in sync_vcpus() by @Lencerf in #205
• Migrate to Rust 2024 by @Lencerf in #221
• ci: fix rustfmt by @Lencerf in #227
• chore: bump version to 0.7.0 by @Lencerf in #233
• dependency updates by @dependabot

Full Changelog: v0.6.0...v0.7.0

v0.6.0

What's Changed

New features

• virtio-ballon device with free page reporting
• PCI device passthrough with legacy VFIO API (container and group)
• io_uring based virtio-blk device

Bug fixes and performance improvements

• device passthrough

  • a8e87c6 fix(vfio): handle the flag NORESIZE of an IRQ
  • 3ef3eb0 fix(vfio): open the iommu device as read-only
  • e30be1f fix(cdev): ignore detach calls if not attached yet

• loader

  • e58f221 fix(pvh): check if the alignment is a power of 2
  • fd0f2d8 fix: let align_up/align_down take number of bits

• virtio devices

  • acdfb5d fix(virtio): monitor ioeventfds with IORING_OP_POLL_ADD
  • 95b9d5f fix(virtio): monitor the waker with IORING_OP_POLL_ADD
  • e9fe9c8 fix(virtio): let devices handle hostside io errors
  • 8968a24 fix(virtio): reset io_uring queue_submits at start up
  • b306c1a perf(virtio): send 1 interrupt in a single loop

• virtio-blk

  • 9a3857f fix(blk): flush disk file on FLUSH requests

• virtio-net (tried to improve latency but failed)

  • 1177f32 Revert "perf(net): deregister tap from poll while handling events"
  • f365429 perf(net): deregister tap from poll while handling events

• hypervisor

  • 608fb13 test(kvm): use 2-MiB page in the guest
  • 8291ce5 fix(kvm): calculate correct mask for 64bit MMIO

Full Changelog: v0.5.0...v0.6.0

v0.5.0

What's Changed

New features

• complete command line help message: check alioth --help and alioth run --help.
• experimental io_uring based virtio-net device: add api=iouring to --net.

Bug fixes and performance improvements

• fix(sev): fix the policy bitfield definition in #101
• fix(vu): allow only 1 in-flight request in #104
• fix(x86): enable fast string in #105
• fix(kvm): clear the high part of mmio write values in #109
• Fix cpuid in #110
• perf(virtio): remove unnecessary wake at startup in #121
• fix(net): detect tap offload cap after setup in #122
• virtio: replace actions with states in #126
• perf(virtio): lock memory layout while running in #132
• refactor(virtio): replace device_id() with an associated const in #133
• Remove Arc<Vec<T>> and Arc<String> in #134

Full Changelog: v0.4.0...v0.5.0

v0.4.0

Disclaimer: Alioth is not an officially supported Google product.

Many thanks to the open source community! Alioth now has 2 users,

1. moturus/motor-os: simple, fast, and secure operating system built for the cloud
2. microvm.nix: NixOS MicroVMs, microvm-nix/microvm.nix#256 (WIP)

New features

• virtio-blk now supports readonly mode: --blk path=/path/to/image,readonly=on|off,
• virtio-net now supports multi queues: --net queue_pairs=2,...(caveat: all queues are still handled by a single VMM thread, it needs more time to investigate ways to improve virtual network performance),
• PCI device passthrough with the VFIO/IOMMUFD API: --vfio cdev=/dev/vfio/devices/vfioX,
• flag --memory to support more options: --memory size=1G,backend=memfd|anon,shared=on|off,transparent_hugepage=on|off,
• serde-aco deserializer is mostly code-complete,
• flag --object to support expressing complex values via command line,
• new doc error-handling.md.

Incoming breaking changes

• flag --blk /path/to/image should be updated to --blk path=/path/to/image[,readonly=on|off],
• flag --mem-size x should be updated to --memory size=x if you do not need virtio-fs --fs, otherwise --memory size=x,backend=memfd.

New Contributors

• @astro made the first contribution in #72

Full Changelog: v0.3.0...v0.4.0