package mirage-xen

v9.0.0 (2025-02-05)

• Use dune-variants, sleeper storage is now in mirage-sleep (#54 @hannesm)

v8.0.3 (2024-04-29)

• Time: remove Timeout exception, and unused timeout and with_timeout functions (#52 @hannesm)
• Remove mirage-profile dependency (#53 @hannesm)

v8.0.2 (2023-03-03)

• Provide Memory.metrics, a metrics source. Remove Mm.metrics metrics source. (#51 @hannesm)

v8.0.1 (2022-10-19)

• Improve performance and take the opportunity to resolve pending processes which are only paused (with Lwt.pause) instead to waiting a sleeping process (#49, @TheLortex, @dinosaure)

v8.0.0 (2022-07-24)

• provide Memory.stat (uses dlmalloc mallinfo - expensive), and Memory.trim (releases free memory), improve Memory.quick_stat accuracy using ocaml-solo5 0.8.1 (@palainp @winux138, #48)

v7.2.0 (2022-03-30)

• lib/bindings: pass CFLAGS from 6.x for compiling libimrage-xen_bindings.a (@palainp, #47, solves mirage/mirage#1299)

v7.1.0 (2022-03-27)

• Rename the freestanding toolchain to solo5 (@dinosaure, @samoht, #39, #43)
• Use ocamlformat (@samoht, #42)

v7.0.0 (2021-01-31)

• Disable formatting to allow CI to succeed (@hannesm, #34)
• Be able to compile & generate documentation even if the package does not exists into the expected dune's workspace (@TheLortex, @dinosaure, #37)
• breaking change mirage-xen defines its own OS module: Xen_os (@dinosaure, #38)

v6.0.1 (2021-11-18)

• Fix OCaml documentation strings (#30 @hannesm)
• Add caml_get_wall_clock to retrieve the wall clock as int64 (#31 @hannesm)
• Don't require opam for the bindings compilation (#32 @sternenseemann)
• Remove checksum_stubs and alloc_pages_stubs (available in mirage-tcpip and io-page), to keep in sync with mirage-solo5 (#33 @dinosaure, adapted by @hannesm to mirage-xen)

v6.0.0 (2020-10-20)

Version 6.0.0 is a re-write of the MirageOS Xen platform stack, with the overall goal of replacing Mini-OS and moving to a minimal, legacy-free codebase which builds MirageOS unikernels as Xen PVHv2 domUs only. At the same time, this change aligns the Xen backend with existing Solo5 backends as much as is practical and replaces the OCaml runtime with that provided by ocaml-freestanding.

This is a breaking change. MirageOS libraries and applications that make use of Xen-specific APIs will need to be updated. See below for a list of the interfaces that have changed.

Requirements changes:

• OCaml 4.08 or later and Dune 2.6 or later are required.
• Xen version 4.10 or later is required, as this is the earliest version which provides production-quality and stable PVHv2 APIs.
• Additionally, the custom Xen version 4.8 used by Qubes OS 4.0 is supported, as this has enough of PVHv2 backported to it.
• Only x86_64 hosts with HAP (EPT) are supported. Support for ARM32 has been removed. Support for ARM64 may be added at a later date if there is interest.

Security posture improvements:

With the move to a Solo5 and ocaml-freestanding base MirageOS gains several notable improvements to security posture for unikernels on Xen:

• Stack smashing protection is enabled unconditionally for all C code.
• W^X is enforced throughout, i.e. .text is read-execute, .rodata is read-only, non-executable and .data, heap and stack are read-write and non-executable.
• The memory allocator used by the OCaml runtime is now dlmalloc (provided by ocaml-freestanding), which is a big improvement over the Mini-OS malloc, and incorporates features such as heap canaries.

Interface changes:

• The Eventchn and Generation modules, previously provided by xen-evtchn have been folded into mirage-xen as OS.Eventchn and OS.Generation respectively. Applications and libraries should replace any dependency on xen-evtchn with one on mirage-xen {>= "6.0.0"} and use the corresponding submodules in OS directly.
• The OS.MM module has been replaced with a new OS.Memory module, with a statistics interface modeled after stdlib's Gc stat type. All units use the system word size rather than pages, which were ill-defined.
• OS.Sched has been removed. These interfaces (notably domain suspend/resume) were present but never fully implemented in the old Xen stack. They are not required for PVH domains or full-system suspend/resume and applications/libraries should remove any calls to them.
• OS.Start_info has been removed. These interfaces were specific to Xen PV, and don't have a direct equivalent for PVH domains.
• OS.Xenctrl has been removed. There are no known users of these interfaces, which appear to be a left-over from earlier versions of the Xen stack.
• OS.Xen.virt_to_mfn has been removed. This is a little-used low-level vestige of Mini-OS, and in the Solo5-based virtual memory arrangement should be replaced with the equivalent computation (addr >> 12) in application code directly.

Dependency changes:

• Now depends on solo5-bindings-xen (for the low-level VCPU initialisation and startup) and ocaml-freestanding (for the OCaml runtime). It follows that -freestanding variants of existing packages such as zarith and gmp are used instead of -xen variants.
• The io-page-xen package is no longer used. Applications/libraries depending on it should replace the dependency with one on io-page.
• As mentioned above, the xen-evtchn package is no longer used and applications/libraries should replace their dependency with one on mirage-xen {>= "6.0.0"}.

C stubs changes:

• alloc_pages_stubs.c: added, provides stubs for Io_page, as in mirage-solo5.
• checksum_stubs.c: added, provides stubs for Tcpip, as in mirage-solo5.
• exit_stubs.c: removed, equivalent provided by ocaml-freestanding.
• sched_stubs.c: removed, no longer required.
• start_info_stubs.c: removed, no longer required.
• xb_stubs.c: removed, no users and no longer required.

Apart from the above, the majority of C stubs which are used by mirage-xen have been renamed to follow the mirage_xen_XXX rather than stub_XXX convention.

The low-level C interfaces to Xen event channels (evtchn.c) and grant tables (gnttab.c) have been re-written from scratch. Some additional interfaces have been added to main.c to replace functionality that was previously part of start_info_stubs.c (obtaining initial PV console and Xenstore ports and I/O rings from Xen).

Due to issues with mixing PIC and non-PIC code when compiling the C stubs with Dune, the build system has been adapted to use a foreign Makefile for libmirage-xen_bindings.a. This is the recommended method to use when building libraries containing C code for use with MirageOS. See conversation in #23 for details.

Relationship with the Solo5 Xen bindings:

For Xen, Solo5 only provides the initial PVH boot, VCPU setup/traps and C-side PV console code. Some Mirage-internal private APIs are provided to allow mirage-xen to interact with the hypervisor -- this is fully explained in Solo5 commit Solo5/solo5@f4b47d1 and follow-ups.

v5.0.0 (2019-11-01)

• Revert the 4.0.0 change, Os_xen is now OS.Xen again (#20 @dinosaure)
• Adapt to mirage-runtime hooks (see mirage/mirage#1010) for at_enter_iter / at_exit_iter / at_exit (#21 @hannesm)
• Bump lower OCaml version to 4.06.0 (#21 @hannesm)

v4.0.1 (2019-07-05)

• Fix mirage-xen pkg-config file to reflect correct location of the bindings (@avsm)

v4.0.0 (2019-06-25)

• Breaking change: move from the OS.Xen module to Os_xen, in order to let packages specifically depend on a particular bit of Xen functionality. To port code, just change the module reference to Os_xen instead of OS. (#16 @TheLortex @avsm)

v3.4.0 (2019-04-22)

• Drop support for old ocaml-gnt package (#12, by @talex5)
• require dune, and conflict with broken version 1.9.1 (#13, by @hannesm)

v3.3.0 (2019-03-22)

• Add grant-handling code to OS.Xen (#9, by @talex5)

v3.2.0 (2019-02-16)

• Port build to dune from ocamlbuild (#8 @avsm)

3.1.0 (2018-11-11)

• bind minios function virt_to_mfn (@cfcs, #4)
• remove OS.Env module (@hannesm, #6)
• update to opam2

3.0.6 (2018-03-13)

• switched build system to topkg and ocamlbuild
• separated from mirage-platform into a custom repository, mirage-xen

3.0.5 (2017-11-19)

• xen: add support for OCaml 4.05.0 (@talex5, #195)

3.0.4 (2017-07-14)

• remove support for versions of OCaml older than 4.04.2, and add support for OCaml 4.04.2. For older revisions of OCaml, use an older revision of mirage-xen-ocaml.

3.0.3 (2017-06-16)

• xen: we need io-page-xen because

  • mirage-xen depends on xen-gnt (for suspend/resume callbacks)
  • xen-gnt depends on io-page (to represent the types of page mappings)
  • io-page needs either io-page-unix or io-page-xen. We can't hardcode a dependency because it needs to be different on Unix / Xen / Solo5. In future we could break the link by adding some kind of pre suspend post resume callback mechanism and then remove the xen-gnt dependency.

• unix: we need io-page-unix because

  • mirage-types-lwt is in the common set linked into all Unikernels by the mirage tool
  • mirage-types-lwt depends on mirage-block-lwt and mirage-net-lwt
  • mirage-block-lwt depends on io-page
  • io-page needs either io-page-unix or io-page-xen. We can't hardcode a dependency because it needs to be different on Unix / Xen / Solo5 In future we could break the link by rethinking the alignment requirements of the interfaces. Perhaps FLOW could be unaligned but raw NETIF and BLOCKIF aligned?

3.0.2 (2017-06-16)

• Remove dependency on io-page. Note this changes the exposed interface of the console and xenstore rings to be Cstruct.ts

3.0.1 (2017-05-29)

• [xen]: Depend on the new shared-memory-ring-lwt package
• Update appveyor configuration
• Reformat CHANGES.md to the topkg/Mirage style

3.0.0 (2017-01-24)

• [xen-ocaml] Add support for OCaml 4.04.0 (#173, by @yomimono)
• don't embed Str into the ocaml runtime (#175, by @hannesm)
• sleep in nanoseconds, not seconds (#168, by @hannesm)
• avoid memsetting NULL (#179, by @rixed)
• use mirage-clock-freestanding instead of mirage-clock-xen (#177, by @hannesm)
• use logs for errors (#171, by @hannesm)
• [xen-ocaml] for compiler version 4.04, set OCAML_OS_TYPE to "xen" (#178, by @yomimono)

2.6.0 (2016-05-05):

• [xen-ocaml] Add support for OCaml 4.03.0
• Add strtod and strtol implementations.
• Add stubbed out isatty function stub.

2.5.0 (2016-05-01):

• Remove use of deprecated Lwt_unix.run
• Support cstruct.2.0.0 (#163)
• Fix typos in license field.

2.4.1 (2016-03-22):

• Don't raise in an at_exit handler on Windows

2.4.0 (2016-03-18):

• mirage-unix now builds on win32
• Add appveyor support
• Add LICENSE file
• Allow packages to be built without the opam command0line tool
• Add OS.Lifecycle module. Allows unikernels to handle shutdown requests.
• Remove unmaintained ns3 module.
• Remove unused machine/ code

2.3.4 (2015-08-17):

• [xen-ocaml] Support OCaml 4.02.3 (#137, by @talex5)
• [xen-posix] Add -Wall to xen-ocaml-build and fix C warnings (#141, by @lnmx)

2.3.3 (2015-07-21):

• [xen-posix] Enable more compiler warnings (#134, by @talex5)
• [xen] Implement times and sysconf (#131, #134, by @talex5)

2.3.2 (2015-05-21):

• [xen] Synchronize Cstruct C stubs with version 1.6.0.

2.3.1 (2015-04-19):

• Fix uninstall of mirage-xen-ocaml (#126, patch from @hannesm)

2.3.0 (2015-03-17):

• Split mirage-xen into three opam packages: mirage-xen-posix (includes and mini-libc), mirage-xen-ocaml (OCaml runtime) and mirage-xen (bindings and OCaml OS libraries) (#125, patch from @hannesm)

2.2.3 (2015-03-16):

• Add opam files for mirage-xen and mirage-unix OPAM packages
• Remove page_stubs.c, now provided by io-page (#122, patch from @hannesm)

2.2.2 (2015-03-04):

• Add generic hooks to mainloop to support background tasks. (#120)
• [xen] Report trace events for GC again; this was disabled temporarily in the 2.2.0 release. (#119)

2.2.1 (2015-01-26):

• Fix Xen compilation with gcc 4.8+ by disabling the stack protector and -fno-tree-loop-distribute-patterns (not compatible with MiniOS). These missing flags were a regression from 2.1.3, which did include them.

2.2.0 (2015-01-23):

This releases adds support for OCaml 4.02+ compilation, and changes the Xen backend build for Mirage significantly by:

• removing the OCaml compiler runtime from the mirage-platform, which makes it simpler to work across multiple revisions of the compiler. It now uses the ocaml-src OPAM package to grab the current switch's version of the OCaml runtime.

• split the Xen runtime build into discrete pkg-config libraries:

  • mirage-xen-posix.pc : in the xen-posix/ directory, is the nano-posix layer built with no knowledge of OCaml
  • mirage-xen-minios.pc: defines the __INSIDE_MINIOS__ macro to expose internal state via the MiniOS headers (for use only by libraries that know exactly what they are doing with the MiniOS)
  • mirage-xen-ocaml.pc: in xen-ocaml/core/, this builds the OCaml asmrun, Bigarray and Str bindings using the mirage-xen-posix layer.
  • mirage-xen-ocaml-bindings.pc: in xen-ocaml/bindings/, these are bindings required by the OCaml libraries to MiniOS. Some of the bindings use MiniOS external state and hence use mirage-xen-minios, whereas others (cstruct_stubs and barrier_stubs are just OCaml bindings and so just use mirage-xen-posix).
  • mirage-xen.pc: depends on all the above to provide the same external interface as the current mirage-platform.

The OCaml code is now built using OASIS, since the C code is built entirely separately and could be moved out into a separate OPAM package entirely.

2.1.3 (2015-01-23):

• [xen] Fix error handling in OS.Main.run to enable a top-level exception to signal to the Xen toolstack that it crashed (versus a clean exit). This in turn lets on_crash="preserve" behaviour work better in Xen VM description files.
• Remove mirage-xen.pc file on uninstall.

2.1.2 (2014-12-20):

[xen] Updated headers and build for Mini-OS 0.5. This involves:

• Require libminios >= 0.5
• Remove old includes directory when installing
• Compile with -fno-builtin (avoids warnings about standard functions)
• Removed complex.h (now provided by Openlibm)
• Include cdefs.h from types.h (needed for __BEGIN_DECLS)
• Removed open from unistd.h (comes from fcntl.h)
• Removed assert.h and __assert_fail (provided by Mini-OS)
• Removed string.h (provided by Mini-OS)
• Removed cdefs.h (provided by Mini-OS)
• Added missing console.h includes (for printk)

2.1.1 (2014-12-17):

• Remove checksum stubs from Unix and Xen, as they are provided by tcpip now.
• [xen] Define UINTx_MAX and SIZE_MAX in stdint.h

2.1.0 (2014-12-07):

• [xen] Report trace events for GC, block_domain, XenStore and event channels. This introduces a new dependency on the mirage-profile package.
• [xen] Install a pkg-config file to allow other projects to compile C stubs against mirage-xen.
• [xen] Remove duplication of OCaml header files inside the include tree.

2.0.1 (2014-12-05):

• [xen] Assert that pages passed to the grant share API are page-aligned. This always happens if they are created via Io_page.create, and probably not true if made by Cstruct.create.
• [xen] Use monotonic time for timing events, not wall-clock time.
• [xen] Provide functions that C code often uses for asserts (abort, printf, etc).

2.0.0 (2014-11-04):

• Remove dietlibc, libm and most of the include files, replacing them with external dependencies on Mini-OS and openlibm.
• Introduce Xen/ARM support that works with both Xen 4.4 and the 4.5dev hypervisor ABI. Testing on Cubieboard2 and Cubietruck devices.
• [xen] Move the Xen main Lwt loop into OCaml code to simplify it (#99).
• Build fixes to work with multiple findlib directories in a single installation (#101 from Petter Urkedal).
• [xen] Install runtime headers for mirage-xen so that external C libraries can be compiled (#102 from James Bielman)
• [xen] Add support for demand-mapping for backend devices via a MiniOS gntmap device (#103).

1.1.1 (2013-02-24):

• xen: support 4096 event channels (up from 8). Each device typically uses one event channel.

1.1.0 (2013-02-01):

• Update to new io-page{,.unix} ocamlfind packages.
• Remove unused Netif module from Unix backend.
• Xen now depends on xen-{evtchn,gnt} packages.
• Add a type 'a io to make it easier to include with the Mirage sigs.

1.0.0 (2013-12-10):

• Set Sys.os_type to Unix in the Xen backend to help compatibility (#78).
• Suppress another dietlibc linker warning for vprintf in Xen.

## 0.9.9 (2013-12-07):

• Fix uninstall target for Unix.
• Remove tuntap stubs from Unix module; they are in ocaml-tuntap now.
• Move OS.Clock out to a toplevel Clock module (the mirage-clock package).
• Move OS.Io_page out to a toplevel Io_page module (the io-page package).
• Update library dependencies to reduce them based on new functionality.
• Install library as mirage-xen or mirage-unix that can coexist.
• Suppress dietlibc linker warnings for sscanf/sprintf.

0.9.8 (2013-11-07):

• Add support for OCaml 4.01.0 in addition to the existing 4.00.1 runtime.
• Major refresh of the NS3 simulation backend, for latest APIs.
• Add Netif statistics counters per-packet.
• [xen] Fix multi-page ring support by granting the correct data pages.
• [unix] flush OS.Console file descriptor more often (#108).
• Fix regression in Io_page.string_blit with non-zero src offset (#71).

0.9.7 (2013-10-05):

• Add Travis continuous integration scripts.
• [xen] zero out freshly allocated io pages.
• [xen] correct reattach xenstore connection after resume.
• [xen] fix suspend/resume
• [xen] switch to interrupts (SCHEDOP_block) rather than polling (SCHEDOP_poll) to allow more than 128 event channels
• [xen] add Activations.after interface to help drivers avoid losing interrupts
• Fix build on older gcc (4.4) versions, as found in CentOS 6.4.

0.9.6 (2013-08-27):

• [xen] adapt to new xenstore interface which allows the same code to be compiled under Unix userspace and xen kernelspace

0.9.5 (2013-08-09):

• Add the mir-rt regression runner to scripts/ (not installed).
• Unhook mir-run from the build, as Mirari replaces it.
• [xen] Port Netif to use the Macaddr module from ocaml-ipaddr.

0.9.4 (2013-08-07):

• [xen] add atomic load/store bindings for shared memory rings
• [xen] add atomic operations necessary for vchan
• [xen] expose memory barriers via Xenctrl ocamlfind package

0.9.3 (2013-07-18):

• [xen] Prevent spinning in Activations.run when a thread is blocked and then awakened.
• [xen] Gnt.grant_table_index is now an int, was an int32.
• [xen] Cleaned some C stubs files, mainly page_stubs.c
• [xen] Improved module Netif: The function create do not take a callback anymore, hidden some private function from the .mli.
• [unix] Add support for building and running on FreeBSD.

0.9.2 (2013-07-09):

• [xen] Add Netif test to wait for a fixed number of ring slots > 0
• [xen] Add Evtchn.close to Xen backend.
• [xen] Disable tree-loop-distribute-patterns to workaround crash with gcc-4.8. Temporary fix until we isolate the bug.
• [xen] Improved the interface of Io_page, implement some missing bits in Gnt.
• [xen] Several modules now have an interface similar to the one in the libxc bindings for OCaml. This makes it possible to write one application that can be compiled for the UNIX or the Xen backend.

0.9.1 (2013-06-11):

• [xen] add mmap stubs to make the default Bigarray module happy.
• OS.Netif.create no longer creates the tuntap interface. Hotplug events are generated from the mirari calling functions instead, removing the policy from this library.

0.9.0 (2013-05-22):

• [xen] Add a simple 'resume hook' mechanism for xen devices
• [xen] Update to new shared ring signature in 0.4.0
• [xen] Allow device providers to be added later
• [xen] Move the blkif implementation to ocaml-xen-block-driver
• [xen] Io_page.string_blit has now an interface similar to String.blit
• [xen] Console.write_s has been renamed Console.write_all
• [xen] Gnttab.unmap_exn now throws an exception on failure, like the xenctrl version. This makes it possible to run the same blkback code in kernelspace and userspace.

0.8.1 (2013-03-27):

• [xen] Fix the Xen block interface to wait for init correctly.

0.8.0 (2013-02-12):

• Remove mir-build script as the Mirari builder does its job now.
• [xen] add Str module C stubs, adapted to work in the Xen backend.

0.7.2 (2013-02-08):

• [xen] Fix the size of the start-of-day Xenstore and console rings.
• Quieten the verbosity of devices sleeping in Xen, to avoid console overflow situations.
• Install the packed cmx along with the cmxa to ensure that the compiler can do cross-module optimization (this is not a fatal error, but will impact performance if the cmx file is not present).

0.7.1 (2012-12-20):

• [unix] Update devices API to use Cstruct 0.6.0

0.7.0 (2012-12-20):

• [xen] Add support for VM suspend/resume/migrate
• [xen] Support for multiple network interfaces
• [xen] Use new shared-memory-ring, removing old builtin version. This is all OCaml except for the memory barrier assembly instructions.
• Update Cstruct to new API in 0.6.0

0.6.1 (2012-12-15):

• [xen] Add an unused ?dev parameter to Netif.create to match the UNIX version.
• [script] Add a mir-build script which converts a native output object into a Xen kernel. It does command-line parsing to be compatible with other Xen outputs in the future (such as the kFreeBSD or Javascript backends, when they are ready).

0.6.0 (2012-12-11):

• [xen] refresh to ocaml-4.00.1 runtime. You must use the correct OPAM switch to match versions, or bad things will happen when the resulting binary is run.

0.5.0 (2012-12-10):

• [xen] Fix spurious floating point exceptions on some machines.
• [ns3] Add NS3-based simulator backend.
• [unix] Add pcap-based Ethernet access in addition to tuntap.

0.4.1 (2012-11-04):

• [xen] fix incorrect reference counting in Io_pages that could potentially cause pages to be reused too early.
• [xen] move Xenstore protocol implementation out to a separate library that provides it as a functor.
• [unix] ignore SIGPIPE in the OS.Main.run function.

0.4.0 (2012-09-11):

• [xen] Add support for mapping and unmapping grant references
• [xen] Support Xen 4.2 reserved console and xenstore maps.
• [xen] Switch the Xenstore and console rings over to use cstruct.
• [xen] Add Evtchn virq interface for stub xenstored.
• [xen] Add Evtchn.unbind.
• [netif] fix checksum calculation code for odd-sized packets.

0.3.0 (2012-09-04):

• Initial public release.