Contributed by pitrh on from the its-puffies-all-the-way-down dept.
TL;DR - a native hypervisor is coming. stay tuned.
For the last few months, I've been working on a hypervisor for OpenBSD. The idea for this started a few years ago, and after playing around with it from time to time, things really started to take shape around the time of the Brisbane hackathon earlier this year. As development accelerated, the OpenBSD Foundation generously offered to fund the project so that I could focus on it in more earnest.
At this point, I think I've made sufficient progress that a public announcement is in order. I've also reached the point where I think other developers can step in and help out as much of the gooey bits in the core of the vmm are functioning the way I want.
Presently, the vmm code I've built is capable of launching a kernel and asking for the root filesystem; it doesn't do much more than that for now. However, getting to this point invovled building most of the scaffolding needed to finish the rest, and like I stated before, more people can now more easily help with what's left (basically the virtio(4) emulation for disks and network interfaces).
One might ask - why not port one of the other hypervisors out there instead of rolling your own from scratch? Fair question. However, for various technical reasons, choosing to port an existing vmm just didn't make a whole lot of sense. For example, I've been baking in support for things that the other implementations don't care about (namely i386 support, shadow paging, nested virtualization, support for legacy peripherals, etc) and trying to backfit support for those things into another hypervisor would probably have been just as hard as building it from the ground up.
The inevitable questions:
Q. What OSes can I run?
A. To start, OSes that support virtio-based devices (most of the CPU goo is done and is basically the same across most OSes once you get that part finished). Later, we'll see if we can expose a place for qemu to attach (maybe mimic KVM) to run legacy OSes or OSes that require BIOS/UEFI boot support. There is no legacy-free mandate in this vmm.
Q. When will it be ready?
A. Hard to say. I hope by the end of October, but no promises. A lot also depends on how much help I get writing some of the virtio backends.
Q. What will be the CPU requirements?
A. Any AMD or Intel CPU that supports hardware virtualization (SVM for AMD, and VMX for Intel). For those CPUs that don't support RVI or EPT, we'll use shadow paging.
Q. What will be the OS requirements?
A. The core tools (vmd(8) and vmmctl(8)) and the main vmm (vmm(4)) will be built in to base, on i386 and amd64. This should be sufficient to run virtio based guests without any additional software requirements.
Q. Yuck, i386?
A. Yes. It helps find bugs. And I urge you to review my last dozen or so commits to i386 for another reason.
And now, the most important question:
Q. How can I help?
A. I would have likely had no time to work on this project for the past few months had it not been for the generous sponsorship of the OpenBSD Foundation. Your donations made that possible, and other projects like this. So, you can help by donating. If you think a hypervisor in OpenBSD is something you'd like to take advantage of, I urge you to go make a donation right now.
And finally, a sample boot:
Enable vmm mode (ala apm/apmd):
# vmmctl -e cpu0: entered VMM mode
Start a VM:
# vmmctl -S -c openbsd_amd64.vmrc /dev/ttyp0
Attach to VM console:
# cu -l /dev/ttyp0 exit save va/pa 0xfffff000bcff000 0xbcff000 exit load va/pa 0xfffff000bd1e000 0xbd1e000 entry load va/pa 0xffffff000bd2c000 0xbd2c000 vmd: new vm with id 1 created loading 64 bit kernel warning: bcopy during ELF kernel load not supported warning: bcopy during ELF kernel load not supported mark[start] = 0x1000000 mark[entry] = 0x1000160 mark[nsym] = 0x1 mark[sym] = 0x1939000 mark[end] = 0x1a1de00 mark[random] = 0x18a4000 mark[erandom] = 0x18a6408 vmd: all vcpu run threads for vm 3 launched vcpu_run_vmx: yielding the cpu vmd: waiting on thread 0 vcpu_run_vmx: yielding the cpu vcpu_run_vmx: yielding the cpu loading 0x1a44000-0x4000000 (0x1a44-0x4000) loading 0x100000-0x1000000 avail_start = 0x26000 avail_end = 0x4000000 First_avail = 0x1a44000 [ bsd ELF symbol table not valid: bad magic ] [ no symbol table formats found ] Copyright (c) 1982, 1986, 1989, 1991, 1993 The Regents of the University of California. All rights reserved. Copyright (c) 1995-2015 OpenBSD. All rights reserved. http://www.OpenBSD.org OpenBSD 5.8-current (GENERIC) #204: Mon Aug 31 01:13:40 PDT 2015 email@example.com:/export/bin/src/OpenBSD/vmm/src/sys/arch/amd64/compile/GENERIC vmd: i8253 PIT: 16 bit counter I/O not supported RTC BIOS diagnostic error ff
real mem = 50331648 (48MB) avail mem = 45101056 (43MB) mpath0 at root scsibus0 at mpath0: 256 targets mainbus0 at root bios0 at mainbus0 acpi at bios0 not configured cpu0 at mainbus0: (uniprocessor) cpu0: Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz cpu0: FPU,VME,DE,PSE,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH ,DS,MMX,FXSR,SSE,SSE2,SS,HTT,PBE,SSE3,PCLMUL,DTES64,DS-CPL,SSSE3,CX16,xTPR,PCID, SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,AVX,F16C,RDRAND,HV,ITSC,FSGSBASE,SMEP,E RMS pvbus0 at mainbus0: OpenBSD vmx_handle_cpuid: unsupported rax=0x40000100 pci0 at mainbus0 bus 0 isa0 at mainbus0 isadma0 at isa0 com0 at isa0 port 0x3f8/8 irq 4: ns8250, no fifo com0: console vmm at mainbus0 not configured vmx_handle_cr: mov to cr8 @ ffffffff8131854a nvram: invalid checksum vscsi0 at root scsibus1 at vscsi0: 256 targets softraid0 at root scsibus2 at softraid0: 256 targets root device:
This means that OpenBSD/amd64 is on its way to becoming a virtualization host operating system with its very own native hypervisor, joining the exclusive club that so far consisted of only OpenBSD/sparc64 with its support for logical domains (LDOMs).
Note that this is still not committed to the regular tree, this is just a teaser for upcoming goodness. To help the work along, head over to http://www.openbsdfoundation.org/donations.html right now and do the right thing!
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