[Qemu-devel] [PATCH 0/4] Introduce the microvm machine type

[Sergio Lopez]

Microvm is a machine type inspired by both NEMU and Firecracker, and
constructed after the machine model implemented by the latter.

It's main purpose is providing users a KVM-only machine type with fast
boot times, minimal attack surface (measured as the number of IO ports
and MMIO regions exposed to the Guest) and small footprint (specially
when combined with the ongoing QEMU modularization effort).

Normally, other than the device support provided by KVM itself,
microvm only supports virtio-mmio devices. Microvm also includes a
legacy mode, which adds an ISA bus with a 16550A serial port, useful
for being able to see the early boot kernel messages.

This is the list of the exposed IO ports and MMIO regions when running
in non-legacy mode:

address-space: memory
    00000000d0000000-00000000d00001ff (prio 0, i/o): virtio-mmio
    00000000d0000200-00000000d00003ff (prio 0, i/o): virtio-mmio
    00000000d0000400-00000000d00005ff (prio 0, i/o): virtio-mmio
    00000000d0000600-00000000d00007ff (prio 0, i/o): virtio-mmio
    00000000d0000800-00000000d00009ff (prio 0, i/o): virtio-mmio
    00000000d0000a00-00000000d0000bff (prio 0, i/o): virtio-mmio
    00000000d0000c00-00000000d0000dff (prio 0, i/o): virtio-mmio
    00000000d0000e00-00000000d0000fff (prio 0, i/o): virtio-mmio
    00000000fee00000-00000000feefffff (prio 4096, i/o): kvm-apic-msi

address-space: I/O
  0000000000000000-000000000000ffff (prio 0, i/o): io
    0000000000000020-0000000000000021 (prio 0, i/o): kvm-pic
    0000000000000040-0000000000000043 (prio 0, i/o): kvm-pit
    000000000000007e-000000000000007f (prio 0, i/o): kvmvapic
    00000000000000a0-00000000000000a1 (prio 0, i/o): kvm-pic
    00000000000004d0-00000000000004d0 (prio 0, i/o): kvm-elcr
    00000000000004d1-00000000000004d1 (prio 0, i/o): kvm-elcr

A QEMU instance with the microvm machine type can be invoked this way:

 - Normal mode:

qemu-system-x86_64 -M microvm -m 512m -smp 2 \
 -kernel vmlinux -append "console=hvc0 root=/dev/vda" \
 -nodefaults -no-user-config \
 -chardev pty,id=virtiocon0,server \
 -device virtio-serial-device \
 -device virtconsole,chardev=virtiocon0 \
 -drive id=test,file=test.img,format=raw,if=none \
 -device virtio-blk-device,drive=test \
 -netdev tap,id=tap0,script=no,downscript=no \
 -device virtio-net-device,netdev=tap0

 - Legacy mode:

qemu-system-x86_64 -M microvm,legacy -m 512m -smp 2 \
 -kernel vmlinux -append "console=ttyS0 root=/dev/vda" \
 -nodefaults -no-user-config \
 -drive id=test,file=test.img,format=raw,if=none \
 -device virtio-blk-device,drive=test \
 -netdev tap,id=tap0,script=no,downscript=no \
 -device virtio-net-device,netdev=tap0 \
 -serial stdio


Sergio Lopez (4):
  hw/i386: Factorize CPU routine
  hw/virtio: Factorize virtio-mmio headers
  hw/i386: Add an Intel MPTable generator
  hw/i386: Introduce the microvm machine type

 default-configs/i386-softmmu.mak            |   1 +
 hw/i386/Kconfig                             |   4 +
 hw/i386/Makefile.objs                       |   2 +
 hw/i386/cpu.c                               | 174 +++++++
 hw/i386/microvm.c                           | 518 ++++++++++++++++++++
 hw/i386/mptable.c                           | 157 ++++++
 hw/i386/pc.c                                | 151 +-----
 hw/i386/pc_piix.c                           |   3 +-
 hw/i386/pc_q35.c                            |   3 +-
 hw/virtio/virtio-mmio.c                     |  35 +-
 hw/virtio/virtio-mmio.h                     |  60 +++
 include/hw/i386/apic.h                      |   1 +
 include/hw/i386/cpu-internal.h              |  32 ++
 include/hw/i386/microvm.h                   |  85 ++++
 include/hw/i386/mptable.h                   |  37 ++
 include/standard-headers/linux/mpspec_def.h | 182 +++++++
 16 files changed, 1264 insertions(+), 181 deletions(-)
 create mode 100644 hw/i386/cpu.c
 create mode 100644 hw/i386/microvm.c
 create mode 100644 hw/i386/mptable.c
 create mode 100644 hw/virtio/virtio-mmio.h
 create mode 100644 include/hw/i386/cpu-internal.h
 create mode 100644 include/hw/i386/microvm.h
 create mode 100644 include/hw/i386/mptable.h
 create mode 100644 include/standard-headers/linux/mpspec_def.h

--
2.21.0