OvmfPkg/Microvm/README

   1
   2 This is an *experimental* port of OVMF for the QEMU microvm
   3 machine type.
   4
   5 microvm background info
   6 -----------------------
   7
   8 microvm is designed for modern, virtio-based workloads.  Most legacy
   9 lpc/isa devices like pit and pic can be turned off.  virtio-mmio
  10 (i.e. '-device virtio-{blk,net,scsi,...}-device') is used for
  11 storage/network/etc.
  12
  13 Optional pcie support is available and any pcie device supported by
  14 QEMU can be plugged in (including virtio-pci if you prefer that over
  15 virtio-mmio).
  16
  17 https://qemu.readthedocs.io/en/latest/system/i386/microvm.html
  18 https://www.kraxel.org/blog/2020/10/qemu-microvm-acpi/
  19
  20 design issues
  21 -------------
  22
  23 Not fully clear yet how to do hardware detection best.  Right now
  24 using device tree to find virtio-mmio devices and pcie host bridge,
  25 can reuse existing ArmVirtPkg code that way.  Needs patched QEMU.
  26
  27 features
  28 --------
  29  [working] serial console
  30  [working] direct kernel boot
  31  [working] virtio-mmio support
  32  [in progress] pcie support
  33
  34 known limitations
  35 -----------------
  36  * rtc=on is required for now.
  37  * can't use separate code/vars (actually an microvm limitation,
  38    there is no pflash support).
  39  * transitional virtio-pci devices do not work.  microvm doesn't
  40    support ioports on pcie, and ovmf doesn't initialize pcie devices
  41    with ioports if there is no address space for them (even though
  42    pcie devices are required to be functional without ioports).
  43
  44 usage
  45 -----
  46 qemu-system-x86_64 \
  47     -nographic \
  48     -machine microvm,acpi=on,pit=off,pic=off,rtc=on \
  49     -bios /path/to/MICROVM.fd \
  50     [ ... more args here ... ]