From e07d27e24d5dc9b11260d81bc2d2444d194baf62 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Mon, 13 Dec 2021 09:16:58 +0100 Subject: [PATCH] OvmfPkg/Microvm: add README Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3599 Signed-off-by: Gerd Hoffmann Acked-by: Jiewen Yao Reviewed-by: Philippe Mathieu-Daude --- OvmfPkg/Microvm/README | 50 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 OvmfPkg/Microvm/README diff --git a/OvmfPkg/Microvm/README b/OvmfPkg/Microvm/README new file mode 100644 index 0000000000..540d39f2ec --- /dev/null +++ b/OvmfPkg/Microvm/README @@ -0,0 +1,50 @@ + +This is an *experimental* port of OVMF for the QEMU microvm +machine type. + +microvm background info +----------------------- + +microvm is designed for modern, virtio-based workloads. Most legacy +lpc/isa devices like pit and pic can be turned off. virtio-mmio +(i.e. '-device virtio-{blk,net,scsi,...}-device') is used for +storage/network/etc. + +Optional pcie support is available and any pcie device supported by +QEMU can be plugged in (including virtio-pci if you prefer that over +virtio-mmio). + +https://qemu.readthedocs.io/en/latest/system/i386/microvm.html +https://www.kraxel.org/blog/2020/10/qemu-microvm-acpi/ + +design issues +------------- + +Not fully clear yet how to do hardware detection best. Right now +using device tree to find virtio-mmio devices and pcie host bridge, +can reuse existing ArmVirtPkg code that way. Needs patched QEMU. + +features +-------- + [working] serial console + [working] direct kernel boot + [working] virtio-mmio support + [in progress] pcie support + +known limitations +----------------- + * rtc=on is required for now. + * can't use separate code/vars (actually an microvm limitation, + there is no pflash support). + * transitional virtio-pci devices do not work. microvm doesn't + support ioports on pcie, and ovmf doesn't initialize pcie devices + with ioports if there is no address space for them (even though + pcie devices are required to be functional without ioports). + +usage +----- +qemu-system-x86_64 \ + -nographic \ + -machine microvm,acpi=on,pit=off,pic=off,rtc=on \ + -bios /path/to/MICROVM.fd \ + [ ... more args here ... ]