Peter Maydell writes: > On Tue, 2 Jul 2019 at 13:14, Sergio Lopez wrote: >> >> 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. > > Could we use virtio-pci instead of virtio-mmio? virtio-mmio is > a bit deprecated and tends not to support all the features that > virtio-pci does. It was introduced mostly as a stopgap while we > didn't have pci support in the aarch64 virt machine, and remains > for legacy "we don't like to break existing working setups" rather > than as a recommended config for new systems. Using virtio-pci implies keeping PCI and ACPI support, defeating a significant part of microvm's purpose. What are the issues with the current state of virtio-mmio? Is there a way I can help to improve the situation? Sergio.