commit 747d636b49ee02f9a93ccf092e74da48baa30eab
author Jiyong Park <jiyong@google.com> Tue Oct 19 17:12:52 2021 +0900
committer Jiyong Park <jiyong@google.com> Wed Oct 20 16:04:34 2021 +0900
tree 5f36a7a9335c13a7df660d9157e6710cef4b1e4e
parent 026df86633f42737727f3c45ce7e4058e84f1896

Use virtio-console for the serial devices

A VM is now provided with two
serial devices. One is the uart device which is used as the output
device for the cases where virtio-console device driver is not
available. In the case of Microdroid, it's used by bootloader (u-boot)
and by the kernel as earlycon. The other is the virtio-serial device. It
is used as the console for the kernel.

This CL has two X86 specific hacks though.

1. The PCI addresses of the boot devices were adjusted. This is because
we have added one more PCI device (the virtio-serial device) and crosvm
for x86_64 puts serial devices prior to the block devices and they all
share the same bus ID. As a result, the block device addresses are all
shifted by 1.

2. The kernel command line embedded in boot.img now has `console=none`.
This is to prevent u-boot from automatically adding `console=ttyS0`. If
we let u-boot do that, then we will have console=ttyS0 together with
console=hvc0. Then each kernel message is printed twice; once to ttyS0
and once again to hvc0.

Bug: 200914564
Test: run a VM
Change-Id: I4349c4d70ac76c1b4ddc77bbff6c9b697b2f1f4e