Re: [Qemu-devel] Announcing qboot, a minimal x86 firmware for QEMU

[Avi Kivity <avi@cloudius-systems.com>]

On 05/27/2015 12:30 PM, Paolo Bonzini wrote:
>
> On 26/05/2015 23:25, Christopher Covington wrote:
>> On 05/25/2015 08:53 AM, Paolo Bonzini wrote:
>>> On 22/05/2015 13:12, Daniel P. Berrange wrote:
>>>> In
>>>> particular I don't see why we need to have a SATA controller and ISA/LPC
>>>> bridge in every virt machine - root PCI bus only should be possible, as you
>>>> can provide disks via virtio-blk or virtio-scsi and serial, parallel, mouse,
>>>> floppy via PCI devices and/or by adding a USB bus in the cases where you
>>>> really need one.
>>> I think removing the ISA/LPC bridge is hard.  It includes the real-time
>>> clock and fw_cfg, for example.
>> Could VirtIO specified replacements make sense for these peripherals?
> Not really.  virtio is too heavyweight and you'd be reinventing the
> wheel unnecessarily.
>
> For example, ARM's "-M virt" uses a pl011 block for the RTC, and also
> uses fw_cfg.  Another commonly used ISA device is the UART, for which
> again -M virt uses a pl031.
>

The RTC can be replaced by kvmclock, the keyboard by virtio-console.  
Maybe we can provide an msr- or pci- based interface to fw_cfg.