Re: [Qemu-devel] [PATCH v2 2/2] hw/arm: Add Arm Enterprise machine type

[Hongbo Zhang <hongbo.zhang@linaro.org>]

On 25 July 2018 at 18:53, Dr. David Alan Gilbert <dgilbert@redhat.com> wrote:
> * Hongbo Zhang (hongbo.zhang@linaro.org) wrote:
>> On 25 July 2018 at 17:54, Andrew Jones <drjones@redhat.com> wrote:
>> > On Wed, Jul 25, 2018 at 01:30:52PM +0800, Hongbo Zhang wrote:
>> >> For the Aarch64, there is one machine 'virt', it is primarily meant to
>> >> run on KVM and execute virtualization workloads, but we need an
>> >> environment as faithful as possible to physical hardware, for supporting
>> >> firmware and OS development for pysical Aarch64 machines.
>> >>
>> >> This patch introduces new machine type 'Enterprise' with main features:
>> >>  - Based on 'virt' machine type.
>> >>  - Re-designed memory map.
>> >>  - EL2 and EL3 are enabled by default.
>> >>  - GIC version 3 by default.
>> >>  - AHCI controller attached to system bus, and then CDROM and hard disc
>> >>    can be added to it.
>> >>  - EHCI controller attached to system bus, with USB mouse and key board
>> >>    installed by default.
>> >>  - E1000E ethernet card on PCIE bus.
>> >>  - VGA display adaptor on PCIE bus.
>> >>  - Default CPU type cortex-a57, 4 cores, and 1G bytes memory.
>> >>  - No virtio functions enabled, since this is to emulate real hardware.
>> >
>> > In the last review it was pointed out that using virtio-pci should still
>> > be "real" enough, so there's not much reason to avoid it. Well, unless
>> > there's some concern as to what drivers are available in the firmware and
>> > guest kernel. But that concern usually only applies to legacy firmwares
>> > and kernels, and therefore shouldn't apply to AArch64.
>> >
>> In real physical arm hardware, *HCI are system memory mapped, not on PCIE.
>> we need a QEMU platform like that. We need firmware developed on this
>> QEMU platform can run on real hardware without change(or only a minor
>> change)
>
> How would you deal with most modern hardware now using XHCI rather than
> EHCI ?
>
Well, EHCI still works well on server, some new X86 servers have both
XHCI and EHCI, Qualcomm Centriq Arm server even has only EHCI, so
currently only the EHCI is added.
I had no strong reason for XHCI or EHCI, if newer is better or some
users have special requirement for XHCI, it can be added too.

> Dave
>
>> Concern is not only available firmwares, but more emphasis is on new
>> firmwares to be developed on this platform (target is developing
>> firmware for hardware, but using qemu if hardware is not available
>> temporarily), if virtio device used, then the newly developed firmware
>> must include virtio front-end codes, but it isn't needed while run on
>> real hardware at last.
>>
>> >>  - No paravirtualized fw_cfg device either.
>> >>
>> >> Arm Trusted Firmware and UEFI porting to this are done accordingly.
>> >>
>> >
>> > How will UEFI get the ACPI tables from QEMU without fw-cfg? I didn't
>> > see any sort of reserved ROM region in the patch for them.
>> >
>> UEFI gets ACPI and kernel from network or mass storage, just like the
>> real hardware.
>> If we develop firmware depends on paravirtualized device like fw_cfg,
>> then we canot run such firmware on real hardware.
>>
>> > Thanks,
>> > drew
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK