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Re: [Qemu-arm] [Qemu-devel] [PATCH] hw/arm: Add SBSA machine type
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH] hw/arm: Add SBSA machine type |
Date: |
Thu, 28 Jun 2018 11:22:16 +0100 |
User-agent: |
Mutt/1.10.0 (2018-05-17) |
On Wed, Jun 27, 2018 at 01:31:17PM +0100, Dr. David Alan Gilbert wrote:
> * Hongbo Zhang (address@hidden) wrote:
> > This patch introduces a new Arm machine type 'SBSA' with features:
> > - Based on legacy 'virt' machine type.
The 'virt' machine type is absolutely *not* legacy. It is the preferred
modern, legacy-free machine type when running virtual machines. Since
aarch64 is greenfield, there is no compelling reason to emulate a
specific physical machine for VMs, hence the 'virt' machine type.
> > - Newly designed memory map.
> > - EL2 and EL3 are enabled 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.
> > - E1000 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.
>
> I'm a bit confused; do you have real modern ARM hardware that has an
> e1000 on it? If I understand correctly, e1000 is the old PCI version
> and the e1000e is at least the more modern PCIe version which makes
> more sense if you're building on PCIe.
Indeed, it makes little sense to default to e1000 if the goal is to make
it legacy-free
> However, if you:
> a) Don't have real hardware with the e1000 on
> b) Do have PCIe
>
> then to my mind it makes sense to use virtio-net-pci rather than
> an e1000e.
If it does down the virtio-* route though, I fail to see any point in
adding the new machine type at all - 'virt' machine type is intended
to be used for guests where everything is paravirtualized, ignoring
physical hardware constraints.
Regards,
Daniel
--
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Re: [Qemu-arm] [Qemu-devel] [PATCH] hw/arm: Add SBSA machine type, Igor Mammedov, 2018/06/27
Re: [Qemu-arm] [Qemu-devel] [PATCH] hw/arm: Add SBSA machine type, Laszlo Ersek, 2018/06/28