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Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine t
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type |
Date: |
Tue, 2 Jul 2019 12:16:25 +0200 |
User-agent: |
NeoMutt/20180716 |
Hi,
> > Can we get rid of the kernel command line hacking please?
> > The virtio-mmio devices should be discoverable somehow.
> >
> > Device tree (as suggested by paolo) would work.
> > Custom acpi device (simliar to fw_cfg) is another option.
> > I'd tend to pick acpi, I wouldn't be surprised if we'll
> > need acpi anyway at some point.
> >
> > Maybe even do both, then switch at runtime depending on -no-acpi
> > (simliar to arm/aarch64).
>
> Microvm tries to do things in the cheapest possible way.
But taking too many shortcuts tends to hurt in the long run.
It also cuts off useful use cases.
I think microvm has more value than just the reduced boot time.
Specifically the reduced attack surface is useful I think, even
beyond container-style workloads. Being able to boot standard
cloud images (with the cloud image kernel loaded via cloud image
boot loader) in microvm would be useful for example.
So, yes, I want microvm being designed in a way that it can run
firmware and have it handle the boot process. For starters just
qboot for fast direct kernel boot, but longer term also seabios
and/or ovmf.
Can look at the seabios side, but probably not before I'm back
from my summer vacation in august. For seabios a simple & reliable
time source would be quite useful. Direct kernel boot might be doable
without that, but as soon as any I/O (read from cloud image disk) is
involved a time source is needed. Right now seabios uses the acpi
pm_timer. tsc should work too if seabios can figure the frequency
without a calibration loop (invtsc should be enough). Maybe seabios
needs kvmclock support ...
Is there any way to detect microvm from the guest? pc/q35 can be
easily detected by looking at the pci host bridge.
Do you have boot time numbers for qboot vs. no-firmware boot?
Is the difference big enough that it makes sense to maintain both?
cheers,
Gerd
- [Qemu-devel] [PATCH v2 0/4] Introduce the microvm machine type, Sergio Lopez, 2019/07/01
- [Qemu-devel] [PATCH v2 1/4] hw/virtio: Factorize virtio-mmio headers, Sergio Lopez, 2019/07/01
- [Qemu-devel] [PATCH v2 3/4] hw/i386: Factorize PVH related functions, Sergio Lopez, 2019/07/01
- [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/01
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Gerd Hoffmann, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type,
Gerd Hoffmann <=
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Gerd Hoffmann, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Paolo Bonzini, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/02
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/18
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Paolo Bonzini, 2019/07/18
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Sergio Lopez, 2019/07/19
- Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Paolo Bonzini, 2019/07/19
Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type, Stefano Garzarella, 2019/07/02