From: Gerd Hoffmann <kraxel@redhat.com>
To: Sergio Lopez <slp@redhat.com>
Cc: ehabkost@redhat.com, maran.wilson@oracle.com, mst@redhat.com,
qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net
Subject: Re: [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type
Date: Tue, 2 Jul 2019 12:16:25 +0200 [thread overview]
Message-ID: <20190702101625.trsg5dnnf2a4woqs@sirius.home.kraxel.org> (raw)
In-Reply-To: <878stgygiu.fsf@redhat.com>
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
next prev parent reply other threads:[~2019-07-02 10:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-01 14:47 [Qemu-devel] [PATCH v2 0/4] Introduce the microvm machine type Sergio Lopez
2019-07-01 14:47 ` [Qemu-devel] [PATCH v2 1/4] hw/virtio: Factorize virtio-mmio headers Sergio Lopez
2019-07-01 14:47 ` [Qemu-devel] [PATCH v2 2/4] hw/i386: Add an Intel MPTable generator Sergio Lopez
2019-07-02 8:02 ` Gerd Hoffmann
2019-07-02 8:37 ` Sergio Lopez
2019-07-02 9:33 ` Gerd Hoffmann
2019-07-01 14:47 ` [Qemu-devel] [PATCH v2 3/4] hw/i386: Factorize PVH related functions Sergio Lopez
2019-07-01 14:47 ` [Qemu-devel] [PATCH v2 4/4] hw/i386: Introduce the microvm machine type Sergio Lopez
2019-07-02 8:17 ` Gerd Hoffmann
2019-07-02 8:42 ` Sergio Lopez
2019-07-02 10:16 ` Gerd Hoffmann [this message]
2019-07-02 10:52 ` Sergio Lopez
2019-07-02 11:50 ` Gerd Hoffmann
2019-07-02 14:06 ` Paolo Bonzini
2019-07-02 14:41 ` Sergio Lopez
2019-07-18 14:34 ` Sergio Lopez
2019-07-18 15:48 ` Paolo Bonzini
2019-07-19 10:30 ` Sergio Lopez
2019-07-19 11:49 ` Paolo Bonzini
2019-07-02 8:19 ` Stefano Garzarella
2019-07-02 8:47 ` Sergio Lopez
2019-07-02 10:37 ` Paolo Bonzini
2019-07-02 11:16 ` Sergio Lopez
2019-07-01 18:32 ` [Qemu-devel] [PATCH v2 0/4] " no-reply
2019-07-01 19:06 ` no-reply
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