From: Marc Zyngier <maz@kernel.org>
To: "Alex Bennée" <alex.bennee@linaro.org>
Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
christoffer.dall@arm.com
Subject: Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs
Date: Tue, 04 Aug 2020 18:16:30 +0100 [thread overview]
Message-ID: <dd535598ec1886f93f374ed5720b6c74@kernel.org> (raw)
In-Reply-To: <87lfiumnc8.fsf@linaro.org>
On 2020-08-04 16:40, Alex Bennée wrote:
> Marc Zyngier <maz@kernel.org> writes:
>
>> On 2020-08-04 15:44, Alex Bennée wrote:
>>> Marc Zyngier <maz@kernel.org> writes:
>>>
>>>> On 2020-08-04 13:44, Alex Bennée wrote:
>>>>> The VIRTIO_PCI support is an idealised PCI bus, we don't need a
>>>>> bunch
>>>>> of bloat for real world hardware for a VirtIO guest.
>>>>
>>>> Who says this guest will only have virtio devices?
>>>
>>> This is true - although what is the point of kvm_guest.config? We
>>> certainly turn on a whole bunch of virt optimised pathways with
>>> PARAVIRT
>>> and HYPERVISOR_GUEST along with the rest of VirtIO.
>>
>> Most of which actually qualifies as bloat itself as far as KVM/arm64
>> is concerned...
>
> So here is the question - does the kernel care about having a blessed
> config for a minimal viable guest? They are certainly used in the cloud
> but I understand the kernel is trying to get away from having a zoo of
> configs. What is the actual point of kvm_guest.config? Just an easy
> enabling for developers?
The cloud vendor I know certainly doesn't provide a "dumbed down"
kernel configuration. What they run is either a distro kernel
or something that fits their environment (which does include
HW PCI devices, and hardly any virtio device).
My take is that this kvm-special config isn't that useful in
the real world, and I don't believe there is such thing as a
"minimal viable guest" config, certainly not across architectures
and VMMs. Hopefully it fits someone's development workflow, but
that's probably it.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-08-04 17:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-04 12:44 [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Alex Bennée
2020-08-04 12:44 ` [PATCH v1 1/3] arm64: allow de-selection of ThunderX PCI controllers Alex Bennée
2020-08-17 17:11 ` Bjorn Helgaas
2020-08-04 12:44 ` [PATCH v1 2/3] arm64: gate the whole of pci-xgene on CONFIG_PCI_XGENE Alex Bennée
2020-08-04 12:44 ` [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs Alex Bennée
2020-08-04 13:46 ` Marc Zyngier
2020-08-04 14:44 ` Alex Bennée
2020-08-04 14:59 ` Marc Zyngier
2020-08-04 15:40 ` Alex Bennée
2020-08-04 17:16 ` Marc Zyngier [this message]
2020-08-04 13:18 ` [RFC PATCH v1 0/3] put arm64 kvm_config on a diet Ard Biesheuvel
2020-08-04 14:47 ` Alex Bennée
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