Re: [PATCH 3/4] hw/arm/virt: Use kvm_arch_get_default_type()

[Gavin Shan]

On 8/9/24 6:59 PM, Peter Maydell wrote:
> On Fri, 9 Aug 2024 at 04:52, Gavin Shan <gshan@redhat.com> wrote:
> > kvm_arch_get_default_type() and kvm_arm_get_max_vm_ipa_size() are
> > interchangeable since the type is equivalent to IPA size (bits)
> > with one exception that IPA size (bits) is 40 when the type is zero.
>
> Well, sort of, but they're conceptually different.
>
> kvm_arch_get_default_type() is the API for "give me the value
> I need to pass to kvm_ioctl(s, KVM_CREATE_VM, type)"; it's
> architecture independent and different architectures do
> different things. In the future Arm might need to do something
> other than "just pass in the IPA size".
>
> kvm_arm_get_max_vm_ipa_size() does exactly what it says on the
> tin: it is an Arm specific function that returns the maximum
> supported IPA size.
>
> I would prefer not to conflate the two.

Agreed. Thanks for the explanation. Lets keep them separate and ignore
this series.

By the way, mc->kvm_type() can be used if one machine (platform) needs
to do more things than kvm_arch_get_default_type(), similar to what we're
doing on 'virt' machine currently.

Thanks,
Gavin