Re: [PATCH 8/8] hw/arm/virt: Disable highmem when on hypervisor.framework

[Peter Maydell]

On Thu, 26 Nov 2020 at 21:36, Alexander Graf <agraf@csgraf.de> wrote:
> The Apple M1 only supports up to 36 bits of physical address space. That
> means we can not fit the 64bit MMIO BAR region into our address space.
>
> To fix this, let's not expose a 64bit MMIO BAR region when running on
> Apple Silicon.
>
> I have not been able to find a way to enumerate that easily, so let's
> just assume we always have that little PA space on hypervisor.framework
> systems.

If you have direct access to the host ID_AA64MMFR0_EL1 you can look
at the PARange field; otherwise start a stunt VM and look at its
ID_AA64MMFR0_EL1.PARange (this is what we do for KVM to query various
things about the VM's capabilities/ID regs).

thanks
-- PMM