Re: [PATCH 3/3] docs/system/arm/virt: Fix documentation for the 'highmem' option

[Eric Auger]

Hi,

On 9/7/21 2:51 PM, Peter Maydell wrote:
> On Sun, 22 Aug 2021 at 15:45, Marc Zyngier <maz@kernel.org> wrote:
>> The documentation for the 'highmem' option indicates that it controls
>> the placement of both devices and RAM. The actual behaviour of QEMU
>> seems to be that RAM is allowed to go beyond the 4GiB limit, and
>> that only devices are constraint by this option.
>>
>> Align the documentation with the actual behaviour.
> I think it would be better to align the behaviour with the documentation.
>
> The intent of 'highmem' is to allow a configuration for use with guests
> that can't address more than 32 bits (originally, 32-bit guests without
> LPAE support compiled in). It seems like a bug that we allow the user
> to specify more RAM than will fit into that 32-bit range. We should
> instead make QEMU exit with an error if the user tries to specify
> both highmem=off and a memory size that's too big to fit.

That's my opinion too

Thanks

Eric
>
> thanks
> -- PMM
>