Re: IPA range (41 bits) larger than the one supported by the host (40 bits)

[Peter Maydell]

On Thu, 26 May 2022 at 07:45, Jiatong Shen <yshxxsjt715@gmail.com> wrote:
>    I am trying to run qemu-system-aarch64 on a Kylin based machine, the host 
> kernel version is 4.19. qemu is versioned 4.2.1. The command I am running is 
> "qemu-system-aarch64 -cpu host -enable-kvm -machine virt -m 
> size=4G,maxmem=512G". This command failed with "qemu-system-aarch64: -m and 
> ,maxmem option values require an IPA range (41 bits) larger than the one 
> supported by the host (40 bits)".
>    I am confused because 2^40 is around 1TB which is greater than 512G. Would 
> be very appreciated to get some insights. Thank you very much for the help in 
> advance.

That's a rather old QEMU version. We reworked the handling of
highmem in the virt board for the 7.0 release -- could you
test whether that also has this problem? (I don't have a
40 bit PA host to hand but I did a quick simulation with
a gdb session and I think 7.0 should fit everything into 40 bits
with those command line options.)

thanks
-- PMM