Re: [PATCH v1 01/14] s390x/s390-virtio-ccw: don't crash on weird RAM sizes

[Thomas Huth]

On 11/09/2024 14.38, David Hildenbrand wrote:
> On 11.09.24 13:28, Janosch Frank wrote:
> > On 9/10/24 7:57 PM, David Hildenbrand wrote:
> > > KVM is not happy when starting a VM with weird RAM sizes:
> > >
> > >     # qemu-system-s390x --enable-kvm --nographic -m 1234K
> > >     qemu-system-s390x: kvm_set_user_memory_region: 
> > > KVM_SET_USER_MEMORY_REGION
> > >       failed, slot=0, start=0x0, size=0x244000: Invalid argument
> > >     kvm_set_phys_mem: error registering slot: Invalid argument
> > >     Aborted (core dumped)
> > >
> > > Let's handle that in a better way by rejecting such weird RAM sizes
> > > right from the start:
> >
> > Huh, I always assumed that ram is handled in multiples of 1MB in QEMU.
>
> Me as well, I did not dig if that changed at some point ... or why such odd 
> sizes would even be required :)

I guess it's there for some old PC hardware ... Remember, 640K ought to be 
enough for anybody.

 Thomas