Re: [qemu-s390x] [PATCH v1] s390x/kvm: Configure page size after memory has actually been initialized

[David Gibson]

On Wed, Mar 27, 2019 at 09:06:53PM +0100, David Hildenbrand wrote:
> On 27.03.19 17:45, Igor Mammedov wrote:
> > On Wed, 27 Mar 2019 14:59:44 +0100
> > David Hildenbrand <address@hidden> wrote:
> > 
> >> Right now we configure the pagesize quite early, when initializing KVM.
> >> This is long before system memory is actually allocated via
> >> memory_region_allocate_system_memory(), and therefore memory backends
> >> marked as mapped.
> >>
> >> Instead, let's configure the maximum page size after initializing
> >> memory in s390_memory_init(). cap_hpage_1m is still properly
> >> configured before creating any CPUs, and therefore before configuring
> >> the CPU model and eventually enabling CMMA.
> >>
> >> We might later want to replace qemu_getrampagesize() by another
> >> detection mechanism, e.g. only looking at mapped, initial memory.
> >> We don't support any memory devices yet, and if so, we can always reject
> >> devices with a page size bigger than the initial page size when
> >> hotplugging. qemu_getrampagesize() should work for now, especially when
> >> converting it to only look at mapped backends.
> >>
> >> Signed-off-by: David Hildenbrand <address@hidden>
> > 
> > Acked-by: Igor Mammedov <address@hidden>
> 
> BTW, do we want
> 
> qemu_getmaxrampagesize()
> qemu_getminrampagesize()

That could work.

> or similar. qemu_getrampagesize() in its current form is really far from
> beautiful.

Yeah, and AFAICT the way it's used here remains incorrect.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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