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From: David Hildenbrand <david@redhat.com>
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Date: Mon, 30 Jul 2018 16:34:33 +0200
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Subject: Re: [Qemu-devel] [PATCH 1/1] s390x/sclp: fix maxram calculation
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To: Christian Borntraeger <borntraeger@de.ibm.com>, Cornelia Huck <cohuck@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, qemu-s390x <qemu-s390x@nongnu.org>, Alexander Graf <agraf@suse.de>, Thomas Huth <thuth@redhat.com>, Richard Henderson <rth@twiddle.net>, Janosch Frank <frankja@linux.vnet.ibm.com>, Halil Pasic <pasic@linux.vnet.ibm.com>, imbrenda@linux.vnet.ibm.com

On 30.07.2018 16:09, Christian Borntraeger wrote:
> We clamp down ram_size to match the sclp increment size. We do
> not do the same for maxram_size, which means for large guests
> with some sizes (e.g. -m 50000) maxram_size differs from ram_size.
> This can break other code (e.g. CMMA migration) which uses maxram_size
> to calculate the number of pages and then throws some errors.

So the only problem is that the buffer size between source and target
differ?

>=20
> Fixes: 82fab5c5b90e468f3e9d54c ("s390x/sclp: remove memory hotplug supp=
ort")
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> CC: qemu-stable@nongnu.org
> CC: David Hildenbrand <david@redhat.com>
> ---
>  hw/s390x/sclp.c | 1 +
>  1 file changed, 1 insertion(+)
>=20
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index bd2a024..4510a80 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -320,6 +320,7 @@ static void sclp_memory_init(SCLPDevice *sclp)
>      initial_mem =3D initial_mem >> increment_size << increment_size;
> =20
>      machine->ram_size =3D initial_mem;
> +    machine->maxram_size =3D initial_mem;
>      /* let's propagate the changed ram size into the global variable. =
*/
>      ram_size =3D initial_mem;
>  }
>=20

I even have a private patch for that already :)

--=20

Thanks,

David / dhildenb