From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37076) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fEClN-0002j7-UX for qemu-devel@nongnu.org; Thu, 03 May 2018 07:51:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fEClJ-0004D0-Ph for qemu-devel@nongnu.org; Thu, 03 May 2018 07:51:06 -0400 Date: Thu, 3 May 2018 17:35:41 +1000 From: David Gibson Message-ID: <20180503073541.GZ13229@umbus.fritz.box> References: <20180503071037.31834-1-david@gibson.dropbear.id.au> <2bd5d47b-5561-fa4a-4277-6ef026ff8749@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="xd76R9tHJzDpbIo0" Content-Disposition: inline In-Reply-To: <2bd5d47b-5561-fa4a-4277-6ef026ff8749@redhat.com> Subject: Re: [Qemu-devel] [PATCH] spapr: Remove support for explicitly allocated RMAs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: groug@kaod.org, lvivier@redhat.com, qemu-ppc@nongnu.org, qemu-devel@nongnu.org --xd76R9tHJzDpbIo0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 03, 2018 at 09:19:34AM +0200, Thomas Huth wrote: > On 03.05.2018 09:10, David Gibson wrote: > > Current POWER cpus allow for a VRMA, a special mapping which describes a > > guest's view of memory when in real mode (MMU off, from the guest's poi= nt > > of view). Older cpus didn't have that which meant that to support a gu= est > > a special host-contiguous region of memory was needed to give the guest= its > > Real Mode Area (RMA). > >=20 > > KVM used to provide special calls to allocate a contiguous RMA for those > > cases. This was useful in the early days of KVM on Power to allow it t= o be > > tested on PowerPC 970 chips as used in Macintosh G5 machines. Now, tho= se > > machines are so old as to be almost irrelevant. >=20 > I still got my YDL PowerStation somewhere in a corner ... but well, > true, I haven't turned on its power since a year or two... or three... >=20 > > The normal qemu deprecation process would require this to be marked > > deprecated then removed in 2 releases. However, this can only be used > > with corresponding support in the host kernel - which was dropped > > years ago (in c17b98cf "KVM: PPC: Book3S HV: Remove code for PPC970 > > processors" of 2014-12-03 to be precise). Therefore it should be ok > > to drop this immediately. >=20 > OK, fair. >=20 > > Just to be clear this only affects *KVM* guests with PowerPC 970, and t= hose > > already require an ancient host kernel. TCG guests with PowerPC 970 sh= ould > > still work. >=20 > Just to be sure: kvm-pr will continue to work on a 970 host, right? In > that case: Yes, KVM PR should be fine. Not that I've tested, but I see no reason it would break. I'll clarify that in the message. > Acked-by: Thomas Huth >=20 --=20 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 --xd76R9tHJzDpbIo0 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAlrqu8oACgkQbDjKyiDZ s5L+rRAAvLSCxFZz7Lo+2COkiPXZMaZ5Xkg7tSrJqu//2ZSFQCty4SfM7WNvF+iD s6d8yMAcig+xez+g5sJ2sSo9EO0cTLV7WUj29oRv9G0FVgo8rlRk3cgSYk/f4um9 J84p6KKDKX3m8n7N7BDN0czPBuWp1IJswbZ/l4q8EC81OywhsHNMRvozj4yVk8dc 1+Hv/+1jwqsNoTeEuhqyNfYpNRaLGM1uMObwLlnBB4h+crDuJFvFgjKGhQVcs0/k CoImrJJOFyOlMAJ0mSYdnbQlH6VLnD9s9d7aWnLXvz6nIi72NioeRAtQnipr3rwH hG100LvF/7phzN0kFLC7eX6HFVmpEKfROI80vTIWijg01yDBOTr0vyv0ODw2hMv2 i7DQfVMmR4cSAoecw52MbpbG723Ba5ovu9osdHTxlIk024154mhDspa00i+seHzn HampLSkHB9wz7/pZfsSHWVcz4t9nO3DekqyiNFMjRwsV74MfDga6K7PstHGz1vZR lqilK1PD/RVqu+ng0EEPNqzQxyNMvhKlXgLUEbvMFqv8zROLSSke+eeyIq1DcLU2 4q5bCHqxuzQVS4Yq3um9VbDPVaJ96/LLxwz77/NFjqzgnoiXgeqjbq0dXO6PMqYr nWiIoeqki2iAbGoxkQEth/Q98UfbNvpjoVJuRyHmLgVb5OprVWQ= =DLm4 -----END PGP SIGNATURE----- --xd76R9tHJzDpbIo0--