From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36619) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ffNZD-0006mx-2l for qemu-devel@nongnu.org; Tue, 17 Jul 2018 06:50:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ffNZB-0007o9-T9 for qemu-devel@nongnu.org; Tue, 17 Jul 2018 06:50:51 -0400 Date: Tue, 17 Jul 2018 20:50:06 +1000 From: David Gibson Message-ID: <20180717105006.GA2272@umbus.fritz.box> References: <152949925592.606785.4717120428688653960.stgit@bahia.lan> <20180621011809.GD32328@umbus.fritz.box> <20180621152321.3ab81d51@bahia.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="mYCpIKhGyMATD0i+" Content-Disposition: inline In-Reply-To: <20180621152321.3ab81d51@bahia.lan> Subject: Re: [Qemu-devel] [PATCH v2 for-2.11.2] spapr: make pseries-2.11 the default machine type List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: Michael Roth , Thomas Huth , qemu-stable@nongnu.org, "Dr. David Alan Gilbert" , qemu-devel@nongnu.org --mYCpIKhGyMATD0i+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 21, 2018 at 03:23:21PM +0200, Greg Kurz wrote: > On Thu, 21 Jun 2018 11:18:09 +1000 > David Gibson wrote: >=20 > > On Wed, Jun 20, 2018 at 02:54:15PM +0200, Greg Kurz wrote: > > > The spapr capability framework was introduced in QEMU 2.12. It allows > > > to have an explicit control on how host features are exposed to the > > > guest. This is especially needed to handle migration between hetero- > > > geneous hosts (eg, POWER8 to POWER9). It is also used to expose fixes/ > > > workarounds against speculative execution vulnerabilities to guests. > > > The framework was hence backported to QEMU 2.11.1, especially these > > > commits: > > >=20 > > > 0fac4aa93074 spapr: Add pseries-2.12 machine type > > > 9070f408f491 spapr: Treat Hardware Transactional Memory (HTM) as an > > > optional capability > > >=20 > > > 0fac4aa93074 has the confusing effect of making pseries-2.12 the defa= ult > > > machine type for QEMU 2.11.1, instead of the expected pseries-2.11. T= his > > > patch changes the default machine back to pseries-2.11. > > >=20 > > > Unfortunately, 9070f408f491 enforces the HTM capability for pseries-2= =2E11 > > > to be enabled by default, ie, when not passing cap-htm on the command > > > line. This breaks several 'make check' testcases that run qemu-system= -ppc64 > > > with TCG. > > >=20 > > > The only sane way to fix this is to adapt the impacted testcases so t= hat > > > they all pass cap-htm=3Doff in this case. This patch does that as wel= l. > > >=20 > > > Signed-off-by: Greg Kurz > > > --- > > > v2: - have the testcases to pass cap-htm=3Doff instead of violating t= he > > > capabilities logic. > > >=20 > > > Upstream doesn't need anything like that since newer pseries machine = types > > > start with HTM disabled by default. This is really a oneshot fix for = 2.11.2, > > > and I've tried to make it as small as possible. > > >=20 > > > This is a full replacement of the previous version. It is based on Mi= ke's > > > staging tree for 2.11: =20 > >=20 > > Thanks for fixing this up > >=20 > > Reviewed-by: David Gibson > >=20 > > Btw, 2.11.z should probably have the 2.12 machine type removed > > entirely, as well as (obviously) not being the default. Not within > > scope for this patch, though. > >=20 >=20 > Well... it is indeed weird but I don't think it hurts. Also, people > may have started using pseries-2.12 with QEMU 2.11.1 (I seem to > remember Mike told me about something like this the other day)... I came back to thinking about this and realized this is a terrible idea. The problem is that because of the way we define the latest machine type, then backwards compat props for the earlier ones, it's very likely that the "pseries-2.12" in 2.11 won't be the same as pseries-2.12 in 2.12, simply because 2.11 won't have the necessary features to implement pseries-2.12 as in 2.12. --=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 --mYCpIKhGyMATD0i+ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAltNyd4ACgkQbDjKyiDZ s5J+1A//eBfhcUm5vO7ZRoRnz2FqMSQee+iRaDtmQ508Vj3mMeM4WudKWwa6lqL9 w5JkeF14vr+ytocvtJ3e86brs+m4lWOleg4DKujSl5Lq7Zco25ypxpHiyFkIwTw/ qkvCocmp8HHN7yQLroP9jCCXwaEbJfdRuszW7HQXm62XPms4CQrnfMXwPgp57Ttc 9ORCsWbK9Qy/zX8zrNYog6abu/OZMByhqHs1CQrL247XfdBELcX1DjKeOCvcvk41 ZPNA00joRCGds3l/h6IBjPsF1bkT54e3AboramWqGkPiNfAKZNwajEW3VyBhrTy7 qMKsBrXOIg7DW+nOPMuW6vM7TkOi1tevvP5fu/F/zNUSNrdSuWbOhur4iJ5HJJqp Qk5QemYTVmUhK45Rilss/hyBxJHHULHAU/wF7Jmz6843KeKWQG23S3ljdAWaUd87 BNu7+kJ/NNTVYu/junO0sj6WdyPFwpBNU2V61fb0iVoPryoESsm2tlhGL4E5Y0IH vu4axFfnyGRrmEVAAwNcn2GsWYJ1HUQuNuSzBSlFsw4fdysutDc1vk2QHHVAXMhH FzeyaV1dBvqxjK4FQpW201GoBDEcnr944FAYNuZpvwP+mPIWeIj5EEVrCfY6yDL9 lKiFiUdotcmUh9HOoDwNDkkfQAxvJyssfHvgNSHCN6UJh+GJwqA= =x8GL -----END PGP SIGNATURE----- --mYCpIKhGyMATD0i+--