From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5253C3F2C6 for ; Tue, 3 Mar 2020 10:03:45 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AD1FC20873 for ; Tue, 3 Mar 2020 10:03:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD1FC20873 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44478 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j94Ou-0002mM-TN for qemu-devel@archiver.kernel.org; Tue, 03 Mar 2020 05:03:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:51268) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j94O0-0001w5-6O for qemu-devel@nongnu.org; Tue, 03 Mar 2020 05:02:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j94Ny-0003XD-Ue for qemu-devel@nongnu.org; Tue, 03 Mar 2020 05:02:48 -0500 Received: from 6.mo2.mail-out.ovh.net ([87.98.165.38]:42846) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j94Ny-0003Wk-OC for qemu-devel@nongnu.org; Tue, 03 Mar 2020 05:02:46 -0500 Received: from player729.ha.ovh.net (unknown [10.108.54.94]) by mo2.mail-out.ovh.net (Postfix) with ESMTP id E93361CD51E for ; Tue, 3 Mar 2020 11:02:42 +0100 (CET) Received: from kaod.org (lns-bzn-46-82-253-208-248.adsl.proxad.net [82.253.208.248]) (Authenticated sender: groug@kaod.org) by player729.ha.ovh.net (Postfix) with ESMTPSA id 321131021BF13; Tue, 3 Mar 2020 10:02:16 +0000 (UTC) Date: Tue, 3 Mar 2020 11:02:15 +0100 From: Greg Kurz To: David Gibson Subject: Re: [PATCH v7 15/17] spapr: Don't clamp RMA to 16GiB on new machine types Message-ID: <20200303110215.769a1f66@bahia.home> In-Reply-To: <20200303034351.333043-16-david@gibson.dropbear.id.au> References: <20200303034351.333043-1-david@gibson.dropbear.id.au> <20200303034351.333043-16-david@gibson.dropbear.id.au> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 3117053894847994342 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedugedruddtiedguddvucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvffukfgjfhfogggtgfesthejredtredtvdenucfhrhhomhepifhrvghgucfmuhhriicuoehgrhhouhhgsehkrghougdrohhrgheqnecukfhppedtrddtrddtrddtpdekvddrvdehfedrvddtkedrvdegkeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhhouggvpehsmhhtphdqohhuthdphhgvlhhopehplhgrhigvrhejvdelrdhhrgdrohhvhhdrnhgvthdpihhnvghtpedtrddtrddtrddtpdhmrghilhhfrhhomhepghhrohhugheskhgrohgurdhorhhgpdhrtghpthhtohepqhgvmhhuqdguvghvvghlsehnohhnghhnuhdrohhrgh X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 87.98.165.38 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lvivier@redhat.com, Thomas Huth , Xiao Guangrong , farosas@linux.ibm.com, aik@ozlabs.ru, "Michael S. Tsirkin" , Mark Cave-Ayland , qemu-devel@nongnu.org, Paolo Bonzini , qemu-ppc@nongnu.org, clg@kaod.org, Igor Mammedov , "Edgar E. Iglesias" , paulus@samba.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 3 Mar 2020 14:43:49 +1100 David Gibson wrote: > In spapr_machine_init() we clamp the size of the RMA to 16GiB and the > comment saying why doesn't make a whole lot of sense. In fact, this was > done because the real mode handling code elsewhere limited the RMA in TCG > mode to the maximum value configurable in LPCR[RMLS], 16GiB. > > But, > * Actually LPCR[RMLS] has been able to encode a 256GiB size for a very > long time, we just didn't implement it properly in the softmmu > * LPCR[RMLS] shouldn't really be relevant anyway, it only was because we > used to abuse the RMOR based translation mode in order to handle the > fact that we're not modelling the hypervisor parts of the cpu > > We've now removed those limitations in the modelling so the 16GiB clamp no > longer serves a function. However, we can't just remove the limit > universally: that would break migration to earlier qemu versions, where > the 16GiB RMLS limit still applies, no matter how bad the reasons for it > are. > > So, we replace the 16GiB clamp, with a clamp to a limit defined in the > machine type class. We set it to 16 GiB for machine types 4.2 and earlier, > but set it to 0 meaning unlimited for the new 5.0 machine type. > > Signed-off-by: David Gibson > --- Reviewed-by: Greg Kurz > hw/ppc/spapr.c | 13 ++++++++----- > include/hw/ppc/spapr.h | 1 + > 2 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index ef7667455c..95bda4a615 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -2701,12 +2701,14 @@ static void spapr_machine_init(MachineState *machine) > > spapr->rma_size = node0_size; > > - /* Actually we don't support unbounded RMA anymore since we added > - * proper emulation of HV mode. The max we can get is 16G which > - * also happens to be what we configure for PAPR mode so make sure > - * we don't do anything bigger than that > + /* > + * Clamp the RMA size based on machine type. This is for > + * migration compatibility with older qemu versions, which limited > + * the RMA size for complicated and mostly bad reasons. > */ > - spapr->rma_size = MIN(spapr->rma_size, 0x400000000ull); > + if (smc->rma_limit) { > + spapr->rma_size = MIN(spapr->rma_size, smc->rma_limit); > + } > > if (spapr->rma_size > node0_size) { > error_report("Numa node 0 has to span the RMA (%#08"HWADDR_PRIx")", > @@ -4598,6 +4600,7 @@ static void spapr_machine_4_2_class_options(MachineClass *mc) > compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len); > smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF; > smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF; > + smc->rma_limit = 16 * GiB; > mc->nvdimm_supported = false; > } > > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h > index 90dbc55931..2015e37ac5 100644 > --- a/include/hw/ppc/spapr.h > +++ b/include/hw/ppc/spapr.h > @@ -126,6 +126,7 @@ struct SpaprMachineClass { > bool pre_4_1_migration; /* don't migrate hpt-max-page-size */ > bool linux_pci_probe; > bool smp_threads_vsmt; /* set VSMT to smp_threads by default */ > + hwaddr rma_limit; /* clamp the RMA to this size */ > > void (*phb_placement)(SpaprMachineState *spapr, uint32_t index, > uint64_t *buid, hwaddr *pio,