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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 C5045C432C0 for ; Mon, 2 Dec 2019 07:07:16 +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 91A6F2146E for ; Mon, 2 Dec 2019 07:07:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91A6F2146E 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]:59746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ibfnf-0003hR-IJ for qemu-devel@archiver.kernel.org; Mon, 02 Dec 2019 02:07:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35319) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ibfkl-0002Aa-9r for qemu-devel@nongnu.org; Mon, 02 Dec 2019 02:04:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ibfkj-0000Yt-EO for qemu-devel@nongnu.org; Mon, 02 Dec 2019 02:04:14 -0500 Received: from 10.mo69.mail-out.ovh.net ([46.105.73.241]:50158) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ibfkj-0000X6-7p for qemu-devel@nongnu.org; Mon, 02 Dec 2019 02:04:13 -0500 Received: from player157.ha.ovh.net (unknown [10.108.54.217]) by mo69.mail-out.ovh.net (Postfix) with ESMTP id 500B273065 for ; Mon, 2 Dec 2019 08:04:09 +0100 (CET) Received: from kaod.org (lfbn-1-2229-223.w90-76.abo.wanadoo.fr [90.76.50.223]) (Authenticated sender: clg@kaod.org) by player157.ha.ovh.net (Postfix) with ESMTPSA id D8C78CB3DBD0; Mon, 2 Dec 2019 07:04:01 +0000 (UTC) Subject: Re: [for-5.0 4/4] spapr: Simplify ovec diff To: David Gibson , groug@kaod.org References: <20191129053356.232413-1-david@gibson.dropbear.id.au> <20191129053356.232413-5-david@gibson.dropbear.id.au> From: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= Message-ID: <28252087-426e-9986-1ffc-edf772f6050d@kaod.org> Date: Mon, 2 Dec 2019 08:04:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191129053356.232413-5-david@gibson.dropbear.id.au> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Ovh-Tracer-Id: 13215813110076312384 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedufedrudejgedguddthecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjqdffgfeufgfipdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefuvfhfhffkffgfgggjtgfgsehtjeertddtfeejnecuhfhrohhmpeevrogurhhitggpnfgvpgfiohgrthgvrhcuoegtlhhgsehkrghougdrohhrgheqnecukfhppedtrddtrddtrddtpdeltddrjeeirdehtddrvddvfeenucfrrghrrghmpehmohguvgepshhmthhpqdhouhhtpdhhvghlohepphhlrgihvghrudehjedrhhgrrdhovhhhrdhnvghtpdhinhgvtheptddrtddrtddrtddpmhgrihhlfhhrohhmpegtlhhgsehkrghougdrohhrghdprhgtphhtthhopehqvghmuhdquggvvhgvlhesnhhonhhgnhhurdhorhhgnecuvehluhhsthgvrhfuihiivgeptd X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 46.105.73.241 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, qemu-ppc@nongnu.org, mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 29/11/2019 06:33, David Gibson wrote: > spapr_ovec_diff(ov, old, new) has somewhat complex semantics. ov is set > to those bits which are in new but not old, and it returns as a boolean > whether or not there are any bits in old but not new. > > It turns out that both callers only care about the second, not the first. > This is basically equivalent to a bitmap subset operation, which is easier > to understand and implement. So replace spapr_ovec_diff() with > spapr_ovec_subset(). > > Cc: Mike Roth > > Signed-off-by: David Gibson Reviewed-by: Cedric Le Goater > --- > hw/ppc/spapr.c | 14 +++----------- > hw/ppc/spapr_hcall.c | 8 ++------ > hw/ppc/spapr_ovec.c | 30 ++++++++++-------------------- > include/hw/ppc/spapr_ovec.h | 4 +--- > 4 files changed, 16 insertions(+), 40 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 5187f5b0a5..32e1cc1d3f 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -1840,8 +1840,6 @@ static bool spapr_ov5_cas_needed(void *opaque) > { > SpaprMachineState *spapr = opaque; > SpaprOptionVector *ov5_mask = spapr_ovec_new(); > - SpaprOptionVector *ov5_legacy = spapr_ovec_new(); > - SpaprOptionVector *ov5_removed = spapr_ovec_new(); > bool cas_needed; > > /* Prior to the introduction of SpaprOptionVector, we had two option > @@ -1873,17 +1871,11 @@ static bool spapr_ov5_cas_needed(void *opaque) > spapr_ovec_set(ov5_mask, OV5_DRCONF_MEMORY); > spapr_ovec_set(ov5_mask, OV5_DRMEM_V2); > > - /* spapr_ovec_diff returns true if bits were removed. we avoid using > - * the mask itself since in the future it's possible "legacy" bits may be > - * removed via machine options, which could generate a false positive > - * that breaks migration. > - */ > - spapr_ovec_intersect(ov5_legacy, spapr->ov5, ov5_mask); > - cas_needed = spapr_ovec_diff(ov5_removed, spapr->ov5, ov5_legacy); > + /* We need extra information if we have any bits outside the mask > + * defined above */ > + cas_needed = !spapr_ovec_subset(spapr->ov5, ov5_mask); > > spapr_ovec_cleanup(ov5_mask); > - spapr_ovec_cleanup(ov5_legacy); > - spapr_ovec_cleanup(ov5_removed); > > return cas_needed; > } > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index 0f19be794c..f1799b1b70 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -1671,7 +1671,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, > target_ulong fdt_bufsize = args[2]; > target_ulong ov_table; > uint32_t cas_pvr; > - SpaprOptionVector *ov1_guest, *ov5_guest, *ov5_cas_old, *ov5_updates; > + SpaprOptionVector *ov1_guest, *ov5_guest, *ov5_cas_old; > bool guest_radix; > Error *local_err = NULL; > bool raw_mode_supported = false; > @@ -1770,9 +1770,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, > /* capabilities that have been added since CAS-generated guest reset. > * if capabilities have since been removed, generate another reset > */ > - ov5_updates = spapr_ovec_new(); > - spapr->cas_reboot = spapr_ovec_diff(ov5_updates, > - ov5_cas_old, spapr->ov5_cas); > + spapr->cas_reboot = !spapr_ovec_subset(ov5_cas_old, spapr->ov5_cas); > spapr_ovec_cleanup(ov5_cas_old); > /* Now that processing is finished, set the radix/hash bit for the > * guest if it requested a valid mode; otherwise terminate the boot. */ > @@ -1849,8 +1847,6 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, > spapr->fdt_blob = fdt; > } > > - spapr_ovec_cleanup(ov5_updates); > - > if (spapr->cas_reboot) { > qemu_system_reset_request(SHUTDOWN_CAUSE_SUBSYSTEM_RESET); > } > diff --git a/hw/ppc/spapr_ovec.c b/hw/ppc/spapr_ovec.c > index 811fadf143..0ff6d1aeae 100644 > --- a/hw/ppc/spapr_ovec.c > +++ b/hw/ppc/spapr_ovec.c > @@ -76,31 +76,21 @@ void spapr_ovec_intersect(SpaprOptionVector *ov, > bitmap_and(ov->bitmap, ov1->bitmap, ov2->bitmap, OV_MAXBITS); > } > > -/* returns true if options bits were removed, false otherwise */ > -bool spapr_ovec_diff(SpaprOptionVector *ov, > - SpaprOptionVector *ov_old, > - SpaprOptionVector *ov_new) > +/* returns true if ov1 has a subset of bits in ov2 */ > +bool spapr_ovec_subset(SpaprOptionVector *ov1, SpaprOptionVector *ov2) > { > - unsigned long *change_mask = bitmap_new(OV_MAXBITS); > - unsigned long *removed_bits = bitmap_new(OV_MAXBITS); > - bool bits_were_removed = false; > + unsigned long *tmp = bitmap_new(OV_MAXBITS); > + bool result; > > - g_assert(ov); > - g_assert(ov_old); > - g_assert(ov_new); > - > - bitmap_xor(change_mask, ov_old->bitmap, ov_new->bitmap, OV_MAXBITS); > - bitmap_and(ov->bitmap, ov_new->bitmap, change_mask, OV_MAXBITS); > - bitmap_and(removed_bits, ov_old->bitmap, change_mask, OV_MAXBITS); > + g_assert(ov1); > + g_assert(ov2); > > - if (!bitmap_empty(removed_bits, OV_MAXBITS)) { > - bits_were_removed = true; > - } > + bitmap_andnot(tmp, ov1->bitmap, ov2->bitmap, OV_MAXBITS); > + result = bitmap_empty(tmp, OV_MAXBITS); > > - g_free(change_mask); > - g_free(removed_bits); > + g_free(tmp); > > - return bits_were_removed; > + return result; > } > > void spapr_ovec_cleanup(SpaprOptionVector *ov) > diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h > index 7891e9caac..2bed517a2b 100644 > --- a/include/hw/ppc/spapr_ovec.h > +++ b/include/hw/ppc/spapr_ovec.h > @@ -66,9 +66,7 @@ SpaprOptionVector *spapr_ovec_clone(SpaprOptionVector *ov_orig); > void spapr_ovec_intersect(SpaprOptionVector *ov, > SpaprOptionVector *ov1, > SpaprOptionVector *ov2); > -bool spapr_ovec_diff(SpaprOptionVector *ov, > - SpaprOptionVector *ov_old, > - SpaprOptionVector *ov_new); > +bool spapr_ovec_subset(SpaprOptionVector *ov1, SpaprOptionVector *ov2); > void spapr_ovec_cleanup(SpaprOptionVector *ov); > void spapr_ovec_set(SpaprOptionVector *ov, long bitnr); > void spapr_ovec_clear(SpaprOptionVector *ov, long bitnr); >