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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 711CDC2D0DB for ; Mon, 20 Jan 2020 14:03:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CBE021D7E for ; Mon, 20 Jan 2020 14:03:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727285AbgATODw (ORCPT ); Mon, 20 Jan 2020 09:03:52 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:37804 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726626AbgATODw (ORCPT ); Mon, 20 Jan 2020 09:03:52 -0500 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id B98CDA86436E8D119C3C; Mon, 20 Jan 2020 22:03:49 +0800 (CST) Received: from [127.0.0.1] (10.173.222.27) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Mon, 20 Jan 2020 22:03:42 +0800 Subject: Re: [PATCH v3 05/32] irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation To: Marc Zyngier , , CC: Eric Auger , James Morse , Julien Thierry , Suzuki K Poulose , Thomas Gleixner , Jason Cooper , Lorenzo Pieralisi , "Andrew Murray" , Robert Richter References: <20191224111055.11836-1-maz@kernel.org> <20191224111055.11836-6-maz@kernel.org> From: Zenghui Yu Message-ID: Date: Mon, 20 Jan 2020 22:03:39 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20191224111055.11836-6-maz@kernel.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.222.27] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marc, On 2019/12/24 19:10, Marc Zyngier wrote: > GICv4.1 defines a new VPE table that is potentially shared between > both the ITSs and the redistributors, following complicated affinity > rules. > > To make things more confusing, the programming of this table at > the redistributor level is reusing the GICv4.0 GICR_VPROPBASER register > for something completely different. > > The code flow is somewhat complexified by the need to respect the > affinities required by the HW, meaning that tables can either be > inherited from a previously discovered ITS or redistributor. > > Signed-off-by: Marc Zyngier Reviewed-by: Zenghui Yu With two very minor concerns below. [...] > +static int allocate_vpe_l1_table(void) > +{ > + void __iomem *vlpi_base = gic_data_rdist_vlpi_base(); > + u64 val, gpsz, npg, pa; > + unsigned int psz = SZ_64K; > + unsigned int np, epp, esz; > + struct page *page; > + > + if (!gic_rdists->has_rvpeid) > + return 0; > + > + /* > + * if VPENDBASER.Valid is set, disable any previously programmed > + * VPE by setting PendingLast while clearing Valid. This has the > + * effect of making sure no doorbell will be generated and we can > + * then safely clear VPROPBASER.Valid. > + */ > + if (gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER) & GICR_VPENDBASER_Valid) > + gits_write_vpendbaser(GICR_VPENDBASER_PendingLast, > + vlpi_base + GICR_VPENDBASER); I'm confused here. The Valid field resets to 0. Under which scenario will the Valid==1 while we're doing initialization for this RD? > + > + /* > + * If we can inherit the configuration from another RD, let's do > + * so. Otherwise, we have to go through the allocation process. We > + * assume that all RDs have the exact same requirements, as > + * nothing will work otherwise. > + */ > + val = inherit_vpe_l1_table_from_rd(&gic_data_rdist()->vpe_table_mask); > + if (val & GICR_VPROPBASER_4_1_VALID) > + goto out; > + > + gic_data_rdist()->vpe_table_mask = kzalloc(sizeof(cpumask_t), GFP_KERNEL); > + if (!gic_data_rdist()->vpe_table_mask) > + return -ENOMEM; > + > + val = inherit_vpe_l1_table_from_its(); > + if (val & GICR_VPROPBASER_4_1_VALID) > + goto out; > + > + /* First probe the page size */ > + val = FIELD_PREP(GICR_VPROPBASER_4_1_PAGE_SIZE, GIC_PAGE_SIZE_64K); > + gits_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER); > + val = gits_read_vpropbaser(vlpi_base + GICR_VPROPBASER); > + gpsz = FIELD_GET(GICR_VPROPBASER_4_1_PAGE_SIZE, val); > + esz = FIELD_GET(GICR_VPROPBASER_4_1_ENTRY_SIZE, val); > + > + switch (gpsz) { > + default: > + gpsz = GIC_PAGE_SIZE_4K; > + /* fall through */ > + case GIC_PAGE_SIZE_4K: > + psz = SZ_4K; > + break; > + case GIC_PAGE_SIZE_16K: > + psz = SZ_16K; > + break; > + case GIC_PAGE_SIZE_64K: > + psz = SZ_64K; > + break; > + } > + > + /* > + * Start populating the register from scratch, including RO fields > + * (which we want to print in debug cases...) > + */ > + val = 0; > + val |= FIELD_PREP(GICR_VPROPBASER_4_1_PAGE_SIZE, gpsz); > + val |= FIELD_PREP(GICR_VPROPBASER_4_1_ENTRY_SIZE, esz); > + > + /* How many entries per GIC page? */ > + esz++; > + epp = psz / (esz * SZ_8); > + > + /* > + * If we need more than just a single L1 page, flag the table > + * as indirect and compute the number of required L1 pages. > + */ > + if (epp < ITS_MAX_VPEID) { > + int nl2; > + > + gic_rdists->flags |= RDIST_FLAGS_VPE_INDIRECT; This flag is set but not used, can we just drop it? Thanks, Zenghui