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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 8E7C8C07E9B for ; Mon, 19 Jul 2021 18:04:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7357761002 for ; Mon, 19 Jul 2021 18:04:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355508AbhGSRXz (ORCPT ); Mon, 19 Jul 2021 13:23:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:45840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349059AbhGSPom (ORCPT ); Mon, 19 Jul 2021 11:44:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D10F8611ED; Mon, 19 Jul 2021 16:23:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711823; bh=Uy2w6FbZRCR+yDAAarJQObrAw8O6iiCpycv6FkGX1BQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hKFt4cIpahxJylO8ZxY9nE46JueepMypQuChd6cP0wk341ws7FN4EuCSmk6GKJY0y DCne2TTxPMvKGwsN63eLc86IzyLPR2GcPS0xRN6UDQ1ZYkZ+W/8d4nuUQC8bdfuwFh HWR2A90kR1jAWsKWTETr9JQWRIb0Xgv1vR1cmXJw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Russell King , Bjorn Helgaas , Sasha Levin Subject: [PATCH 5.12 144/292] PCI: Dynamically map ECAM regions Date: Mon, 19 Jul 2021 16:53:26 +0200 Message-Id: <20210719144947.217081067@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144942.514164272@linuxfoundation.org> References: <20210719144942.514164272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Russell King [ Upstream commit 8fe55ef23387ce3c7488375b1fd539420d7654bb ] Attempting to boot 32-bit ARM kernels under QEMU's 3.x virt models fails when we have more than 512M of RAM in the model as we run out of vmalloc space for the PCI ECAM regions. This failure will be silent when running libvirt, as the console in that situation is a PCI device. In this configuration, the kernel maps the whole ECAM, which QEMU sets up for 256 buses, even when maybe only seven buses are in use. Each bus uses 1M of ECAM space, and ioremap() adds an additional guard page between allocations. The kernel vmap allocator will align these regions to 512K, resulting in each mapping eating 1.5M of vmalloc space. This means we need 384M of vmalloc space just to map all of these, which is very wasteful of resources. Fix this by only mapping the ECAM for buses we are going to be using. In my setups, this is around seven buses in most guests, which is 10.5M of vmalloc space - way smaller than the 384M that would otherwise be required. This also means that the kernel can boot without forcing extra RAM into highmem with the vmalloc= argument, or decreasing the virtual RAM available to the guest. Suggested-by: Arnd Bergmann Link: https://lore.kernel.org/r/E1lhCAV-0002yb-50@rmk-PC.armlinux.org.uk Signed-off-by: Russell King Signed-off-by: Bjorn Helgaas Reviewed-by: Arnd Bergmann Signed-off-by: Sasha Levin --- drivers/pci/ecam.c | 54 ++++++++++++++++++++++++++++++++++------ include/linux/pci-ecam.h | 1 + 2 files changed, 47 insertions(+), 8 deletions(-) diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c index d2a1920bb055..1c40d2506aef 100644 --- a/drivers/pci/ecam.c +++ b/drivers/pci/ecam.c @@ -32,7 +32,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev, struct pci_config_window *cfg; unsigned int bus_range, bus_range_max, bsz; struct resource *conflict; - int i, err; + int err; if (busr->start > busr->end) return ERR_PTR(-EINVAL); @@ -50,6 +50,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev, cfg->busr.start = busr->start; cfg->busr.end = busr->end; cfg->busr.flags = IORESOURCE_BUS; + cfg->bus_shift = bus_shift; bus_range = resource_size(&cfg->busr); bus_range_max = resource_size(cfgres) >> bus_shift; if (bus_range > bus_range_max) { @@ -77,13 +78,6 @@ struct pci_config_window *pci_ecam_create(struct device *dev, cfg->winp = kcalloc(bus_range, sizeof(*cfg->winp), GFP_KERNEL); if (!cfg->winp) goto err_exit_malloc; - for (i = 0; i < bus_range; i++) { - cfg->winp[i] = - pci_remap_cfgspace(cfgres->start + i * bsz, - bsz); - if (!cfg->winp[i]) - goto err_exit_iomap; - } } else { cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz); if (!cfg->win) @@ -129,6 +123,44 @@ void pci_ecam_free(struct pci_config_window *cfg) } EXPORT_SYMBOL_GPL(pci_ecam_free); +static int pci_ecam_add_bus(struct pci_bus *bus) +{ + struct pci_config_window *cfg = bus->sysdata; + unsigned int bsz = 1 << cfg->bus_shift; + unsigned int busn = bus->number; + phys_addr_t start; + + if (!per_bus_mapping) + return 0; + + if (busn < cfg->busr.start || busn > cfg->busr.end) + return -EINVAL; + + busn -= cfg->busr.start; + start = cfg->res.start + busn * bsz; + + cfg->winp[busn] = pci_remap_cfgspace(start, bsz); + if (!cfg->winp[busn]) + return -ENOMEM; + + return 0; +} + +static void pci_ecam_remove_bus(struct pci_bus *bus) +{ + struct pci_config_window *cfg = bus->sysdata; + unsigned int busn = bus->number; + + if (!per_bus_mapping || busn < cfg->busr.start || busn > cfg->busr.end) + return; + + busn -= cfg->busr.start; + if (cfg->winp[busn]) { + iounmap(cfg->winp[busn]); + cfg->winp[busn] = NULL; + } +} + /* * Function to implement the pci_ops ->map_bus method */ @@ -167,6 +199,8 @@ EXPORT_SYMBOL_GPL(pci_ecam_map_bus); /* ECAM ops */ const struct pci_ecam_ops pci_generic_ecam_ops = { .pci_ops = { + .add_bus = pci_ecam_add_bus, + .remove_bus = pci_ecam_remove_bus, .map_bus = pci_ecam_map_bus, .read = pci_generic_config_read, .write = pci_generic_config_write, @@ -178,6 +212,8 @@ EXPORT_SYMBOL_GPL(pci_generic_ecam_ops); /* ECAM ops for 32-bit access only (non-compliant) */ const struct pci_ecam_ops pci_32b_ops = { .pci_ops = { + .add_bus = pci_ecam_add_bus, + .remove_bus = pci_ecam_remove_bus, .map_bus = pci_ecam_map_bus, .read = pci_generic_config_read32, .write = pci_generic_config_write32, @@ -187,6 +223,8 @@ const struct pci_ecam_ops pci_32b_ops = { /* ECAM ops for 32-bit read only (non-compliant) */ const struct pci_ecam_ops pci_32b_read_ops = { .pci_ops = { + .add_bus = pci_ecam_add_bus, + .remove_bus = pci_ecam_remove_bus, .map_bus = pci_ecam_map_bus, .read = pci_generic_config_read32, .write = pci_generic_config_write, diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h index 65d3d83015c3..944da75ff25c 100644 --- a/include/linux/pci-ecam.h +++ b/include/linux/pci-ecam.h @@ -55,6 +55,7 @@ struct pci_ecam_ops { struct pci_config_window { struct resource res; struct resource busr; + unsigned int bus_shift; void *priv; const struct pci_ecam_ops *ops; union { -- 2.30.2