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GET /api/patches/807997/?format=api
{ "id": 807997, "url": "http://patchwork.ozlabs.org/api/patches/807997/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170831033412.1971-1-aik@ozlabs.ru/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<20170831033412.1971-1-aik@ozlabs.ru>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/20170831033412.1971-1-aik@ozlabs.ru/", "date": "2017-08-31T03:34:12", "name": "[kernel] powerpc/powernv: Update comment about shifting IOV BAR", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "ea03b75b0bb288d590121c24bbd2a79cc0f58000", "submitter": { "id": 7621, "url": "http://patchwork.ozlabs.org/api/people/7621/?format=api", "name": "Alexey Kardashevskiy", "email": "aik@ozlabs.ru" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170831033412.1971-1-aik@ozlabs.ru/mbox/", "series": [ { "id": 731, "url": "http://patchwork.ozlabs.org/api/series/731/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=731", "date": "2017-08-31T03:34:12", "name": "[kernel] powerpc/powernv: Update comment about shifting IOV BAR", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/731/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/807997/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/807997/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Received": [ "from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68])\n\t(using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xjSgd1nsSz9sMN\n\tfor <patchwork-incoming@ozlabs.org>;\n\tThu, 31 Aug 2017 13:35:25 +1000 (AEST)", "from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 3xjSgc67z6zDqXv\n\tfor <patchwork-incoming@ozlabs.org>;\n\tThu, 31 Aug 2017 13:35:24 +1000 (AEST)", "from ozlabs.ru (ozlabs.ru [107.173.13.209])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 3xjSfL5V5WzDqF4\n\tfor <linuxppc-dev@lists.ozlabs.org>;\n\tThu, 31 Aug 2017 13:34:18 +1000 (AEST)", "from vpl1.ozlabs.ibm.com (localhost [IPv6:::1])\n\tby ozlabs.ru (Postfix) with ESMTP id 320673A60023;\n\tWed, 30 Aug 2017 23:35:23 -0400 (EDT)" ], "From": "Alexey Kardashevskiy <aik@ozlabs.ru>", "To": "Benjamin Herrenschmidt <benh@kernel.crashing.org>", "Subject": "[PATCH kernel] powerpc/powernv: Update comment about shifting IOV\n\tBAR", "Date": "Thu, 31 Aug 2017 13:34:12 +1000", "Message-Id": "<20170831033412.1971-1-aik@ozlabs.ru>", "X-Mailer": "git-send-email 2.11.0", "X-BeenThere": "linuxppc-dev@lists.ozlabs.org", "X-Mailman-Version": "2.1.23", "Precedence": "list", "List-Id": "Linux on PowerPC Developers Mail List\n\t<linuxppc-dev.lists.ozlabs.org>", "List-Unsubscribe": "<https://lists.ozlabs.org/options/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>", "List-Archive": "<http://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>", "List-Subscribe": "<https://lists.ozlabs.org/listinfo/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>", "Cc": "Alexey Kardashevskiy <aik@ozlabs.ru>,\n\tAlistair Popple <alistair@popple.id.au>,\n\tBjorn Helgaas <helgaas@kernel.org>, \n\tshan.gavin@gmail.com, Paul Mackerras <paulus@samba.org>,\n\tlinuxppc-dev@lists.ozlabs.org, David Gibson <david@gibson.dropbear.id.au>", "Errors-To": "linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org", "Sender": "\"Linuxppc-dev\"\n\t<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>" }, "content": "From: Benjamin Herrenschmidt <benh@kernel.crashing.org>\n\nFrom: Alexey Kardashevskiy <aik@ozlabs.ru>\n\nThis updates the comment about creating a hole in /proc/iomem which\nshould not be normally happening but it does in the powernv platform\ndue the way MMIO M64 BARs are organised in the IODA2-capable hardware.\n\nSigned-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>\n---\n\nIt has been mentioned multiple times (last one -\nhttps://www.spinics.net/lists/linux-pci/msg64084.html ) that the comment\nis not informative enough for people not particularly familiar with\nthe POWER8 IO hardware.\n\nThis attempt aims to:\n1. explain why we shift the resource\n2. explain why nothing can use that hole as a resource while it is \"free\"\n(I am not sure that this is the case actually)\n\nPlease comment, everyone, let's have this very well documented while\nI remember these bits :) Thanks.\n---\n arch/powerpc/platforms/powernv/pci-ioda.c | 10 +++++++---\n 1 file changed, 7 insertions(+), 3 deletions(-)", "diff": "diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c\nindex 48de308224d6..c4a36ae78c95 100644\n--- a/arch/powerpc/platforms/powernv/pci-ioda.c\n+++ b/arch/powerpc/platforms/powernv/pci-ioda.c\n@@ -1002,9 +1002,13 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)\n \t}\n \n \t/*\n-\t * After doing so, there would be a \"hole\" in the /proc/iomem when\n-\t * offset is a positive value. It looks like the device return some\n-\t * mmio back to the system, which actually no one could use it.\n+\t * Since M64 BAR shares segments among all possible 256 PEs,\n+\t * we have to shift the beginning of PF IOV BAR to make it start from\n+\t * the segment which belongs to the PE number assigned to the first VF.\n+\t * This creates a \"hole\" in the /proc/iomem which could be used for\n+\t * allocating other resources, however this is not expected to happen\n+\t * on IODA as the only possibility would be a PCI hotplug and IODA\n+\t * hardware only allows it on a slot with dedicated PHB.\n \t */\n \tfor (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {\n \t\tres = &dev->resource[i + PCI_IOV_RESOURCES];\n", "prefixes": [ "kernel" ] }