From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752522AbbJORQG (ORCPT ); Thu, 15 Oct 2015 13:16:06 -0400 Received: from mail.kernel.org ([198.145.29.136]:44457 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752031AbbJORQD (ORCPT ); Thu, 15 Oct 2015 13:16:03 -0400 Date: Thu, 15 Oct 2015 12:16:00 -0500 From: Bjorn Helgaas To: Ethan Zhao Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] iov: restore NumVFs register to 0 before return from virtfn_max_buses() Message-ID: <20151015171600.GB17702@localhost> References: <1442373593-8342-1-git-send-email-ethan.zhao@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1442373593-8342-1-git-send-email-ethan.zhao@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ethan, On Wed, Sep 16, 2015 at 12:19:53PM +0900, Ethan Zhao wrote: > After commit 4449f079722c ("PCI: Calculate maximum number of buses > required for VFs"),the initial value of NumVFs register was left to > non-zero after sriov_init() and no VFs was enabled in device driver. > this changed the behaviour of kernel exported by lspci and sysfs etc. > so this patch restore the NumVFs register to zero after the > calculation of max_VF_buses was done and before return from > virtfn_max_buses(). > > Tested on stable 4.1 and passed building on stable 4.3-rc1 > > Signed-off-by: Ethan Zhao > Tested-by: Sriharsha Yadagudde Can you test the patch below? I'm trying to avoid touching PCI_SRIOV_NUM_VF in more than one place, and I think it's OK to set it and test offset/stride at the end, instead of setting NUM_VF to zero, testing offset/stride, computing max_bus, then setting NUM_VF to zero again. Bjorn commit 8e20e89658f23b8d16b1e21810e9f63c8625129c Author: Bjorn Helgaas Date: Thu Oct 15 11:31:21 2015 -0500 PCI: Set SR-IOV NumVFs to zero after enumeration The enumeration path should leave NumVFs set to zero. But after 4449f079722c ("PCI: Calculate maximum number of buses required for VFs"), we call virtfn_max_buses() in the enumeration path, which changes NumVFs. This NumVFs change is visible via lspci and sysfs until a driver enables SR-IOV. Set NumVFs to zero after virtfn_max_buses() computes the maximum number of buses. Fixes: 4449f079722c ("PCI: Calculate maximum number of buses required for VFs") Based-on-patch-by: Ethan Zhao Signed-off-by: Bjorn Helgaas diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index ee0ebff..0202ab0 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -384,7 +384,7 @@ static int sriov_init(struct pci_dev *dev, int pos) int rc; int nres; u32 pgsz; - u16 ctrl, total, offset, stride; + u16 ctrl, total; struct pci_sriov *iov; struct resource *res; struct pci_dev *pdev; @@ -414,11 +414,6 @@ static int sriov_init(struct pci_dev *dev, int pos) found: pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl); - pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, 0); - pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset); - pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride); - if (!offset || (total > 1 && !stride)) - return -EIO; pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz); i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0; @@ -456,8 +451,6 @@ found: iov->nres = nres; iov->ctrl = ctrl; iov->total_VFs = total; - iov->offset = offset; - iov->stride = stride; iov->pgsz = pgsz; iov->self = dev; pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap); @@ -475,6 +468,11 @@ found: dev->sriov = iov; dev->is_physfn = 1; iov->max_VF_buses = virtfn_max_buses(dev); + pci_iov_set_numvfs(dev, 0); + if (!iov->offset || (total > 1 && !iov->stride)) { + rc = -EIO; + goto failed; + } return 0; @@ -484,6 +482,7 @@ failed: res->flags = 0; } + dev->sriov = NULL; kfree(iov); return rc; }