From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758204AbbJ3Dsf (ORCPT ); Thu, 29 Oct 2015 23:48:35 -0400 Received: from e28smtp01.in.ibm.com ([122.248.162.1]:44827 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757689AbbJ3Dsd (ORCPT ); Thu, 29 Oct 2015 23:48:33 -0400 X-Helo: d28dlp03.in.ibm.com X-MailFrom: weiyang@linux.vnet.ibm.com X-RcptTo: linux-pci@vger.kernel.org Date: Fri, 30 Oct 2015 11:48:21 +0800 From: Wei Yang To: Bjorn Helgaas Cc: Alexander Duyck , linux-pci@vger.kernel.org, Ethan Zhao , Wei Yang , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/7] PCI: Set SR-IOV NumVFs to zero after enumeration Message-ID: <20151030034821.GB3551@richards-mbp.cn.ibm.com> Reply-To: Wei Yang References: <20151029221701.11908.82718.stgit@bhelgaas-glaptop2.roam.corp.google.com> <20151029222254.11908.78884.stgit@bhelgaas-glaptop2.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151029222254.11908.78884.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15103003-4790-0000-0000-00000B40B7E5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 29, 2015 at 05:22:54PM -0500, Bjorn Helgaas wrote: >ines: 115 > >From: Alexander Duyck > >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. > >Iterate from TotalVFs down to zero so NumVFs is zero when we're finished >computing the maximum number of buses. Validate offset and stride in >the loop, so we can test it at every possible NumVFs setting. Rename >virtfn_max_buses() to compute_max_vf_buses() to hint that it does have a >side effect of updating iov->max_VF_buses. > >[bhelgaas: changelog, rename, allow numVF==1 && stride==0, rework loop, >reverse sense of error path] >Fixes: 4449f079722c ("PCI: Calculate maximum number of buses required for VFs") >Based-on-patch-by: Ethan Zhao >Signed-off-by: Alexander Duyck >Signed-off-by: Bjorn Helgaas >--- > drivers/pci/iov.c | 41 ++++++++++++++++++++++------------------- > 1 file changed, 22 insertions(+), 19 deletions(-) > >diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c >index 0cdb2d1..1b1acc2 100644 >--- a/drivers/pci/iov.c >+++ b/drivers/pci/iov.c >@@ -54,24 +54,29 @@ static inline void pci_iov_set_numvfs(struct pci_dev *dev, int nr_virtfn) > * The PF consumes one bus number. NumVFs, First VF Offset, and VF Stride > * determine how many additional bus numbers will be consumed by VFs. > * >- * Iterate over all valid NumVFs and calculate the maximum number of bus >- * numbers that could ever be required. >+ * Iterate over all valid NumVFs, validate offset and stride, and calculate >+ * the maximum number of bus numbers that could ever be required. > */ >-static inline u8 virtfn_max_buses(struct pci_dev *dev) >+static int compute_max_vf_buses(struct pci_dev *dev) > { > struct pci_sriov *iov = dev->sriov; >- int nr_virtfn; >- u8 max = 0; >- int busnr; >+ int nr_virtfn, busnr, rc = 0; > >- for (nr_virtfn = 1; nr_virtfn <= iov->total_VFs; nr_virtfn++) { >+ for (nr_virtfn = iov->total_VFs; nr_virtfn; nr_virtfn--) { Hmm... I agree to iterate the nr_virtfn from total_VFs to 0, which keep the original logic, before my patch. > pci_iov_set_numvfs(dev, nr_virtfn); >+ if (!iov->offset || (nr_virtfn > 1 && !iov->stride)) { ^^^ Should be this? if (!iov->offset || (iov->total_VFs > 1 && !iov->stride)) >+ rc = -EIO; >+ goto out; >+ } >+ > busnr = pci_iov_virtfn_bus(dev, nr_virtfn - 1); >- if (busnr > max) >- max = busnr; >+ if (busnr > iov->max_VF_buses) >+ iov->max_VF_buses = busnr; > } > >- return max; >+out: >+ pci_iov_set_numvfs(dev, 0); >+ return rc; > } > > static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr) >@@ -384,7 +389,7 @@ 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; >@@ -410,11 +415,6 @@ 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; > Original code will return when it found this condition, so that we don't need to bother to do those initialization and then fall back. So I suggest to keep it here. > pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total); > if (!total) >@@ -456,8 +456,6 @@ 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); >@@ -474,10 +472,15 @@ found: > > dev->sriov = iov; > dev->is_physfn = 1; >- iov->max_VF_buses = virtfn_max_buses(dev); >+ rc = compute_max_vf_buses(dev); >+ if (rc) >+ goto fail_max_buses; > > return 0; > >+fail_max_buses: >+ dev->sriov = NULL; The dev->sriov is allocated with kzalloc(), seems we forget to release it? >+ dev->is_physfn = 0; > failed: > for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) { > res = &dev->resource[i + PCI_IOV_R -- Richard Yang Help you, Help me