From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 15 Sep 2015 11:10:16 -0500 From: Bjorn Helgaas To: Ethan Zhao Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iov: initialize NumVFs register to 0 at the end of sriov_init() Message-ID: <20150915161016.GB27964@google.com> References: <1440150685-6690-1-git-send-email-ethan.zhao@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1440150685-6690-1-git-send-email-ethan.zhao@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Fri, Aug 21, 2015 at 06:51:25PM +0900, Ethan Zhao wrote: > After commit 4449f079722c ("PCI: Calculate maximum number of buses > required for VFs"),the initial value of NumVFs register was set 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 initialize the NumVFs register to zero after the > calculation of max_VF_buses was done. > > Tested on stable 4.1 and passed building on stable 4.2-rc7 > > Signed-off-by: Ethan Zhao > Tested-by: Sriharsha Yadagudde > --- > drivers/pci/iov.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > index ee0ebff..6969084 100644 > --- a/drivers/pci/iov.c > +++ b/drivers/pci/iov.c > @@ -476,6 +476,7 @@ found: > dev->is_physfn = 1; > iov->max_VF_buses = virtfn_max_buses(dev); > > + pci_iov_set_numvfs(dev, 0); I think it would be better to put this in virtfn_max_buses(), where we clobbered numVFs in the first place. I'd also read the original value and restore it, e.g., pci_read_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, &numvfs); for (nr_virtfn = 1; nr_virtfn <= iov->total_VFs; nr_virtfn++) { ... } pci_iov_set_numvfs(dev, numvfs); return max; I know sriov_init() sets numVFs to zero before it calls virtfn_max_buses(), but why rely on that extra knowledge? > return 0; > > failed: > -- > 1.8.3.1 >