On Thu, Oct 15, 2015 at 12:16:00PM -0500, Bjorn Helgaas wrote:
> 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 <ethan.zhao@xxxxxxxxxx>
> > Tested-by: Sriharsha Yadagudde <sriharsha.devdas@xxxxxxxxxx>
>
> 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.
I applied the patch below to pci/virtualization for v4.4.
> commit 8e20e89658f23b8d16b1e21810e9f63c8625129c
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> 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 <ethan.zhao@xxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> 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;
> }
> --
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