On Fri, Aug 11, 2017 at 06:19:33PM +1000, Alexey Kardashevskiy wrote: > From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> > > The PowerNV platform is the only user of pcibios_sriov_disable(). > The IOV BAR could be shifted by pci_iov_update_resource(). The > warning message in the function is printed if the IOV capability > is in enabled (PCI_SRIOV_CTRL_VFE && PCI_SRIOV_CTRL_MSE) state. > > This is the backtrace of what is happening: > pci_disable_sriov > sriov_disable > pnv_pci_sriov_disable > pnv_pci_vf_resource_shift > pci_update_resource > pci_iov_update_resource > > This fixes the issue by disabling IOV capability before calling > pcibios_sriov_disable(). With it, the disabling path matches > the enabling path: pcibios_sriov_enable() is called before the > IOV capability is enabled. > > Cc: shan.gavin@xxxxxxxxx > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > Cc: Paul Mackerras <paulus@xxxxxxxxx> > Reported-by: Carol L Soto <clsoto@xxxxxxxxxx> > Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> > Tested-by: Carol L Soto <clsoto@xxxxxxxxxx> > Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> > --- > > This is repost. Since Gavin left the team, I am trying to push it out. > The previos converstion is here: https://patchwork.ozlabs.org/patch/732653/ I gave up on the previous issue. I think this patch makes sense as-is at least as far as the fact that we can't update a struct resource while the device is still consuming it. I reworked the changelog to emphasize that. I assume the fact that pci_iov_update_resource() dropped the resource update caused some user-visible issue later on, and I might mention that, too, if I knew what it was. Here's what I would consider putting on pci/virtualization (the diff is unchanged from your post): commit 08132e7759b3929bea0ccdf8afe81ebf05351389 Author: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> Date: Fri Aug 11 18:19:33 2017 +1000 PCI: Disable VF decoding before updating resources in pcibios_sriov_disable() A struct resource represents the address space consumed by a device. We should not modify that resource while the device is actively using the address space. For VFs, pci_iov_update_resource() enforces this by printing a warning and doing nothing if the VFE (VF Enable) and MSE (VF Memory Space Enable) bits are set. Previously, both sriov_enable() and sriov_disable() called the pcibios_sriov_disable() arch hook, which may update the struct resource, while VFE and MSE were enabled. This effectively dropped the resource update pcibios_sriov_disable() intended to do. Disable VF memory decoding before calling pcibios_sriov_disable(). Reported-by: Carol L Soto <clsoto@xxxxxxxxxx> Tested-by: Carol L Soto <clsoto@xxxxxxxxxx> Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: shan.gavin@xxxxxxxxx Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 120485d6f352..ac41c8be9200 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -331,7 +331,6 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) while (i--) pci_iov_remove_virtfn(dev, i, 0); - pcibios_sriov_disable(dev); err_pcibios: iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE); pci_cfg_access_lock(dev); @@ -339,6 +338,8 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) ssleep(1); pci_cfg_access_unlock(dev); + pcibios_sriov_disable(dev); + if (iov->link != dev->devfn) sysfs_remove_link(&dev->dev.kobj, "dep_link"); @@ -357,14 +358,14 @@ static void sriov_disable(struct pci_dev *dev) for (i = 0; i < iov->num_VFs; i++) pci_iov_remove_virtfn(dev, i, 0); - pcibios_sriov_disable(dev); - iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE); pci_cfg_access_lock(dev); pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl); ssleep(1); pci_cfg_access_unlock(dev); + pcibios_sriov_disable(dev); + if (iov->link != dev->devfn) sysfs_remove_link(&dev->dev.kobj, "dep_link");
