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/ Two questions were raised then. I'll try to comment on this below. >1) "res" is already in the resource tree, so we shouldn't be changing > its start address, because that may make the tree inconsistent, > e.g., the resource may no longer be completely contained in its > parent, it may conflict with a sibling, etc. We should not, yes. But... At the boot time IOV BAR gets as much MMIO space as it can possibly use. (Embarassingly I cannot trace where this is coming from, 8GB is selected via pci_assign_unassigned_root_bus_resources() path somehow). For example, it is 256*32MB=8GB where 256 is maximum PEs number and 32MB is a PF/VF BAR size. Whatever shifting we do afterwards, the boudaries of that 8GB area do not change and we test it in pnv_pci_vf_resource_shift(): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/platforms/powernv/pci-ioda.c#n987 > 2) If we update "res->start", shouldn't we update "res->end" > correspondingly? We have to update the PF's IOV BAR address as we allocate PEs dynamically and we do not know in advance where our VF numbers start in that 8GB window. So we change IOV BASR start. Changing the end may make it look more like there is a free area to use but in reality it won't be usable as well as the area we "release" by shifting the start address. We could probably move that M64 MMIO window by the same delta in opposite direction so the IOV BAR start address would remain the same but its VF#0 would be mapped to let's say PF#5. I am just afraid there is an alignment requirement for these M64 window start address; and this would be even more tricky to manage. We could also create reserved areas for the amount of space "release" by moving the start address, not sure how though. So how do we proceed with this particular patch now? Thanks. --- drivers/pci/iov.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) 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"); -- 2.11.0
