On Thu, Oct 15, 2015 at 02:31:16PM -0500, Bjorn Helgaas wrote: > On Thu, Oct 08, 2015 at 10:20:17AM -0500, Ben Shelton wrote: > > For some SR-IOV devices, the number of available virtual functions increases > > after enabling ARI. Currently, SRIOV_NUM_VF is read and saved off before the > > ARI control bit is enabled in SRIOV_CTRL. This causes an issue when VFs are > > enabled. > > > > At device init, SRIOV_INITIAL_VF and SRIOV_NUM_VF are specified to contain the > > number of available VFs for the device. sriov_enable() does a sanity check > > that SRIOV_INITIAL_VF is not greater than iov->total_VFs, the saved-off value > > of SRIOV_NUM_VF. Since the value of both SRIOV_INITIAL_VF and SRIOV_NUM_VF has > > increased after enabling the ARI bit, the check fails, and the VFs cannot be > > enabled. > > > > To fix the issue, write SRIOV_CTRL first, and then read SRIOV_NUM_VF. > > > > Signed-off-by: Ben Shelton <benjamin.h.shelton@xxxxxxxxx> > > I applied this as follows to pci/virtualization for v4.4, thanks, Ben! I dropped this one for now, pending the resolution of my questions in http://lkml.kernel.org/r/20151016180701.GB21346@localhost > commit 3aa71da412fedaee133b4b6e4be4b801c59d6c91 > Author: Ben Shelton <benjamin.h.shelton@xxxxxxxxx> > Date: Thu Oct 15 12:35:17 2015 -0500 > > PCI: Enable SR-IOV ARI Capable Hierarchy before reading TotalVFs > > For some SR-IOV devices, the number of available virtual functions, i.e., > TotalVFs, increases after setting the ARI Capable Hierarchy bit in the > SR-IOV Control register. This violates the SR-IOV spec, r1.1, sec 3.3.6, > which says TotalVFs is HwInit, but we don't need TotalVFs before setting > the ARI Capable bit anyway. > > Set the ARI Capable Hierarchy bit (if ARI is enabled in the upstream > bridge) before reading TotalVFs. > > [bhelgaas: changelog] > Signed-off-by: Ben Shelton <benjamin.h.shelton@xxxxxxxxx> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > index 0202ab0..f8bfc1d 100644 > --- a/drivers/pci/iov.c > +++ b/drivers/pci/iov.c > @@ -399,10 +399,6 @@ static int sriov_init(struct pci_dev *dev, int pos) > ssleep(1); > } > > - pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total); > - if (!total) > - return 0; > - > ctrl = 0; > list_for_each_entry(pdev, &dev->bus->devices, bus_list) > if (pdev->is_physfn) > @@ -415,6 +411,10 @@ static int sriov_init(struct pci_dev *dev, int pos) > found: > pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl); > > + pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total); > + if (!total) > + return 0; > + > pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz); > i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0; > pgsz &= ~((1 << i) - 1); > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
