On Mon, 2013-06-03 at 07:28 +0000, Sethi Varun-B16395 wrote: > > -----Original Message----- > > From: iommu-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx [mailto:iommu- > > bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Alex Williamson > > Sent: Friday, May 31, 2013 12:09 AM > > To: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; dwmw2@xxxxxxxxxxxxx; > > joro@xxxxxxxxxx > > Cc: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > Subject: [PATCH] iommu: amd/intel: Remove multifunction assumption around > > grouping > > > > If a device is multifunction and does not have ACS enabled then we assume > > that the entire package lacks ACS and use function 0 as the base of the > > group. The PCIe spec however states that components are permitted to > > implement ACS on some, none, or all of their applicable functions. It's > > therefore conceivable that function 0 may be fully independent and > > support ACS while other functions do not. Instead use the lowest > > function of the slot that does not have ACS enabled as the base of the > > group. This may be the current device, which is intentional. So long as > > we use a consistent algorithm, all the non-ACS functions will be grouped > > together and ACS functions will get separate groups. > > > > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> > > --- > > drivers/iommu/amd_iommu.c | 25 +++++++++++++++++++------ > > drivers/iommu/intel-iommu.c | 25 +++++++++++++++++++------ > > 2 files changed, 38 insertions(+), 12 deletions(-) > > > > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index > > 1d84be1..565c745 100644 > > --- a/drivers/iommu/amd_iommu.c > > +++ b/drivers/iommu/amd_iommu.c > > @@ -287,14 +287,27 @@ static struct pci_dev *get_isolation_root(struct > > pci_dev *pdev) > > > > /* > > * If it's a multifunction device that does not support our > > - * required ACS flags, add to the same group as function 0. > > + * required ACS flags, add to the same group as lowest numbered > > + * function that also does not suport the required ACS flags. > > */ > > if (dma_pdev->multifunction && > > - !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) > > - swap_pci_ref(&dma_pdev, > > - pci_get_slot(dma_pdev->bus, > > - PCI_DEVFN(PCI_SLOT(dma_pdev->devfn), > > - 0))); > > + !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) { > > + u8 i, slot = PCI_SLOT(dma_pdev->devfn); > > + > > + for (i = 0; i < 8; i++) { > > + struct pci_dev *tmp; > > + > > + tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i)); > > + if (!tmp) > > + continue; > > + > > + if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) { > > + swap_pci_ref(&dma_pdev, tmp); > > + break; > > + } > > + pci_dev_put(tmp); > > + } > > + } > > > > /* > > * Devices on the root bus go through the iommu. If that's not us, > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > > index b4f0e28..eec0d3e 100644 > > --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -4182,14 +4182,27 @@ static int intel_iommu_add_device(struct device > > *dev) > > > > /* > > * If it's a multifunction device that does not support our > > - * required ACS flags, add to the same group as function 0. > > + * required ACS flags, add to the same group as lowest numbered > > + * function that also does not suport the required ACS flags. > > */ > > if (dma_pdev->multifunction && > > - !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) > > - swap_pci_ref(&dma_pdev, > > - pci_get_slot(dma_pdev->bus, > > - PCI_DEVFN(PCI_SLOT(dma_pdev->devfn), > > - 0))); > > + !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) { > > + u8 i, slot = PCI_SLOT(dma_pdev->devfn); > > + > > + for (i = 0; i < 8; i++) { > [Sethi Varun-B16395] A macro like PCI_MAX_FUNCTIONS would improve code readability. Ok, I see a couple defines of PCI_MAX_FUNCTION, I guess we could add one to iommu/pci.h too. > > + struct pci_dev *tmp; > > + > > + tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i)); > > + if (!tmp) > > + continue; > > + > > + if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) { > > + swap_pci_ref(&dma_pdev, tmp); > > + break; > > + } > > + pci_dev_put(tmp); > > + } > > + } > > It would be nice if this code could be represented as a function in a common file like iommu/pci.c. I agree, but I haven't gotten any feedback on iommu/pci.c yet and didn't want this patch to depend on that series. There are probably more opportunities to consolidate there. Thanks, Alex -- 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
