I am working with SR-IOV and I have a question regarding the function
sriov_init() in ../drivers/pci/iov.c (linux versions 3.4.9 and 3.13.4)
In sriov_init() the code first checks whether the PF is a Root complex
endpoint (0x9) or an Express Endpoint (0x0) as shown in the code
snippet below. If it is neither it returns the No device error.
static int sriov_init(struct pci_dev *dev, int pos)
{
int i;
int rc;
int nres;
u32 pgsz;
u16 ctrl, total, offset, stride;
struct pci_sriov *iov;
struct resource *res;
struct pci_dev *pdev;
if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_END &&
pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT)
return -ENODEV;
My question is why PCI_EXP_TYPE_LEG_END (0x1) is omitted as being a
valid endpoint. By excluding Legacy endpoints it fails enabling
SR-IOV on a VGA PF.
Is there a design/specification reason why legacy was excluded or was
it just an assumption that VGA would never support SR-IOV?
If there is no valid reason to exclude PCI_EXP_TYPE_LEG_END, I would
like to discuss having it included as a valid endpoint for SR-IOV.
Thanks,
Kelly
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