On Fri, Jul 17, 2015 at 10:14:43AM +1000, Gavin Shan wrote:
>When VF BAR size is equal to 128MB or bigger than that, we extend
>the corresponding PF's IOV BAR to cover number of total VFs supported
>by the PF. Otherwise, we extend the PF's IOV BAR to cover 256 VFs.
>For the former case, we have to create compound PE, which includes
>4 VFs. Those 4 VFs included in the compound PE can't be passed through
>to different guests, which isn't good.
>
>The gate (128MB) was choosen based on the assumption that each PHB
>supports 64GB M64 space and one PF's IOV BAR can be extended to be
>as huge as 1/4 of that, which is 16GB. However, the IOV BAR can be
>extended to half of PHB's M64 window when the PF seats behind the
>root port. In that case, the gate can be enlarged to be 256MB to
>avoid compound PE as we can.
>
>Signed-off-by: Gavin Shan <gws...@linux.vnet.ibm.com>
>---
> arch/powerpc/platforms/powernv/pci-ioda.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
>b/arch/powerpc/platforms/powernv/pci-ioda.c
>index 6ec62b9..5b2e88f 100644
>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>@@ -2721,6 +2721,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
>pci_dev *pdev)
> struct resource *res;
> int i;
> resource_size_t size;
>+ resource_size_t limit;
> struct pci_dn *pdn;
> int mul, total_vfs;
>
>@@ -2730,6 +2731,18 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
>pci_dev *pdev)
> hose = pci_bus_to_host(pdev->bus);
> phb = hose->private_data;
>
>+ /*
>+ * When the PF seats behind root port, the IOV BAR can
>+ * consume half of the PHB's M64 window. Otherwise,
>+ * 1/4 of the PHB's M64 window can be consumed to the
>+ * maximal degree.
>+ */
>+ if (!pci_is_root_bus(pdev->bus) &&
>+ pci_is_root_bus(pdev->bus->self->bus))
>+ limit = 128;
>+ else
>+ limit = 256;
>+
I sent it too fast. The limit should be reversed: 256 when PF seats behind the
root port. Otherwise, it should be 128. I will send follow-up v2 after waiting
for couple of days in case there are some comments for this revision.
> pdn = pci_get_pdn(pdev);
> pdn->vfs_expanded = 0;
>
>@@ -2748,11 +2761,9 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
>pci_dev *pdev)
> }
>
> size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);
>-
>- /* bigger than 64M */
>- if (size > (1 << 26)) {
>- dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size
>is bigger than 64M, roundup power2\n",
>- i, res);
>+ if (size >= (limit * 0x100000)) {
>+ dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size
>is bigger than %lldMB, roundup power2\n",
>+ i, res, limit);
> pdn->m64_per_iov = M64_PER_IOV;
> mul = roundup_pow_of_two(total_vfs);
> break;
Thanks,
Gavin
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