Based on the limitation of M64 Window size, when VF BAR size is bigger than
64MB, IOV BAR just round up power of 2 of the total_vfs. While the 64MB is
a magic boundary in code, which is hard to maintain.
This patch replaces the hard coded boundary with gate, which is calculated
from m64_segsize and adds comment to explain the reason for it.
Signed-off-by: Wei Yang <weiy...@linux.vnet.ibm.com>
---
arch/powerpc/platforms/powernv/pci-ioda.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
b/arch/powerpc/platforms/powernv/pci-ioda.c
index f5d110c..31dcedc 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2702,7 +2702,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
pci_dev *pdev)
struct pnv_phb *phb;
struct resource *res;
int i;
- resource_size_t size;
+ resource_size_t size, gate;
struct pci_dn *pdn;
int mul, total_vfs;
@@ -2718,6 +2718,17 @@ static void pnv_pci_ioda_fixup_iov_resources(struct
pci_dev *pdev)
total_vfs = pci_sriov_get_totalvfs(pdev);
mul = phb->ioda.total_pe;
+ /*
+ * If bigger than or equal to half of m64_segsize, just round up power
+ * of two.
+ *
+ * Generally, one M64 BAR maps one IOV BAR. To avoid conflict with
+ * other devices, IOV BAR size is expanded to be (total_pe * VF size).
+ * When VF size is half of m64_segsize , the expanded size would equal
+ * to half of the whole M64 Window size, which will exhaust the M64
+ * Window and limit the system flexibility.
+ */
+ gate = phb->ioda.m64_segsize >> 1;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &pdev->resource[i + PCI_IOV_RESOURCES];
@@ -2732,10 +2743,11 @@ 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);
+ /* bigger than or equal to gate */
+ if (size >= gate) {
+ dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size "
+ "is bigger than %lld, roundup power2\n",
+ i, res, gate);
mul = roundup_pow_of_two(total_vfs);
pdn->m64_single_mode = true;
break;
--
1.7.9.5
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