On 08/06/2015 02:35 PM, Gavin Shan wrote:

On Wed, Aug 05, 2015 at 09:24:58AM +0800, Wei Yang wrote:

quoted

On PHB_IODA2, we enable SRIOV devices by mapping IOV BAR with M64 BARs. If
a SRIOV device's BAR is not 64-bit prefetchable, this is not assigned from
M64 windwo, which means M64 BAR can't work on it.

s/PHB_IODA2/PHB3

No, it is IODA2. OPEL does PHB3-specific bits, the host kernel just uses OPAL.

s/windwo/window

quoted

This patch makes this explicit.

Signed-off-by: Wei Yang <redacted>

The idea sounds right, but there is one question as below.

quoted

---
arch/powerpc/platforms/powernv/pci-ioda.c |   25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 5738d31..9b41dba 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c

@@ -908,9 +908,6 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)

		if (!res->flags || !res->parent)
			continue;

-		if (!pnv_pci_is_mem_pref_64(res->flags))
-			continue;
-
		/*
		 * The actual IOV BAR range is determined by the start address
		 * and the actual size for num_vfs VFs BAR.  This check is to

@@ -939,9 +936,6 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)

		if (!res->flags || !res->parent)
			continue;

-		if (!pnv_pci_is_mem_pref_64(res->flags))
-			continue;
-
		size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
		res2 = *res;
		res->start += size * offset;

@@ -1221,9 +1215,6 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)

		if (!res->flags || !res->parent)
			continue;

-		if (!pnv_pci_is_mem_pref_64(res->flags))
-			continue;
-
		for (j = 0; j < vf_groups; j++) {
			do {
				win = find_next_zero_bit(&phb->ioda.m64_bar_alloc,

@@ -1510,6 +1501,12 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)

	pdn = pci_get_pdn(pdev);

	if (phb->type == PNV_PHB_IODA2) {
+		if (!pdn->vfs_expanded) {
+			dev_info(&pdev->dev, "don't support this SRIOV device"
+				" with non M64 VF BAR\n");
+			return -EBUSY;
+		}
+

It would be -ENOSPC since -EBUSY indicates the devices (VFs) are temparily
unavailable. For this case, the VFs are permanently unavailable because of
running out of space to accomodate M64 and non-M64 VF BARs.

The error message could be printed with dev_warn() and it would be precise
as below or something else you prefer:

	dev_warn(&pdev->dev, "SRIOV not supported because of non-M64 VF BAR\n");

Both messages are cryptic.

If it is not M64 BAR, then what is it? It is always in one of M64 BARs (in 
the worst case - BAR#15?), the difference is if it is segmented or not, no?

quoted

		/* Calculate available PE for required VFs */
		mutex_lock(&phb->ioda.pe_alloc_mutex);
		pdn->offset = bitmap_find_next_zero_area(

@@ -2774,9 +2771,10 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)

		if (!res->flags || res->parent)
			continue;
		if (!pnv_pci_is_mem_pref_64(res->flags)) {
-			dev_warn(&pdev->dev, " non M64 VF BAR%d: %pR\n",
+			dev_warn(&pdev->dev, "Don't support SR-IOV with"
+					" non M64 VF BAR%d: %pR. \n",
				 i, res);
-			continue;
+			return;
		}

		size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);

@@ -2795,11 +2793,6 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)

		res = &pdev->resource[i + PCI_IOV_RESOURCES];
		if (!res->flags || res->parent)
			continue;
-		if (!pnv_pci_is_mem_pref_64(res->flags)) {
-			dev_warn(&pdev->dev, "Skipping expanding VF BAR%d: %pR\n",
-				 i, res);
-			continue;
-		}

When any one IOV BAR on the PF is non-M64, none of the VFs can be enabled.
Will we still allocate/assign M64 or M32 resources for the IOV BARs? If so,
I think it can be avoided.

quoted

		dev_dbg(&pdev->dev, " Fixing VF BAR%d: %pR to\n", i, res);
		size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);
--
1.7.9.5

-- 
Alexey