Subject: Re: [PATCH v3 6/6] powerpc/powernv: allocate sparse PE# when using M64 BAR in Single PE mode

From: Gavin Shan <[email-masked]>
Date: Fri, 14 Aug 2015 11:03:00 +1000

On Thu, Aug 13, 2015 at 10:11:11PM +0800, Wei Yang wrote:
>When M64 BAR is set to Single PE mode, the PE# assigned to VF could be
>sparse.
>
>This patch restructures the patch to allocate sparse PE# for VFs when M64
>BAR is set to Single PE mode.
>
>Signed-off-by: Wei Yang <[email-masked]>
>---
> arch/powerpc/include/asm/pci-bridge.h     |    2 +-
> arch/powerpc/platforms/powernv/pci-ioda.c |   59 +++++++++++++++++++----------
> 2 files changed, 41 insertions(+), 20 deletions(-)
>
>diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
>index 9d33ada..b026ef8 100644
>--- a/arch/powerpc/include/asm/pci-bridge.h
>+++ b/arch/powerpc/include/asm/pci-bridge.h
>@@ -214,7 +214,7 @@ struct pci_dn {
> #ifdef CONFIG_PCI_IOV
> 	u16     vfs_expanded;		/* number of VFs IOV BAR expanded */
> 	u16     num_vfs;		/* number of VFs enabled*/
>-	int     offset;			/* PE# for the first VF PE */
>+	int     pe_num_map[MAX_M64_BAR];/* PE# for the first VF PE or array */

Same question as to "m64_map". pdn for non-PF doesn't need it.

> 	bool    m64_single_mode;	/* Use M64 BAR in Single Mode */
> #define IODA_INVALID_M64        (-1)
> 	int      m64_map[PCI_SRIOV_NUM_BARS][MAX_M64_BAR];
>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>index 1e6ac86..7633538 100644
>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>@@ -1232,7 +1232,7 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>
> 			/* Map the M64 here */
> 			if (pdn->m64_single_mode) {
>-				pe_num = pdn->offset + j;
>+				pe_num = pdn->pe_num_map[j];
> 				rc = opal_pci_map_pe_mmio_window(phb->opal_id,
> 						pe_num, OPAL_M64_WINDOW_TYPE,
> 						pdn->m64_map[i][j], 0);
>@@ -1336,7 +1336,7 @@ void pnv_pci_sriov_disable(struct pci_dev *pdev)
> 	struct pnv_phb        *phb;
> 	struct pci_dn         *pdn;
> 	struct pci_sriov      *iov;
>-	u16 num_vfs;
>+	u16 num_vfs, i;
>
> 	bus = pdev->bus;
> 	hose = pci_bus_to_host(bus);
>@@ -1350,14 +1350,17 @@ void pnv_pci_sriov_disable(struct pci_dev *pdev)
>
> 	if (phb->type == PNV_PHB_IODA2) {
> 		if (!pdn->m64_single_mode)
>-			pnv_pci_vf_resource_shift(pdev, -pdn->offset);
>+			pnv_pci_vf_resource_shift(pdev, -pdn->pe_num_map[0]);
>
> 		/* Release M64 windows */
> 		pnv_pci_vf_release_m64(pdev);
>
> 		/* Release PE numbers */
>-		bitmap_clear(phb->ioda.pe_alloc, pdn->offset, num_vfs);
>-		pdn->offset = 0;
>+		if (pdn->m64_single_mode) {
>+			for (i = 0; i < num_vfs; i++)
>+				pnv_ioda_free_pe(phb, pdn->pe_num_map[i]);
>+		} else
>+			bitmap_clear(phb->ioda.pe_alloc, pdn->pe_num_map[0], num_vfs);
> 	}
> }
>
>@@ -1383,7 +1386,10 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>
> 	/* Reserve PE for each VF */
> 	for (vf_index = 0; vf_index < num_vfs; vf_index++) {
>-		pe_num = pdn->offset + vf_index;
>+		if (pdn->m64_single_mode)
>+			pe_num = pdn->pe_num_map[vf_index];
>+		else
>+			pe_num = pdn->pe_num_map[0] + vf_index;
>
> 		pe = &phb->ioda.pe_array[pe_num];
> 		pe->pe_number = pe_num;
>@@ -1425,6 +1431,7 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
> 	struct pnv_phb        *phb;
> 	struct pci_dn         *pdn;
> 	int                    ret;
>+	u16                    i;
>
> 	bus = pdev->bus;
> 	hose = pci_bus_to_host(bus);
>@@ -1448,19 +1455,30 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
> 		}
>
> 		/* Calculate available PE for required VFs */
>-		mutex_lock(&phb->ioda.pe_alloc_mutex);
>-		pdn->offset = bitmap_find_next_zero_area(
>-			phb->ioda.pe_alloc, phb->ioda.total_pe,
>-			0, num_vfs, 0);
>-		if (pdn->offset >= phb->ioda.total_pe) {
>+		if (pdn->m64_single_mode) {
>+			for (i = 0; i < num_vfs; i++)
>+				pdn->pe_num_map[i] = IODA_INVALID_PE;
>+			for (i = 0; i < num_vfs; i++) {
>+				pdn->pe_num_map[i] = pnv_ioda_alloc_pe(phb);
>+				if (pdn->pe_num_map[i] == IODA_INVALID_PE) {
>+					ret = -EBUSY;
>+					goto m64_failed;
>+				}
>+			}
>+		} else {
>+			mutex_lock(&phb->ioda.pe_alloc_mutex);
>+			pdn->pe_num_map[0] = bitmap_find_next_zero_area(
>+				phb->ioda.pe_alloc, phb->ioda.total_pe,
>+				0, num_vfs, 0);
>+			if (pdn->pe_num_map[0] >= phb->ioda.total_pe) {
>+				mutex_unlock(&phb->ioda.pe_alloc_mutex);
>+				dev_info(&pdev->dev, "Failed to enable VF%d\n", num_vfs);
>+				return -EBUSY;
>+			}
>+			bitmap_set(phb->ioda.pe_alloc, pdn->pe_num_map[0], num_vfs);
> 			mutex_unlock(&phb->ioda.pe_alloc_mutex);
>-			dev_info(&pdev->dev, "Failed to enable VF%d\n", num_vfs);
>-			pdn->offset = 0;
>-			return -EBUSY;
> 		}
>-		bitmap_set(phb->ioda.pe_alloc, pdn->offset, num_vfs);
> 		pdn->num_vfs = num_vfs;
>-		mutex_unlock(&phb->ioda.pe_alloc_mutex);
>
> 		/* Assign M64 window accordingly */
> 		ret = pnv_pci_vf_assign_m64(pdev, num_vfs);
>@@ -1475,7 +1493,7 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
> 		 * Otherwise, the PE# for the VF will conflict with others.
> 		 */
> 		if (!pdn->m64_single_mode) {
>-			ret = pnv_pci_vf_resource_shift(pdev, pdn->offset);
>+			ret = pnv_pci_vf_resource_shift(pdev, pdn->pe_num_map[0]);
> 			if (ret)
> 				goto m64_failed;
> 		}
>@@ -1487,8 +1505,11 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
> 	return 0;
>
> m64_failed:
>-	bitmap_clear(phb->ioda.pe_alloc, pdn->offset, num_vfs);
>-	pdn->offset = 0;
>+	if (pdn->m64_single_mode) {
>+		for (i = 0; i < num_vfs; i++)
>+			pnv_ioda_free_pe(phb, pdn->pe_num_map[i]);

if pdn->pe_num_map[i] isn't valid PE number, what will happen?

>+	} else
>+		bitmap_clear(phb->ioda.pe_alloc, pdn->pe_num_map[0], num_vfs);
>
> 	return ret;
> }
>-- 
>1.7.9.5
>