Subject: Re: [PATCH V5 3/6] powerpc/powernv: use one M64 BAR in Single PE mode for one VF BAR

From: Gavin Shan <[email-masked]>
Date: Wed, 14 Oct 2015 12:15:32 +1100

On Tue, Oct 13, 2015 at 01:29:44PM +0800, Wei Yang wrote:
>On Tue, Oct 13, 2015 at 02:32:49PM +1100, Gavin Shan wrote:
>>On Tue, Oct 13, 2015 at 10:50:42AM +0800, Wei Yang wrote:
>>>On Tue, Oct 13, 2015 at 10:55:27AM +1100, Gavin Shan wrote:
>>>>On Fri, Oct 09, 2015 at 10:46:53AM +0800, Wei Yang wrote:
>>>>>In current implementation, when VF BAR is bigger than 64MB, it uses 4 M64
>>>>>BARs in Single PE mode to cover the number of VFs required to be enabled.
>>>>>By doing so, several VFs would be in one VF Group and leads to interference
>>>>>between VFs in the same group.
>>>>>
>>>>>And in this patch, m64_wins is renamed to m64_map, which means index number
>>>>>of the M64 BAR used to map the VF BAR. Based on Gavin's comments.
>>>>>
>>>>>This patch changes the design by using one M64 BAR in Single PE mode for
>>>>>one VF BAR. This gives absolute isolation for VFs.
>>>>>
>>>>>Signed-off-by: Wei Yang <[email-masked]>
>>>>>Reviewed-by: Gavin Shan <[email-masked]>
>>>>>Acked-by: Alexey Kardashevskiy <[email-masked]>
>>>>>---
>>>>> arch/powerpc/include/asm/pci-bridge.h     |   5 +-
>>>>> arch/powerpc/platforms/powernv/pci-ioda.c | 169 ++++++++++++------------------
>>>>> 2 files changed, 68 insertions(+), 106 deletions(-)
>>>>>
>>>>>diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
>>>>>index 712add5..8aeba4c 100644
>>>>>--- a/arch/powerpc/include/asm/pci-bridge.h
>>>>>+++ b/arch/powerpc/include/asm/pci-bridge.h
>>>>>@@ -214,10 +214,9 @@ struct pci_dn {
>>>>> 	u16     vfs_expanded;		/* number of VFs IOV BAR expanded */
>>>>> 	u16     num_vfs;		/* number of VFs enabled*/
>>>>> 	int     offset;			/* PE# for the first VF PE */
>>>>>-#define M64_PER_IOV 4
>>>>>-	int     m64_per_iov;
>>>>>+	bool    m64_single_mode;	/* Use M64 BAR in Single Mode */
>>>>> #define IODA_INVALID_M64        (-1)
>>>>>-	int     m64_wins[PCI_SRIOV_NUM_BARS][M64_PER_IOV];
>>>>>+	int     (*m64_map)[PCI_SRIOV_NUM_BARS];
>>>>> #endif /* CONFIG_PCI_IOV */
>>>>> #endif
>>>>> 	struct list_head child_list;
>>>>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>>>>index 7da476b..2886f90 100644
>>>>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>>>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>>>>@@ -1148,29 +1148,36 @@ static void pnv_pci_ioda_setup_PEs(void)
>>>>> }
>>>>>
>>>>> #ifdef CONFIG_PCI_IOV
>>>>>-static int pnv_pci_vf_release_m64(struct pci_dev *pdev)
>>>>>+static int pnv_pci_vf_release_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> {
>>>>> 	struct pci_bus        *bus;
>>>>> 	struct pci_controller *hose;
>>>>> 	struct pnv_phb        *phb;
>>>>> 	struct pci_dn         *pdn;
>>>>> 	int                    i, j;
>>>>>+	int                    m64_bars;
>>>>>
>>>>> 	bus = pdev->bus;
>>>>> 	hose = pci_bus_to_host(bus);
>>>>> 	phb = hose->private_data;
>>>>> 	pdn = pci_get_pdn(pdev);
>>>>>
>>>>>+	if (pdn->m64_single_mode)
>>>>>+		m64_bars = num_vfs;
>>>>>+	else
>>>>>+		m64_bars = 1;
>>>>>+
>>>>> 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++)
>>>>>-		for (j = 0; j < M64_PER_IOV; j++) {
>>>>>-			if (pdn->m64_wins[i][j] == IODA_INVALID_M64)
>>>>>+		for (j = 0; j < m64_bars; j++) {
>>>>>+			if (pdn->m64_map[j][i] == IODA_INVALID_M64)
>>>>> 				continue;
>>>>> 			opal_pci_phb_mmio_enable(phb->opal_id,
>>>>>-				OPAL_M64_WINDOW_TYPE, pdn->m64_wins[i][j], 0);
>>>>>-			clear_bit(pdn->m64_wins[i][j], &phb->ioda.m64_bar_alloc);
>>>>>-			pdn->m64_wins[i][j] = IODA_INVALID_M64;
>>>>>+				OPAL_M64_WINDOW_TYPE, pdn->m64_map[j][i], 0);
>>>>>+			clear_bit(pdn->m64_map[j][i], &phb->ioda.m64_bar_alloc);
>>>>>+			pdn->m64_map[j][i] = IODA_INVALID_M64;
>>>>> 		}
>>>>>
>>>>>+	kfree(pdn->m64_map);
>>>>> 	return 0;
>>>>> }
>>>>>
>>>>>@@ -1187,8 +1194,7 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	int                    total_vfs;
>>>>> 	resource_size_t        size, start;
>>>>> 	int                    pe_num;
>>>>>-	int                    vf_groups;
>>>>>-	int                    vf_per_group;
>>>>>+	int                    m64_bars;
>>>>>
>>>>> 	bus = pdev->bus;
>>>>> 	hose = pci_bus_to_host(bus);
>>>>>@@ -1196,26 +1202,26 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	pdn = pci_get_pdn(pdev);
>>>>> 	total_vfs = pci_sriov_get_totalvfs(pdev);
>>>>>
>>>>>-	/* Initialize the m64_wins to IODA_INVALID_M64 */
>>>>>-	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++)
>>>>>-		for (j = 0; j < M64_PER_IOV; j++)
>>>>>-			pdn->m64_wins[i][j] = IODA_INVALID_M64;
>>>>>+	if (pdn->m64_single_mode)
>>>>>+		m64_bars = num_vfs;
>>>>>+	else
>>>>>+		m64_bars = 1;
>>>>>+
>>>>>+	pdn->m64_map = kmalloc(sizeof(*pdn->m64_map) * m64_bars, GFP_KERNEL);
>>>>>+	if (!pdn->m64_map)
>>>>>+		return -ENOMEM;
>>>>>+	/* Initialize the m64_map to IODA_INVALID_M64 */
>>>>>+	for (i = 0; i < m64_bars ; i++)
>>>>>+		for (j = 0; j < PCI_SRIOV_NUM_BARS; j++)
>>>>>+			pdn->m64_map[i][j] = IODA_INVALID_M64;
>>>>>
>>>>>-	if (pdn->m64_per_iov == M64_PER_IOV) {
>>>>>-		vf_groups = (num_vfs <= M64_PER_IOV) ? num_vfs: M64_PER_IOV;
>>>>>-		vf_per_group = (num_vfs <= M64_PER_IOV)? 1:
>>>>>-			roundup_pow_of_two(num_vfs) / pdn->m64_per_iov;
>>>>>-	} else {
>>>>>-		vf_groups = 1;
>>>>>-		vf_per_group = 1;
>>>>>-	}
>>>>>
>>>>> 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
>>>>> 		res = &pdev->resource[i + PCI_IOV_RESOURCES];
>>>>> 		if (!res->flags || !res->parent)
>>>>> 			continue;
>>>>>
>>>>>-		for (j = 0; j < vf_groups; j++) {
>>>>>+		for (j = 0; j < m64_bars; j++) {
>>>>> 			do {
>>>>> 				win = find_next_zero_bit(&phb->ioda.m64_bar_alloc,
>>>>> 						phb->ioda.m64_bar_idx + 1, 0);
>>>>>@@ -1224,12 +1230,11 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 					goto m64_failed;
>>>>> 			} while (test_and_set_bit(win, &phb->ioda.m64_bar_alloc));
>>>>>
>>>>>-			pdn->m64_wins[i][j] = win;
>>>>>+			pdn->m64_map[j][i] = win;
>>>>>
>>>>>-			if (pdn->m64_per_iov == M64_PER_IOV) {
>>>>>+			if (pdn->m64_single_mode) {
>>>>> 				size = pci_iov_resource_size(pdev,
>>>>> 							PCI_IOV_RESOURCES + i);
>>>>>-				size = size * vf_per_group;
>>>>> 				start = res->start + size * j;
>>>>> 			} else {
>>>>> 				size = resource_size(res);
>>>>>@@ -1237,16 +1242,16 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 			}
>>>>>
>>>>> 			/* Map the M64 here */
>>>>>-			if (pdn->m64_per_iov == M64_PER_IOV) {
>>>>>+			if (pdn->m64_single_mode) {
>>>>> 				pe_num = pdn->offset + j;
>>>>> 				rc = opal_pci_map_pe_mmio_window(phb->opal_id,
>>>>> 						pe_num, OPAL_M64_WINDOW_TYPE,
>>>>>-						pdn->m64_wins[i][j], 0);
>>>>>+						pdn->m64_map[j][i], 0);
>>>>> 			}
>>>>>
>>>>> 			rc = opal_pci_set_phb_mem_window(phb->opal_id,
>>>>> 						 OPAL_M64_WINDOW_TYPE,
>>>>>-						 pdn->m64_wins[i][j],
>>>>>+						 pdn->m64_map[j][i],
>>>>> 						 start,
>>>>> 						 0, /* unused */
>>>>> 						 size);
>>>>>@@ -1258,12 +1263,12 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 				goto m64_failed;
>>>>> 			}
>>>>>
>>>>>-			if (pdn->m64_per_iov == M64_PER_IOV)
>>>>>+			if (pdn->m64_single_mode)
>>>>> 				rc = opal_pci_phb_mmio_enable(phb->opal_id,
>>>>>-				     OPAL_M64_WINDOW_TYPE, pdn->m64_wins[i][j], 2);
>>>>>+				     OPAL_M64_WINDOW_TYPE, pdn->m64_map[j][i], 2);
>>>>> 			else
>>>>> 				rc = opal_pci_phb_mmio_enable(phb->opal_id,
>>>>>-				     OPAL_M64_WINDOW_TYPE, pdn->m64_wins[i][j], 1);
>>>>>+				     OPAL_M64_WINDOW_TYPE, pdn->m64_map[j][i], 1);
>>>>>
>>>>> 			if (rc != OPAL_SUCCESS) {
>>>>> 				dev_err(&pdev->dev, "Failed to enable M64 window #%d: %llx\n",
>>>>>@@ -1275,7 +1280,7 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	return 0;
>>>>>
>>>>> m64_failed:
>>>>>-	pnv_pci_vf_release_m64(pdev);
>>>>>+	pnv_pci_vf_release_m64(pdev, num_vfs);
>>>>> 	return -EBUSY;
>>>>> }
>>>>>
>>>>>@@ -1302,15 +1307,13 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
>>>>> 	iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
>>>>> }
>>>>>
>>>>>-static void pnv_ioda_release_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>>>>>+static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
>>>>> {
>>>>> 	struct pci_bus        *bus;
>>>>> 	struct pci_controller *hose;
>>>>> 	struct pnv_phb        *phb;
>>>>> 	struct pnv_ioda_pe    *pe, *pe_n;
>>>>> 	struct pci_dn         *pdn;
>>>>>-	u16                    vf_index;
>>>>>-	int64_t                rc;
>>>>>
>>>>> 	bus = pdev->bus;
>>>>> 	hose = pci_bus_to_host(bus);
>>>>>@@ -1320,35 +1323,6 @@ static void pnv_ioda_release_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	if (!pdev->is_physfn)
>>>>> 		return;
>>>>>
>>>>>-	if (pdn->m64_per_iov == M64_PER_IOV && num_vfs > M64_PER_IOV) {
>>>>>-		int   vf_group;
>>>>>-		int   vf_per_group;
>>>>>-		int   vf_index1;
>>>>>-
>>>>>-		vf_per_group = roundup_pow_of_two(num_vfs) / pdn->m64_per_iov;
>>>>>-
>>>>>-		for (vf_group = 0; vf_group < M64_PER_IOV; vf_group++)
>>>>>-			for (vf_index = vf_group * vf_per_group;
>>>>>-				vf_index < (vf_group + 1) * vf_per_group &&
>>>>>-				vf_index < num_vfs;
>>>>>-				vf_index++)
>>>>>-				for (vf_index1 = vf_group * vf_per_group;
>>>>>-					vf_index1 < (vf_group + 1) * vf_per_group &&
>>>>>-					vf_index1 < num_vfs;
>>>>>-					vf_index1++){
>>>>>-
>>>>>-					rc = opal_pci_set_peltv(phb->opal_id,
>>>>>-						pdn->offset + vf_index,
>>>>>-						pdn->offset + vf_index1,
>>>>>-						OPAL_REMOVE_PE_FROM_DOMAIN);
>>>>>-
>>>>>-					if (rc)
>>>>>-					    dev_warn(&pdev->dev, "%s: Failed to unlink same group PE#%d(%lld)\n",
>>>>>-						__func__,
>>>>>-						pdn->offset + vf_index1, rc);
>>>>>-				}
>>>>>-	}
>>>>>-
>>>>> 	list_for_each_entry_safe(pe, pe_n, &phb->ioda.pe_list, list) {
>>>>> 		if (pe->parent_dev != pdev)
>>>>> 			continue;
>>>>>@@ -1383,14 +1357,14 @@ void pnv_pci_sriov_disable(struct pci_dev *pdev)
>>>>> 	num_vfs = pdn->num_vfs;
>>>>>
>>>>> 	/* Release VF PEs */
>>>>>-	pnv_ioda_release_vf_PE(pdev, num_vfs);
>>>>>+	pnv_ioda_release_vf_PE(pdev);
>>>>>
>>>>> 	if (phb->type == PNV_PHB_IODA2) {
>>>>>-		if (pdn->m64_per_iov == 1)
>>>>>+		if (!pdn->m64_single_mode)
>>>>> 			pnv_pci_vf_resource_shift(pdev, -pdn->offset);
>>>>>
>>>>> 		/* Release M64 windows */
>>>>>-		pnv_pci_vf_release_m64(pdev);
>>>>>+		pnv_pci_vf_release_m64(pdev, num_vfs);
>>>>>
>>>>> 		/* Release PE numbers */
>>>>> 		bitmap_clear(phb->ioda.pe_alloc, pdn->offset, num_vfs);
>>>>>@@ -1409,7 +1383,6 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	int                    pe_num;
>>>>> 	u16                    vf_index;
>>>>> 	struct pci_dn         *pdn;
>>>>>-	int64_t                rc;
>>>>>
>>>>> 	bus = pdev->bus;
>>>>> 	hose = pci_bus_to_host(bus);
>>>>>@@ -1454,37 +1427,6 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>>>>>
>>>>> 		pnv_pci_ioda2_setup_dma_pe(phb, pe);
>>>>> 	}
>>>>>-
>>>>>-	if (pdn->m64_per_iov == M64_PER_IOV && num_vfs > M64_PER_IOV) {
>>>>>-		int   vf_group;
>>>>>-		int   vf_per_group;
>>>>>-		int   vf_index1;
>>>>>-
>>>>>-		vf_per_group = roundup_pow_of_two(num_vfs) / pdn->m64_per_iov;
>>>>>-
>>>>>-		for (vf_group = 0; vf_group < M64_PER_IOV; vf_group++) {
>>>>>-			for (vf_index = vf_group * vf_per_group;
>>>>>-			     vf_index < (vf_group + 1) * vf_per_group &&
>>>>>-			     vf_index < num_vfs;
>>>>>-			     vf_index++) {
>>>>>-				for (vf_index1 = vf_group * vf_per_group;
>>>>>-				     vf_index1 < (vf_group + 1) * vf_per_group &&
>>>>>-				     vf_index1 < num_vfs;
>>>>>-				     vf_index1++) {
>>>>>-
>>>>>-					rc = opal_pci_set_peltv(phb->opal_id,
>>>>>-						pdn->offset + vf_index,
>>>>>-						pdn->offset + vf_index1,
>>>>>-						OPAL_ADD_PE_TO_DOMAIN);
>>>>>-
>>>>>-					if (rc)
>>>>>-					    dev_warn(&pdev->dev, "%s: Failed to link same group PE#%d(%lld)\n",
>>>>>-						__func__,
>>>>>-						pdn->offset + vf_index1, rc);
>>>>>-				}
>>>>>-			}
>>>>>-		}
>>>>>-	}
>>>>> }
>>>>>
>>>>> int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
>>>>>@@ -1507,6 +1449,15 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
>>>>> 			return -ENOSPC;
>>>>> 		}
>>>>>
>>>>>+		/*
>>>>>+		 * When M64 BARs functions in Single PE mode, the number of VFs
>>>>>+		 * could be enabled must be less than the number of M64 BARs.
>>>>>+		 */
>>>>>+		if (pdn->m64_single_mode && num_vfs > phb->ioda.m64_bar_idx) {
>>>>>+			dev_info(&pdev->dev, "Not enough M64 BAR for VFs\n");
>>>>>+			return -EBUSY;
>>>>>+		}
>>>>>+
>>>>> 		/* Calculate available PE for required VFs */
>>>>> 		mutex_lock(&phb->ioda.pe_alloc_mutex);
>>>>> 		pdn->offset = bitmap_find_next_zero_area(
>>>>>@@ -1534,7 +1485,7 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
>>>>> 		 * the IOV BAR according to the PE# allocated to the VFs.
>>>>> 		 * Otherwise, the PE# for the VF will conflict with others.
>>>>> 		 */
>>>>>-		if (pdn->m64_per_iov == 1) {
>>>>>+		if (!pdn->m64_single_mode) {
>>>>> 			ret = pnv_pci_vf_resource_shift(pdev, pdn->offset);
>>>>> 			if (ret)
>>>>> 				goto m64_failed;
>>>>>@@ -1567,8 +1518,7 @@ int pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
>>>>> 	/* Allocate PCI data */
>>>>> 	add_dev_pci_data(pdev);
>>>>>
>>>>>-	pnv_pci_sriov_enable(pdev, num_vfs);
>>>>>-	return 0;
>>>>>+	return pnv_pci_sriov_enable(pdev, num_vfs);
>>>>> }
>>>>> #endif /* CONFIG_PCI_IOV */
>>>>>
>>>>>@@ -2762,9 +2712,9 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
>>>>>
>>>>> 	pdn = pci_get_pdn(pdev);
>>>>> 	pdn->vfs_expanded = 0;
>>>>>+	pdn->m64_single_mode = false;
>>>>>
>>>>> 	total_vfs = pci_sriov_get_totalvfs(pdev);
>>>>>-	pdn->m64_per_iov = 1;
>>>>> 	mul = phb->ioda.total_pe;
>>>>>
>>>>> 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
>>>>>@@ -2784,8 +2734,8 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
>>>>> 		if (size > (1 << 26)) {
>>>>> 			dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size is bigger than 64M, roundup power2\n",
>>>>> 				 i, res);
>>>>>-			pdn->m64_per_iov = M64_PER_IOV;
>>>>> 			mul = roundup_pow_of_two(total_vfs);
>>>>>+			pdn->m64_single_mode = true;
>>>>> 			break;
>>>>> 		}
>>>>> 	}
>>>>>@@ -2987,6 +2937,8 @@ static resource_size_t pnv_pci_window_alignment(struct pci_bus *bus,
>>>>> static resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
>>>>> 						      int resno)
>>>>> {
>>>>>+	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
>>>>>+	struct pnv_phb *phb = hose->private_data;
>>>>> 	struct pci_dn *pdn = pci_get_pdn(pdev);
>>>>> 	resource_size_t align;
>>>>>
>>>>>@@ -2995,12 +2947,23 @@ static resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
>>>>> 	 * SR-IOV. While from hardware perspective, the range mapped by M64
>>>>> 	 * BAR should be size aligned.
>>>>> 	 *
>>>>>+	 * When IOV BAR is mapped with M64 BAR in Single PE mode, the extra
>>>>>+	 * powernv-specific hardware restriction is gone. But if just use the
>>>>>+	 * VF BAR size as the alignment, PF BAR / VF BAR may be allocated with
>>>>>+	 * in one segment of M64 #15, which introduces the PE conflict between
>>>>>+	 * PF and VF. Based on this, the minimum alignment of an IOV BAR is
>>>>>+	 * m64_segsize.
>>>>>+	 *
>>>>
>>>>When M64 BARs run in single mode, it still requires 32MB aligned. Does
>>>>"the extra powernv-specific hardware restriction" includes the limitation
>>>>or not?
>>>>
>>>
>>>The 32MB aligned you mentioned is the size of VF BAR?
>>>
>>>The answer is No. "the extra powernv-specific hardware restriction" only
>>>mentioned the total M64 BAR alignment.
>>>
>>
>>No, it's PHB's M64 BAR. there are 16 in total. When it's running in single PE
>>mode, it requires 32MB alignment at least. Extracted from PHB3 spec:
>>
>>When Single PE = 1, Bits 02:26 are the base address to compare
>>against the MSB 25 AIB address bits, 0:24, out of 0:49 (32MB aligned).
>>Bits 27:31 are the upper 5 bits of the PE# that owns the entire address
>>space defined by this BAR.
>>
>
>Good, looks we have another hardware specific requirement.
>
>While it is not proper to handle it here. This requirement effects the whole
>pci resource assignment.
>

Even PHB's M64 BAR runs in shared mode, it still have minimal alignment.
I'm suprised that you even don't know that... I never suggest to fix it
here, but the comments needs to be fixed here to avoid confusing others.

>Linux kernel doesn't assign VF BAR individually, it assigns the IOV BAR and
>VF BAR is a piece in it and they are continuous. So this means if the VF BAR
>is less than 32MB and we want to use M64 BAR in Single PE mode, this would
>make two VF BAR sits in one PE.
>

hrm, how can VF BAR can be assigned invididually? Remember there is one set
of PCI config registers tracking one IOV BAR that could be made of multiple VF
BARs. From this perspective, VF BAR is a "virtual" concept without corresponding
"real" config registers

>My suggestion is to add this check in pnv_pci_ioda_fixup_iov_resources(), when
>we decide to use M64 BAR in Single PE mode to cover a IOV BAR, each VF BAR
>should be at least 32MB. When this condition is met, the alignment from M64
>Single PE mode is met too.
>

That would be best place to check and add another limitation as I can see for
now.

>>>>> 	 * This function returns the total IOV BAR size if M64 BAR is in
>>>>> 	 * Shared PE mode or just the individual size if not.
>>>>>+	 * If the M64 BAR is in Single PE mode, return the VF BAR size or
>>>>>+	 * M64 segment size if IOV BAR size is less.
>>>>> 	 */
>>>>> 	align = pci_iov_resource_size(pdev, resno);
>>>>> 	if (!pdn->vfs_expanded)
>>>>> 		return align;
>>>>>+	if (pdn->m64_single_mode)
>>>>>+		return max(align, (resource_size_t)phb->ioda.m64_segsize);
>>>>>
>>>>> 	return pdn->vfs_expanded * align;
>>>>> }
>>>>>-- 
>>>>>2.5.0
>>>>>
>>>
>>>-- 
>>>Richard Yang
>>>Help you, Help me
>
>-- 
>Richard Yang
>Help you, Help me