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powerpc/powernv/sriov: Make single PE mode a per-BAR setting 

Using single PE BARs to map an SR-IOV BAR is really a choice about what
strategy to use when mapping a BAR. It doesn't make much sense for this to
be a global setting since a device might have one large BAR which needs to
be mapped with single PE windows and another smaller BAR that can be mapped
with a regular segmented window. Make the segmented vs single decision a
per-BAR setting and clean up the logic that decides which mode to use.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-15-oohall@gmail.com
This commit is contained in:
Oliver O'Halloran 2020-07-22 16:57:14 +10:00 committed by Michael Ellerman
parent a0be516f81
commit 4c51f3e1e8
2 changed files with 73 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

131
arch/powerpc/platforms/powernv/pci-sriov.c
View File

@ -146,21 +146,17 @@
static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
{
struct pnv_phb *phb = pci_bus_to_pnvhb(pdev->bus);
const resource_size_t gate = phb->ioda.m64_segsize >> 2;
struct resource *res;
int i;
resource_size_t size, total_vf_bar_sz;
resource_size_t vf_bar_sz;
struct pnv_iov_data *iov;
int mul, total_vfs;
int mul;
iov = kzalloc(sizeof(*iov), GFP_KERNEL);
if (!iov)
goto disable_iov;
pdev->dev.archdata.iov_data = iov;
total_vfs = pci_sriov_get_totalvfs(pdev);
mul = phb->ioda.total_pe_num;
total_vf_bar_sz = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &pdev->resource[i + PCI_IOV_RESOURCES];
@ -172,50 +168,50 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
goto disable_iov;
}
total_vf_bar_sz += pci_iov_resource_size(pdev,
i + PCI_IOV_RESOURCES);
vf_bar_sz = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);
/*
* If bigger than quarter of M64 segment size, just round up
* power of two.
* Generally, one segmented M64 BAR maps one IOV BAR. However,
* if a VF BAR is too large we end up wasting a lot of space.
* If each VF needs more than 1/4 of the default m64 segment
* then each VF BAR should be mapped in single-PE mode to reduce
* the amount of space required. This does however limit the
* number of VFs we can support.
*
* Generally, one M64 BAR maps one IOV BAR. To avoid conflict
* with other devices, IOV BAR size is expanded to be
* (total_pe * VF_BAR_size). When VF_BAR_size is half of M64
* segment size , the expanded size would equal to half of the
* whole M64 space size, which will exhaust the M64 Space and
* limit the system flexibility. This is a design decision to
* set the boundary to quarter of the M64 segment size.
* The 1/4 limit is arbitrary and can be tweaked.
*/
if (total_vf_bar_sz > gate) {
mul = roundup_pow_of_two(total_vfs);
dev_info(&pdev->dev,
"VF BAR Total IOV size %llx > %llx, roundup to %d VFs\n",
total_vf_bar_sz, gate, mul);
iov->m64_single_mode = true;
break;
}
}
if (vf_bar_sz > (phb->ioda.m64_segsize >> 2)) {
/*
* On PHB3, the minimum size alignment of M64 BAR in
* single mode is 32MB. If this VF BAR is smaller than
* 32MB, but still too large for a segmented window
* then we can't map it and need to disable SR-IOV for
* this device.
*/
if (vf_bar_sz < SZ_32M) {
pci_err(pdev, "VF BAR%d: %pR can't be mapped in single PE mode\n",
i, res);
goto disable_iov;
}
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &pdev->resource[i + PCI_IOV_RESOURCES];
if (!res->flags || res->parent)
iov->m64_single_mode[i] = true;
continue;
}
size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);
/*
* On PHB3, the minimum size alignment of M64 BAR in single
* mode is 32MB.
* This BAR can be mapped with one segmented window, so adjust
* te resource size to accommodate.
*/
if (iov->m64_single_mode && (size < SZ_32M))
goto disable_iov;
pci_dbg(pdev, " Fixing VF BAR%d: %pR to\n", i, res);
res->end = res->start + vf_bar_sz * mul - 1;
pci_dbg(pdev, " %pR\n", res);
dev_dbg(&pdev->dev, " Fixing VF BAR%d: %pR to\n", i, res);
res->end = res->start + size * mul - 1;
dev_dbg(&pdev->dev, " %pR\n", res);
dev_info(&pdev->dev, "VF BAR%d: %pR (expanded to %d VFs for PE alignment)",
pci_info(pdev, "VF BAR%d: %pR (expanded to %d VFs for PE alignment)",
i, res, mul);
iov->need_shift = true;
}
iov->vfs_expanded = mul;
return;
@ -259,42 +255,40 @@ void pnv_pci_ioda_fixup_iov(struct pci_dev *pdev)
resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
int resno)
{
struct pnv_phb *phb = pci_bus_to_pnvhb(pdev->bus);
struct pnv_iov_data *iov = pnv_iov_get(pdev);
resource_size_t align;
/*
* iov can be null if we have an SR-IOV device with IOV BAR that can't
* be placed in the m64 space (i.e. The BAR is 32bit or non-prefetch).
* In that case we don't allow VFs to be enabled since one of their
* BARs would not be placed in the correct PE.
*/
if (!iov)
return align;
if (!iov->vfs_expanded)
return align;
align = pci_iov_resource_size(pdev, resno);
/*
* If we're using single mode then we can just use the native VF BAR
* alignment. We validated that it's possible to use a single PE
* window above when we did the fixup.
*/
if (iov->m64_single_mode[resno - PCI_IOV_RESOURCES])
return align;
/*
* On PowerNV platform, IOV BAR is mapped by M64 BAR to enable the
* 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.
*
* This function returns the total IOV BAR size if M64 BAR is in
* Shared PE mode or just VF BAR 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);
/*
* iov can be null if we have an SR-IOV device with IOV BAR that can't
* be placed in the m64 space (i.e. The BAR is 32bit or non-prefetch).
* In that case we don't allow VFs to be enabled so just return the
* default alignment.
*/
if (!iov)
return align;
if (!iov->vfs_expanded)
return align;
if (iov->m64_single_mode)
return max(align, (resource_size_t)phb->ioda.m64_segsize);
return iov->vfs_expanded * align;
}
@ -449,7 +443,7 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
continue;
/* don't need single mode? map everything in one go! */
if (!iov->m64_single_mode) {
if (!iov->m64_single_mode[i]) {
win = pnv_pci_alloc_m64_bar(phb, iov);
if (win < 0)
goto m64_failed;
@ -542,6 +536,8 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)
res = &dev->resource[i + PCI_IOV_RESOURCES];
if (!res->flags || !res->parent)
continue;
if (iov->m64_single_mode[i])
continue;
/*
* The actual IOV BAR range is determined by the start address
@ -573,6 +569,8 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)
res = &dev->resource[i + PCI_IOV_RESOURCES];
if (!res->flags || !res->parent)
continue;
if (iov->m64_single_mode[i])
continue;
size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
res2 = *res;
@ -618,8 +616,8 @@ static void pnv_pci_sriov_disable(struct pci_dev *pdev)
/* Release VF PEs */
pnv_ioda_release_vf_PE(pdev);
/* Un-shift the IOV BAR resources */
if (!iov->m64_single_mode)
/* Un-shift the IOV BARs if we need to */
if (iov->need_shift)
pnv_pci_vf_resource_shift(pdev, -base_pe);
/* Release M64 windows */
@ -736,9 +734,8 @@ static 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 (!iov->m64_single_mode) {
ret = pnv_pci_vf_resource_shift(pdev,
base_pe->pe_number);
if (iov->need_shift) {
ret = pnv_pci_vf_resource_shift(pdev, base_pe->pe_number);
if (ret)
goto shift_failed;
}

11
arch/powerpc/platforms/powernv/pci.h
View File

@ -243,8 +243,15 @@ struct pnv_iov_data {
/* pointer to the array of VF PEs. num_vfs long*/
struct pnv_ioda_pe *vf_pe_arr;
/* Did we map the VF BARs with single-PE IODA BARs? */
bool m64_single_mode;
/* Did we map the VF BAR with single-PE IODA BARs? */
bool m64_single_mode[PCI_SRIOV_NUM_BARS];
/*
* True if we're using any segmented windows. In that case we need
* shift the start of the IOV resource the segment corresponding to
* the allocated PE.
*/
bool need_shift;
/*
* Bit mask used to track which m64 windows are used to map the