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    SubjectRe: [PATCH kernel v9 21/32] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window
    On Sat, Apr 25, 2015 at 10:14:45PM +1000, Alexey Kardashevskiy wrote:
    > This is a part of moving DMA window programming to an iommu_ops
    > callback. pnv_pci_ioda2_set_window() takes an iommu_table_group as
    > a first parameter (not pnv_ioda_pe) as it is going to be used as
    > a callback for VFIO DDW code.
    >
    > This adds pnv_pci_ioda2_tvt_invalidate() to invalidate TVT as it is
    > a good thing to do.

    What's the TVT and why is invalidating it a good thing?

    Also, it looks like it didn't add it, just move it.

    > It does not have immediate effect now as the table
    > is never recreated after reboot but it will in the following patches.
    >
    > This should cause no behavioural change.
    >
    > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
    > Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

    Really? I don't remember this one.

    > ---
    > Changes:
    > v9:
    > * initialize pe->table_group.tables[0] at the very end when
    > tbl is fully initialized
    > * moved pnv_pci_ioda2_tvt_invalidate() from earlier patch
    > ---
    > arch/powerpc/platforms/powernv/pci-ioda.c | 67 +++++++++++++++++++++++--------
    > 1 file changed, 51 insertions(+), 16 deletions(-)
    >
    > diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
    > index b9b3773..59baa15 100644
    > --- a/arch/powerpc/platforms/powernv/pci-ioda.c
    > +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
    > @@ -1960,6 +1960,52 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
    > __free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
    > }
    >
    > +static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
    > + struct iommu_table *tbl)
    > +{
    > + struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
    > + table_group);
    > + struct pnv_phb *phb = pe->phb;
    > + int64_t rc;
    > + const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
    > + const __u64 win_size = tbl->it_size << tbl->it_page_shift;
    > +
    > + pe_info(pe, "Setting up window at %llx..%llx "
    > + "pgsize=0x%x tablesize=0x%lx\n",
    > + start_addr, start_addr + win_size - 1,
    > + 1UL << tbl->it_page_shift, tbl->it_size << 3);
    > +
    > + tbl->it_table_group = &pe->table_group;
    > +
    > + /*
    > + * Map TCE table through TVT. The TVE index is the PE number
    > + * shifted by 1 bit for 32-bits DMA space.
    > + */
    > + rc = opal_pci_map_pe_dma_window(phb->opal_id,
    > + pe->pe_number,
    > + pe->pe_number << 1,
    > + 1,
    > + __pa(tbl->it_base),
    > + tbl->it_size << 3,
    > + 1ULL << tbl->it_page_shift);
    > + if (rc) {
    > + pe_err(pe, "Failed to configure TCE table, err %ld\n", rc);
    > + goto fail;
    > + }
    > +
    > + pnv_pci_ioda2_tvt_invalidate(pe);
    > +
    > + /* Store fully initialized *tbl (may be external) in PE */
    > + pe->table_group.tables[0] = *tbl;

    Hrm, a non-atomic copy of a whole structure into the array. Is that
    really what you want?

    > + return 0;
    > +fail:
    > + if (pe->tce32_seg >= 0)
    > + pe->tce32_seg = -1;
    > +
    > + return rc;
    > +}
    > +
    > static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
    > {
    > uint16_t window_id = (pe->pe_number << 1 ) + 1;
    > @@ -2068,21 +2114,16 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
    > pe->table_group.ops = &pnv_pci_ioda2_ops;
    > #endif
    >
    > - /*
    > - * Map TCE table through TVT. The TVE index is the PE number
    > - * shifted by 1 bit for 32-bits DMA space.
    > - */
    > - rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
    > - pe->pe_number << 1, 1, __pa(tbl->it_base),
    > - tbl->it_size << 3, 1ULL << tbl->it_page_shift);
    > + rc = pnv_pci_ioda2_set_window(&pe->table_group, tbl);
    > if (rc) {
    > pe_err(pe, "Failed to configure 32-bit TCE table,"
    > " err %ld\n", rc);
    > - goto fail;
    > + pnv_pci_free_table(tbl);
    > + if (pe->tce32_seg >= 0)
    > + pe->tce32_seg = -1;
    > + return;
    > }
    >
    > - pnv_pci_ioda2_tvt_invalidate(pe);
    > -
    > /* OPAL variant of PHB3 invalidated TCEs */
    > if (pe->tce_inval_reg)
    > tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
    > @@ -2103,12 +2144,6 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
    > /* Also create a bypass window */
    > if (!pnv_iommu_bypass_disabled)
    > pnv_pci_ioda2_setup_bypass_pe(phb, pe);
    > -
    > - return;
    > -fail:
    > - if (pe->tce32_seg >= 0)
    > - pe->tce32_seg = -1;
    > - pnv_pci_free_table(tbl);
    > }
    >
    > static void pnv_ioda_setup_dma(struct pnv_phb *phb)

    --
    David Gibson | I'll have my music baroque, and my code
    david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
    | _way_ _around_!
    http://www.ozlabs.org/~dgibson
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