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    Subject[PATCH v5 14/29] vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control
    Date
    This replaces iommu_take_ownership()/iommu_release_ownership() calls
    with the callback calls and it is up to the platform code to call
    iommu_take_ownership()/iommu_release_ownership() if needed.

    Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
    ---
    arch/powerpc/include/asm/iommu.h | 4 +--
    arch/powerpc/kernel/iommu.c | 50 ++++++++++++++++++++++++++++---------
    drivers/vfio/vfio_iommu_spapr_tce.c | 4 +--
    3 files changed, 42 insertions(+), 16 deletions(-)

    diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
    index 667aa1a..b9e50d3 100644
    --- a/arch/powerpc/include/asm/iommu.h
    +++ b/arch/powerpc/include/asm/iommu.h
    @@ -225,8 +225,8 @@ extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
    unsigned long entry);

    extern void iommu_flush_tce(struct iommu_table *tbl);
    -extern int iommu_take_ownership(struct iommu_table *tbl);
    -extern void iommu_release_ownership(struct iommu_table *tbl);
    +extern int iommu_take_ownership(struct iommu_table_group *table_group);
    +extern void iommu_release_ownership(struct iommu_table_group *table_group);

    extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
    extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
    diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
    index 7794dce..8358631 100644
    --- a/arch/powerpc/kernel/iommu.c
    +++ b/arch/powerpc/kernel/iommu.c
    @@ -1050,7 +1050,7 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
    }
    EXPORT_SYMBOL_GPL(iommu_tce_build);

    -int iommu_take_ownership(struct iommu_table *tbl)
    +static int iommu_table_take_ownership(struct iommu_table *tbl)
    {
    unsigned long sz = (tbl->it_size + 7) >> 3;

    @@ -1064,19 +1064,36 @@ int iommu_take_ownership(struct iommu_table *tbl)

    memset(tbl->it_map, 0xff, sz);

    - /*
    - * Disable iommu bypass, otherwise the user can DMA to all of
    - * our physical memory via the bypass window instead of just
    - * the pages that has been explicitly mapped into the iommu
    - */
    - if (tbl->set_bypass)
    - tbl->set_bypass(tbl, false);
    + return 0;
    +}
    +
    +static void iommu_table_release_ownership(struct iommu_table *tbl);
    +
    +int iommu_take_ownership(struct iommu_table_group *table_group)
    +{
    + int i, j, rc = 0;
    +
    + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
    + struct iommu_table *tbl = &table_group->tables[i];
    +
    + if (!tbl->it_map)
    + continue;
    +
    + rc = iommu_table_take_ownership(tbl);
    + if (rc) {
    + for (j = 0; j < i; ++j)
    + iommu_table_release_ownership(
    + &table_group->tables[j]);
    +
    + return rc;
    + }
    + }

    return 0;
    }
    EXPORT_SYMBOL_GPL(iommu_take_ownership);

    -void iommu_release_ownership(struct iommu_table *tbl)
    +static void iommu_table_release_ownership(struct iommu_table *tbl)
    {
    unsigned long sz = (tbl->it_size + 7) >> 3;

    @@ -1086,9 +1103,18 @@ void iommu_release_ownership(struct iommu_table *tbl)
    if (tbl->it_offset == 0)
    set_bit(0, tbl->it_map);

    - /* The kernel owns the device now, we can restore the iommu bypass */
    - if (tbl->set_bypass)
    - tbl->set_bypass(tbl, true);
    +}
    +
    +extern void iommu_release_ownership(struct iommu_table_group *table_group)
    +{
    + int i;
    +
    + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
    + struct iommu_table *tbl = &table_group->tables[i];
    +
    + if (tbl->it_map)
    + iommu_table_release_ownership(tbl);
    + }
    }
    EXPORT_SYMBOL_GPL(iommu_release_ownership);

    diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
    index 9b02040..6372b3b 100644
    --- a/drivers/vfio/vfio_iommu_spapr_tce.c
    +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
    @@ -809,7 +809,7 @@ static int tce_iommu_attach_group(void *iommu_data,
    goto unlock_exit;
    }

    - ret = iommu_take_ownership(&table_group->tables[0]);
    + ret = iommu_take_ownership(table_group);
    if (!ret)
    container->grp = iommu_group;

    @@ -846,7 +846,7 @@ static void tce_iommu_detach_group(void *iommu_data,
    table_group = iommu_group_get_iommudata(iommu_group);
    BUG_ON(!table_group);

    - iommu_release_ownership(&table_group->tables[0]);
    + iommu_release_ownership(table_group);

    unlock_exit:
    mutex_unlock(&container->lock);
    --
    2.0.0


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