Re: [PATCH v4 07/11] powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new helper

Alexey Kardashevskiy
2021-05-10T07:34:14Z

On 5/1/21 02:31, Leonardo Bras wrote:
> Add a new helper _iommu_table_setparms(), and use it in
> iommu_table_setparms() and iommu_table_setparms_lpar() to avoid duplicated
> code.
>
> Also, setting tbl->it_ops was happening outsite iommu_table_setparms*(),
> so move it to the new helper. Since we need the iommu_table_ops to be
> declared before used, move iommu_table_lpar_multi_ops and
> iommu_table_pseries_ops to before their respective iommu_table_setparms*().
>
> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>

This does not apply anymore as it conflicts with my 4be518d838809e2135.

> ---
> arch/powerpc/platforms/pseries/iommu.c | 100 ++++++++++++-------------
> 1 file changed, 50 insertions(+), 50 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 5a70ecd579b8..89cb6e9e9f31 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -53,6 +53,11 @@ enum {
> DDW_EXT_QUERY_OUT_SIZE = 2
> };
>
> +#ifdef CONFIG_IOMMU_API
> +static int tce_exchange_pseries(struct iommu_table *tbl, long index, unsigned long *tce,
> + enum dma_data_direction *direction, bool realmode);
> +#endif

Instead of declaring this so far from the the code which needs it, may
be add

struct iommu_table_ops iommu_table_lpar_multi_ops;

right before iommu_table_setparms() (as the sctruct is what you actually
want there), and you won't need to move iommu_table_pseries_ops as well.

> +
> static struct iommu_table *iommu_pseries_alloc_table(int node)
> {
> struct iommu_table *tbl;
> @@ -501,6 +506,28 @@ static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn,
> return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg);
> }
>
> +static inline void _iommu_table_setparms(struct iommu_table *tbl, unsigned long busno,

The underscore is confusing, may be iommu_table_do_setparms()?
iommu_table_setparms_common()? Not sure. I cannot recall a single
function with just one leading underscore, I suspect I was pushed back
when I tried adding one ages ago :) "inline" seems excessive, the
compiler will probably figure it out anyway.

> + unsigned long liobn, unsigned long win_addr,
> + unsigned long window_size, unsigned long page_shift,
> + unsigned long base, struct iommu_table_ops *table_ops)

Make "base" a pointer. Or, better, just keep setting it directly in
iommu_table_setparms() rather than passing 0 around.

The same comment about "liobn" - set it in iommu_table_setparms_lpar().
The reviewer will see what field atters in what situation imho.

> +{
> + tbl->it_busno = busno;
> + tbl->it_index = liobn;
> + tbl->it_offset = win_addr >> page_shift;
> + tbl->it_size = window_size >> page_shift;
> + tbl->it_page_shift = page_shift;
> + tbl->it_base = base;
> + tbl->it_blocksize = 16;
> + tbl->it_type = TCE_PCI;
> + tbl->it_ops = table_ops;
> +}
> +
> +struct iommu_table_ops iommu_table_pseries_ops = {
> + .set = tce_build_pSeries,
> + .clear = tce_free_pSeries,
> + .get = tce_get_pseries
> +};
> +
> static void iommu_table_setparms(struct pci_controller *phb,
> struct device_node *dn,
> struct iommu_table *tbl)
> @@ -509,8 +536,13 @@ static void iommu_table_setparms(struct pci_controller *phb,
> const unsigned long *basep;
> const u32 *sizep;
>
> - node = phb->dn;
> + /* Test if we are going over 2GB of DMA space */
> + if (phb->dma_window_base_cur + phb->dma_window_size > SZ_2G) {
> + udbg_printf("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> + panic("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> + }
>
> + node = phb->dn;
> basep = of_get_property(node, "linux,tce-base", NULL);
> sizep = of_get_property(node, "linux,tce-size", NULL);
> if (basep == NULL || sizep == NULL) {
> @@ -519,33 +551,25 @@ static void iommu_table_setparms(struct pci_controller *phb,
> return;
> }
>
> - tbl->it_base = (unsigned long)__va(*basep);
> + _iommu_table_setparms(tbl, phb->bus->number, 0, phb->dma_window_base_cur,
> + phb->dma_window_size, IOMMU_PAGE_SHIFT_4K,
> + (unsigned long)__va(*basep), &iommu_table_pseries_ops);
>
> if (!is_kdump_kernel())
> memset((void *)tbl->it_base, 0, *sizep);
>
> - tbl->it_busno = phb->bus->number;
> - tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
> -
> - /* Units of tce entries */
> - tbl->it_offset = phb->dma_window_base_cur >> tbl->it_page_shift;
> -
> - /* Test if we are going over 2GB of DMA space */
> - if (phb->dma_window_base_cur + phb->dma_window_size > 0x80000000ul) {
> - udbg_printf("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> - panic("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> - }
> -
> phb->dma_window_base_cur += phb->dma_window_size;
> -
> - /* Set the tce table size - measured in entries */
> - tbl->it_size = phb->dma_window_size >> tbl->it_page_shift;
> -
> - tbl->it_index = 0;
> - tbl->it_blocksize = 16;
> - tbl->it_type = TCE_PCI;
> }
>
> +struct iommu_table_ops iommu_table_lpar_multi_ops = {
> + .set = tce_buildmulti_pSeriesLP,
> +#ifdef CONFIG_IOMMU_API
> + .xchg_no_kill = tce_exchange_pseries,
> +#endif
> + .clear = tce_freemulti_pSeriesLP,
> + .get = tce_get_pSeriesLP
> +};
> +
> /*
> * iommu_table_setparms_lpar
> *
> @@ -557,28 +581,17 @@ static void iommu_table_setparms_lpar(struct pci_controller *phb,
> struct iommu_table_group *table_group,
> const __be32 *dma_window)
> {
> - unsigned long offset, size;
> + unsigned long offset, size, liobn;
>
> - of_parse_dma_window(dn, dma_window, &tbl->it_index, &offset, &size);
> + of_parse_dma_window(dn, dma_window, &liobn, &offset, &size);
>
> - tbl->it_busno = phb->bus->number;
> - tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
> - tbl->it_base = 0;
> - tbl->it_blocksize = 16;
> - tbl->it_type = TCE_PCI;
> - tbl->it_offset = offset >> tbl->it_page_shift;
> - tbl->it_size = size >> tbl->it_page_shift;
> + _iommu_table_setparms(tbl, phb->bus->number, liobn, offset, size, IOMMU_PAGE_SHIFT_4K, 0,
> + &iommu_table_lpar_multi_ops);
>
> table_group->tce32_start = offset;
> table_group->tce32_size = size;
> }
>
> -struct iommu_table_ops iommu_table_pseries_ops = {
> - .set = tce_build_pSeries,
> - .clear = tce_free_pSeries,
> - .get = tce_get_pseries
> -};
> -
> static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
> {
> struct device_node *dn;
> @@ -647,7 +660,6 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
> tbl = pci->table_group->tables[0];
>
> iommu_table_setparms(pci->phb, dn, tbl);
> - tbl->it_ops = &iommu_table_pseries_ops;
> iommu_init_table(tbl, pci->phb->node, 0, 0);
>
> /* Divide the rest (1.75GB) among the children */
> @@ -664,7 +676,7 @@ static int tce_exchange_pseries(struct iommu_table *tbl, long index, unsigned
> bool realmode)
> {
> long rc;
> - unsigned long ioba = (unsigned long) index << tbl->it_page_shift;
> + unsigned long ioba = (unsigned long)index << tbl->it_page_shift;

Unrelated change, why, did checkpatch.pl complain?

> unsigned long flags, oldtce = 0;
> u64 proto_tce = iommu_direction_to_tce_perm(*direction);
> unsigned long newtce = *tce | proto_tce;
> @@ -686,15 +698,6 @@ static int tce_exchange_pseries(struct iommu_table *tbl, long index, unsigned
> }
> #endif
>
> -struct iommu_table_ops iommu_table_lpar_multi_ops = {
> - .set = tce_buildmulti_pSeriesLP,
> -#ifdef CONFIG_IOMMU_API
> - .xchg_no_kill = tce_exchange_pseries,
> -#endif
> - .clear = tce_freemulti_pSeriesLP,
> - .get = tce_get_pSeriesLP
> -};
> -
> static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
> {
> struct iommu_table *tbl;
> @@ -729,7 +732,6 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
> tbl = ppci->table_group->tables[0];
> iommu_table_setparms_lpar(ppci->phb, pdn, tbl,
> ppci->table_group, dma_window);
> - tbl->it_ops = &iommu_table_lpar_multi_ops;
> iommu_init_table(tbl, ppci->phb->node, 0, 0);
> iommu_register_group(ppci->table_group,
> pci_domain_nr(bus), 0);
> @@ -758,7 +760,6 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
> PCI_DN(dn)->table_group = iommu_pseries_alloc_group(phb->node);
> tbl = PCI_DN(dn)->table_group->tables[0];
> iommu_table_setparms(phb, dn, tbl);
> - tbl->it_ops = &iommu_table_pseries_ops;
> iommu_init_table(tbl, phb->node, 0, 0);
> set_iommu_table_base(&dev->dev, tbl);
> return;
> @@ -1436,7 +1437,6 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
> tbl = pci->table_group->tables[0];
> iommu_table_setparms_lpar(pci->phb, pdn, tbl,
> pci->table_group, dma_window);
> - tbl->it_ops = &iommu_table_lpar_multi_ops;
> iommu_init_table(tbl, pci->phb->node, 0, 0);
> iommu_register_group(pci->table_group,
> pci_domain_nr(pci->phb->bus), 0);
>

--
Alexey