[PATCH v2 10/14] powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new helper

Alexey Kardashevskiy aik at ozlabs.ru
Tue Sep 29 13:56:36 AEST 2020



On 12/09/2020 03:07, Leonardo Bras wrote:
> Cc: linuxppc-dev at lists.ozlabs.org, linux-kernel at vger.kernel.org,
> 
> 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*().
> 
> The tce_exchange_pseries() also had to be moved up, since it's used in
> iommu_table_lpar_multi_ops.xchg_no_kill.


Use forward declarations (preferred) or make a separate patch for moving 
chunks (I do not see much point).


> 
> Signed-off-by: Leonardo Bras <leobras.c at gmail.com>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 149 ++++++++++++-------------
>   1 file changed, 72 insertions(+), 77 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 510ccb0521af..abd36b257725 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -495,12 +495,62 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
>   	return rc;
>   }
>   
> +#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)
> +{
> +	long rc;
> +	unsigned long ioba = (unsigned long)index << tbl->it_page_shift;
> +	unsigned long flags, oldtce = 0;
> +	u64 proto_tce = iommu_direction_to_tce_perm(*direction);
> +	unsigned long newtce = *tce | proto_tce;
> +
> +	spin_lock_irqsave(&tbl->large_pool.lock, flags);
> +
> +	rc = plpar_tce_get((u64)tbl->it_index, ioba, &oldtce);
> +	if (!rc)
> +		rc = plpar_tce_put((u64)tbl->it_index, ioba, newtce);
> +
> +	if (!rc) {
> +		*direction = iommu_tce_direction(oldtce);
> +		*tce = oldtce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> +	}
> +
> +	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
> +
> +	return rc;
> +}
> +#endif
> +
>   static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn,
>   		unsigned long num_pfn, void *arg)
>   {
>   	return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg);
>   }
>   
> +static inline void _iommu_table_setparms(struct iommu_table *tbl, unsigned long busno,
> +					 unsigned long liobn, unsigned long win_addr,
> +					 unsigned long window_size, unsigned long page_shift,
> +					 unsigned long base, struct iommu_table_ops *table_ops)
> +{
> +	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 +559,13 @@ 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 > 0x80000000ul) {
> +		udbg_printf("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> +		panic("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
> +	}


s/0x80000000ul/2*SZ_1G/

but more to the point - why this check? QEMU can create windows at 0 and 
as big as the VM requested. And I am pretty sure I can construct QEMU 
command line such as it won't have MMIO32 at all and a 4GB default DMA 
window.


>   
> +	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 +574,25 @@ 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 +604,17 @@ 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 +683,6 @@ 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 */
> @@ -658,43 +693,6 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
>   	pr_debug("ISA/IDE, window size is 0x%llx\n", pci->phb->dma_window_size);
>   }
>   
> -#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)
> -{
> -	long rc;
> -	unsigned long ioba = (unsigned long) index << tbl->it_page_shift;
> -	unsigned long flags, oldtce = 0;
> -	u64 proto_tce = iommu_direction_to_tce_perm(*direction);
> -	unsigned long newtce = *tce | proto_tce;
> -
> -	spin_lock_irqsave(&tbl->large_pool.lock, flags);
> -
> -	rc = plpar_tce_get((u64)tbl->it_index, ioba, &oldtce);
> -	if (!rc)
> -		rc = plpar_tce_put((u64)tbl->it_index, ioba, newtce);
> -
> -	if (!rc) {
> -		*direction = iommu_tce_direction(oldtce);
> -		*tce = oldtce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
> -	}
> -
> -	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
> -
> -	return rc;
> -}
> -#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 +727,6 @@ 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 +755,6 @@ 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;
> @@ -1385,7 +1381,6 @@ 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


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