Re: [PATCH kernel v10 16/34] powerpc/spapr: vfio: Replace iommu_table with iommu_table_group

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 05/14/2015 11:21 AM, Gavin Shan wrote:
> On Tue, May 12, 2015 at 01:39:05AM +1000, Alexey Kardashevskiy wrote:
>> Modern IBM POWERPC systems support multiple (currently two) TCE tables
>> per IOMMU group (a.k.a. PE). This adds a iommu_table_group container
>> for TCE tables. Right now just one table is supported.
>>
>> This defines iommu_table_group struct which stores pointers to
>> iommu_group and iommu_table(s). This replaces iommu_table with
>> iommu_table_group where iommu_table was used to identify a group:
>> - iommu_register_group();
>> - iommudata of generic iommu_group;
>>
>> This removes @data from iommu_table as it_table_group provides
>> same access to pnv_ioda_pe.
>>
>> For IODA, instead of embedding iommu_table, the new iommu_table_group
>> keeps pointers to those. The iommu_table structs are allocated
>> dynamically.
>>
>> For P5IOC2, both iommu_table_group and iommu_table are embedded into
>> PE struct. As there is no EEH and SRIOV support for P5IOC2,
>> iommu_free_table() should not be called on iommu_table struct pointers
>> so we can keep it embedded in pnv_phb::p5ioc2.
>>
>> For pSeries, this replaces multiple calls of kzalloc_node() with a new
>> iommu_pseries_alloc_group() helper and stores the table group struct
>> pointer into the pci_dn struct. For release, a iommu_table_free_group()
>> helper is added.
>>
>> This moves iommu_table struct allocation from SR-IOV code to
>> the generic DMA initialization code in pnv_pci_ioda_setup_dma_pe and
>> pnv_pci_ioda2_setup_dma_pe as this is where DMA is actually initialized.
>> This change is here because those lines had to be changed anyway.
>>
>> This should cause no behavioural change.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>
> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>
>> ---
>> Changes:
>> v10:
>> * new to the series, separated from
>> "powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group"
>> * iommu_table is not embedded into iommu_table_group but allocated
>> dynamically in most cases
>> * iommu_table allocation is moved to a single place for IODA2's
>> pnv_pci_ioda_setup_dma_pe where it belongs to
>> * added list of groups into iommu_table; most of the code just looks at
>> the first item to keep the patch simpler
>> ---
>> arch/powerpc/include/asm/iommu.h            |  17 +++--
>> arch/powerpc/include/asm/pci-bridge.h       |   2 +-
>> arch/powerpc/kernel/iommu.c                 |  17 ++---
>> arch/powerpc/platforms/powernv/pci-ioda.c   |  55 +++++++-------
>> arch/powerpc/platforms/powernv/pci-p5ioc2.c |  18 +++--
>> arch/powerpc/platforms/powernv/pci.h        |   3 +-
>> arch/powerpc/platforms/pseries/iommu.c      | 107 +++++++++++++++++++---------
>> drivers/vfio/vfio_iommu_spapr_tce.c         |  23 +++---
>> 8 files changed, 152 insertions(+), 90 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
>> index e2a45c3..61bde1a 100644
>> --- a/arch/powerpc/include/asm/iommu.h
>> +++ b/arch/powerpc/include/asm/iommu.h
>> @@ -92,13 +92,10 @@ struct iommu_table {
>> 	unsigned long *it_map;       /* A simple allocation bitmap for now */
>> 	unsigned long  it_page_shift;/* table iommu page size */
>> #ifdef CONFIG_IOMMU_API
>> -	struct iommu_group *it_group;
>> +	struct iommu_table_group *it_table_group;
>> #endif
>> 	struct iommu_table_ops *it_ops;
>> 	void (*set_bypass)(struct iommu_table *tbl, bool enable);
>> -#ifdef CONFIG_PPC_POWERNV
>> -	void           *data;
>> -#endif
>> };
>>
>> /* Pure 2^n version of get_order */
>> @@ -130,13 +127,21 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
>> extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
>> 					    int nid);
>> #ifdef CONFIG_IOMMU_API
>> -extern void iommu_register_group(struct iommu_table *tbl,
>> +
>> +#define IOMMU_TABLE_GROUP_MAX_TABLES	1
>> +
>> +struct iommu_table_group {
>> +	struct iommu_group *group;
>> +	struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
>> +};
>> +
>> +extern void iommu_register_group(struct iommu_table_group *table_group,
>> 				 int pci_domain_number, unsigned long pe_num);
>> extern int iommu_add_device(struct device *dev);
>> extern void iommu_del_device(struct device *dev);
>> extern int __init tce_iommu_bus_notifier_init(void);
>> #else
>> -static inline void iommu_register_group(struct iommu_table *tbl,
>> +static inline void iommu_register_group(struct iommu_table_group *table_group,
>> 					int pci_domain_number,
>> 					unsigned long pe_num)
>> {
>> diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
>> index 1811c44..e2d7479 100644
>> --- a/arch/powerpc/include/asm/pci-bridge.h
>> +++ b/arch/powerpc/include/asm/pci-bridge.h
>> @@ -185,7 +185,7 @@ struct pci_dn {
>>
>> 	struct  pci_dn *parent;
>> 	struct  pci_controller *phb;	/* for pci devices */
>> -	struct	iommu_table *iommu_table;	/* for phb's or bridges */
>> +	struct	iommu_table_group *table_group;	/* for phb's or bridges */
>> 	struct	device_node *node;	/* back-pointer to the device_node */
>>
>> 	int	pci_ext_config_space;	/* for pci devices */
>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
>> index 16be6aa..79e8b43 100644
>> --- a/arch/powerpc/kernel/iommu.c
>> +++ b/arch/powerpc/kernel/iommu.c
>> @@ -886,11 +886,12 @@ EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm);
>>   */
>> static void group_release(void *iommu_data)
>> {
>> -	struct iommu_table *tbl = iommu_data;
>> -	tbl->it_group = NULL;
>> +	struct iommu_table_group *table_group = iommu_data;
>> +
>> +	table_group->group = NULL;
>> }
>>
>> -void iommu_register_group(struct iommu_table *tbl,
>> +void iommu_register_group(struct iommu_table_group *table_group,
>> 		int pci_domain_number, unsigned long pe_num)
>> {
>> 	struct iommu_group *grp;
>> @@ -902,8 +903,8 @@ void iommu_register_group(struct iommu_table *tbl,
>> 				PTR_ERR(grp));
>> 		return;
>> 	}
>> -	tbl->it_group = grp;
>> -	iommu_group_set_iommudata(grp, tbl, group_release);
>> +	table_group->group = grp;
>> +	iommu_group_set_iommudata(grp, table_group, group_release);
>> 	name = kasprintf(GFP_KERNEL, "domain%d-pe%lx",
>> 			pci_domain_number, pe_num);
>> 	if (!name)
>> @@ -1091,7 +1092,7 @@ int iommu_add_device(struct device *dev)
>> 	}
>>
>> 	tbl = get_iommu_table_base(dev);
>> -	if (!tbl || !tbl->it_group) {
>> +	if (!tbl || !tbl->it_table_group || !tbl->it_table_group->group) {
>> 		pr_debug("%s: Skipping device %s with no tbl\n",
>> 			 __func__, dev_name(dev));
>> 		return 0;
>> @@ -1099,7 +1100,7 @@ int iommu_add_device(struct device *dev)
>>
>> 	pr_debug("%s: Adding %s to iommu group %d\n",
>> 		 __func__, dev_name(dev),
>> -		 iommu_group_id(tbl->it_group));
>> +		 iommu_group_id(tbl->it_table_group->group));
>>
>> 	if (PAGE_SIZE < IOMMU_PAGE_SIZE(tbl)) {
>> 		pr_err("%s: Invalid IOMMU page size %lx (%lx) on %s\n",
>> @@ -1108,7 +1109,7 @@ int iommu_add_device(struct device *dev)
>> 		return -EINVAL;
>> 	}
>>
>> -	return iommu_group_add_device(tbl->it_group, dev);
>> +	return iommu_group_add_device(tbl->it_table_group->group, dev);
>> }
>> EXPORT_SYMBOL_GPL(iommu_add_device);
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 1b43e25..02ed448 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -1087,10 +1087,6 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, int all)
>> 		return;
>> 	}
>>
>> -	pe->tce32_table = kzalloc_node(sizeof(struct iommu_table),
>> -			GFP_KERNEL, hose->node);
>> -	pe->tce32_table->data = pe;
>> -
>> 	/* Associate it with all child devices */
>> 	pnv_ioda_setup_same_PE(bus, pe);
>>
>> @@ -1292,11 +1288,12 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
>> 	struct iommu_table    *tbl;
>> 	unsigned long         addr;
>> 	int64_t               rc;
>> +	struct iommu_table_group *table_group;
>>
>> 	bus = dev->bus;
>> 	hose = pci_bus_to_host(bus);
>> 	phb = hose->private_data;
>> -	tbl = pe->tce32_table;
>> +	tbl = pe->table_group.tables[0];
>> 	addr = tbl->it_base;
>>
>> 	opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
>> @@ -1311,13 +1308,14 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
>> 	if (rc)
>> 		pe_warn(pe, "OPAL error %ld release DMA window\n", rc);
>>
>> -	if (tbl->it_group) {
>> -		iommu_group_put(tbl->it_group);
>> -		BUG_ON(tbl->it_group);
>> +	table_group = tbl->it_table_group;
>> +	if (table_group->group) {
>> +		iommu_group_put(table_group->group);
>> +		BUG_ON(table_group->group);
>> 	}
>> 	iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
>> 	free_pages(addr, get_order(TCE32_TABLE_SIZE));
>> -	pe->tce32_table = NULL;
>> +	pe->table_group.tables[0] = NULL;
>> }
>>
>> static void pnv_ioda_release_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>> @@ -1465,10 +1463,6 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>> 			continue;
>> 		}
>>
>> -		pe->tce32_table = kzalloc_node(sizeof(struct iommu_table),
>> -				GFP_KERNEL, hose->node);
>> -		pe->tce32_table->data = pe;
>> -
>> 		/* Put PE to the list */
>> 		mutex_lock(&phb->ioda.pe_list_mutex);
>> 		list_add_tail(&pe->list, &phb->ioda.pe_list);
>> @@ -1603,7 +1597,7 @@ static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *pdev
>>
>> 	pe = &phb->ioda.pe_array[pdn->pe_number];
>> 	WARN_ON(get_dma_ops(&pdev->dev) != &dma_iommu_ops);
>> -	set_iommu_table_base(&pdev->dev, pe->tce32_table);
>> +	set_iommu_table_base(&pdev->dev, pe->table_group.tables[0]);
>> 	/*
>> 	 * Note: iommu_add_device() will fail here as
>> 	 * for physical PE: the device is already added by now;
>> @@ -1636,7 +1630,7 @@ static int pnv_pci_ioda_dma_set_mask(struct pnv_phb *phb,
>> 	} else {
>> 		dev_info(&pdev->dev, "Using 32-bit DMA via iommu\n");
>> 		set_dma_ops(&pdev->dev, &dma_iommu_ops);
>> -		set_iommu_table_base(&pdev->dev, pe->tce32_table);
>> +		set_iommu_table_base(&pdev->dev, pe->table_group.tables[0]);
>> 	}
>> 	*pdev->dev.dma_mask = dma_mask;
>> 	return 0;
>> @@ -1670,7 +1664,7 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe,
>> 	struct pci_dev *dev;
>>
>> 	list_for_each_entry(dev, &bus->devices, bus_list) {
>> -		set_iommu_table_base(&dev->dev, pe->tce32_table);
>> +		set_iommu_table_base(&dev->dev, pe->table_group.tables[0]);
>> 		iommu_add_device(&dev->dev);
>>
>> 		if (dev->subordinate)
>> @@ -1681,7 +1675,8 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe,
>> static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
>> 		unsigned long index, unsigned long npages, bool rm)
>> {
>> -	struct pnv_ioda_pe *pe = tbl->data;
>> +	struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> +			struct pnv_ioda_pe, table_group);
>> 	__be64 __iomem *invalidate = rm ?
>> 		(__be64 __iomem *)pe->tce_inval_reg_phys :
>> 		(__be64 __iomem *)tbl->it_index;
>> @@ -1758,7 +1753,8 @@ static struct iommu_table_ops pnv_ioda1_iommu_ops = {
>> static void pnv_pci_ioda2_tce_invalidate(struct iommu_table *tbl,
>> 		unsigned long index, unsigned long npages, bool rm)
>> {
>> -	struct pnv_ioda_pe *pe = tbl->data;
>> +	struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> +			struct pnv_ioda_pe, table_group);
>> 	unsigned long start, end, inc;
>> 	__be64 __iomem *invalidate = rm ?
>> 		(__be64 __iomem *)pe->tce_inval_reg_phys :
>> @@ -1834,8 +1830,12 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>> 	if (WARN_ON(pe->tce32_seg >= 0))
>> 		return;
>>
>> -	tbl = pe->tce32_table;
>> -	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
>> +	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>> +			phb->hose->node);
>> +	tbl->it_table_group = &pe->table_group;
>> +	pe->table_group.tables[0] = tbl;
>> +	iommu_register_group(&pe->table_group, phb->hose->global_number,
>> +			pe->pe_number);
>>
>> 	/* Grab a 32-bit TCE table */
>> 	pe->tce32_seg = base;
>> @@ -1914,7 +1914,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>>
>> static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
>> {
>> -	struct pnv_ioda_pe *pe = tbl->data;
>> +	struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> +			struct pnv_ioda_pe, table_group);
>> 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
>> 	int64_t rc;
>>
>> @@ -1948,10 +1949,10 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb,
>> 	pe->tce_bypass_base = 1ull << 59;
>>
>> 	/* Install set_bypass callback for VFIO */
>> -	pe->tce32_table->set_bypass = pnv_pci_ioda2_set_bypass;
>> +	pe->table_group.tables[0]->set_bypass = pnv_pci_ioda2_set_bypass;
>
> It could be simplied as:
>
> 	tbl->set_bypass = pnv_pci_ioda2_set_bypass;

No, this is worse in this case. The whole idea of the patch to be 
mechanical as much as we can. That means:
s/tce32_table/table_group.tables[0]/
If I do what you suggest, the reviewers will have to look further if "tbl" 
has been initialized properly, etc.

And later in this patchset I am getting rid of 
pnv_pci_ioda2_setup_bypass_pe so there is no point to try making it look 
nice :)

>>
>> 	/* Enable bypass by default */
>> -	pnv_pci_ioda2_set_bypass(pe->tce32_table, true);
>> +	pnv_pci_ioda2_set_bypass(pe->table_group.tables[0], true);
>
> Similar to above:
>
> 	tbl->set_bypass(tbl, true);
>
>> }
>>
>> static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>> @@ -1968,8 +1969,12 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>> 	if (WARN_ON(pe->tce32_seg >= 0))
>> 		return;
>>
>> -	tbl = pe->tce32_table;
>> -	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
>> +	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>> +			phb->hose->node);
>> +	tbl->it_table_group = &pe->table_group;
>> +	pe->table_group.tables[0] = tbl;
>> +	iommu_register_group(&pe->table_group, phb->hose->global_number,
>> +			pe->pe_number);
>>
>> 	/* The PE will reserve all possible 32-bits space */
>> 	pe->tce32_seg = 0;
>> diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> index 2722c1a..4ea9def 100644
>> --- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> +++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> @@ -92,14 +92,16 @@ static struct iommu_table_ops pnv_p5ioc2_iommu_ops = {
>> static void pnv_pci_p5ioc2_dma_dev_setup(struct pnv_phb *phb,
>> 					 struct pci_dev *pdev)
>> {
>> -	if (phb->p5ioc2.iommu_table.it_map == NULL) {
>> -		phb->p5ioc2.iommu_table.it_ops = &pnv_p5ioc2_iommu_ops;
>> -		iommu_init_table(&phb->p5ioc2.iommu_table, phb->hose->node);
>> -		iommu_register_group(&phb->p5ioc2.iommu_table,
>> +	struct iommu_table *tbl = phb->p5ioc2.table_group.tables[0];
>> +
>> +	if (!tbl->it_map) {
>> +		tbl->it_ops = &pnv_p5ioc2_iommu_ops;
>> +		iommu_init_table(tbl, phb->hose->node);
>> +		iommu_register_group(&phb->p5ioc2.table_group,
>> 				pci_domain_nr(phb->hose->bus), phb->opal_id);
>> 	}
>>
>> -	set_iommu_table_base(&pdev->dev, &phb->p5ioc2.iommu_table);
>> +	set_iommu_table_base(&pdev->dev, tbl);
>> 	iommu_add_device(&pdev->dev);
>> }
>>
>> @@ -180,6 +182,12 @@ static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np, u64 hub_id,
>> 	pnv_pci_setup_iommu_table(&phb->p5ioc2.iommu_table,
>> 				  tce_mem, tce_size, 0,
>> 				  IOMMU_PAGE_SHIFT_4K);
>> +	/*
>> +	 * We do not allocate iommu_table as we do not support
>> +	 * hotplug or SRIOV on P5IOC2 and therefore iommu_free_table()
>> +	 * should not be called for phb->p5ioc2.table_group.tables[0] ever.
>> +	 */
>> +	phb->p5ioc2.table_group.tables[0] = &phb->p5ioc2.iommu_table;
>> }
>>
>> void __init pnv_pci_init_p5ioc2_hub(struct device_node *np)
>> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>> index ec26afd..720cc99 100644
>> --- a/arch/powerpc/platforms/powernv/pci.h
>> +++ b/arch/powerpc/platforms/powernv/pci.h
>> @@ -57,7 +57,7 @@ struct pnv_ioda_pe {
>> 	/* "Base" iommu table, ie, 4K TCEs, 32-bit DMA */
>> 	int			tce32_seg;
>> 	int			tce32_segcount;
>> -	struct iommu_table	*tce32_table;
>> +	struct iommu_table_group table_group;
>> 	phys_addr_t		tce_inval_reg_phys;
>>
>> 	/* 64-bit TCE bypass region */
>> @@ -123,6 +123,7 @@ struct pnv_phb {
>> 	union {
>> 		struct {
>> 			struct iommu_table iommu_table;
>> +			struct iommu_table_group table_group;
>> 		} p5ioc2;
>>
>> 		struct {
>> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
>> index 4f2ab90..ad5ac6d 100644
>> --- a/arch/powerpc/platforms/pseries/iommu.c
>> +++ b/arch/powerpc/platforms/pseries/iommu.c
>> @@ -52,14 +52,49 @@
>>
>> #include "pseries.h"
>>
>> -static void iommu_pseries_free_table(struct iommu_table *tbl,
>> +static struct iommu_table_group *iommu_pseries_alloc_group(int node)
>
> Since it's a static function, the name could be simplied to
> iommu_group_alloc(), or alloc_iommu_group(). But it might
> not the style you like :-)

Giving it the name like this I am telling people not to try reusing it for 
anything else + easier to grep.


>
>> +{
>> +	struct iommu_table_group *table_group = NULL;
>> +	struct iommu_table *tbl = NULL;
>> +
>> +	table_group = kzalloc_node(sizeof(struct iommu_table_group), GFP_KERNEL,
>> +			   node);
>> +	if (!table_group)
>> +		goto fail_exit;
>> +
>> +	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
>> +	if (!tbl)
>> +		goto fail_exit;
>> +
>> +	tbl->it_table_group = table_group;
>> +	table_group->tables[0] = tbl;
>> +
>> +	return table_group;
>> +
>> +fail_exit:
>> +	kfree(table_group);
>> +	kfree(tbl);
>> +
>> +	return NULL;
>> +}
>> +
>> +static void iommu_pseries_free_group(struct iommu_table_group *table_group,
>> 		const char *node_name)
>
> Same suggestion as above.
>
>> {
>> -	if (tbl->it_group) {
>> -		iommu_group_put(tbl->it_group);
>> -		BUG_ON(tbl->it_group);
>> +	struct iommu_table *tbl;
>> +
>> +	if (!table_group)
>> +		return;
>> +
>> +	if (table_group->group) {
>> +		iommu_group_put(table_group->group);
>> +		BUG_ON(table_group->group);
>> 	}
>> +
>> +	tbl = table_group->tables[0];
>> 	iommu_free_table(tbl, node_name);
>
> It might worthy to have one check:
>
> 	if (table_group->tables[0])
> 		iommu_free_table(table_group->tables[0], node_name);


BUG_ON() - may be. (table_group->tables[0] == NULL) cannot happen normally 
(no memory corruption, etc) as iommu_pseries_alloc_group() allocated both 
table_group and table or nothing.


>
>> +
>> +	kfree(table_group);
>> }
>>
>> static void tce_invalidate_pSeries_sw(struct iommu_table *tbl,
>> @@ -629,13 +664,13 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
>> 	pci->phb->dma_window_size = 0x8000000ul;
>> 	pci->phb->dma_window_base_cur = 0x8000000ul;
>>
>> -	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>> -			   pci->phb->node);
>> +	pci->table_group = iommu_pseries_alloc_group(pci->phb->node);
>> +	tbl = pci->table_group->tables[0];
>
> The orginal code isn't checking "!pci->table_group". If this function is
> called only at bootup time, it would be nice to see kernel crash. Otherwise,
> I guess it's still worthy to have the check :-)


kzalloc_node() is supposed to print something when fails.



-- 
Alexey