From d853adc7adf601d7d6823afe3ed396065a3e08d1 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 21 Oct 2021 00:23:15 +1100 Subject: powerpc/pseries/iommu: Create huge DMA window if no MMIO32 is present The iommu_init_table() helper takes an address range to reserve in the IOMMU table being initialized to exclude MMIO addresses, this is useful if the window stretches far beyond 4GB (although wastes some TCEs). At the moment the code searches for such MMIO32 range and fails if none found which is considered a problem while it really is not: it is actually better as this says there is no MMIO32 to reserve and we can use usually wasted TCEs. Furthermore PHYP never actually allows creating windows starting at busaddress=0 so this MMIO32 range is never useful. This removes error exit and initializes the table with zero range if no MMIO32 is detected. Fixes: 381ceda88c4c ("powerpc/pseries/iommu: Make use of DDW for indirect mapping") Signed-off-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211020132315.2287178-5-aik@ozlabs.ru --- arch/powerpc/platforms/pseries/iommu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 8f921e38ce74..a52af8fbf571 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -1411,18 +1411,19 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn) } else { struct iommu_table *newtbl; int i; + unsigned long start = 0, end = 0; for (i = 0; i < ARRAY_SIZE(pci->phb->mem_resources); i++) { const unsigned long mask = IORESOURCE_MEM_64 | IORESOURCE_MEM; /* Look for MMIO32 */ - if ((pci->phb->mem_resources[i].flags & mask) == IORESOURCE_MEM) + if ((pci->phb->mem_resources[i].flags & mask) == IORESOURCE_MEM) { + start = pci->phb->mem_resources[i].start; + end = pci->phb->mem_resources[i].end; break; + } } - if (i == ARRAY_SIZE(pci->phb->mem_resources)) - goto out_del_list; - /* New table for using DDW instead of the default DMA window */ newtbl = iommu_pseries_alloc_table(pci->phb->node); if (!newtbl) { @@ -1432,8 +1433,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn) iommu_table_setparms_common(newtbl, pci->phb->bus->number, create.liobn, win_addr, 1UL << len, page_shift, NULL, &iommu_table_lpar_multi_ops); - iommu_init_table(newtbl, pci->phb->node, pci->phb->mem_resources[i].start, - pci->phb->mem_resources[i].end); + iommu_init_table(newtbl, pci->phb->node, start, end); pci->table_group->tables[1] = newtbl; -- cgit v1.2.3-58-ga151