diff options
Diffstat (limited to 'arch/s390/pci/pci_dma.c')
| -rw-r--r-- | arch/s390/pci/pci_dma.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c index 93223bd110c3..1f4540d6bd2d 100644 --- a/arch/s390/pci/pci_dma.c +++ b/arch/s390/pci/pci_dma.c @@ -18,6 +18,8 @@ static struct kmem_cache *dma_region_table_cache; static struct kmem_cache *dma_page_table_cache; static int s390_iommu_strict; +static u64 s390_iommu_aperture; +static u32 s390_iommu_aperture_factor = 1; static int zpci_refresh_global(struct zpci_dev *zdev) { @@ -565,15 +567,19 @@ int zpci_dma_init_device(struct zpci_dev *zdev) /* * Restrict the iommu bitmap size to the minimum of the following: - * - main memory size + * - s390_iommu_aperture which defaults to high_memory * - 3-level pagetable address limit minus start_dma offset * - DMA address range allowed by the hardware (clp query pci fn) * * Also set zdev->end_dma to the actual end address of the usable * range, instead of the theoretical maximum as reported by hardware. + * + * This limits the number of concurrently usable DMA mappings since + * for each DMA mapped memory address we need a DMA address including + * extra DMA addresses for multiple mappings of the same memory address. */ zdev->start_dma = PAGE_ALIGN(zdev->start_dma); - zdev->iommu_size = min3((u64) high_memory, + zdev->iommu_size = min3(s390_iommu_aperture, ZPCI_TABLE_SIZE_RT - zdev->start_dma, zdev->end_dma - zdev->start_dma + 1); zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1; @@ -660,6 +666,12 @@ static int __init dma_alloc_cpu_table_caches(void) int __init zpci_dma_init(void) { + s390_iommu_aperture = (u64)high_memory; + if (!s390_iommu_aperture_factor) + s390_iommu_aperture = ULONG_MAX; + else + s390_iommu_aperture *= s390_iommu_aperture_factor; + return dma_alloc_cpu_table_caches(); } @@ -692,3 +704,12 @@ static int __init s390_iommu_setup(char *str) } __setup("s390_iommu=", s390_iommu_setup); + +static int __init s390_iommu_aperture_setup(char *str) +{ + if (kstrtou32(str, 10, &s390_iommu_aperture_factor)) + s390_iommu_aperture_factor = 1; + return 1; +} + +__setup("s390_iommu_aperture=", s390_iommu_aperture_setup); |