From 4f7e0babbc7c46fc0db4f5c14fe96bf6f4d69502 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 18 Jul 2019 15:11:37 +1000 Subject: [PATCH] powerpc/iommu: Allow bypass-only for DMA POWER8 and newer support a bypass mode which maps all host memory to PCI buses so an IOMMU table is not always required. However if we fail to create such a table, the DMA setup fails and the kernel does not boot. This skips the 32bit DMA setup check if the bypass is selected. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190718051139.74787-3-aik@ozlabs.ru --- arch/powerpc/kernel/dma-iommu.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c index a0879674a9c8..c963d704fa31 100644 --- a/arch/powerpc/kernel/dma-iommu.c +++ b/arch/powerpc/kernel/dma-iommu.c @@ -122,18 +122,17 @@ int dma_iommu_dma_supported(struct device *dev, u64 mask) { struct iommu_table *tbl = get_iommu_table_base(dev); - if (!tbl) { - dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx" - ", table unavailable\n", mask); - return 0; - } - if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) { dev->archdata.iommu_bypass = true; dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n"); return 1; } + if (!tbl) { + dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask); + return 0; + } + if (tbl->it_offset > (mask >> tbl->it_page_shift)) { dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", -- 2.45.2