Commit edea902c1c1e ("powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests") disabled dma_iommu_ops path, for secure VMs. The rationale for disabling the dma_iommu_ops path, was to use the dma_direct path, since it had inbuilt support for bounce-buffering through SWIOTLB.
However dma_iommu_ops is functionally much richer. Depending on the capabilities of the platform, it can handle direct DMA; with or without bounce buffering, and it can handle indirect DMA. Hence its better to leverage the richer functionality supported by dma_iommu_ops. Renable dma_iommu_ops path for pseries Secure VMs. Signed-off-by: Ram Pai <linux...@us.ibm.com> --- arch/powerpc/platforms/pseries/iommu.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 0720831..6adf4d3 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -36,7 +36,6 @@ #include <asm/udbg.h> #include <asm/mmzone.h> #include <asm/plpar_wrappers.h> -#include <asm/svm.h> #include <asm/ultravisor.h> #include "pseries.h" @@ -1337,15 +1336,7 @@ void iommu_init_early_pSeries(void) of_reconfig_notifier_register(&iommu_reconfig_nb); register_memory_notifier(&iommu_mem_nb); - /* - * Secure guest memory is inacessible to devices so regular DMA isn't - * possible. - * - * In that case keep devices' dma_map_ops as NULL so that the generic - * DMA code path will use SWIOTLB to bounce buffers for DMA. - */ - if (!is_secure_guest()) - set_pci_dma_ops(&dma_iommu_ops); + set_pci_dma_ops(&dma_iommu_ops); } static int __init disable_multitce(char *str) -- 1.8.3.1