This allows the default behaviour to be controlled by a kernel config option instead of changing the command line for the kernel to include "iommu.strict=0" on ARM64 where this is desired.
This is similar to CONFIG_IOMMU_DEFAULT_PASSTHROUGH. Note: At present, intel_iommu, amd_iommu and s390_iommu use lazy mode as default, so there is no need to add code for them. Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com> --- drivers/iommu/Kconfig | 14 ++++++++++++++ drivers/iommu/iommu.c | 5 +++++ 2 files changed, 19 insertions(+) diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 6f07f3b21816c64..5daa110d0e83a07 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -85,6 +85,20 @@ config IOMMU_DEFAULT_PASSTHROUGH If unsure, say N here. +config IOMMU_DMA_DEFAULT_LAZY_MODE + bool "IOMMU DMA use lazy mode to flush IOTLB and free IOVA" + depends on IOMMU_API + help + Support lazy mode, where for every IOMMU DMA unmap operation, the + flush operation of IOTLB and the free operation of IOVA are deferred. + They are only guaranteed to be done before the related IOVA will be + reused. Removing the need to pass in kernel parameters through + command line. For example, iommu.strict=0 on ARM64. If this is + enabled, you can still disable with kernel parameters, such as + iommu.strict=1 depending on the architecture. + + If unsure, say N here. + config OF_IOMMU def_bool y depends on OF && IOMMU_API diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 33a982e33716369..5acb98e79b5b32d 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -43,7 +43,12 @@ #else static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_DMA; #endif + +#ifdef CONFIG_IOMMU_DMA_DEFAULT_LAZY_MODE +static bool iommu_dma_strict __read_mostly; +#else static bool iommu_dma_strict __read_mostly = true; +#endif struct iommu_callback_data { const struct iommu_ops *ops; -- 1.8.3 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu