Messages in this thread Patch in this message | | | From | John Garry <> | Subject | [PATCH v11 1/3] iommu: Enhance IOMMU default DMA mode build options | Date | Tue, 8 Jun 2021 21:18:26 +0800 |
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From: Zhen Lei <thunder.leizhen@huawei.com>
First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the opportunity to set {lazy|strict} mode as default at build time. Then put the two config options in a choice, as they are mutually exclusive.
[jpg: Make choice between strict and lazy only (and not passthrough)] Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: John Garry <john.garry@huawei.com> --- drivers/iommu/Kconfig | 35 +++++++++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 3 ++- 2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 1f111b399bca..369a3af9e5bf 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -90,6 +90,41 @@ config IOMMU_DEFAULT_PASSTHROUGH If unsure, say N here. +choice + prompt "IOMMU default DMA mode" + depends on IOMMU_API + depends on X86 || IA64 || X86_64 || ARM || ARM64 + + default IOMMU_DEFAULT_STRICT + help + This option allows an IOMMU DMA mode to be chosen at build time, to + override the default DMA mode of each ARCH, removing the need to + pass in kernel parameters through command line. It is still possible + to provide ARCH-specific or common boot options to override this + option. + + If unsure, keep the default. + +config IOMMU_DEFAULT_LAZY + bool "lazy" + 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. + +config IOMMU_DEFAULT_STRICT + bool "strict" + help + For every IOMMU DMA unmap operation, the flush operation of IOTLB and + the free operation of IOVA are guaranteed to be done in the unmap + function. + + This mode is safer than lazy mode, but it may be slower in some high + performance scenarios. + +endchoice + config OF_IOMMU def_bool y depends on OF && IOMMU_API diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 966426a96520..177b0dafc535 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -29,7 +29,8 @@ static struct kset *iommu_group_kset; static DEFINE_IDA(iommu_group_ida); static unsigned int iommu_def_domain_type __read_mostly; -static bool iommu_dma_strict __read_mostly = true; +static bool iommu_dma_strict __read_mostly = + IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT); static u32 iommu_cmd_line __read_mostly; struct iommu_group { -- 2.26.2
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