diff options
| author | Zhen Lei <thunder.leizhen@huawei.com> | 2021-07-12 19:12:17 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-07-26 13:27:38 +0200 |
| commit | 712d8f205835c1d170e85d7811da3d9f36d8fab7 (patch) | |
| tree | 1a3c0c3868e40bae3b9dd2bb62a1197f2f1c6cf0 /drivers | |
| parent | d8577d2e331dc06f5871afa6b76035dd8b74c903 (diff) | |
iommu: Enhance IOMMU default DMA mode build options
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 an 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>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1626088340-5838-4-git-send-email-john.garry@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/Kconfig | 40 | ||||
| -rw-r--r-- | drivers/iommu/iommu.c | 2 |
2 files changed, 41 insertions, 1 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 07b7c25cbed8..9cd5d7afc766 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -90,6 +90,46 @@ config IOMMU_DEFAULT_PASSTHROUGH If unsure, say N here. +choice + prompt "IOMMU default DMA IOTLB invalidation mode" + depends on IOMMU_DMA + + default IOMMU_DEFAULT_STRICT + help + This option allows an IOMMU DMA IOTLB invalidation mode to be + chosen at build time, to override the default mode of each ARCH, + removing the need to pass in kernel parameters through command line. + It is still possible to provide common boot params to override this + config. + + If unsure, keep the default. + +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. + +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. + + The isolation provided in this mode is not as secure as STRICT mode, + such that a vulnerable time window may be created between the DMA + unmap and the mappings cached in the IOMMU IOTLB or device TLB + finally being invalidated, where the device could still access the + memory which has already been unmapped by the device driver. + However this mode may provide better performance in high throughput + scenarios, and is still considerably more secure than passthrough + mode or no IOMMU. + +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 69d7d4865668..bd9ccce387c5 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -30,7 +30,7 @@ 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 { |