On 2019/3/22 22:42, John Garry wrote:
> On 22/03/2019 14:11, Zhen Lei wrote:
>
>> 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
>> defalut, so there is no need to add code for them.
>
> /s/defalut/default/
>
>>
>> Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
>> ---
>> drivers/iommu/Kconfig | 14 ++++++++++++++
>> drivers/iommu/iommu.c | 5 +++++
>
> Do we need to update kernel-parameters.txt for iommu.strict?
>
>> 2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
>> index 6f07f3b21816c64..5ec9780f564eaf8 100644
>> --- a/drivers/iommu/Kconfig
>> +++ b/drivers/iommu/Kconfig
>> @@ -85,6 +85,20 @@ config IOMMU_DEFAULT_PASSTHROUGH
>>
>> If unsure, say N here.
>>
>> +config IOMMU_LAZY_MODE
>
> maybe should add "DMA" to the name, and even "DEFAULT"
OK, thanks
>
>> + bool "IOMMU use lazy mode to flush IOTLB and free IOVA"
>> + depends on IOMMU_API
>> + help
>> + For every IOMMU unmap operation, the flush operation of IOTLB and the
>> free
>> + operation of IOVA are deferred.
>
> This is a bit unclear, as there is no context. I think that you need to say
> something like, "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
>> iommu.strict=0
>> + through command line on ARM64(Now, intel_iommu, amd_iommu, s390_iommu
>> use
>> + lazy mode as deault).
>
> prone to going out-of-date
>
> If this is enabled, you can still disable with kernel
>> + parameters, such as iommu.strict=1, intel_iommu=strict,
>> amd_iommu=fullflush
>> + or s390_iommu=strict 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..e307d70d1578b3b 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_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
>>
>>
>>
>
> Cheers
>
>
>
>
> .
>
--
Thanks!
BestRegards
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