Currently the non-strict or lazy mode of TLB invalidation can only be set for all or no domains. This works well for development platforms where setting to non-strict/lazy mode is fine for performance reasons but on production devices, we need a more fine grained control to allow only certain peripherals to support this mode where we can be sure that it is safe. So add support to filter non-strict/lazy mode based on the device names that are passed via cmdline parameter "iommu.nonstrict_device".
Example: iommu.nonstrict_device="7c4000.sdhci,a600000.dwc3,6048000.etr" Signed-off-by: Sai Prakash Ranjan <saiprakash.ran...@codeaurora.org> --- drivers/iommu/iommu.c | 37 +++++++++++++++++++++++++++++++++---- 1 file changed, 33 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 609bd25bf154..fd10a073f557 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -32,6 +32,9 @@ static unsigned int iommu_def_domain_type __read_mostly; static bool iommu_dma_strict __read_mostly = true; static u32 iommu_cmd_line __read_mostly; +#define DEVICE_NAME_LEN 1024 +static char nonstrict_device[DEVICE_NAME_LEN] __read_mostly; + struct iommu_group { struct kobject kobj; struct kobject *devices_kobj; @@ -327,6 +330,32 @@ static int __init iommu_dma_setup(char *str) } early_param("iommu.strict", iommu_dma_setup); +static int __init iommu_nonstrict_filter_setup(char *str) +{ + strlcpy(nonstrict_device, str, DEVICE_NAME_LEN); + return 1; +} +__setup("iommu.nonstrict_device=", iommu_nonstrict_filter_setup); + +static bool iommu_nonstrict_device(struct device *dev) +{ + char *filter, *device; + + if (!dev) + return false; + + filter = kstrdup(nonstrict_device, GFP_KERNEL); + if (!filter) + return false; + + while ((device = strsep(&filter, ","))) { + if (!strcmp(device, dev_name(dev))) + return true; + } + + return false; +} + static ssize_t iommu_group_attr_show(struct kobject *kobj, struct attribute *__attr, char *buf) { @@ -1470,7 +1499,7 @@ static int iommu_get_def_domain_type(struct device *dev) static int iommu_group_alloc_default_domain(struct bus_type *bus, struct iommu_group *group, - unsigned int type) + unsigned int type, struct device *dev) { struct iommu_domain *dom; @@ -1489,7 +1518,7 @@ static int iommu_group_alloc_default_domain(struct bus_type *bus, if (!group->domain) group->domain = dom; - if (!iommu_dma_strict) { + if (!iommu_dma_strict || iommu_nonstrict_device(dev)) { int attr = 1; iommu_domain_set_attr(dom, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, @@ -1509,7 +1538,7 @@ static int iommu_alloc_default_domain(struct iommu_group *group, type = iommu_get_def_domain_type(dev); - return iommu_group_alloc_default_domain(dev->bus, group, type); + return iommu_group_alloc_default_domain(dev->bus, group, type, dev); } /** @@ -1684,7 +1713,7 @@ static void probe_alloc_default_domain(struct bus_type *bus, if (!gtype.type) gtype.type = iommu_def_domain_type; - iommu_group_alloc_default_domain(bus, group, gtype.type); + iommu_group_alloc_default_domain(bus, group, gtype.type, NULL); } base-commit: e46b3c0d011eab9933c183d5b47569db8e377281 -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation