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iommu: Express DMA strictness via the domain type

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Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

 - Automatically implies strict mode for untrusted devices by
   virtue of their IOMMU_DOMAIN_DMA override.
 - Ensures that we only end up using flush queues for drivers
   which are aware of them and can actually benefit.
 - Allows us to handle flush queue init failure by falling back
   to strict mode instead of leaving it to possibly blow up later.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/47083d69155577f1367877b1594921948c366eb3.1628682049.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Robin Murphy 2021-08-11 13:21:34 +01:00 committed by Joerg Roedel
parent 78ca078459
commit c208916fe6
3 changed files with 11 additions and 14 deletions
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10
drivers/iommu/dma-iommu.c
View File

@ -370,13 +370,15 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
init_iova_domain(iovad, 1UL << order, base_pfn);
if (!cookie->fq_domain && !dev_is_untrusted(dev) &&
domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) {
/* If the FQ fails we can simply fall back to strict mode */
if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain) {
if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
iommu_dma_entry_dtor))
iommu_dma_entry_dtor)) {
pr_warn("iova flush queue initialization failed\n");
else
domain->type = IOMMU_DOMAIN_DMA;
} else {
cookie->fq_domain = domain;
}
}
return iova_reserve_iommu_regions(dev, domain);

14
drivers/iommu/iommu.c
View File

@ -136,6 +136,9 @@ static int __init iommu_subsys_init(void)
}
}
if (!iommu_default_passthrough() && !iommu_dma_strict)
iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ;
pr_info("Default domain type: %s %s\n",
iommu_domain_type_str(iommu_def_domain_type),
(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
@ -355,17 +358,10 @@ early_param("iommu.strict", iommu_dma_setup);
void iommu_set_dma_strict(void)
{
iommu_dma_strict = true;
if (iommu_def_domain_type == IOMMU_DOMAIN_DMA_FQ)
iommu_def_domain_type = IOMMU_DOMAIN_DMA;
}
bool iommu_get_dma_strict(struct iommu_domain *domain)
{
/* only allow lazy flushing for DMA domains */
if (domain->type == IOMMU_DOMAIN_DMA)
return iommu_dma_strict;
return true;
}
EXPORT_SYMBOL_GPL(iommu_get_dma_strict);
static ssize_t iommu_group_attr_show(struct kobject *kobj,
struct attribute *__attr, char *buf)
{

1
include/linux/iommu.h
View File

@ -504,7 +504,6 @@ int iommu_set_pgtable_quirks(struct iommu_domain *domain,
unsigned long quirks);
void iommu_set_dma_strict(void);
bool iommu_get_dma_strict(struct iommu_domain *domain);
extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
unsigned long iova, int flags);