On 2023/8/15 1:25, Jason Gunthorpe wrote:
Ah, I went over all this again and decided to try again, it is too
complicated. This patch can do what the commit message says and the
following patches are even simpler:
Yes. This method is more concise. Some nits below.
/*
* Combine the driver's choosen def_domain_type across all the devices in a
* group. Drivers must give a consistent result.
*/
static int iommu_get_def_domain_type(struct iommu_group *group,
struct device *dev, int cur_type)
{
const struct iommu_ops *ops = group_iommu_ops(group);
int type;
if (!ops->def_domain_type)
return cur_type;
type = ops->def_domain_type(dev);
if (!type || cur_type == type)
return cur_type;
if (!cur_type)
return type;
dev_err_ratelimited(
dev,
"IOMMU driver error, requesting conflicting def_domain_type, %s and %s, for devices in group %u.\n",
iommu_domain_type_str(cur_type), iommu_domain_type_str(type),
group->id);
/*
* Try to recover, drivers are allowed to force IDENITY or DMA, IDENTITY
* takes precedence.
*/
if (cur_type || type == IOMMU_DOMAIN_IDENTITY)
return IOMMU_DOMAIN_IDENTITY;
No need to check cur_type. It already returned if cur_type is 0.
return cur_type;
}
/*
* A target_type of 0 will select the best domain type. 0 can be returned in
* this case meaning the global default should be used.
*/
static int iommu_get_default_domain_type(struct iommu_group *group,
int target_type)
{
struct device *untrusted = NULL;
struct group_device *gdev;
int driver_type = 0;
lockdep_assert_held(&group->mutex);
/*
* ARM32 drivers supporting CONFIG_ARM_DMA_USE_IOMMU can declare an
* identity_domain and it will automatically become their default
* domain. Later on ARM_DMA_USE_IOMMU will install its UNMANAGED domain.
* Override the selection to IDENTITY.
*/
if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
static_assert(!(IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) &&
IS_ENABLED(CONFIG_IOMMU_DMA)));
IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) is duplicate with the condition in
the if statement. So only
static_assert(!IS_ENABLED(CONFIG_IOMMU_DMA));
?
driver_type = IOMMU_DOMAIN_IDENTITY;
}
for_each_group_device(group, gdev) {
driver_type = iommu_get_def_domain_type(group, gdev->dev,
driver_type);
No need to call this in the loop body?
if (dev_is_pci(gdev->dev) && to_pci_dev(gdev->dev)->untrusted) {
/*
* No ARM32 using systems will set untrusted, it cannot
* work.
*/
if (WARN_ON(IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)))
return -1;
untrusted = gdev->dev;
}
}
if (untrusted) {
if (driver_type && driver_type != IOMMU_DOMAIN_DMA) {
dev_err_ratelimited(
untrusted,
"Device is not trusted, but driver is overriding group %u to %s, refusing to probe.\n",
group->id, iommu_domain_type_str(driver_type));
return -1;
}
driver_type = IOMMU_DOMAIN_DMA;
}
if (target_type) {
if (driver_type && target_type != driver_type)
return -1;
return target_type;
}
return driver_type;
}
Best regards,
baolu
