From: Joerg Roedel <jroe...@suse.de>
[ Upstream commit bd421264ed307dd296eab036851221b225071a32 ]
The IOMMU core code has support for deferring the attachment of a domain
to a device. This is needed in kdump kernels where the new domain must
not be attached to a device before the device driver takes it over.
When the AMD IOMMU driver got converted to use the dma-iommu
implementation, the deferred attaching got lost. The code in
dma-iommu.c has support for deferred attaching, but it calls into
iommu_attach_device() to actually do it. But iommu_attach_device()
will check if the device should be deferred in it code-path and do
nothing, breaking deferred attachment.
Move the is_deferred_attach() check out of the attach_device path and
into iommu_group_add_device() to make deferred attaching work from the
dma-iommu code.
Fixes: 795bbbb9b6f8 ("iommu/dma-iommu: Handle deferred devices")
Reported-by: Jerry Snitselaar <jsnit...@redhat.com>
Suggested-by: Robin Murphy <robin.mur...@arm.com>
Signed-off-by: Joerg Roedel <jroe...@suse.de>
Tested-by: Jerry Snitselaar <jsnit...@redhat.com>
Cc: Jerry Snitselaar <jsnit...@redhat.com>
Cc: Tom Murphy <murph...@tcd.ie>
Cc: Robin Murphy <robin.mur...@arm.com>
Link: https://lore.kernel.org/r/20200519130340.14564-1-j...@8bytes.org
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/iommu/iommu.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8d2477941fd9..22b28076d48e 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -692,6 +692,15 @@ out:
return ret;
}
+static bool iommu_is_attach_deferred(struct iommu_domain *domain,
+ struct device *dev)
+{
+ if (domain->ops->is_attach_deferred)
+ return domain->ops->is_attach_deferred(domain, dev);
+
+ return false;
+}
+
/**
* iommu_group_add_device - add a device to an iommu group
* @group: the group into which to add the device (reference should be held)
@@ -746,7 +755,7 @@ rename:
mutex_lock(&group->mutex);
list_add_tail(&device->list, &group->devices);
- if (group->domain)
+ if (group->domain && !iommu_is_attach_deferred(group->domain, dev))
ret = __iommu_attach_device(group->domain, dev);
mutex_unlock(&group->mutex);
if (ret)
@@ -1652,9 +1661,6 @@ static int __iommu_attach_device(struct iommu_domain
*domain,
struct device *dev)
{
int ret;
- if ((domain->ops->is_attach_deferred != NULL) &&
- domain->ops->is_attach_deferred(domain, dev))
- return 0;
if (unlikely(domain->ops->attach_dev == NULL))
return -ENODEV;
@@ -1726,8 +1732,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
static void __iommu_detach_device(struct iommu_domain *domain,
struct device *dev)
{
- if ((domain->ops->is_attach_deferred != NULL) &&
- domain->ops->is_attach_deferred(domain, dev))
+ if (iommu_is_attach_deferred(domain, dev))
return;
if (unlikely(domain->ops->detach_dev == NULL))
--
2.25.1
