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authorJoerg Roedel <jroedel@suse.de>2020-05-19 15:03:40 +0200
committerJoerg Roedel <jroedel@suse.de>2020-05-19 15:05:43 +0200
commitbd421264ed307dd296eab036851221b225071a32 (patch)
tree61927cf6cef2607118ec52d79611abd56354039e
parentea90228c7b2ae6646bb6381385229aabb6f14cd2 (diff)
downloadlinux-bd421264ed307dd296eab036851221b225071a32.tar.gz
iommu: Fix deferred domain attachment
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 <jsnitsel@redhat.com> Suggested-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Tested-by: Jerry Snitselaar <jsnitsel@redhat.com> Cc: Jerry Snitselaar <jsnitsel@redhat.com> Cc: Tom Murphy <murphyt7@tcd.ie> Cc: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/20200519130340.14564-1-joro@8bytes.org
-rw-r--r--drivers/iommu/iommu.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 7b375421afba..1faa08c8bbb4 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -693,6 +693,15 @@ 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)
@@ -747,7 +756,7 @@ 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)
@@ -1653,9 +1662,6 @@ 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;
@@ -1727,8 +1733,7 @@ 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))