This patch adds a new exported function to amd_iommu_v2, which returns 1 if the
amd_iommu_v2 initialization function has completed, and 0 otherwise.
This is necessary for the case when amd_iommu_v2 is compiled inside the kernel
image (not as module) and another module (e.g. amdkfd), which is also compiled
inside the kernel image, is dependent on amd_iommu_v2 functionality.
In that case, there is no mechanism in the kernel that enforces the order of
loading between the two modules. Therefore, If the amd_iommu_v2 is loaded
_after_ the other module, and the other module calls one of
amd_iommu_v2 exported functions _before_ amd_iommu_v2 is loaded, than that
function will fail, and as a result, the calling module may fail as well.
Note that when the two modules are compiled as modules, this situation can't
occur as the kernel enforces the order of loading.
Signed-off-by: Oded Gabbay <oded.gab...@amd.com>
---
drivers/iommu/amd_iommu_v2.c | 11 +++++++++++
include/linux/amd-iommu.h | 2 ++
2 files changed, 13 insertions(+)
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 1e6360e..2456f18 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -895,6 +895,14 @@ out_unlock:
}
EXPORT_SYMBOL(amd_iommu_set_invalidate_ctx_cb);
+static int iommu_v2_init_completed;
+
+int amd_iommu_v2_is_init_completed(void)
+{
+ return iommu_v2_init_completed;
+}
+EXPORT_SYMBOL(amd_iommu_v2_is_init_completed);
+
static int __init amd_iommu_v2_init(void)
{
int ret;
@@ -903,6 +911,7 @@ static int __init amd_iommu_v2_init(void)
if (!amd_iommu_v2_supported()) {
pr_info("AMD IOMMUv2 functionality not available on this
system\n");
+ iommu_v2_init_completed = 1;
/*
* Load anyway to provide the symbols to other modules
* which may use AMD IOMMUv2 optionally.
@@ -919,6 +928,8 @@ static int __init amd_iommu_v2_init(void)
amd_iommu_register_ppr_notifier(&ppr_nb);
+ iommu_v2_init_completed = 1;
+
return 0;
out:
diff --git a/include/linux/amd-iommu.h b/include/linux/amd-iommu.h
index 2b08e79..115c03a 100644
--- a/include/linux/amd-iommu.h
+++ b/include/linux/amd-iommu.h
@@ -169,6 +169,8 @@ typedef void (*amd_iommu_invalidate_ctx)(struct pci_dev
*pdev, int pasid);
extern int amd_iommu_set_invalidate_ctx_cb(struct pci_dev *pdev,
amd_iommu_invalidate_ctx cb);
+extern int amd_iommu_v2_is_init_completed(void);
+
#else
static inline int amd_iommu_detect(void) { return -ENODEV; }
--
2.1.0
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