[PATCH 2/2 for Linux 5.4] iommu/vt-d: Don't dereference iommu_device if IOMMU_API is not built

Filippo Sironi
2021-02-02T00:01:52Z

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

commit 9def3b1a07c41e21c68a0eb353e3e569fdd1d2b1 upstream.

Since commit c40aaaac1018 ("iommu/vt-d: Gracefully handle DMAR units
with no supported address widths") dmar.c needs struct iommu_device to
be selected. We can drop this dependency by not dereferencing struct
iommu_device if IOMMU_API is not selected and by reusing the information
stored in iommu->drhd->ignored instead.

This fixes the following build error when IOMMU_API is not selected:

drivers/iommu/dmar.c: In function ‘free_iommu’:
drivers/iommu/dmar.c:1139:41: error: ‘struct iommu_device’ has no member named ‘ops’
1139 | if (intel_iommu_enabled && iommu->iommu.ops) {
^

Fixes: c40aaaac1018 ("iommu/vt-d: Gracefully handle DMAR units with no supported address widths")
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20201013073055.11262-1-brgl@bgdev.pl
Signed-off-by: Joerg Roedel <jroedel@suse.de>
[ - context change due to moving drivers/iommu/dmar.c to
drivers/iommu/intel/dmar.c
- set the drhr in the iommu like in upstream commit b1012ca8dc4f
("iommu/vt-d: Skip TE disabling on quirky gfx dedicated iommu") ]
Signed-off-by: Filippo Sironi <sironi@amazon.de>
---
drivers/iommu/dmar.c | 3 ++-
include/linux/intel-iommu.h | 2 ++
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index a5f69d9bb0b8..1b9795743276 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1114,6 +1114,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
}

drhd->iommu = iommu;
+ iommu->drhd = drhd;

return 0;

@@ -1128,7 +1129,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

static void free_iommu(struct intel_iommu *iommu)
{
- if (intel_iommu_enabled && iommu->iommu.ops) {
+ if (intel_iommu_enabled && !iommu->drhd->ignored) {
iommu_device_unregister(&iommu->iommu);
iommu_device_sysfs_remove(&iommu->iommu);
}
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 6b559d25a84e..88ac8edf44e3 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -556,6 +556,8 @@ struct intel_iommu {
struct iommu_device iommu; /* IOMMU core code handle */
int node;
u32 flags; /* Software defined flags */
+
+ struct dmar_drhd_unit *drhd;
};

/* PCI domain-device relationship */
--
2.17.1

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