iommufd/selftest: Add mock_viommu_cache_invalidate

Similar to the coverage of cache_invalidate_user for iotlb invalidation,
add a device cache and a viommu_cache_invalidate function to test it out.

Link: https://patch.msgid.link/r/a29c7c23d7cd143fb26ab68b3618e0957f485fdb.1730836308.git.nicolinc@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: nicolinc

drivers/iommu/iommufd/iommufd_test.h

@@ -54,6 +54,11 @@ enum {
 	MOCK_NESTED_DOMAIN_IOTLB_NUM = 4,
 };
 
+enum {
+	MOCK_DEV_CACHE_ID_MAX = 3,
+	MOCK_DEV_CACHE_NUM = 4,
+};
+
 struct iommu_test_cmd {
 	__u32 size;
 	__u32 op;
@@ -152,6 +157,7 @@ struct iommu_test_hw_info {
 /* Should not be equal to any defined value in enum iommu_hwpt_data_type */
 #define IOMMU_HWPT_DATA_SELFTEST 0xdead
 #define IOMMU_TEST_IOTLB_DEFAULT 0xbadbeef
+#define IOMMU_TEST_DEV_CACHE_DEFAULT 0xbaddad
 
 /**
  * struct iommu_hwpt_selftest
@@ -182,4 +188,23 @@ struct iommu_hwpt_invalidate_selftest {
 
 #define IOMMU_VIOMMU_TYPE_SELFTEST 0xdeadbeef
 
+/* Should not be equal to any defined value in enum iommu_viommu_invalidate_data_type */
+#define IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST 0xdeadbeef
+#define IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST_INVALID 0xdadbeef
+
+/**
+ * struct iommu_viommu_invalidate_selftest - Invalidation data for Mock VIOMMU
+ *                                        (IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST)
+ * @flags: Invalidate flags
+ * @cache_id: Invalidate cache entry index
+ *
+ * If IOMMU_TEST_INVALIDATE_ALL is set in @flags, @cache_id will be ignored
+ */
+struct iommu_viommu_invalidate_selftest {
+#define IOMMU_TEST_INVALIDATE_FLAG_ALL (1 << 0)
+	__u32 flags;
+	__u32 vdev_id;
+	__u32 cache_id;
+};
+
 #endif

drivers/iommu/iommufd/selftest.c

@@ -163,6 +163,7 @@ struct mock_dev {
 	struct device dev;
 	unsigned long flags;
 	int id;
+	u32 cache[MOCK_DEV_CACHE_NUM];
 };
 
 static inline struct mock_dev *to_mock_dev(struct device *dev)
@@ -609,9 +610,80 @@ mock_viommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
 	return &mock_nested->domain;
 }
 
+static int mock_viommu_cache_invalidate(struct iommufd_viommu *viommu,
+					struct iommu_user_data_array *array)
+{
+	struct iommu_viommu_invalidate_selftest *cmds;
+	struct iommu_viommu_invalidate_selftest *cur;
+	struct iommu_viommu_invalidate_selftest *end;
+	int rc;
+
+	/* A zero-length array is allowed to validate the array type */
+	if (array->entry_num == 0 &&
+	    array->type == IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST) {
+		array->entry_num = 0;
+		return 0;
+	}
+
+	cmds = kcalloc(array->entry_num, sizeof(*cmds), GFP_KERNEL);
+	if (!cmds)
+		return -ENOMEM;
+	cur = cmds;
+	end = cmds + array->entry_num;
+
+	static_assert(sizeof(*cmds) == 3 * sizeof(u32));
+	rc = iommu_copy_struct_from_full_user_array(
+		cmds, sizeof(*cmds), array,
+		IOMMU_VIOMMU_INVALIDATE_DATA_SELFTEST);
+	if (rc)
+		goto out;
+
+	while (cur != end) {
+		struct mock_dev *mdev;
+		struct device *dev;
+		int i;
+
+		if (cur->flags & ~IOMMU_TEST_INVALIDATE_FLAG_ALL) {
+			rc = -EOPNOTSUPP;
+			goto out;
+		}
+
+		if (cur->cache_id > MOCK_DEV_CACHE_ID_MAX) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		xa_lock(&viommu->vdevs);
+		dev = iommufd_viommu_find_dev(viommu,
+					      (unsigned long)cur->vdev_id);
+		if (!dev) {
+			xa_unlock(&viommu->vdevs);
+			rc = -EINVAL;
+			goto out;
+		}
+		mdev = container_of(dev, struct mock_dev, dev);
+
+		if (cur->flags & IOMMU_TEST_INVALIDATE_FLAG_ALL) {
+			/* Invalidate all cache entries and ignore cache_id */
+			for (i = 0; i < MOCK_DEV_CACHE_NUM; i++)
+				mdev->cache[i] = 0;
+		} else {
+			mdev->cache[cur->cache_id] = 0;
+		}
+		xa_unlock(&viommu->vdevs);
+
+		cur++;
+	}
+out:
+	array->entry_num = cur - cmds;
+	kfree(cmds);
+	return rc;
+}
+
 static struct iommufd_viommu_ops mock_viommu_ops = {
 	.destroy = mock_viommu_destroy,
 	.alloc_domain_nested = mock_viommu_alloc_domain_nested,
+	.cache_invalidate = mock_viommu_cache_invalidate,
 };
 
 static struct iommufd_viommu *mock_viommu_alloc(struct device *dev,
@@ -782,7 +854,7 @@ static void mock_dev_release(struct device *dev)
 static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 {
 	struct mock_dev *mdev;
-	int rc;
+	int rc, i;
 
 	if (dev_flags &
 	    ~(MOCK_FLAGS_DEVICE_NO_DIRTY | MOCK_FLAGS_DEVICE_HUGE_IOVA))
@@ -796,6 +868,8 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 	mdev->flags = dev_flags;
 	mdev->dev.release = mock_dev_release;
 	mdev->dev.bus = &iommufd_mock_bus_type.bus;
+	for (i = 0; i < MOCK_DEV_CACHE_NUM; i++)
+		mdev->cache[i] = IOMMU_TEST_DEV_CACHE_DEFAULT;
 
 	rc = ida_alloc(&mock_dev_ida, GFP_KERNEL);
 	if (rc < 0)