[PATCH v7 1/9] iommu: Add cache_invalidate_user op

Yi Liu
2023-12-21T15:39:53Z

From: Lu Baolu <baolu.lu@linux.intel.com>

The updates of the PTEs in the nested page table will be propagated to the
hardware caches on both IOMMU (IOTLB) and devices (DevTLB/ATC).

Add a new domain op cache_invalidate_user for the userspace to flush the
hardware caches for a nested domain through iommufd. No wrapper for it,
as it's only supposed to be used by iommufd. Then, pass in invalidation
requests in form of a user data array conatining a number of invalidation
data entries.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
include/linux/iommu.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 6291aa7b079b..5c4a17f13761 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -284,6 +284,24 @@ struct iommu_user_data {
size_t len;
};

+/**
+ * struct iommu_user_data_array - iommu driver specific user space data array
+ * @type: The data type of all the entries in the user buffer array
+ * @uptr: Pointer to the user buffer array for copy_from_user()
+ * @entry_len: The fixed-width length of a entry in the array, in bytes
+ * @entry_num: The number of total entries in the array
+ *
+ * A array having a @entry_num number of @entry_len sized entries, each entry is
+ * user space data, an uAPI defined in include/uapi/linux/iommufd.h where @type
+ * is also defined as enum iommu_xyz_data_type.
+ */
+struct iommu_user_data_array {
+ unsigned int type;
+ void __user *uptr;
+ size_t entry_len;
+ u32 entry_num;
+};
+
/**
* __iommu_copy_struct_from_user - Copy iommu driver specific user space data
* @dst_data: Pointer to an iommu driver specific user data that is defined in
@@ -440,6 +458,13 @@ struct iommu_ops {
* @iotlb_sync_map: Sync mappings created recently using @map to the hardware
* @iotlb_sync: Flush all queued ranges from the hardware TLBs and empty flush
* queue
+ * @cache_invalidate_user: Flush hardware cache for user space IO page table.
+ * The @domain must be IOMMU_DOMAIN_NESTED. The @array
+ * passes in the cache invalidation requests, in form
+ * of a driver data structure. The driver must update
+ * array->entry_num to report the number of handled
+ * invalidation requests. The driver data structure
+ * must be defined in include/uapi/linux/iommufd.h
* @iova_to_phys: translate iova to physical address
* @enforce_cache_coherency: Prevent any kind of DMA from bypassing IOMMU_CACHE,
* including no-snoop TLPs on PCIe or other platform
@@ -465,6 +490,8 @@ struct iommu_domain_ops {
size_t size);
void (*iotlb_sync)(struct iommu_domain *domain,
struct iommu_iotlb_gather *iotlb_gather);
+ int (*cache_invalidate_user)(struct iommu_domain *domain,
+ struct iommu_user_data_array *array);

phys_addr_t (*iova_to_phys)(struct iommu_domain *domain,
dma_addr_t iova);
--
2.34.1