[PATCH v7 2/9] iommufd: Add IOMMU_HWPT_INVALIDATE

Yi Liu
2023-12-21T15:39:54Z

In nested translation, the stage-1 page table is user-managed but cached
by the IOMMU hardware, so an update on present page table entries in the
stage-1 page table should be followed with a cache invalidation.

Add an IOMMU_HWPT_INVALIDATE ioctl to support such a cache invalidation.
It takes hwpt_id to specify the iommu_domain, and a multi-entry array to
support multiple invalidation requests in one ioctl.

This also adds the cache invalidation data structure for Intel VT-d to have
a complete story. Intel iommu driver support will be added in later patch.

Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/hw_pagetable.c | 36 +++++++++
drivers/iommu/iommufd/iommufd_private.h | 10 +++
drivers/iommu/iommufd/main.c | 3 +
include/uapi/linux/iommufd.h | 100 ++++++++++++++++++++++++
4 files changed, 149 insertions(+)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index cbb5df0a6c32..6389a9809c7b 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -371,3 +371,39 @@ int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd)
iommufd_put_object(ucmd->ictx, &hwpt_paging->common.obj);
return rc;
}
+
+int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_hwpt_invalidate *cmd = ucmd->cmd;
+ struct iommu_user_data_array data_array = {
+ .type = cmd->req_type,
+ .uptr = u64_to_user_ptr(cmd->reqs_uptr),
+ .entry_len = cmd->req_len,
+ .entry_num = cmd->req_num,
+ };
+ struct iommufd_hw_pagetable *hwpt;
+ u32 done_num = 0;
+ int rc;
+
+ if (cmd->req_num && (!cmd->reqs_uptr || !cmd->req_len)) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ hwpt = iommufd_get_hwpt_nested(ucmd, cmd->hwpt_id);
+ if (IS_ERR(hwpt)) {
+ rc = PTR_ERR(hwpt);
+ goto out;
+ }
+
+ rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
+ &data_array);
+ done_num = data_array.entry_num;
+
+ iommufd_put_object(ucmd->ictx, &hwpt->obj);
+out:
+ cmd->req_num = done_num;
+ if (iommufd_ucmd_respond(ucmd, sizeof(*cmd)))
+ return -EFAULT;
+ return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index abae041e256f..991f864d1f9b 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -328,6 +328,15 @@ iommufd_get_hwpt_paging(struct iommufd_ucmd *ucmd, u32 id)
IOMMUFD_OBJ_HWPT_PAGING),
struct iommufd_hwpt_paging, common.obj);
}
+
+static inline struct iommufd_hw_pagetable *
+iommufd_get_hwpt_nested(struct iommufd_ucmd *ucmd, u32 id)
+{
+ return container_of(iommufd_get_object(ucmd->ictx, id,
+ IOMMUFD_OBJ_HWPT_NESTED),
+ struct iommufd_hw_pagetable, obj);
+}
+
int iommufd_hwpt_set_dirty_tracking(struct iommufd_ucmd *ucmd);
int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd);

@@ -345,6 +354,7 @@ void iommufd_hwpt_paging_abort(struct iommufd_object *obj);
void iommufd_hwpt_nested_destroy(struct iommufd_object *obj);
void iommufd_hwpt_nested_abort(struct iommufd_object *obj);
int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd);
+int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd);

static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
struct iommufd_hw_pagetable *hwpt)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index c9091e46d208..e4f6dfc3474f 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -323,6 +323,7 @@ union ucmd_buffer {
struct iommu_hwpt_alloc hwpt;
struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap;
struct iommu_hwpt_set_dirty_tracking set_dirty_tracking;
+ struct iommu_hwpt_invalidate cache;
struct iommu_ioas_alloc alloc;
struct iommu_ioas_allow_iovas allow_iovas;
struct iommu_ioas_copy ioas_copy;
@@ -362,6 +363,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
struct iommu_hwpt_get_dirty_bitmap, data),
IOCTL_OP(IOMMU_HWPT_SET_DIRTY_TRACKING, iommufd_hwpt_set_dirty_tracking,
struct iommu_hwpt_set_dirty_tracking, __reserved),
+ IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
+ struct iommu_hwpt_invalidate, __reserved),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
struct iommu_ioas_alloc, out_ioas_id),
IOCTL_OP(IOMMU_IOAS_ALLOW_IOVAS, iommufd_ioas_allow_iovas,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 0b2bc6252e2c..e501ef4f7ec1 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -49,6 +49,7 @@ enum {
IOMMUFD_CMD_GET_HW_INFO,
IOMMUFD_CMD_HWPT_SET_DIRTY_TRACKING,
IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP,
+ IOMMUFD_CMD_HWPT_INVALIDATE,
};

/**
@@ -613,4 +614,103 @@ struct iommu_hwpt_get_dirty_bitmap {
#define IOMMU_HWPT_GET_DIRTY_BITMAP _IO(IOMMUFD_TYPE, \
IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP)

+/**
+ * enum iommu_hwpt_invalidate_data_type - IOMMU HWPT Cache Invalidation
+ * Data Type
+ * @IOMMU_HWPT_INVALIDATE_DATA_VTD_S1: Invalidation data for VTD_S1
+ */
+enum iommu_hwpt_invalidate_data_type {
+ IOMMU_HWPT_INVALIDATE_DATA_VTD_S1,
+};
+
+/**
+ * enum iommu_hwpt_vtd_s1_invalidate_flags - Flags for Intel VT-d
+ * stage-1 cache invalidation
+ * @IOMMU_VTD_INV_FLAGS_LEAF: The LEAF flag indicates whether only the
+ * leaf PTE caching needs to be invalidated
+ * and other paging structure caches can be
+ * preserved.
+ */
+enum iommu_hwpt_vtd_s1_invalidate_flags {
+ IOMMU_VTD_INV_FLAGS_LEAF = 1 << 0,
+};
+
+/**
+ * enum iommu_hwpt_vtd_s1_invalidate_error - Result of invalidation
+ * @IOMMU_HWPT_INVALIDATE_VTD_S1_ICE: Invalidation Completion Error, details
+ * refer to 11.4.7.1 Fault Status Register
+ * of VT-d specification.
+ * @IOMMU_HWPT_INVALIDATE_VTD_S1_ITE: Invalidation Time-out Error, details
+ * refer to 11.4.7.1 Fault Status Register
+ * of VT-d specification.
+ */
+enum iommu_hwpt_vtd_s1_invalidate_error {
+ IOMMU_HWPT_INVALIDATE_VTD_S1_ICE = 1 << 0,
+ IOMMU_HWPT_INVALIDATE_VTD_S1_ITE = 1 << 1,
+};
+
+/**
+ * struct iommu_hwpt_vtd_s1_invalidate - Intel VT-d cache invalidation
+ * (IOMMU_HWPT_INVALIDATE_DATA_VTD_S1)
+ * @addr: The start address of the addresses to be invalidated. It needs
+ * to be 4KB aligned.
+ * @npages: Number of contiguous 4K pages to be invalidated.
+ * @flags: Combination of enum iommu_hwpt_vtd_s1_invalidate_flags
+ * @inv_error: One of enum iommu_hwpt_vtd_s1_invalidate_error
+ *
+ * The Intel VT-d specific invalidation data for user-managed stage-1 cache
+ * invalidation in nested translation. Userspace uses this structure to
+ * tell the impacted cache scope after modifying the stage-1 page table.
+ *
+ * Invalidating all the caches related to the page table by setting @addr
+ * to be 0 and @npages to be U64_MAX.
+ *
+ * @inv_error is meaningful only if the request is handled by kernel. This
+ * can be known by checking struct iommu_hwpt_invalidate::req_num output.
+ * @inv_error only covers the errors detected by hardware after submitting the
+ * invalidation. The software detected errors would go through the normal
+ * ioctl errno.
+ */
+struct iommu_hwpt_vtd_s1_invalidate {
+ __aligned_u64 addr;
+ __aligned_u64 npages;
+ __u32 flags;
+ __u32 inv_error;
+};
+
+/**
+ * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
+ * @size: sizeof(struct iommu_hwpt_invalidate)
+ * @hwpt_id: HWPT ID of a nested HWPT for cache invalidation
+ * @reqs_uptr: User pointer to an array having @req_num of cache invalidation
+ * requests. The request entries in the array are of fixed width
+ * @req_len, and contain a user data structure for invalidation
+ * request specific to the given hardware page table.
+ * @req_type: One of enum iommu_hwpt_invalidate_data_type, defining the data
+ * type of all the entries in the invalidation request array. It
+ * should be a type supported by the hwpt pointed by @hwpt_id.
+ * @req_len: Length (in bytes) of a request entry in the request array
+ * @req_num: Input the number of cache invalidation requests in the array.
+ * Output the number of requests successfully handled by kernel.
+ * @__reserved: Must be 0.
+ *
+ * Invalidate the iommu cache for user-managed page table. Modifications on a
+ * user-managed page table should be followed by this operation to sync cache.
+ * Each ioctl can support one or more cache invalidation requests in the array
+ * that has a total size of @req_len * @req_num.
+ *
+ * An empty invalidation request array by setting @req_num==0 is allowed, and
+ * @req_len and @reqs_uptr would be ignored in this case. This can be used to
+ * check if the given @req_type is supported or not by kernel.
+ */
+struct iommu_hwpt_invalidate {
+ __u32 size;
+ __u32 hwpt_id;
+ __aligned_u64 reqs_uptr;
+ __u32 req_type;
+ __u32 req_len;
+ __u32 req_num;
+ __u32 __reserved;
+};
+#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
#endif
--
2.34.1