[PATCH 08/12] iommufd/device: Report supported hwpt_types

Yi Liu
2023-03-09T08:10:31Z

This provides a way for userspace to probe the supported hwpt data
types by kernel. Currently, kernel only supports IOMMU_HWPT_TYPE_DEFAULT,
new types would be added per vendor drivers' extension.

Userspace that wants to allocate hw_pagetable with user data should check
this. While for the allocation without user data, no need for it. It is
supported by default.

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/device.c | 1 +
drivers/iommu/iommufd/hw_pagetable.c | 18 +++++++++++++++---
drivers/iommu/iommufd/iommufd_private.h | 2 ++
drivers/iommu/iommufd/main.c | 2 +-
include/uapi/linux/iommufd.h | 8 ++++++++
5 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 19cd6df46c6a..0328071dcac1 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -322,6 +322,7 @@ int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd)

cmd->out_data_type = ops->driver_type;
cmd->data_len = length;
+ cmd->out_hwpt_type_bitmap = iommufd_hwpt_type_bitmaps[ops->driver_type];

rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 67facca98de1..160712256c64 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -173,6 +173,14 @@ static const size_t iommufd_hwpt_alloc_data_size[] = {
[IOMMU_HWPT_TYPE_DEFAULT] = 0,
};

+/*
+ * bitmaps of supported hwpt types of by underlying iommu, indexed
+ * by ops->driver_type which is one of enum iommu_hw_info_type.
+ */
+const u64 iommufd_hwpt_type_bitmaps[] = {
+ [IOMMU_HW_INFO_TYPE_DEFAULT] = BIT_ULL(IOMMU_HWPT_TYPE_DEFAULT),
+};
+
int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
{
struct iommu_hwpt_alloc *cmd = ucmd->cmd;
@@ -182,7 +190,7 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
struct iommufd_ioas *ioas;
const struct iommu_ops *ops;
void *data = NULL;
- u32 klen;
+ u32 driver_type, klen;
int rc;

if (cmd->__reserved || cmd->flags)
@@ -198,8 +206,12 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
goto out_put_idev;
}

- /* Only support IOMMU_HWPT_TYPE_DEFAULT for now */
- if (cmd->data_type != IOMMU_HWPT_TYPE_DEFAULT) {
+ driver_type = ops->driver_type;
+
+ /* data_type should be a supported type by the driver */
+ if (WARN_ON(driver_type >= ARRAY_SIZE(iommufd_hwpt_type_bitmaps)) ||
+ !((1 << cmd->data_type) &
+ iommufd_hwpt_type_bitmaps[driver_type])) {
rc = -EINVAL;
goto out_put_idev;
}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index d879264d1acf..164ccfc2e6e0 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -321,6 +321,8 @@ iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id)
void iommufd_device_destroy(struct iommufd_object *obj);
int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd);

+extern const u64 iommufd_hwpt_type_bitmaps[];
+
struct iommufd_access {
struct iommufd_object obj;
struct iommufd_ctx *ictx;
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 2cf45f65b637..7ec3ceac01b3 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -298,7 +298,7 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc,
data_uptr),
IOCTL_OP(IOMMU_DEVICE_GET_HW_INFO, iommufd_device_get_hw_info,
- struct iommu_hw_info, __reserved),
+ struct iommu_hw_info, out_hwpt_type_bitmap),
IOCTL_OP(IOMMU_HWPT_INVALIDATE, iommufd_hwpt_invalidate,
struct iommu_hwpt_invalidate, data_uptr),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index d0962c41f8d6..e2eff9c56ab3 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -421,6 +421,8 @@ enum iommu_hw_info_type {
* @out_data_type: Output the iommu hardware info type, it is one of
* enum iommu_hw_info_type.
* @__reserved: Must be 0
+ * @out_hwpt_type_bitmap: Output the supported page table type. Each
+ * bit is defined in enum iommu_hwpt_type.
*
* Query the hardware iommu information for given device which has been
* bound to iommufd. @data_len is the size of the buffer which captures
@@ -435,6 +437,11 @@ enum iommu_hw_info_type {
* The @out_data_type will be filled if the ioctl succeeds. It would
* be used to decode the data filled in the buffer pointed by @data_ptr.
*
+ * @out_hwpt_type_bitmap reports the supported hwpt types. This differs
+ * per the @out_data_type. Userspace should check it before allocating a
+ * user-managed hw_pagetable with user data, unless it allocates a default
+ * hw_pagetable that does not need user data.
+ *
* This is only available for the physical devices bound to iommufd as
* only physical devices can have hardware IOMMU.
*/
@@ -446,6 +453,7 @@ struct iommu_hw_info {
__aligned_u64 data_ptr;
__u32 out_data_type;
__u32 __reserved;
+ __aligned_u64 out_hwpt_type_bitmap;
};
#define IOMMU_DEVICE_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_GET_HW_INFO)

--
2.34.1