[PATCH 18/22] iommufd: Introduce iommufd_viommu_ops.hw_queue_init

Suravee Suthikulpanit
2026-03-30T08:44:25Z

This is mainly used by AMD vIOMMU to initialize virtualize hardware queue
using guest physical address where the address is specified via
@hw_queue->base_addr.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
drivers/iommu/iommufd/viommu.c | 125 +++++++++++++++++++++++----------
include/linux/iommufd.h | 5 +-
2 files changed, 91 insertions(+), 39 deletions(-)

diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 462b457ffd0c..59b31b3e36be 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -353,62 +353,35 @@ iommufd_hw_queue_alloc_phys(struct iommu_hw_queue_alloc *cmd,
return ERR_PTR(rc);
}

-int iommufd_hw_queue_alloc_ioctl(struct iommufd_ucmd *ucmd)
+static int _iommufd_hw_queue_init_phys(struct iommufd_ucmd *ucmd,
+ struct iommufd_viommu *viommu)
{
struct iommu_hw_queue_alloc *cmd = ucmd->cmd;
struct iommufd_hw_queue *hw_queue;
- struct iommufd_viommu *viommu;
struct iommufd_access *access;
size_t hw_queue_size;
phys_addr_t base_pa;
- u64 last;
int rc;

- if (cmd->flags || cmd->type == IOMMU_HW_QUEUE_TYPE_DEFAULT)
- return -EOPNOTSUPP;
- if (!cmd->length)
- return -EINVAL;
- if (check_add_overflow(cmd->nesting_parent_iova, cmd->length - 1,
- &last))
- return -EOVERFLOW;
-
- viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
- if (IS_ERR(viommu))
- return PTR_ERR(viommu);
-
- if (!viommu->ops || !viommu->ops->get_hw_queue_size ||
- !viommu->ops->hw_queue_init_phys) {
- rc = -EOPNOTSUPP;
- goto out_put_viommu;
- }
-
hw_queue_size = viommu->ops->get_hw_queue_size(viommu, cmd->type);
- if (!hw_queue_size) {
- rc = -EOPNOTSUPP;
- goto out_put_viommu;
- }
+ if (!hw_queue_size)
+ return -EOPNOTSUPP;

/*
* It is a driver bug for providing a hw_queue_size smaller than the
* core HW queue structure size
*/
- if (WARN_ON_ONCE(hw_queue_size < sizeof(*hw_queue))) {
- rc = -EOPNOTSUPP;
- goto out_put_viommu;
- }
+ if (WARN_ON_ONCE(hw_queue_size < sizeof(*hw_queue)))
+ return -EOPNOTSUPP;

hw_queue = (struct iommufd_hw_queue *)_iommufd_object_alloc_ucmd(
ucmd, hw_queue_size, IOMMUFD_OBJ_HW_QUEUE);
- if (IS_ERR(hw_queue)) {
- rc = PTR_ERR(hw_queue);
- goto out_put_viommu;
- }
+ if (IS_ERR(hw_queue))
+ return PTR_ERR(hw_queue);

access = iommufd_hw_queue_alloc_phys(cmd, viommu, &base_pa);
- if (IS_ERR(access)) {
- rc = PTR_ERR(access);
- goto out_put_viommu;
- }
+ if (IS_ERR(access))
+ return PTR_ERR(access);

hw_queue->viommu = viommu;
refcount_inc(&viommu->obj.users);
@@ -419,9 +392,85 @@ int iommufd_hw_queue_alloc_ioctl(struct iommufd_ucmd *ucmd)

rc = viommu->ops->hw_queue_init_phys(hw_queue, cmd->index, base_pa);
if (rc)
- goto out_put_viommu;
+ return rc;

cmd->out_hw_queue_id = hw_queue->obj.id;
+ return rc;
+}
+
+static int _iommufd_hw_queue_init(struct iommufd_ucmd *ucmd,
+ struct iommufd_viommu *viommu)
+{
+ struct iommu_hw_queue_alloc *cmd = ucmd->cmd;
+ struct iommufd_hw_queue *hw_queue;
+ size_t hw_queue_size;
+ int rc;
+
+ hw_queue_size = viommu->ops->get_hw_queue_size(viommu, cmd->type);
+ if (!hw_queue_size)
+ return -EOPNOTSUPP;
+
+ /*
+ * It is a driver bug for providing a hw_queue_size smaller than the
+ * core HW queue structure size
+ */
+ if (WARN_ON_ONCE(hw_queue_size < sizeof(*hw_queue)))
+ return -EOPNOTSUPP;
+
+ hw_queue = (struct iommufd_hw_queue *)_iommufd_object_alloc_ucmd(
+ ucmd, hw_queue_size, IOMMUFD_OBJ_HW_QUEUE);
+ if (IS_ERR(hw_queue))
+ return PTR_ERR(hw_queue);
+
+ hw_queue->viommu = viommu;
+ refcount_inc(&viommu->obj.users);
+ hw_queue->access = NULL;
+ hw_queue->type = cmd->type;
+ hw_queue->length = cmd->length;
+ hw_queue->base_addr = cmd->nesting_parent_iova;
+
+ rc = viommu->ops->hw_queue_init(hw_queue, cmd->index);
+ if (rc)
+ return rc;
+
+ cmd->out_hw_queue_id = hw_queue->obj.id;
+ return rc;
+}
+
+int iommufd_hw_queue_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_hw_queue_alloc *cmd = ucmd->cmd;
+ struct iommufd_viommu *viommu;
+ u64 last;
+ int rc;
+
+ if (cmd->flags || cmd->type == IOMMU_HW_QUEUE_TYPE_DEFAULT)
+ return -EOPNOTSUPP;
+ if (!cmd->length)
+ return -EINVAL;
+ if (check_add_overflow(cmd->nesting_parent_iova, cmd->length - 1,
+ &last))
+ return -EOVERFLOW;
+
+ viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+ if (IS_ERR(viommu))
+ return PTR_ERR(viommu);
+
+ if (!viommu->ops || !viommu->ops->get_hw_queue_size) {
+ rc = -EOPNOTSUPP;
+ goto out_put_viommu;
+ }
+
+ if (viommu->ops->hw_queue_init_phys)
+ rc = _iommufd_hw_queue_init_phys(ucmd, viommu);
+ else if (viommu->ops->hw_queue_init)
+ rc = _iommufd_hw_queue_init(ucmd, viommu);
+ else
+ rc = -EOPNOTSUPP;
+
+ if (rc)
+ goto out_put_viommu;
+
rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));

out_put_viommu:
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 6e7efe83bc5d..c0030677e13c 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -180,6 +180,9 @@ struct iommufd_hw_queue {
* the physical location of the guest queue
* If driver has a deinit function to revert what this op
* does, it should set it to the @hw_queue->destroy pointer
+ * @hw_queue_init: Similar to hw_queue_init_phys, but driver providing this op
+ * indicates that HW accesses the guest queue memory via
+ * @hw_queue->baseaddr.
*/
struct iommufd_viommu_ops {
void (*destroy)(struct iommufd_viommu *viommu);
@@ -192,9 +195,9 @@ struct iommufd_viommu_ops {
int (*vdevice_init)(struct iommufd_vdevice *vdev);
size_t (*get_hw_queue_size)(struct iommufd_viommu *viommu,
enum iommu_hw_queue_type queue_type);
- /* AMD's HW will add hw_queue_init simply using @hw_queue->base_addr */
int (*hw_queue_init_phys)(struct iommufd_hw_queue *hw_queue, u32 index,
phys_addr_t base_addr_pa);
+ int (*hw_queue_init)(struct iommufd_hw_queue *hw_queue, u32 index);
};

#if IS_ENABLED(CONFIG_IOMMUFD)
--
2.34.1