[RFC PATCH 13/42] iommufd: Add a KVM HW pagetable object

Yan Zhao
2023-12-02T09:50:47Z

Add new obj type IOMMUFD_OBJ_HWPT_KVM for KVM HW page tables, which
correspond to iommu stage 2 domains whose paging strcutures and mappings
are managed by KVM.

Extend the IOMMU_HWPT_ALLOC ioctl to accept KVM HW page table specific
data of "struct iommu_hwpt_kvm_info".

The real allocator iommufd_hwpt_kvm_alloc() is now an empty function and
will be implemented in next patch when config IOMMUFD_KVM_HWPT is on.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
drivers/iommu/iommufd/device.c | 13 +++++----
drivers/iommu/iommufd/hw_pagetable.c | 29 +++++++++++++++++++-
drivers/iommu/iommufd/iommufd_private.h | 35 +++++++++++++++++++++++++
drivers/iommu/iommufd/main.c | 4 +++
4 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 59d3a07300d93..83af6b7e2784b 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -629,7 +629,8 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,

switch (pt_obj->type) {
case IOMMUFD_OBJ_HWPT_NESTED:
- case IOMMUFD_OBJ_HWPT_PAGING: {
+ case IOMMUFD_OBJ_HWPT_PAGING:
+ case IOMMUFD_OBJ_HWPT_KVM: {
struct iommufd_hw_pagetable *hwpt =
container_of(pt_obj, struct iommufd_hw_pagetable, obj);

@@ -667,8 +668,9 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
/**
* iommufd_device_attach - Connect a device to an iommu_domain
* @idev: device to attach
- * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING
- * Output the IOMMUFD_OBJ_HWPT_PAGING ID
+ * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING, or
+ * IOMMUFD_OBJ_HWPT_KVM
+ * Output the IOMMUFD_OBJ_HWPT_PAGING ID or IOMMUFD_OBJ_HWPT_KVM ID
*
* This connects the device to an iommu_domain, either automatically or manually
* selected. Once this completes the device could do DMA.
@@ -696,8 +698,9 @@ EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, IOMMUFD);
/**
* iommufd_device_replace - Change the device's iommu_domain
* @idev: device to change
- * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING
- * Output the IOMMUFD_OBJ_HWPT_PAGING ID
+ * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING, or
+ * IOMMUFD_OBJ_HWPT_KVM
+ * Output the IOMMUFD_OBJ_HWPT_PAGING ID or IOMMUFD_OBJ_HWPT_KVM ID
*
* This is the same as::
*
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 367459d92f696..c8430ec42cdf8 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -273,6 +273,31 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
if (IS_ERR(idev))
return PTR_ERR(idev);

+ if (cmd->data_type == IOMMU_HWPT_DATA_KVM) {
+ struct iommu_hwpt_kvm_info kvm_data;
+ struct iommufd_hwpt_kvm *hwpt_kvm;
+
+ if (!cmd->data_len || cmd->data_len != sizeof(kvm_data) ||
+ !cmd->data_uptr) {
+ rc = -EINVAL;
+ goto out_put_idev;
+ }
+ rc = copy_struct_from_user(&kvm_data, sizeof(kvm_data),
+ u64_to_user_ptr(cmd->data_uptr),
+ cmd->data_len);
+ if (rc)
+ goto out_put_idev;
+
+ hwpt_kvm = iommufd_hwpt_kvm_alloc(ucmd->ictx, idev, cmd->flags,
+ &kvm_data);
+ if (IS_ERR(hwpt_kvm)) {
+ rc = PTR_ERR(hwpt_kvm);
+ goto out_put_idev;
+ }
+ hwpt = &hwpt_kvm->common;
+ goto out_respond;
+ }
+
pt_obj = iommufd_get_object(ucmd->ictx, cmd->pt_id, IOMMUFD_OBJ_ANY);
if (IS_ERR(pt_obj)) {
rc = -EINVAL;
@@ -310,6 +335,7 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
goto out_put_pt;
}

+out_respond:
cmd->out_hwpt_id = hwpt->obj.id;
rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
if (rc)
@@ -323,7 +349,8 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
if (ioas)
mutex_unlock(&ioas->mutex);
out_put_pt:
- iommufd_put_object(pt_obj);
+ if (cmd->data_type != IOMMU_HWPT_DATA_KVM)
+ iommufd_put_object(pt_obj);
out_put_idev:
iommufd_put_object(&idev->obj);
return rc;
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 160521800d9b4..a46a6e3e537f9 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -125,6 +125,7 @@ enum iommufd_object_type {
IOMMUFD_OBJ_DEVICE,
IOMMUFD_OBJ_HWPT_PAGING,
IOMMUFD_OBJ_HWPT_NESTED,
+ IOMMUFD_OBJ_HWPT_KVM,
IOMMUFD_OBJ_IOAS,
IOMMUFD_OBJ_ACCESS,
#ifdef CONFIG_IOMMUFD_TEST
@@ -266,17 +267,33 @@ struct iommufd_hwpt_nested {
struct iommufd_hwpt_paging *parent;
};

+struct iommufd_hwpt_kvm {
+ struct iommufd_hw_pagetable common;
+ void *context;
+};
+
static inline bool hwpt_is_paging(struct iommufd_hw_pagetable *hwpt)
{
return hwpt->obj.type == IOMMUFD_OBJ_HWPT_PAGING;
}

+static inline bool hwpt_is_kvm(struct iommufd_hw_pagetable *hwpt)
+{
+ return hwpt->obj.type == IOMMUFD_OBJ_HWPT_KVM;
+}
+
static inline struct iommufd_hwpt_paging *
to_hwpt_paging(struct iommufd_hw_pagetable *hwpt)
{
return container_of(hwpt, struct iommufd_hwpt_paging, common);
}

+static inline struct iommufd_hwpt_kvm *
+to_hwpt_kvm(struct iommufd_hw_pagetable *hwpt)
+{
+ return container_of(hwpt, struct iommufd_hwpt_kvm, common);
+}
+
static inline struct iommufd_hwpt_paging *
iommufd_get_hwpt_paging(struct iommufd_ucmd *ucmd, u32 id)
{
@@ -413,4 +430,22 @@ static inline bool iommufd_selftest_is_mock_dev(struct device *dev)
return false;
}
#endif
+
+struct iommu_hwpt_kvm_info;
+static inline struct iommufd_hwpt_kvm *
+iommufd_hwpt_kvm_alloc(struct iommufd_ctx *ictx,
+ struct iommufd_device *idev, u32 flags,
+ const struct iommu_hwpt_kvm_info *kvm_data)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void iommufd_hwpt_kvm_abort(struct iommufd_object *obj)
+{
+}
+
+static inline void iommufd_hwpt_kvm_destroy(struct iommufd_object *obj)
+{
+}
+
#endif
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 6edef860f91cc..0798c1279133f 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -499,6 +499,10 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
.destroy = iommufd_hwpt_nested_destroy,
.abort = iommufd_hwpt_nested_abort,
},
+ [IOMMUFD_OBJ_HWPT_KVM] = {
+ .destroy = iommufd_hwpt_kvm_destroy,
+ .abort = iommufd_hwpt_kvm_abort,
+ },
#ifdef CONFIG_IOMMUFD_TEST
[IOMMUFD_OBJ_SELFTEST] = {
.destroy = iommufd_selftest_destroy,
--
2.17.1