On Sat, 26 Oct 2024 at 07:50, Nicolin Chen <nicolinc@xxxxxxxxxx> wrote:
>
> Now a vIOMMU holds a shareable nesting parent HWPT. So, it can act like
> that nesting parent HWPT to allocate a nested HWPT.
>
> Support that in the IOMMU_HWPT_ALLOC ioctl handler, and update its kdoc.
>
> Also, add an iommufd_hwpt_nested_alloc_for_viommu helper to allocate a
> nested HWPT for a vIOMMU object. Since a vIOMMU object holds the parent
> hwpt's refcount already, increase the refcount of the vIOMMU only.
>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> ---
> drivers/iommu/iommufd/iommufd_private.h | 1 +
> include/uapi/linux/iommufd.h | 14 ++---
> drivers/iommu/iommufd/hw_pagetable.c | 71 ++++++++++++++++++++++++-
> 3 files changed, 79 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
> index 9adf8d616796..8c9ab35eaea5 100644
> --- a/drivers/iommu/iommufd/iommufd_private.h
> +++ b/drivers/iommu/iommufd/iommufd_private.h
> @@ -288,6 +288,7 @@ struct iommufd_hwpt_paging {
> struct iommufd_hwpt_nested {
> struct iommufd_hw_pagetable common;
> struct iommufd_hwpt_paging *parent;
> + struct iommufd_viommu *viommu;
> };
>
> static inline bool hwpt_is_paging(struct iommufd_hw_pagetable *hwpt)
> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
> index 3d320d069654..717659b9fdce 100644
> --- a/include/uapi/linux/iommufd.h
> +++ b/include/uapi/linux/iommufd.h
> @@ -430,7 +430,7 @@ enum iommu_hwpt_data_type {
> * @size: sizeof(struct iommu_hwpt_alloc)
> * @flags: Combination of enum iommufd_hwpt_alloc_flags
> * @dev_id: The device to allocate this HWPT for
> - * @pt_id: The IOAS or HWPT to connect this HWPT to
> + * @pt_id: The IOAS or HWPT or vIOMMU to connect this HWPT to
> * @out_hwpt_id: The ID of the new HWPT
> * @__reserved: Must be 0
> * @data_type: One of enum iommu_hwpt_data_type
> @@ -449,11 +449,13 @@ enum iommu_hwpt_data_type {
> * IOMMU_HWPT_DATA_NONE. The HWPT can be allocated as a parent HWPT for a
> * nesting configuration by passing IOMMU_HWPT_ALLOC_NEST_PARENT via @flags.
> *
> - * A user-managed nested HWPT will be created from a given parent HWPT via
> - * @pt_id, in which the parent HWPT must be allocated previously via the
> - * same ioctl from a given IOAS (@pt_id). In this case, the @data_type
> - * must be set to a pre-defined type corresponding to an I/O page table
> - * type supported by the underlying IOMMU hardware.
> + * A user-managed nested HWPT will be created from a given vIOMMU (wrapping a
> + * parent HWPT) or a parent HWPT via @pt_id, in which the parent HWPT must be
> + * allocated previously via the same ioctl from a given IOAS (@pt_id). In this
> + * case, the @data_type must be set to a pre-defined type corresponding to an
> + * I/O page table type supported by the underlying IOMMU hardware. The device
> + * via @dev_id and the vIOMMU via @pt_id must be associated to the same IOMMU
> + * instance.
> *
> * If the @data_type is set to IOMMU_HWPT_DATA_NONE, @data_len and
> * @data_uptr should be zero. Otherwise, both @data_len and @data_uptr
> diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
> index d06bf6e6c19f..1df5d40c93df 100644
> --- a/drivers/iommu/iommufd/hw_pagetable.c
> +++ b/drivers/iommu/iommufd/hw_pagetable.c
> @@ -57,7 +57,10 @@ void iommufd_hwpt_nested_destroy(struct iommufd_object *obj)
> container_of(obj, struct iommufd_hwpt_nested, common.obj);
>
> __iommufd_hwpt_destroy(&hwpt_nested->common);
> - refcount_dec(&hwpt_nested->parent->common.obj.users);
> + if (hwpt_nested->viommu)
> + refcount_dec(&hwpt_nested->viommu->obj.users);
> + else
> + refcount_dec(&hwpt_nested->parent->common.obj.users);
> }
>
> void iommufd_hwpt_nested_abort(struct iommufd_object *obj)
> @@ -260,6 +263,56 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
> return ERR_PTR(rc);
> }
>
> +/**
> + * iommufd_viommu_alloc_hwpt_nested() - Get a hwpt_nested for a vIOMMU
> + * @viommu: vIOMMU ojbect to associate the hwpt_nested/domain with
> + * @user_data: user_data pointer. Must be valid
> + *
> + * Allocate a new IOMMU_DOMAIN_NESTED for a vIOMMU and return it as a NESTED
> + * hw_pagetable.
> + */
> +static struct iommufd_hwpt_nested *
> +iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags,
> + const struct iommu_user_data *user_data)
> +{
> + struct iommufd_hwpt_nested *hwpt_nested;
> + struct iommufd_hw_pagetable *hwpt;
> + int rc;
> +
> + if (flags)
> + return ERR_PTR(-EOPNOTSUPP);
This check should be removed.
When a user page fault is required, IOMMU_HWPT_FAULT_ID_VALID is set.
if (cmd->flags & IOMMU_HWPT_FAULT_ID_VALID) {
By the way, has qemu changed compared with v3?
I still got a hardware error in this version, in check
Thanks
