Messages in this thread | | | Date | Thu, 7 Dec 2023 14:59:17 +0800 | Subject | Re: [PATCH v6 2/6] iommufd: Add IOMMU_HWPT_INVALIDATE | From | Yi Liu <> |
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On 2023/11/17 21:07, Yi Liu wrote: > 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. > > Check cache_invalidate_user op in the iommufd_hw_pagetable_alloc_nested, > since all nested domains need that. > > 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 | 35 +++++++++++++++++++++++++ > drivers/iommu/iommufd/iommufd_private.h | 9 +++++++ > drivers/iommu/iommufd/main.c | 3 +++ > include/uapi/linux/iommufd.h | 35 +++++++++++++++++++++++++ > 4 files changed, 82 insertions(+) > > diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c > index 2abbeafdbd22..367459d92f69 100644 > --- a/drivers/iommu/iommufd/hw_pagetable.c > +++ b/drivers/iommu/iommufd/hw_pagetable.c > @@ -238,6 +238,11 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx, > rc = -EINVAL; > goto out_abort; > } > + /* Driver is buggy by missing cache_invalidate_user in domain_ops */ > + if (WARN_ON_ONCE(!hwpt->domain->ops->cache_invalidate_user)) { > + rc = -EINVAL; > + goto out_abort; > + } > return hwpt_nested; > > out_abort: > @@ -370,4 +375,34 @@ int iommufd_hwpt_get_dirty_bitmap(struct iommufd_ucmd *ucmd) > > iommufd_put_object(&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; > + int rc = 0; > + > + if (cmd->req_type == IOMMU_HWPT_DATA_NONE) > + return -EINVAL; > + if (!cmd->reqs_uptr || !cmd->req_len || !cmd->req_num) > + return -EINVAL; > + > + hwpt = iommufd_hw_pagetable_get_nested(ucmd, cmd->hwpt_id); > + if (IS_ERR(hwpt)) > + return PTR_ERR(hwpt); > + > + rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain, &data_array, > + &cmd->out_driver_error_code); > + cmd->req_num = data_array.entry_num; > + if (iommufd_ucmd_respond(ucmd, sizeof(*cmd))) > + return -EFAULT; > + iommufd_put_object(&hwpt->obj); > + return rc; > } > diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h > index a74cfefffbc6..160521800d9b 100644 > --- a/drivers/iommu/iommufd/iommufd_private.h > +++ b/drivers/iommu/iommufd/iommufd_private.h > @@ -301,6 +301,7 @@ 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) > @@ -318,6 +319,14 @@ static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx, > refcount_dec(&hwpt->obj.users); > } > > +static inline struct iommufd_hw_pagetable * > +iommufd_hw_pagetable_get_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); > +} > + > struct iommufd_group { > struct kref ref; > struct mutex lock; > diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c > index 45b9d40773b1..6edef860f91c 100644 > --- a/drivers/iommu/iommufd/main.c > +++ b/drivers/iommu/iommufd/main.c > @@ -309,6 +309,7 @@ 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; > @@ -348,6 +349,8 @@ 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, out_driver_error_code), > 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..7f92cecc87d7 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 +614,38 @@ struct iommu_hwpt_get_dirty_bitmap { > #define IOMMU_HWPT_GET_DIRTY_BITMAP _IO(IOMMUFD_TYPE, \ > IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP) > > +/** > + * 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_data_type, defining the data type of all > + * the entries in the invalidation request array. It should suit > + * with the data_type passed per the allocation of the hwpt pointed > + * by @hwpt_id.
@Jason and Kevin,
Here a check with you two. I had a conversation with Nic on the definition of req_type here. It was added to support potential multiple kinds of cache invalidation data types for a invalidating cache for a single hwpt type[1]. But we defined it as reusing the hwpt_data_type. In this way, it is not able to support the potential case in[1]. is it? Shall we define a separate enum for invalidation data types? And how can we let user know the available invalidation data types for a hwpt type? Any idea?
[1] https://lore.kernel.org/linux-iommu/20231018163720.GA3952@nvidia.com/
> + * @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. > + * @out_driver_error_code: Report a driver speicifc error code upon failure. > + * It's optional, driver has a choice to fill it or > + * not. > + * > + * 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. > + */ > +struct iommu_hwpt_invalidate { > + __u32 size; > + __u32 hwpt_id; > + __aligned_u64 reqs_uptr; > + __u32 req_type; > + __u32 req_len; > + __u32 req_num; > + __u32 out_driver_error_code; > +}; > +#define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE) > #endif
-- Regards, Yi Liu
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