[PATCH v7 4/6] drm/xe/uapi: Define drm_xe_vm_get_faults

[Zhang, Jianxun]

Sorry if my reply is still in a wrong format. I have set plain text in the web-based outlook this time but don't know if it really works.

Refer to my inline comment, thanks.
________________________________________
From: Cavitt, Jonathan <jonathan.cavitt at intel.com>
Sent: Tuesday, March 11, 2025 7:11 AM
To: Brost, Matthew; Zhang, Jianxun
Cc: intel-xe at lists.freedesktop.org; Gupta, saurabhg; Zuo, Alex; joonas.lahtinen at linux.intel.com; Lin, Shuicheng; dri-devel at lists.freedesktop.org; Cavitt, Jonathan
Subject: RE: [PATCH v7 4/6] drm/xe/uapi: Define drm_xe_vm_get_faults

-----Original Message-----
From: Brost, Matthew <matthew.brost at intel.com>
Sent: Monday, March 10, 2025 9:51 PM
To: Cavitt, Jonathan <jonathan.cavitt at intel.com>
Cc: intel-xe at lists.freedesktop.org; Gupta, saurabhg <saurabhg.gupta at intel.com>; Zuo, Alex <alex.zuo at intel.com>; joonas.lahtinen at linux.intel.com; Zhang, Jianxun <jianxun.zhang at intel.com>; Lin, Shuicheng <shuicheng.lin at intel.com>; dri-devel at lists.freedesktop.org
Subject: Re: [PATCH v7 4/6] drm/xe/uapi: Define drm_xe_vm_get_faults
>
> On Mon, Mar 10, 2025 at 05:18:32PM +0000, Jonathan Cavitt wrote:
> > Add initial declarations for the drm_xe_vm_get_faults ioctl.
> >
> > Signed-off-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
> > ---
> >  include/uapi/drm/xe_drm.h | 49 +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 49 insertions(+)
> >
> > diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> > index 616916985e3f..90c2fcdbd5c1 100644
> > --- a/include/uapi/drm/xe_drm.h
> > +++ b/include/uapi/drm/xe_drm.h
> > @@ -81,6 +81,7 @@ extern "C" {
> >   *  - &DRM_IOCTL_XE_EXEC
> >   *  - &DRM_IOCTL_XE_WAIT_USER_FENCE
> >   *  - &DRM_IOCTL_XE_OBSERVATION
> > + *  - %DRM_IOCTL_XE_VM_GET_FAULTS
>
> This should be a generic "get VM property" IOCTL, not a specific IOCTL
> that only retrieves faults. This allows for future expansion of the
> uAPI.

Question from @Zhang, Jianxun :
"""
But first of all, should we regard faults as a property?
"""
-Jonathan Cavitt

Thanks for Jonathan relaying my question here. I just feel it is a little strange to treat "faults" as "property". Perhaps it is just a naming thing. But I get KMD wants to take an extensible and consolidated approach. Either/any way works for me in UMD.

Thanks!

>
> >   */
> >
> >  /*
> > @@ -102,6 +103,7 @@ extern "C" {
> >  #define DRM_XE_EXEC                        0x09
> >  #define DRM_XE_WAIT_USER_FENCE             0x0a
> >  #define DRM_XE_OBSERVATION         0x0b
> > +#define DRM_XE_VM_GET_FAULTS               0x0c
> >
> >  /* Must be kept compact -- no holes */
> >
> > @@ -117,6 +119,7 @@ extern "C" {
> >  #define DRM_IOCTL_XE_EXEC                  DRM_IOW(DRM_COMMAND_BASE + DRM_XE_EXEC, struct drm_xe_exec)
> >  #define DRM_IOCTL_XE_WAIT_USER_FENCE               DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_WAIT_USER_FENCE, struct drm_xe_wait_user_fence)
> >  #define DRM_IOCTL_XE_OBSERVATION           DRM_IOW(DRM_COMMAND_BASE + DRM_XE_OBSERVATION, struct drm_xe_observation_param)
> > +#define DRM_IOCTL_XE_VM_GET_FAULTS         DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_VM_GET_FAULTS, struct drm_xe_vm_get_faults)
> >
> >  /**
> >   * DOC: Xe IOCTL Extensions
> > @@ -1189,6 +1192,52 @@ struct drm_xe_vm_bind {
> >     __u64 reserved[2];
> >  };
> >
> > +struct xe_vm_fault {
> > +   /** @address: Address of the fault, if relevant */
> > +   __u64 address;
> > +#define DRM_XE_FAULT_ADDRESS_TYPE_NONE_EXT         0
> > +#define DRM_XE_FAULT_ADDRESS_TYPE_READ_INVALID_EXT 1
> > +#define DRM_XE_FAULT_ADDRESS_TYPE_WRITE_INVALID_EXT        2
> > +   /** @address_type: , if relevant */
> > +   __u32 address_type;
> > +   /**
> > +    * @address_precision: Precision of faulted address, if relevant.
> > +    * Currently only SZ_4K.
> > +    */
> > +   __u32 address_precision;
> > +   /** @reserved: MBZ */
> > +   __u64 reserved[3];
> > +};
> > +
> > +/**
> > + * struct drm_xe_vm_get_faults - Input of &DRM_IOCTL_XE_VM_GET_FAULTS
> > + *
> > + * The user provides a VM ID, and the ioctl will
> > + *
> > + */
> > +struct drm_xe_vm_get_faults {
> > +   /** @extensions: Pointer to the first extension struct, if any */
> > +   __u64 extensions;
> > +
> > +   /** @vm_id: The ID of the VM to query the properties of */
> > +   __u32 vm_id;
> > +
> > +   /** @size: Size to allocate for @ptr */
> > +   __u32 size;
> > +
> > +   /** @fault_count: Number of faults to be returned */
> > +   __u32 fault_count;
> > +
>
> fault_count is implied by size.
>
> Matt
>
> > +   /** @pad: MBZ */
> > +   __u32 pad;
> > +
> > +   /** @reserved: MBZ */
> > +   __u64 reserved[2];
> > +
> > +   /** @faults: Pointer to user-defined array of xe_vm_fault of flexible size */
> > +   __u64 faults;
> > +};
> > +
> >  /**
> >   * struct drm_xe_exec_queue_create - Input of &DRM_IOCTL_XE_EXEC_QUEUE_CREATE
> >   *
> > --
> > 2.43.0
> >
>