On Fri, Mar 21, 2025 at 07:00:57PM -0400, M Henning wrote:
> This is a pointer in the gpu's virtual address space. It must be
> aligned according to ctxsw_align and be at least ctxsw_size bytes
> (where those values come from the nouveau_abi16_ioctl_get_zcull_info
> structure). I'll change the description to say that much.
>
> Yes, this is GEM-backed. I'm actually not entirely sure what the
> requirements are here, since this part is reverse-engineered. I think
> NOUVEAU_GEM_DOMAIN_VRAM and NOUVEAU_GEM_DOMAIN_GART are both okay. The
> proprietary driver allocates this buffer using
> NV_ESC_RM_VID_HEAP_CONTROL and sets attr = NVOS32_ATTR_LOCATION_ANY |
> NVOS32_ATTR_PAGE_SIZE_BIG | NVOS32_ATTR_PHYSICALITY_CONTIGUOUS, attr2
> = NVOS32_ATTR2_GPU_CACHEABLE_YES | NVOS32_ATTR2_ZBC_PREFER_NO_ZBC.
(Please do not top post.)
What I mean is how do you map the backing GEM into the GPU's virtual address
space? Since it's bound to a channel, I assume that it must be ensured it's
properly mapped when work is pushed to the channel. Is it mapped through
VM_BIND?
>
> On Thu, Mar 20, 2025 at 2:34 PM Danilo Krummrich <d...@kernel.org> wrote:
> >
> > On Wed, Mar 12, 2025 at 05:36:15PM -0400, Mel Henning wrote:
> > > diff --git a/include/uapi/drm/nouveau_drm.h
> > > b/include/uapi/drm/nouveau_drm.h
> >
> > Same here, please split the uAPI change in a separate commit.
> >
> > > index 33361784eb4e..e9638f4dd7e6 100644
> > > --- a/include/uapi/drm/nouveau_drm.h
> > > +++ b/include/uapi/drm/nouveau_drm.h
> > > @@ -448,6 +448,20 @@ struct drm_nouveau_get_zcull_info {
> > > __u32 ctxsw_align;
> > > };
> > >
> > > +struct drm_nouveau_set_zcull_ctxsw_buffer {
> > > + /**
> > > + * @ptr: The virtual address for the buffer, or null to bind nothing
> > > + */
> > > + __u64 addr;
> >
> > What is this buffer? Is this a GEM object backed buffer? How is it mapped?
> >
> > > +
> > > + /**
> > > + * @channel: the channel to set the buffer on
> > > + */
> > > + __u32 channel;
> > > +
> > > + __u32 pad;
> > > +};
> > > +
> > > #define DRM_NOUVEAU_GETPARAM 0x00
> > > #define DRM_NOUVEAU_SETPARAM 0x01 /* deprecated */
> > > #define DRM_NOUVEAU_CHANNEL_ALLOC 0x02
> > > @@ -462,6 +476,7 @@ struct drm_nouveau_get_zcull_info {
> > > #define DRM_NOUVEAU_VM_BIND 0x11
> > > #define DRM_NOUVEAU_EXEC 0x12
> > > #define DRM_NOUVEAU_GET_ZCULL_INFO 0x13
> > > +#define DRM_NOUVEAU_SET_ZCULL_CTXSW_BUFFER 0x14
> > > #define DRM_NOUVEAU_GEM_NEW 0x40
> > > #define DRM_NOUVEAU_GEM_PUSHBUF 0x41
> > > #define DRM_NOUVEAU_GEM_CPU_PREP 0x42
> > > @@ -532,6 +547,7 @@ struct drm_nouveau_svm_bind {
> > > #define DRM_IOCTL_NOUVEAU_EXEC DRM_IOWR(DRM_COMMAND_BASE +
> > > DRM_NOUVEAU_EXEC, struct drm_nouveau_exec)
> > >
> > > #define DRM_IOCTL_NOUVEAU_GET_ZCULL_INFO DRM_IOR (DRM_COMMAND_BASE +
> > > DRM_NOUVEAU_GET_ZCULL_INFO, struct drm_nouveau_get_zcull_info)
> > > +#define DRM_IOCTL_NOUVEAU_SET_ZCULL_CTXSW_BUFFER DRM_IOW
> > > (DRM_COMMAND_BASE + DRM_NOUVEAU_SET_ZCULL_CTXSW_BUFFER, struct
> > > drm_nouveau_set_zcull_ctxsw_buffer)
> > > #if defined(__cplusplus)
> > > }
> > > #endif
> > > --
> > > 2.48.1
> > >
