Nouveau - Nov 2021 - [PATCH] ce/gf100: fix incorrect CE0 address calculation on some GPUs

From: Ben Skeggs <bskeggs at redhat.com>

The code which constructs the modules for each engine present on the GPU
passes -1 for 'instance' on non-instanced engines, which affects how the
name for a sub-device is generated.  This is then stored as 'instance 0'
in nvkm_subdev.inst, so code can potentially be shared with earlier GPUs
that only had a single instance of an engine.

However, GF100's CE constructor uses this value to calculate the address
of its falcon before it's translated, resulting in CE0 getting the wrong
address.

This slightly modifies the approach, always passing a valid instance for
engines that *can* have multiple copies, and having the code for earlier
GPUs explicitly ask for non-instanced name generation.

Bug: https://gitlab.freedesktop.org/drm/nouveau/-/issues/91

Fixes: 50551b15c760 ("drm/nouveau/ce: switch to instanced
constructor")
Cc: <stable at vger.kernel.org> # v5.12+
Signed-off-by: Ben Skeggs <bskeggs at redhat.com>
---
 drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c    | 2 +-
 drivers/gpu/drm/nouveau/nvkm/engine/device/base.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
b/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
index 704df0f2d1f1..09a112af2f89 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
@@ -78,6 +78,6 @@ int
 gt215_ce_new(struct nvkm_device *device, enum nvkm_subdev_type type, int inst,
 	     struct nvkm_engine **pengine)
 {
-	return nvkm_falcon_new_(&gt215_ce, device, type, inst,
+	return nvkm_falcon_new_(&gt215_ce, device, type, -1,
 				(device->chipset != 0xaf), 0x104000, pengine);
 }
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
index ca75c5f6ecaf..b51d690f375f 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
@@ -3147,8 +3147,7 @@ nvkm_device_ctor(const struct nvkm_device_func *func,
 	WARN_ON(device->chip->ptr.inst & ~((1 <<
ARRAY_SIZE(device->ptr)) - 1));             \
 	for (j = 0; device->chip->ptr.inst && j <
ARRAY_SIZE(device->ptr); j++) {            \
 		if ((device->chip->ptr.inst & BIT(j)) && (subdev_mask &
BIT_ULL(type))) {    \
-			int inst = (device->chip->ptr.inst == 1) ? -1 : (j);                 \
-			ret = device->chip->ptr.ctor(device, (type), inst,
&device->ptr[j]); \
+			ret = device->chip->ptr.ctor(device, (type), (j),
&device->ptr[j]);  \
 			subdev = nvkm_device_subdev(device, (type), (j));                    \
 			if (ret) {                                                           \
 				nvkm_subdev_del(&subdev);                                    \
-- 
2.31.1

On Wed, Nov 3, 2021 at 2:11 AM Ben Skeggs <skeggsb at gmail.com>
wrote:
>
> From: Ben Skeggs <bskeggs at redhat.com>
>
> The code which constructs the modules for each engine present on the GPU
> passes -1 for 'instance' on non-instanced engines, which affects
how the
> name for a sub-device is generated.  This is then stored as 'instance
0'
> in nvkm_subdev.inst, so code can potentially be shared with earlier GPUs
> that only had a single instance of an engine.
>
> However, GF100's CE constructor uses this value to calculate the
address
> of its falcon before it's translated, resulting in CE0 getting the
wrong
> address.
>
> This slightly modifies the approach, always passing a valid instance for
> engines that *can* have multiple copies, and having the code for earlier
> GPUs explicitly ask for non-instanced name generation.
>
> Bug: https://gitlab.freedesktop.org/drm/nouveau/-/issues/91
>
> Fixes: 50551b15c760 ("drm/nouveau/ce: switch to instanced
constructor")
> Cc: <stable at vger.kernel.org> # v5.12+
> Signed-off-by: Ben Skeggs <bskeggs at redhat.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c    | 2 +-
>  drivers/gpu/drm/nouveau/nvkm/engine/device/base.c | 3 +--
>  2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
b/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
> index 704df0f2d1f1..09a112af2f89 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/engine/ce/gt215.c
> @@ -78,6 +78,6 @@ int
>  gt215_ce_new(struct nvkm_device *device, enum nvkm_subdev_type type, int
inst,
>              struct nvkm_engine **pengine)
>  {
> -       return nvkm_falcon_new_(&gt215_ce, device, type, inst,
> +       return nvkm_falcon_new_(&gt215_ce, device, type, -1,
>                                 (device->chipset != 0xaf), 0x104000,
pengine);
>  }
> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
> index ca75c5f6ecaf..b51d690f375f 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
> @@ -3147,8 +3147,7 @@ nvkm_device_ctor(const struct nvkm_device_func *func,
>         WARN_ON(device->chip->ptr.inst & ~((1 <<
ARRAY_SIZE(device->ptr)) - 1));             \
>         for (j = 0; device->chip->ptr.inst && j <
ARRAY_SIZE(device->ptr); j++) {            \
>                 if ((device->chip->ptr.inst & BIT(j)) &&
(subdev_mask & BIT_ULL(type))) {    \
> -                       int inst = (device->chip->ptr.inst == 1) ? -1
: (j);                 \
> -                       ret = device->chip->ptr.ctor(device, (type),
inst, &device->ptr[j]); \
> +                       ret = device->chip->ptr.ctor(device, (type),
(j), &device->ptr[j]);  \
>                         subdev = nvkm_device_subdev(device, (type), (j));  
\
>                         if (ret) {                                         
\
>                                 nvkm_subdev_del(&subdev);              
\
> --
> 2.31.1
>
Reviewed-by: Karol Herbst <kherbst at redhat.com>