cxl/hdm: dev_warn() on unsupported mixed mode decoder

[PATCH] cxl/hdm: dev_warn() on unsupported mixed mode decoder

Posted by alison.schofield@intel.com 2 years, 6 months ago

From: Alison Schofield <alison.schofield@intel.com>

A mixed mode decoder is programmed with device physical addresses
that span both ram and pmem partitions of a memdev.

Linux does not support mixed mode decoders. The driver rejects
sysfs writes that try to set decoder mode to mixed, and if a
resource bieng allocated is not wholly contained in either the
pmem or ram partition of a memdev, it is also rejected. Basically,
the CXL region driver is not going to create regions with mixed
mode decoders, but the BIOS could.

If the kernel driver sees the mixed mode decoder, it will fail to
enable the region, and emit a dev_dbg() message.

A dev_dbg() is not noisy enough in this case. Change the message
to be a dev_warn() that explicitly says mixed mode is not supported.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 drivers/cxl/core/hdm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 45deda18ed32..9eaf93c8ebb0 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -294,8 +294,8 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
 	else if (resource_contains(&cxlds->ram_res, res))
 		cxled->mode = CXL_DECODER_RAM;
 	else {
-		dev_dbg(dev, "decoder%d.%d: %pr mixed\n", port->id,
-			cxled->cxld.id, cxled->dpa_res);
+		dev_warn(dev, "decoder%d.%d: %pr mixed mode not supported\n",
+			 port->id, cxled->cxld.id, cxled->dpa_res);
 		cxled->mode = CXL_DECODER_MIXED;
 	}
 

base-commit: a5fcd228ca1db9810ba1ed461c90b6ee933b9daf
-- 
2.37.3

Re: [PATCH] cxl/hdm: dev_warn() on unsupported mixed mode decoder

Posted by Dave Jiang 2 years, 6 months ago


On 2/17/23 6:38 PM, alison.schofield@intel.com wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> A mixed mode decoder is programmed with device physical addresses
> that span both ram and pmem partitions of a memdev.
> 
> Linux does not support mixed mode decoders. The driver rejects
> sysfs writes that try to set decoder mode to mixed, and if a
> resource bieng allocated is not wholly contained in either the
> pmem or ram partition of a memdev, it is also rejected. Basically,
> the CXL region driver is not going to create regions with mixed
> mode decoders, but the BIOS could.
> 
> If the kernel driver sees the mixed mode decoder, it will fail to
> enable the region, and emit a dev_dbg() message.
> 
> A dev_dbg() is not noisy enough in this case. Change the message
> to be a dev_warn() that explicitly says mixed mode is not supported.
> 
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>   drivers/cxl/core/hdm.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 45deda18ed32..9eaf93c8ebb0 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -294,8 +294,8 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
>   	else if (resource_contains(&cxlds->ram_res, res))
>   		cxled->mode = CXL_DECODER_RAM;
>   	else {
> -		dev_dbg(dev, "decoder%d.%d: %pr mixed\n", port->id,
> -			cxled->cxld.id, cxled->dpa_res);
> +		dev_warn(dev, "decoder%d.%d: %pr mixed mode not supported\n",
> +			 port->id, cxled->cxld.id, cxled->dpa_res);
>   		cxled->mode = CXL_DECODER_MIXED;
>   	}
>   
> 
> base-commit: a5fcd228ca1db9810ba1ed461c90b6ee933b9daf

Re: [PATCH] cxl/hdm: dev_warn() on unsupported mixed mode decoder

Posted by Jonathan Cameron 2 years, 6 months ago

On Fri, 17 Feb 2023 17:38:34 -0800
alison.schofield@intel.com wrote:

> From: Alison Schofield <alison.schofield@intel.com>
> 
> A mixed mode decoder is programmed with device physical addresses
> that span both ram and pmem partitions of a memdev.
> 
> Linux does not support mixed mode decoders. The driver rejects
> sysfs writes that try to set decoder mode to mixed, and if a
> resource bieng allocated is not wholly contained in either the
> pmem or ram partition of a memdev, it is also rejected. Basically,
> the CXL region driver is not going to create regions with mixed
> mode decoders, but the BIOS could.
> 
> If the kernel driver sees the mixed mode decoder, it will fail to
> enable the region, and emit a dev_dbg() message.
> 
> A dev_dbg() is not noisy enough in this case. Change the message
> to be a dev_warn() that explicitly says mixed mode is not supported.
> 
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Makes sense.
FWIW
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/cxl/core/hdm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 45deda18ed32..9eaf93c8ebb0 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -294,8 +294,8 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
>  	else if (resource_contains(&cxlds->ram_res, res))
>  		cxled->mode = CXL_DECODER_RAM;
>  	else {
> -		dev_dbg(dev, "decoder%d.%d: %pr mixed\n", port->id,
> -			cxled->cxld.id, cxled->dpa_res);
> +		dev_warn(dev, "decoder%d.%d: %pr mixed mode not supported\n",
> +			 port->id, cxled->cxld.id, cxled->dpa_res);
>  		cxled->mode = CXL_DECODER_MIXED;
>  	}
>  
> 
> base-commit: a5fcd228ca1db9810ba1ed461c90b6ee933b9daf

Re: [PATCH] cxl/hdm: dev_warn() on unsupported mixed mode decoder

Posted by Verma, Vishal L 2 years, 6 months ago

On Fri, 2023-02-17 at 17:38 -0800, alison.schofield@intel.com wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> A mixed mode decoder is programmed with device physical addresses
> that span both ram and pmem partitions of a memdev.
> 
> Linux does not support mixed mode decoders. The driver rejects
> sysfs writes that try to set decoder mode to mixed, and if a
> resource bieng allocated is not wholly contained in either the
> pmem or ram partition of a memdev, it is also rejected. Basically,
> the CXL region driver is not going to create regions with mixed
> mode decoders, but the BIOS could.
> 
> If the kernel driver sees the mixed mode decoder, it will fail to
> enable the region, and emit a dev_dbg() message.
> 
> A dev_dbg() is not noisy enough in this case. Change the message
> to be a dev_warn() that explicitly says mixed mode is not supported.
> 
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  drivers/cxl/core/hdm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Looks good,
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>

> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 45deda18ed32..9eaf93c8ebb0 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -294,8 +294,8 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
>         else if (resource_contains(&cxlds->ram_res, res))
>                 cxled->mode = CXL_DECODER_RAM;
>         else {
> -               dev_dbg(dev, "decoder%d.%d: %pr mixed\n", port->id,
> -                       cxled->cxld.id, cxled->dpa_res);
> +               dev_warn(dev, "decoder%d.%d: %pr mixed mode not supported\n",
> +                        port->id, cxled->cxld.id, cxled->dpa_res);
>                 cxled->mode = CXL_DECODER_MIXED;
>         }
>  
> 
> base-commit: a5fcd228ca1db9810ba1ed461c90b6ee933b9daf