Re: [RFC PATCH 2/6] acpi: numa: Add support to enumerate and store extended linear address mode

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Fri, 27 Sep 2024 07:16:54 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> Store the address mode as part of the cache attriutes. Export the mode
> attribute to sysfs as all other cache attributes.
> 
> Link: https://lore.kernel.org/linux-cxl/668333b17e4b2_5639294fd@dwillia2-xfh.jf.intel.com.notmuch/
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Minor things inline. Basically looks fine.

Jonathan

> ---
>  Documentation/ABI/stable/sysfs-devices-node | 7 +++++++
>  drivers/acpi/numa/hmat.c                    | 3 +++
>  drivers/base/node.c                         | 2 ++
>  include/linux/node.h                        | 7 +++++++
>  4 files changed, 19 insertions(+)
> 
> diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node
> index 402af4b2b905..9016cc4f027c 100644
> --- a/Documentation/ABI/stable/sysfs-devices-node
> +++ b/Documentation/ABI/stable/sysfs-devices-node
> @@ -177,6 +177,13 @@ Description:
>  		The cache write policy: 0 for write-back, 1 for write-through,
>  		other or unknown.
>  
> +What:		/sys/devices/system/node/nodeX/memory_side_cache/indexY/mode
> +Date:		September 2024
> +Contact:	Dave Jiang <dave.jiang@intel.com>
> +Description:
> +		The address mode: 0 for reserved, 1 for extended-lniear,

linear

also, is 0 reserved or unknown? I'm confused.


> +		other unknown.
> +
>  What:		/sys/devices/system/node/nodeX/x86/sgx_total_bytes
>  Date:		November 2021
>  Contact:	Jarkko Sakkinen <jarkko@kernel.org>
> diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c
> index 1a902a02390f..39524f36be5b 100644
> --- a/drivers/acpi/numa/hmat.c
> +++ b/drivers/acpi/numa/hmat.c
> @@ -506,6 +506,9 @@ static __init int hmat_parse_cache(union acpi_subtable_headers *header,
>  	switch ((attrs & ACPI_HMAT_CACHE_ASSOCIATIVITY) >> 8) {
>  	case ACPI_HMAT_CA_DIRECT_MAPPED:
>  		tcache->cache_attrs.indexing = NODE_CACHE_DIRECT_MAP;
> +		/* Extended Linear mode is only valid if cache is direct mapped */
> +		if (cache->address_mode == ACPI_HMAT_CACHE_MODE_EXTENDED_LINEAR)
> +			tcache->cache_attrs.mode = NODE_CACHE_MODE_EXTENDED_LINEAR;
>  		break;
>  	case ACPI_HMAT_CA_COMPLEX_CACHE_INDEXING:
>  		tcache->cache_attrs.indexing = NODE_CACHE_INDEXED;
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index eb72580288e6..744be5470728 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -244,12 +244,14 @@ CACHE_ATTR(size, "%llu")
>  CACHE_ATTR(line_size, "%u")
>  CACHE_ATTR(indexing, "%u")
>  CACHE_ATTR(write_policy, "%u")
> +CACHE_ATTR(mode, "%u")
>  
>  static struct attribute *cache_attrs[] = {
>  	&dev_attr_indexing.attr,
>  	&dev_attr_size.attr,
>  	&dev_attr_line_size.attr,
>  	&dev_attr_write_policy.attr,
> +	&dev_attr_mode.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(cache);
> diff --git a/include/linux/node.h b/include/linux/node.h
> index 9a881c2208b3..589951c5e36f 100644
> --- a/include/linux/node.h
> +++ b/include/linux/node.h
> @@ -57,6 +57,11 @@ enum cache_write_policy {
>  	NODE_CACHE_WRITE_OTHER,
>  };
>  
> +enum cache_mode {
> +	NODE_CACHE_MODE_UNKOWN,
UNKNOWN

> +	NODE_CACHE_MODE_EXTENDED_LINEAR,
> +};
> +
>  /**
>   * struct node_cache_attrs - system memory caching attributes
>   *
> @@ -65,6 +70,7 @@ enum cache_write_policy {
>   * @size:		Total size of cache in bytes
>   * @line_size:		Number of bytes fetched on a cache miss
>   * @level:		The cache hierarchy level
> + * @mode:		The address mode
>   */
>  struct node_cache_attrs {
>  	enum cache_indexing indexing;
> @@ -72,6 +78,7 @@ struct node_cache_attrs {
>  	u64 size;
>  	u16 line_size;
>  	u8 level;
> +	u16 mode;
>  };
>  
>  #ifdef CONFIG_HMEM_REPORTING