On Mon, 06 Feb 2023 13:50:15 -0700
Dave Jiang <dave.jiang@xxxxxxxxx> wrote:
> Provide a callback function to the CDAT parser in order to parse the Device
> Scoped Memory Affinity Structure (DSMAS). Each DSMAS structure contains the
> DPA range and its associated attributes in each entry. See the CDAT
> specification for details.
>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Hi Dave,
A few minor questions / comments inline,
Jonathan
> ---
> drivers/cxl/core/cdat.c | 25 +++++++++++++++++++++++++
> drivers/cxl/core/port.c | 2 ++
> drivers/cxl/cxl.h | 11 +++++++++++
> drivers/cxl/port.c | 8 ++++++++
> 4 files changed, 46 insertions(+)
>
> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
> index be09c8a690f5..f9a64a0f1ee4 100644
> --- a/drivers/cxl/core/cdat.c
> +++ b/drivers/cxl/core/cdat.c
> @@ -96,3 +96,28 @@ int cdat_table_parse_dslbis(void *table, cdat_tbl_entry_handler handler, void *a
> return cdat_table_parse_entries(ACPI_CDAT_TYPE_DSLBIS, header, &proc, 0);
> }
> EXPORT_SYMBOL_NS_GPL(cdat_table_parse_dslbis, CXL);
> +
> +int cxl_dsmas_parse_entry(struct acpi_cdat_header *header, void *arg)
> +{
> + struct cxl_port *port = (struct cxl_port *)arg;
> + struct dsmas_entry *dent;
> + struct acpi_cdat_dsmas *dsmas;
> +
> + if (header->type != ACPI_CDAT_TYPE_DSMAS)
> + return -EINVAL;
> +
> + dent = devm_kzalloc(&port->dev, sizeof(*dent), GFP_KERNEL);
> + if (!dent)
> + return -ENOMEM;
> +
> + dsmas = (struct acpi_cdat_dsmas *)((unsigned long)header + sizeof(*header));
I'd prefer header + 1
> + dent->handle = dsmas->dsmad_handle;
> + dent->dpa_range.start = dsmas->dpa_base_address;
> + dent->dpa_range.end = dsmas->dpa_base_address + dsmas->dpa_length - 1;
> +
> + mutex_lock(&port->cdat.dsmas_lock);
> + list_add_tail(&dent->list, &port->cdat.dsmas_list);
> + mutex_unlock(&port->cdat.dsmas_lock);
> + return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_dsmas_parse_entry, CXL);
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index fe78daf7e7c8..2b27319cfd42 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -660,6 +660,8 @@ static struct cxl_port *cxl_port_alloc(struct device *uport,
> device_set_pm_not_required(dev);
> dev->bus = &cxl_bus_type;
> dev->type = &cxl_port_type;
> + INIT_LIST_HEAD(&port->cdat.dsmas_list);
> + mutex_init(&port->cdat.dsmas_lock);
>
> return port;
>
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 839a121c1997..1e5e69f08480 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -8,6 +8,7 @@
> #include <linux/bitfield.h>
> #include <linux/bitops.h>
> #include <linux/log2.h>
> +#include <linux/list.h>
> #include <linux/io.h>
> #include <linux/acpi.h>
>
> @@ -520,6 +521,8 @@ struct cxl_port {
> struct cxl_cdat {
> void *table;
> size_t length;
> + struct list_head dsmas_list;
> + struct mutex dsmas_lock; /* lock for dsmas_list */
I'm curious, what might race with the dsmas_list changing and hence what is lock for?
> } cdat;
> bool cdat_available;
> };
> @@ -698,6 +701,12 @@ static inline struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
> }
> #endif
>
> +struct dsmas_entry {
> + struct list_head list;
> + struct range dpa_range;
> + u16 handle;
handle is 1 byte in the spec. Why larger here?
> +};
> +
> typedef int (*cdat_tbl_entry_handler)(struct acpi_cdat_header *header, void *arg);
>
> u8 cdat_table_checksum(u8 *buffer, u32 length);
> @@ -706,6 +715,8 @@ int cdat_table_parse_dsmas(void *table, cdat_tbl_entry_handler handler,
> int cdat_table_parse_dslbis(void *table, cdat_tbl_entry_handler handler,
> void *arg);
>
> +int cxl_dsmas_parse_entry(struct acpi_cdat_header *header, void *arg);
> +
> /*
> * Unit test builds overrides this to __weak, find the 'strong' version
> * of these symbols in tools/testing/cxl/.
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 5453771bf330..b1da73e99bab 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -61,6 +61,14 @@ static int cxl_port_probe(struct device *dev)
> if (rc)
> return rc;
>
> + if (port->cdat.table) {
> + rc = cdat_table_parse_dsmas(port->cdat.table,
> + cxl_dsmas_parse_entry,
> + (void *)port);
> + if (rc < 0)
> + dev_dbg(dev, "Failed to parse DSMAS: %d\n", rc);
> + }
> +
> rc = cxl_hdm_decode_init(cxlds, cxlhdm);
> if (rc)
> return rc;
>
>
