Vishal Verma wrote:
> Add libcxl APIs to create a region under a given root decoder, and to
> set different attributes for the new region. These allow setting the
> size, interleave_ways, interleave_granularity, uuid, and the target
> devices for the newly minted cxl_region object.
>
> Cc: Dan Williams <[email protected]>
> Signed-off-by: Vishal Verma <[email protected]>
> ---
> Documentation/cxl/lib/libcxl.txt | 69 ++++++
> cxl/lib/private.h | 2 +
> cxl/lib/libcxl.c | 377 ++++++++++++++++++++++++++++++-
> cxl/libcxl.h | 23 +-
> cxl/lib/libcxl.sym | 16 ++
> 5 files changed, 484 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/cxl/lib/libcxl.txt
> b/Documentation/cxl/lib/libcxl.txt
> index 7a38ce4..c3a8f36 100644
> --- a/Documentation/cxl/lib/libcxl.txt
> +++ b/Documentation/cxl/lib/libcxl.txt
> @@ -508,6 +508,75 @@ device to represent the root of a PCI device hierarchy.
> The
> cxl_target_get_physical_node() helper returns the device name of that
> companion object in the PCI hierarchy.
>
> +==== REGIONS
> +A CXL region is composed of one or more slices of CXL memdevs, with
> configurable
> +interleave settings - both the number of interleave ways, and the interleave
> +granularity. In terms of hierarchy, it is the child of a CXL root decoder. A
> root
> +decoder (recall that this corresponds to an ACPI CEDT.CFMWS 'window'), may
> have
> +multiple chile regions, but a region is strictly tied to one root decoder.
Mmm, that's a spicy region.
s/chile/child/
> +
> +A region also defines a set of mappings which are slices of capacity on a
> memdev,
Since the above already defined that a region is composed of one or more
slices of CXL memdevs, how about:
"The slices that compose a region are called mappings. A mapping is a
tuple of 'memdev', 'endpoint decoder', and the 'position'.
> +each represented by an endpoint decoder.
> +
> +===== REGION: Enumeration
> +----
> +struct cxl_region *cxl_region_get_first(struct cxl_decoder *decoder);
> +struct cxl_region *cxl_region_get_next(struct cxl_region *region);
> +
> +#define cxl_region_foreach(decoder, region)
> \
> + for (region = cxl_region_get_first(decoder); region != NULL; \
> + region = cxl_region_get_next(region))
> +
> +#define cxl_region_foreach_safe(decoder, region, _region)
> \
> + for (region = cxl_region_get_first(decoder), \
> + _region = region ? cxl_region_get_next(region) : NULL; \
> + region != NULL; \
> + region = _region, \
> + _region = _region ? cxl_region_get_next(_region) : NULL)
> +----
> +
> +===== REGION: Attributes
> +----
> +int cxl_region_get_id(struct cxl_region *region);
> +const char *cxl_region_get_devname(struct cxl_region *region);
> +void cxl_region_get_uuid(struct cxl_region *region, uuid_t uu);
> +unsigned long long cxl_region_get_size(struct cxl_region *region);
> +unsigned long long cxl_region_get_resource(struct cxl_region *region);
> +unsigned int cxl_region_get_interleave_ways(struct cxl_region *region);
> +unsigned int cxl_region_get_interleave_granularity(struct cxl_region
> *region);
> +struct cxl_decoder *cxl_region_get_target_decoder(struct cxl_region *region,
> + int position);
> +int cxl_region_set_size(struct cxl_region *region, unsigned long long size);
> +int cxl_region_set_uuid(struct cxl_region *region, uuid_t uu);
> +int cxl_region_set_interleave_ways(struct cxl_region *region,
> + unsigned int ways);
> +int cxl_region_set_interleave_granularity(struct cxl_region *region,
> + unsigned int granularity);
> +int cxl_region_set_target(struct cxl_region *region, int position,
> + struct cxl_decoder *decoder);
> +int cxl_region_clear_target(struct cxl_region *region, int position);
> +int cxl_region_clear_all_targets(struct cxl_region *region);
> +int cxl_region_decode_commit(struct cxl_region *region);
> +int cxl_region_decode_reset(struct cxl_region *region);
> +----
> +
> +A region's resource attribute is the Host Physical Address at which the
> region's
> +address space starts. The region's address space is a subset of the parent
> root
> +decoder's address space.
> +
> +The interleave ways is the number of component memdevs participating in the
> +region.
> +
> +The interleave granularity depends on the root decoder's granularity, and
> must
> +follow the interleave math rules defined in the CXL spec.
> +
> +Regions have a list of targets 0..N, which are programmed with the name of an
> +endpoint decoder under each participating memdev.
> +
> +The 'decode_commit' and 'decode_reset' attributes reserve and free DPA space
> +on a given memdev by allocating an endpoint decoder, and programming it based
> +on the region's interleave geometry.
> +
> include::../../copyright.txt[]
>
> SEE ALSO
> diff --git a/cxl/lib/private.h b/cxl/lib/private.h
> index da49a6c..8619bb1 100644
> --- a/cxl/lib/private.h
> +++ b/cxl/lib/private.h
> @@ -110,6 +110,8 @@ struct cxl_decoder {
> int nr_targets;
> int id;
> enum cxl_decoder_mode mode;
> + unsigned int interleave_ways;
> + unsigned int interleave_granularity;
> bool pmem_capable;
> bool volatile_capable;
> bool mem_capable;
> diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
> index 8dd804c..b4d7890 100644
> --- a/cxl/lib/libcxl.c
> +++ b/cxl/lib/libcxl.c
> @@ -17,6 +17,7 @@
> #include <ccan/minmax/minmax.h>
> #include <ccan/array_size/array_size.h>
> #include <ccan/short_types/short_types.h>
> +#include <ccan/container_of/container_of.h>
>
> #include <util/log.h>
> #include <util/list.h>
> @@ -412,6 +413,39 @@ CXL_EXPORT int cxl_region_enable(struct cxl_region
> *region)
> return 0;
> }
>
> +static int cxl_region_delete_name(struct cxl_decoder *decoder,
> + const char *devname)
> +{
> + struct cxl_ctx *ctx = cxl_decoder_get_ctx(decoder);
> + char *path = decoder->dev_buf;
> + int rc;
> +
> + sprintf(path, "%s/delete_region", decoder->dev_path);
> + rc = sysfs_write_attr(ctx, path, devname);
> + if (rc != 0) {
> + err(ctx, "error deleting region: %s\n", strerror(-rc));
> + return rc;
> + }
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_delete(struct cxl_region *region)
> +{
> + struct cxl_decoder *decoder = cxl_region_get_decoder(region);
> + const char *devname = cxl_region_get_devname(region);
> + int rc;
> +
> + if (cxl_region_is_enabled(region))
> + return -EBUSY;
> +
> + rc = cxl_region_delete_name(decoder, devname);
> + if (rc != 0)
> + return rc;
> +
> + free_region(region);
> + return 0;
> +}
> +
> static void *add_cxl_region(void *parent, int id, const char *cxlregion_base)
> {
> const char *devname = devpath_to_devname(cxlregion_base);
> @@ -589,6 +623,258 @@ cxl_region_get_interleave_granularity(struct cxl_region
> *region)
> return region->interleave_granularity;
> }
>
> +CXL_EXPORT struct cxl_decoder *
> +cxl_region_get_target_decoder(struct cxl_region *region, int position)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + struct cxl_decoder *decoder;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + if (snprintf(path, len, "%s/target%d", region->dev_path, position) >=
> + len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return NULL;
> + }
> +
> + rc = sysfs_read_attr(ctx, path, buf);
> + if (rc < 0) {
> + err(ctx, "%s: error reading target%d: %s\n", devname,
> + position, strerror(-rc));
> + return NULL;
> + }
> +
> + decoder = cxl_decoder_get_by_name(ctx, buf);
> + if (!decoder) {
> + err(ctx, "%s: error locating decoder for target%d\n", devname,
> + position);
> + return NULL;
> + }
> + return decoder;
> +}
> +
> +CXL_EXPORT int cxl_region_set_size(struct cxl_region *region,
> + unsigned long long size)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + if (size == 0) {
> + dbg(ctx, "%s: cannot use %s to delete a region\n", __func__,
> + devname);
> + return -EINVAL;
> + }
> +
> + if (snprintf(path, len, "%s/size", region->dev_path) >= len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + sprintf(buf, "%#llx\n", size);
> + rc = sysfs_write_attr(ctx, path, buf);
> + if (rc < 0)
> + return rc;
> +
> + region->size = size;
> +
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_set_uuid(struct cxl_region *region, uuid_t uu)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + char uuid[SYSFS_ATTR_SIZE];
> +
> + if (snprintf(path, len, "%s/uuid", region->dev_path) >= len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + uuid_unparse(uu, uuid);
> + rc = sysfs_write_attr(ctx, path, uuid);
> + if (rc != 0)
> + return rc;
> + memcpy(region->uuid, uu, sizeof(uuid_t));
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_set_interleave_ways(struct cxl_region *region,
> + unsigned int ways)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + if (snprintf(path, len, "%s/interleave_ways",
> + region->dev_path) >= len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + sprintf(buf, "%u\n", ways);
> + rc = sysfs_write_attr(ctx, path, buf);
> + if (rc < 0)
> + return rc;
> +
> + region->interleave_ways = ways;
> +
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_set_interleave_granularity(struct cxl_region
> *region,
> + unsigned int granularity)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + if (snprintf(path, len, "%s/interleave_granularity",
> + region->dev_path) >= len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + sprintf(buf, "%u\n", granularity);
> + rc = sysfs_write_attr(ctx, path, buf);
> + if (rc < 0)
> + return rc;
> +
> + region->interleave_granularity = granularity;
> +
> + return 0;
> +}
> +
> +static int region_write_target(struct cxl_region *region, int position,
> + struct cxl_decoder *decoder)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + const char *dec_name = "";
> +
> + if (decoder)
> + dec_name = cxl_decoder_get_devname(decoder);
> +
> + if (snprintf(path, len, "%s/target%d", region->dev_path, position) >=
> + len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + rc = sysfs_write_attr(ctx, path, dec_name);
> + if (rc < 0)
> + return rc;
> +
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_set_target(struct cxl_region *region, int position,
> + struct cxl_decoder *decoder)
> +{
> + if (!decoder)
> + return -ENXIO;
> +
> + return region_write_target(region, position, decoder);
> +}
> +
> +CXL_EXPORT int cxl_region_clear_target(struct cxl_region *region, int
> position)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int rc;
> +
> + if (cxl_region_is_enabled(region)) {
> + err(ctx, "%s: can't clear targets on an active region\n",
> + devname);
> + return -EBUSY;
> + }
> +
> + rc = region_write_target(region, position, NULL);
> + if (rc) {
> + err(ctx, "%s: error clearing target%d: %s\n",
> + devname, position, strerror(-rc));
> + return rc;
> + }
> +
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_clear_all_targets(struct cxl_region *region)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + unsigned int ways, i;
> + int rc;
> +
> + if (cxl_region_is_enabled(region)) {
> + err(ctx, "%s: can't clear targets on an active region\n",
> + devname);
> + return -EBUSY;
> + }
> +
> + ways = cxl_region_get_interleave_ways(region);
> + if (ways == 0 || ways == UINT_MAX)
> + return -ENXIO;
> +
> + for (i = 0; i < ways; i++) {
> + rc = region_write_target(region, i, NULL);
> + if (rc) {
> + err(ctx, "%s: error clearing target%d: %s\n",
> + devname, i, strerror(-rc));
> + return rc;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int set_region_decode(struct cxl_region *region,
> + enum cxl_decode_state decode_state)
> +{
> + const char *devname = cxl_region_get_devname(region);
> + struct cxl_ctx *ctx = cxl_region_get_ctx(region);
> + int len = region->buf_len, rc;
> + char *path = region->dev_buf;
> + char buf[SYSFS_ATTR_SIZE];
> +
> + if (snprintf(path, len, "%s/commit", region->dev_path) >= len) {
> + err(ctx, "%s: buffer too small!\n", devname);
> + return -ENXIO;
> + }
> +
> + sprintf(buf, "%d\n", decode_state);
> + rc = sysfs_write_attr(ctx, path, buf);
> + if (rc < 0)
> + return rc;
> +
> + region->decode_state = decode_state;
> +
> + return 0;
> +}
> +
> +CXL_EXPORT int cxl_region_decode_commit(struct cxl_region *region)
> +{
> + return set_region_decode(region, CXL_DECODE_COMMIT);
> +}
> +
> +CXL_EXPORT int cxl_region_decode_reset(struct cxl_region *region)
> +{
> + return set_region_decode(region, CXL_DECODE_RESET);
> +}
> +
> static struct cxl_decoder *__cxl_port_match_decoder(struct cxl_port *port,
> const char *ident)
> {
> @@ -623,8 +909,8 @@ static struct cxl_decoder *cxl_port_find_decoder(struct
> cxl_port *port,
> return NULL;
> }
>
> -static struct cxl_decoder *cxl_decoder_get_by_name(struct cxl_ctx *ctx,
> - const char *ident)
> +CXL_EXPORT struct cxl_decoder *cxl_decoder_get_by_name(struct cxl_ctx *ctx,
> + const char *ident)
> {
> struct cxl_bus *bus;
>
> @@ -1387,6 +1673,18 @@ static void *add_cxl_decoder(void *parent, int id,
> const char *cxldecoder_base)
> } else
> decoder->mode = CXL_DECODER_MODE_NONE;
>
> + sprintf(path, "%s/interleave_granularity", cxldecoder_base);
> + if (sysfs_read_attr(ctx, path, buf) < 0)
> + decoder->interleave_granularity = UINT_MAX;
> + else
> + decoder->interleave_granularity = strtoul(buf, NULL, 0);
> +
> + sprintf(path, "%s/interleave_ways", cxldecoder_base);
> + if (sysfs_read_attr(ctx, path, buf) < 0)
> + decoder->interleave_ways = UINT_MAX;
> + else
> + decoder->interleave_ways = strtoul(buf, NULL, 0);
> +
> switch (port->type) {
> case CXL_PORT_ENDPOINT:
> sprintf(path, "%s/dpa_resource", cxldecoder_base);
> @@ -1719,6 +2017,63 @@ CXL_EXPORT bool cxl_decoder_is_locked(struct
> cxl_decoder *decoder)
> return decoder->locked;
> }
>
> +CXL_EXPORT unsigned int
> +cxl_decoder_get_interleave_granularity(struct cxl_decoder *decoder)
> +{
> + return decoder->interleave_granularity;
> +}
> +
> +CXL_EXPORT unsigned int
> +cxl_decoder_get_interleave_ways(struct cxl_decoder *decoder)
> +{
> + return decoder->interleave_ways;
> +}
> +
> +CXL_EXPORT struct cxl_region *
> +cxl_decoder_create_pmem_region(struct cxl_decoder *decoder)
> +{
> + struct cxl_ctx *ctx = cxl_decoder_get_ctx(decoder);
> + char *path = decoder->dev_buf;
> + char buf[SYSFS_ATTR_SIZE];
> + struct cxl_region *region;
> + int rc;
> +
> + sprintf(path, "%s/create_pmem_region", decoder->dev_path);
> + rc = sysfs_read_attr(ctx, path, buf);
> + if (rc < 0) {
> + err(ctx, "failed to read new region name: %s\n",
> + strerror(-rc));
> + return NULL;
> + }
> +
> + rc = sysfs_write_attr(ctx, path, buf);
> + if (rc < 0) {
> + err(ctx, "failed to write new region name: %s\n",
> + strerror(-rc));
> + return NULL;
> + }
I think there either needs to be a "decoder->regions_init = 0" here, or
a direct call to "add_cxl_region(decoder...)" just in case this context
had already listed regions before creating a new one.
I like the precision of "add_cxl_region()", but that needs to open code
some of the internals of sysfs_device_parse(), so maybe
"decoder->regions_init = 0" is ok for now.
> +
> + /* create_region was successful, walk to the new region */
> + cxl_region_foreach(decoder, region) {
> + const char *devname = cxl_region_get_devname(region);
> +
> + if (strcmp(devname, buf) == 0)
> + goto found;
> + }
> +
> + /*
> + * If walking to the region we just created failed, something has gone
> + * very wrong. Attempt to delete it to avoid leaving a dangling region
> + * id behind.
> + */
> + err(ctx, "failed to add new region to libcxl\n");
> + cxl_region_delete_name(decoder, buf);
> + return NULL;
> +
> + found:
> + return region;
> +}
> +
> CXL_EXPORT int cxl_decoder_get_nr_targets(struct cxl_decoder *decoder)
> {
> return decoder->nr_targets;
> @@ -1729,6 +2084,24 @@ CXL_EXPORT const char *cxl_decoder_get_devname(struct
> cxl_decoder *decoder)
> return devpath_to_devname(decoder->dev_path);
> }
>
> +CXL_EXPORT struct cxl_memdev *
> +cxl_ep_decoder_get_memdev(struct cxl_decoder *decoder)
Hmm, this is the only place where the API assumes the type of the
decoder. The other root-only or endpoint-only decoder attribute getters
are just cxl_decoder_get_*(), so I think drop the "_ep".
Other than the items listed above, this looks good.
Reviewed-by: Dan Williams <[email protected]>
