On Thu, Aug 12, 2021 at 06:52:23PM +0530, Aneesh Kumar K.V wrote: > PAPR interface currently supports two different ways of communicating resource > grouping details to the OS. These are referred to as Form 0 and Form 1 > associativity grouping. Form 0 is the older format and is now considered > deprecated. This patch adds another resource grouping named FORM2. > > Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
Though there a couple of cosmetic issues and one bad memory access
issue (though only in the case of buggy firmware).
[snip]
> +Form 2
> +-------
> +Form 2 associativity format adds separate device tree properties
> representing NUMA node distance
> +thereby making the node distance computation flexible. Form 2 also allows
> flexible primary
> +domain numbering. With numa distance computation now detached from the index
> value in
> +"ibm,associativity-reference-points" property, Form 2 allows a large number
> of primary domain
> +ids at the same domainID index representing resource groups of different
> performance/latency
> +characteristics.
> +
> +Hypervisor indicates the usage of FORM2 associativity using bit 2 of byte 5
> in the
> +"ibm,architecture-vec-5" property.
> +
> +"ibm,numa-lookup-index-table" property contains a list of one or more
> numbers representing
> +the domainIDs present in the system. The offset of the domainID in this
> property is
> +used as an index while computing numa distance information via
> "ibm,numa-distance-table".
> +
> +prop-encoded-array: The number N of the domainIDs encoded as with
> encode-int, followed by
> +N domainID encoded as with encode-int
> +
> +For ex:
> +"ibm,numa-lookup-index-table" = {4, 0, 8, 250, 252}. The offset of domainID
> 8 (2) is used when
Since you're using dts syntax below, it probably makes sense to use it
here as well.
> +computing the distance of domain 8 from other domains present in the system.
> For the rest of
> +this document, this offset will be referred to as domain distance offset.
> +
> +"ibm,numa-distance-table" property contains a list of one or more numbers
> representing the NUMA
> +distance between resource groups/domains present in the system.
> +
> +prop-encoded-array: The number N of the distance values encoded as with
> encode-int, followed by
> +N distance values encoded as with encode-bytes. The max distance value we
> could encode is 255.
> +The number N must be equal to the square of m where m is the number of
> domainIDs in the
> +numa-lookup-index-table.
> +
> +For ex:
> +ibm,numa-lookup-index-table = <3 0 8 40>;
> +ibm,numa-distace-table = <9>, /bits/ 8 < 10 20 80
> + 20 10 160
> + 80 160 10>;
[snip]
> +
> + /* FORM2 affinity */
> + nid = of_node_to_nid_single(node);
> + if (nid == NUMA_NO_NODE)
> + return;
> +
> + /*
> + * With FORM2 we expect NUMA distance of all possible NUMA
> + * nodes to be provided during boot.
> + */
> + WARN(numa_distance_table[nid][nid] == -1,
> + "NUMA distance details for node %d not provided\n", nid);
> +}
> +
> +/*
> + * ibm,numa-lookup-index-table= {N, domainid1, domainid2, ..... domainidN}
> + * ibm,numa-distance-table = { N, 1, 2, 4, 5, 1, 6, .... N elements}
.. and here too.
> + */
> +static void initialize_form2_numa_distance_lookup_table(void)
> +{
> + int i, j;
> + struct device_node *root;
> + const __u8 *numa_dist_table;
> + const __be32 *numa_lookup_index;
> + int numa_dist_table_length;
> + int max_numa_index, distance_index;
> +
> + if (firmware_has_feature(FW_FEATURE_OPAL))
> + root = of_find_node_by_path("/ibm,opal");
> + else
> + root = of_find_node_by_path("/rtas");
> + if (!root)
> + root = of_find_node_by_path("/");
> +
> + numa_lookup_index = of_get_property(root,
> "ibm,numa-lookup-index-table", NULL);
> + max_numa_index = of_read_number(&numa_lookup_index[0], 1);
> +
> + /* first element of the array is the size and is encode-int */
> + numa_dist_table = of_get_property(root, "ibm,numa-distance-table",
> NULL);
> + numa_dist_table_length = of_read_number((const __be32
> *)&numa_dist_table[0], 1);
> + /* Skip the size which is encoded int */
> + numa_dist_table += sizeof(__be32);
> +
> + pr_debug("numa_dist_table_len = %d, numa_dist_indexes_len = %d\n",
> + numa_dist_table_length, max_numa_index);
You validate numa_dist_table_length below. However, AFAICT you don't
anywhere check that the property actually has the length its first
element claims it does. Yes, that represents a firmware bug, but it's
probably best if we don't ready past the end of the array in that
case, which I think is what will happen now.
Same applies for the lookup-index-table.
> + for (i = 0; i < max_numa_index; i++)
> + /* +1 skip the max_numa_index in the property */
> + numa_id_index_table[i] = of_read_number(&numa_lookup_index[i +
> 1], 1);
> +
> +
> + if (numa_dist_table_length != max_numa_index * max_numa_index) {
> + WARN(1, "Wrong NUMA distance information\n");
> + /* consider everybody else just remote. */
> + for (i = 0; i < max_numa_index; i++) {
> + for (j = 0; j < max_numa_index; j++) {
> + int nodeA = numa_id_index_table[i];
> + int nodeB = numa_id_index_table[j];
> +
> + if (nodeA == nodeB)
> + numa_distance_table[nodeA][nodeB] =
> LOCAL_DISTANCE;
> + else
> + numa_distance_table[nodeA][nodeB] =
> REMOTE_DISTANCE;
> + }
> + }
> + }
> +
> + distance_index = 0;
> + for (i = 0; i < max_numa_index; i++) {
> + for (j = 0; j < max_numa_index; j++) {
> + int nodeA = numa_id_index_table[i];
> + int nodeB = numa_id_index_table[j];
> +
> + numa_distance_table[nodeA][nodeB] =
> numa_dist_table[distance_index++];
> + pr_debug("dist[%d][%d]=%d ", nodeA, nodeB,
> numa_distance_table[nodeA][nodeB]);
> + }
> + }
> + of_node_put(root);
> }
>
> static int __init find_primary_domain_index(void)
> @@ -344,6 +449,9 @@ static int __init find_primary_domain_index(void)
> */
> if (firmware_has_feature(FW_FEATURE_OPAL)) {
> affinity_form = FORM1_AFFINITY;
> + } else if (firmware_has_feature(FW_FEATURE_FORM2_AFFINITY)) {
> + dbg("Using form 2 affinity\n");
> + affinity_form = FORM2_AFFINITY;
> } else if (firmware_has_feature(FW_FEATURE_FORM1_AFFINITY)) {
> dbg("Using form 1 affinity\n");
> affinity_form = FORM1_AFFINITY;
> @@ -388,9 +496,12 @@ static int __init find_primary_domain_index(void)
>
> index = of_read_number(&distance_ref_points[1], 1);
> } else {
> + /*
> + * Both FORM1 and FORM2 affinity find the primary domain details
> + * at the same offset.
> + */
> index = of_read_number(distance_ref_points, 1);
> }
> -
> /*
> * Warn and cap if the hardware supports more than
> * MAX_DISTANCE_REF_POINTS domains.
> @@ -819,6 +930,12 @@ static int __init parse_numa_properties(void)
>
> dbg("NUMA associativity depth for CPU/Memory: %d\n",
> primary_domain_index);
>
> + /*
> + * If it is FORM2 initialize the distance table here.
> + */
> + if (affinity_form == FORM2_AFFINITY)
> + initialize_form2_numa_distance_lookup_table();
> +
> /*
> * Even though we connect cpus to numa domains later in SMP
> * init, we need to know the node ids now. This is because
> diff --git a/arch/powerpc/platforms/pseries/firmware.c
> b/arch/powerpc/platforms/pseries/firmware.c
> index 5d4c2bc20bba..f162156b7b68 100644
> --- a/arch/powerpc/platforms/pseries/firmware.c
> +++ b/arch/powerpc/platforms/pseries/firmware.c
> @@ -123,6 +123,7 @@ vec5_fw_features_table[] = {
> {FW_FEATURE_PRRN, OV5_PRRN},
> {FW_FEATURE_DRMEM_V2, OV5_DRMEM_V2},
> {FW_FEATURE_DRC_INFO, OV5_DRC_INFO},
> + {FW_FEATURE_FORM2_AFFINITY, OV5_FORM2_AFFINITY},
> };
>
> static void __init fw_vec5_feature_init(const char *vec5, unsigned long len)
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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