source: trunk/packages/xen-3.1/xen-3.1/xen/arch/x86/srat.c @ 34

/*
 * ACPI 3.0 based NUMA setup
 * Copyright 2004 Andi Kleen, SuSE Labs.
 *
 * Reads the ACPI SRAT table to figure out what memory belongs to which CPUs.
 *
 * Called from acpi_numa_init while reading the SRAT and SLIT tables.
 * Assumes all memory regions belonging to a single proximity domain
 * are in one chunk. Holes between them will be included in the node.
 * 
 * Adapted for Xen: Ryan Harper <ryanh@us.ibm.com>
 */

#include <xen/init.h>
#include <xen/mm.h>
#include <xen/inttypes.h>
#include <xen/nodemask.h>
#include <xen/acpi.h>
#include <xen/numa.h>
#include <asm/page.h>

static struct acpi_table_slit *acpi_slit;

static nodemask_t nodes_parsed __initdata;
static nodemask_t nodes_found __initdata;
static struct node nodes[MAX_NUMNODES] __initdata;
static u8 pxm2node[256] = { [0 ... 255] = 0xff };

/* Too small nodes confuse the VM badly. Usually they result
   from BIOS bugs. */
#define NODE_MIN_SIZE (4*1024*1024)

static int node_to_pxm(int n);

int pxm_to_node(int pxm)
{
        if ((unsigned)pxm >= 256)
                return -1;
        /* Extend 0xff to (int)-1 */
        return (signed char)pxm2node[pxm];
}

static __init int setup_node(int pxm)
{
        unsigned node = pxm2node[pxm];
        if (node == 0xff) {
                if (nodes_weight(nodes_found) >= MAX_NUMNODES)
                        return -1;
                node = first_unset_node(nodes_found); 
                node_set(node, nodes_found);
                pxm2node[pxm] = node;
        }
        return pxm2node[pxm];
}

static __init int conflicting_nodes(u64 start, u64 end)
{
        int i;
        for_each_node_mask(i, nodes_parsed) {
                struct node *nd = &nodes[i];
                if (nd->start == nd->end)
                        continue;
                if (nd->end > start && nd->start < end)
                        return i;
                if (nd->end == end && nd->start == start)
                        return i;
        }
        return -1;
}

static __init void cutoff_node(int i, u64 start, u64 end)
{
        struct node *nd = &nodes[i];
        if (nd->start < start) {
                nd->start = start;
                if (nd->end < nd->start)
                        nd->start = nd->end;
        }
        if (nd->end > end) {
                nd->end = end;
                if (nd->start > nd->end)
                        nd->start = nd->end;
        }
}

static __init void bad_srat(void)
{
        int i;
        printk(KERN_ERR "SRAT: SRAT not used.\n");
        acpi_numa = -1;
        for (i = 0; i < MAX_LOCAL_APIC; i++)
                apicid_to_node[i] = NUMA_NO_NODE;
}

static __init inline int srat_disabled(void)
{
        return numa_off || acpi_numa < 0;
}

/*
 * A lot of BIOS fill in 10 (= no distance) everywhere. This messes
 * up the NUMA heuristics which wants the local node to have a smaller
 * distance than the others.
 * Do some quick checks here and only use the SLIT if it passes.
 */
static __init int slit_valid(struct acpi_table_slit *slit)
{
        int i, j;
        int d = slit->localities;
        for (i = 0; i < d; i++) {
                for (j = 0; j < d; j++)  {
                        u8 val = slit->entry[d*i + j];
                        if (i == j) {
                                if (val != 10)
                                        return 0;
                        } else if (val <= 10)
                                return 0;
                }
        }
        return 1;
}

/* Callback for SLIT parsing */
void __init acpi_numa_slit_init(struct acpi_table_slit *slit)
{
        if (!slit_valid(slit)) {
                printk(KERN_INFO "ACPI: SLIT table looks invalid. Not used.\n");
                return;
        }
        acpi_slit = slit;
}

/* Callback for Proximity Domain -> LAPIC mapping */
void __init
acpi_numa_processor_affinity_init(struct acpi_table_processor_affinity *pa)
{
        int pxm, node;
        if (srat_disabled())
                return;
        if (pa->header.length != sizeof(struct acpi_table_processor_affinity)) {                bad_srat();
                return;
        }
        if (pa->flags.enabled == 0)
                return;
        pxm = pa->proximity_domain;
        node = setup_node(pxm);
        if (node < 0) {
                printk(KERN_ERR "SRAT: Too many proximity domains %x\n", pxm);
                bad_srat();
                return;
        }
        apicid_to_node[pa->apic_id] = node;
        acpi_numa = 1;
        printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
               pxm, pa->apic_id, node);
}

/* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
void __init
acpi_numa_memory_affinity_init(struct acpi_table_memory_affinity *ma)
{
        struct node *nd;
        u64 start, end;
        int node, pxm;
        int i;

        if (srat_disabled())
                return;
        if (ma->header.length != sizeof(struct acpi_table_memory_affinity)) {
                bad_srat();
                return;
        }
        if (ma->flags.enabled == 0)
                return;
        start = ma->base_addr_lo | ((u64)ma->base_addr_hi << 32);
        end = start + (ma->length_lo | ((u64)ma->length_hi << 32));
        pxm = ma->proximity_domain;
        node = setup_node(pxm);
        if (node < 0) {
                printk(KERN_ERR "SRAT: Too many proximity domains.\n");
                bad_srat();
                return;
        }
        /* It is fine to add this area to the nodes data it will be used later*/
        if (ma->flags.hot_pluggable == 1)
                printk(KERN_INFO "SRAT: hot plug zone found %"PRIx64" - %"PRIx64" \n",
                                start, end);
        i = conflicting_nodes(start, end);
        if (i == node) {
                printk(KERN_WARNING
                "SRAT: Warning: PXM %d (%"PRIx64"-%"PRIx64") overlaps with itself (%"
                PRIx64"-%"PRIx64")\n", pxm, start, end, nodes[i].start, nodes[i].end);
        } else if (i >= 0) {
                printk(KERN_ERR
                       "SRAT: PXM %d (%"PRIx64"-%"PRIx64") overlaps with PXM %d (%"
                       PRIx64"-%"PRIx64")\n", pxm, start, end, node_to_pxm(i),
                           nodes[i].start, nodes[i].end);
                bad_srat();
                return;
        }
        nd = &nodes[node];
        if (!node_test_and_set(node, nodes_parsed)) {
                nd->start = start;
                nd->end = end;
        } else {
                if (start < nd->start)
                        nd->start = start;
                if (nd->end < end)
                        nd->end = end;
        }
        printk(KERN_INFO "SRAT: Node %u PXM %u %"PRIx64"-%"PRIx64"\n", node, pxm,
               nd->start, nd->end);
}

/* Sanity check to catch more bad SRATs (they are amazingly common).
   Make sure the PXMs cover all memory. */
static int nodes_cover_memory(void)
{
        int i;
        u64 pxmram, e820ram;

        pxmram = 0;
        for_each_node_mask(i, nodes_parsed) {
                u64 s = nodes[i].start >> PAGE_SHIFT;
                u64 e = nodes[i].end >> PAGE_SHIFT;
                pxmram += e - s;
        }

        e820ram = max_page;
        /* We seem to lose 3 pages somewhere. Allow a bit of slack. */
        if ((long)(e820ram - pxmram) >= 1*1024*1024) {
                printk(KERN_ERR "SRAT: PXMs only cover %"PRIu64"MB of your %"
                        PRIu64"MB e820 RAM. Not used.\n",
                        (pxmram << PAGE_SHIFT) >> 20,
                        (e820ram << PAGE_SHIFT) >> 20);
                return 0;
        }
        return 1;
}

static void unparse_node(int node)
{
        int i;
        node_clear(node, nodes_parsed);
        for (i = 0; i < MAX_LOCAL_APIC; i++) {
                if (apicid_to_node[i] == node)
                        apicid_to_node[i] = NUMA_NO_NODE;
        }
}

void __init acpi_numa_arch_fixup(void) {}

/* Use the information discovered above to actually set up the nodes. */
int __init acpi_scan_nodes(u64 start, u64 end)
{
        int i;

        /* First clean up the node list */
        for (i = 0; i < MAX_NUMNODES; i++) {
                cutoff_node(i, start, end);
                if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE)
                        unparse_node(i);
        }

        if (acpi_numa <= 0)
                return -1;

        if (!nodes_cover_memory()) {
                bad_srat();
                return -1;
        }

        memnode_shift = compute_hash_shift(nodes, MAX_NUMNODES);
        if (memnode_shift < 0) {
                printk(KERN_ERR
                     "SRAT: No NUMA node hash function found. Contact maintainer\n");
                bad_srat();
                return -1;
        }

        /* Finally register nodes */
        for_each_node_mask(i, nodes_parsed)
                setup_node_bootmem(i, nodes[i].start, nodes[i].end);
        for (i = 0; i < NR_CPUS; i++) { 
                if (cpu_to_node[i] == NUMA_NO_NODE)
                        continue;
                if (!node_isset(cpu_to_node[i], nodes_parsed))
                        numa_set_node(i, NUMA_NO_NODE);
        }
        numa_init_array();
        return 0;
}

static int node_to_pxm(int n)
{
       int i;
       if (pxm2node[n] == n)
               return n;
       for (i = 0; i < 256; i++)
               if (pxm2node[i] == n)
                       return i;
       return 0;
}

int __node_distance(int a, int b)
{
        int index;

        if (!acpi_slit)
                return a == b ? 10 : 20;
        index = acpi_slit->localities * node_to_pxm(a);
        return acpi_slit->entry[index + node_to_pxm(b)];
}

EXPORT_SYMBOL(__node_distance);