memory: compress phys_map node pointers to 16 bits
Use an expanding vector to store nodes. Allocation is baroque to g_renew() potentially invalidating pointers; this will be addressed later. Signed-off-by: Avi Kivity <avi@redhat.com>
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			@ -201,13 +201,19 @@ static uint16_t phys_section_unassigned;
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struct PhysPageEntry {
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    union {
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        uint16_t leaf; /* index into phys_sections */
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        PhysPageEntry *node;
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        uint16_t node; /* index into phys_map_nodes */
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    } u;
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};
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/* Simple allocator for PhysPageEntry nodes */
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static PhysPageEntry (*phys_map_nodes)[L2_SIZE];
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static unsigned phys_map_nodes_nb, phys_map_nodes_nb_alloc;
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#define PHYS_MAP_NODE_NIL ((uint16_t)~0)
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/* This is a multi-level map on the physical address space.
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   The bottom level has pointers to PhysPageDesc.  */
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static PhysPageEntry phys_map;
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static PhysPageEntry phys_map = { .u.node = PHYS_MAP_NODE_NIL };
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static void io_mem_init(void);
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static void memory_map_init(void);
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			@ -403,6 +409,32 @@ static inline PageDesc *page_find(tb_page_addr_t index)
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}
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#if !defined(CONFIG_USER_ONLY)
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static PhysPageEntry *phys_map_node_alloc(uint16_t *ptr)
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{
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    unsigned i;
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    uint16_t ret;
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    /* Assign early to avoid the pointer being invalidated by g_renew() */
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    *ptr = ret = phys_map_nodes_nb++;
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    assert(ret != PHYS_MAP_NODE_NIL);
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    if (ret == phys_map_nodes_nb_alloc) {
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        typedef PhysPageEntry Node[L2_SIZE];
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        phys_map_nodes_nb_alloc = MAX(phys_map_nodes_nb_alloc * 2, 16);
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        phys_map_nodes = g_renew(Node, phys_map_nodes,
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                                 phys_map_nodes_nb_alloc);
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    }
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    for (i = 0; i < L2_SIZE; ++i) {
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        phys_map_nodes[ret][i].u.node = PHYS_MAP_NODE_NIL;
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    }
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    return phys_map_nodes[ret];
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}
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static void phys_map_nodes_reset(void)
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{
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    phys_map_nodes_nb = 0;
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}
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static uint16_t *phys_page_find_alloc(target_phys_addr_t index, int alloc)
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{
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    PhysPageEntry *lp, *p;
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			@ -412,18 +444,20 @@ static uint16_t *phys_page_find_alloc(target_phys_addr_t index, int alloc)
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    /* Level 1..N.  */
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    for (i = P_L2_LEVELS - 1; i >= 0; i--) {
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        if (lp->u.node == NULL) {
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        if (lp->u.node == PHYS_MAP_NODE_NIL) {
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            if (!alloc) {
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                return NULL;
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            }
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            lp->u.node = p = g_malloc0(sizeof(PhysPageEntry) * L2_SIZE);
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            p = phys_map_node_alloc(&lp->u.node);
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            if (i == 0) {
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                for (j = 0; j < L2_SIZE; j++) {
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                    p[j].u.leaf = phys_section_unassigned;
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                }
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            }
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        } else {
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            p = phys_map_nodes[lp->u.node];
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        }
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        lp = &lp->u.node[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
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        lp = &p[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
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    }
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    return &lp->u.leaf;
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			@ -2538,12 +2572,13 @@ static void destroy_page_desc(uint16_t section_index)
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static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
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{
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    unsigned i;
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    PhysPageEntry *p = lp->u.node;
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    PhysPageEntry *p;
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    if (!p) {
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    if (lp->u.node == PHYS_MAP_NODE_NIL) {
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        return;
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    }
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    p = phys_map_nodes[lp->u.node];
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    for (i = 0; i < L2_SIZE; ++i) {
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        if (level > 0) {
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            destroy_l2_mapping(&p[i], level - 1);
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			@ -2551,13 +2586,13 @@ static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
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            destroy_page_desc(p[i].u.leaf);
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        }
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    }
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    g_free(p);
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    lp->u.node = NULL;
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    lp->u.node = PHYS_MAP_NODE_NIL;
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}
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static void destroy_all_mappings(void)
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{
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    destroy_l2_mapping(&phys_map, P_L2_LEVELS - 1);
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    phys_map_nodes_reset();
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}
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static uint16_t phys_section_add(MemoryRegionSection *section)
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			@ -3543,6 +3578,7 @@ static void core_begin(MemoryListener *listener)
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{
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    destroy_all_mappings();
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    phys_sections_clear();
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    phys_map.u.node = PHYS_MAP_NODE_NIL;
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    phys_section_unassigned = dummy_section(&io_mem_unassigned);
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}
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