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linux-user: Track shm regions with an interval tree 

Remove the fixed size shm_regions[] array.
Remove references when other mappings completely remove
or replace a region.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-08-20 13:39:37 -07:00
parent ceda5688b6
commit 044e95c81e
1 changed files with 53 additions and 28 deletions
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81
linux-user/mmap.c
View File

@ -24,18 +24,11 @@
#include "user-internals.h"
#include "user-mmap.h"
#include "target_mman.h"
#include "qemu/interval-tree.h"
static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
static __thread int mmap_lock_count;
#define N_SHM_REGIONS 32
static struct shm_region {
abi_ulong start;
abi_ulong size;
bool in_use;
} shm_regions[N_SHM_REGIONS];
void mmap_lock(void)
{
if (mmap_lock_count++ == 0) {
@ -73,6 +66,44 @@ void mmap_fork_end(int child)
}
}
/* Protected by mmap_lock. */
static IntervalTreeRoot shm_regions;
static void shm_region_add(abi_ptr start, abi_ptr last)
{
IntervalTreeNode *i = g_new0(IntervalTreeNode, 1);
i->start = start;
i->last = last;
interval_tree_insert(i, &shm_regions);
}
static abi_ptr shm_region_find(abi_ptr start)
{
IntervalTreeNode *i;
for (i = interval_tree_iter_first(&shm_regions, start, start); i;
i = interval_tree_iter_next(i, start, start)) {
if (i->start == start) {
return i->last;
}
}
return 0;
}
static void shm_region_rm_complete(abi_ptr start, abi_ptr last)
{
IntervalTreeNode *i, *n;
for (i = interval_tree_iter_first(&shm_regions, start, last); i; i = n) {
n = interval_tree_iter_next(i, start, last);
if (i->start >= start && i->last <= last) {
interval_tree_remove(i, &shm_regions);
g_free(i);
}
}
}
/*
* Validate target prot bitmask.
* Return the prot bitmask for the host in *HOST_PROT.
@ -729,6 +760,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
page_set_flags(passthrough_last + 1, last, page_flags);
}
}
shm_region_rm_complete(start, last);
the_end:
trace_target_mmap_complete(start);
if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
@ -826,6 +858,7 @@ int target_munmap(abi_ulong start, abi_ulong len)
mmap_lock();
mmap_reserve_or_unmap(start, len);
page_set_flags(start, start + len - 1, 0);
shm_region_rm_complete(start, start + len - 1);
mmap_unlock();
return 0;
@ -915,8 +948,10 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
new_addr = h2g(host_addr);
prot = page_get_flags(old_addr);
page_set_flags(old_addr, old_addr + old_size - 1, 0);
shm_region_rm_complete(old_addr, old_addr + old_size - 1);
page_set_flags(new_addr, new_addr + new_size - 1,
prot | PAGE_VALID | PAGE_RESET);
shm_region_rm_complete(new_addr, new_addr + new_size - 1);
}
mmap_unlock();
return new_addr;
@ -1045,6 +1080,7 @@ abi_ulong target_shmat(CPUArchState *cpu_env, int shmid,
WITH_MMAP_LOCK_GUARD() {
void *host_raddr;
abi_ulong last;
if (shmaddr) {
host_raddr = shmat(shmid, (void *)g2h_untagged(shmaddr), shmflg);
@ -1066,19 +1102,14 @@ abi_ulong target_shmat(CPUArchState *cpu_env, int shmid,
return get_errno(-1);
}
raddr = h2g(host_raddr);
last = raddr + shm_info.shm_segsz - 1;
page_set_flags(raddr, raddr + shm_info.shm_segsz - 1,
page_set_flags(raddr, last,
PAGE_VALID | PAGE_RESET | PAGE_READ |
(shmflg & SHM_RDONLY ? 0 : PAGE_WRITE));
for (int i = 0; i < N_SHM_REGIONS; i++) {
if (!shm_regions[i].in_use) {
shm_regions[i].in_use = true;
shm_regions[i].start = raddr;
shm_regions[i].size = shm_info.shm_segsz;
break;
}
}
shm_region_rm_complete(raddr, last);
shm_region_add(raddr, last);
}
/*
@ -1102,23 +1133,17 @@ abi_long target_shmdt(abi_ulong shmaddr)
/* shmdt pointers are always untagged */
WITH_MMAP_LOCK_GUARD() {
int i;
for (i = 0; i < N_SHM_REGIONS; ++i) {
if (shm_regions[i].in_use && shm_regions[i].start == shmaddr) {
break;
}
}
if (i == N_SHM_REGIONS) {
abi_ulong last = shm_region_find(shmaddr);
if (last == 0) {
return -TARGET_EINVAL;
}
rv = get_errno(shmdt(g2h_untagged(shmaddr)));
if (rv == 0) {
abi_ulong size = shm_regions[i].size;
abi_ulong size = last - shmaddr + 1;
shm_regions[i].in_use = false;
page_set_flags(shmaddr, shmaddr + size - 1, 0);
page_set_flags(shmaddr, last, 0);
shm_region_rm_complete(shmaddr, last);
mmap_reserve_or_unmap(shmaddr, size);
}
}