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accel/tcg: Use g_free_rcu for user-exec interval trees 

Because we allow lockless lookups, we have to be careful
when it is freed.  Use rcu to delay the free until safe.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-12-24 05:06:29 -08:00
parent 1b660f42ef
commit 177a8cb83b
1 changed files with 10 additions and 8 deletions
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18
accel/tcg/user-exec.c
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@ -22,6 +22,7 @@
#include "exec/exec-all.h"
#include "tcg/tcg.h"
#include "qemu/bitops.h"
#include "qemu/rcu.h"
#include "exec/cpu_ldst.h"
#include "exec/translate-all.h"
#include "exec/helper-proto.h"
@ -136,6 +137,7 @@ bool handle_sigsegv_accerr_write(CPUState *cpu, sigset_t *old_set,
}
typedef struct PageFlagsNode {
struct rcu_head rcu;
IntervalTreeNode itree;
int flags;
} PageFlagsNode;
@ -266,7 +268,7 @@ static bool pageflags_unset(target_ulong start, target_ulong last)
}
} else if (p_last <= last) {
/* Range completely covers node -- remove it. */
g_free(p);
g_free_rcu(p, rcu);
} else {
/* Truncate the node from the start. */
p->itree.start = last + 1;
@ -311,7 +313,7 @@ static void pageflags_create_merge(target_ulong start, target_ulong last,
if (prev) {
if (next) {
prev->itree.last = next->itree.last;
g_free(next);
g_free_rcu(next, rcu);
} else {
prev->itree.last = last;
}
@ -376,7 +378,7 @@ static bool pageflags_set_clear(target_ulong start, target_ulong last,
p->flags = merge_flags;
} else {
interval_tree_remove(&p->itree, &pageflags_root);
g_free(p);
g_free_rcu(p, rcu);
}
goto done;
}
@ -421,7 +423,7 @@ static bool pageflags_set_clear(target_ulong start, target_ulong last,
p->flags = merge_flags;
} else {
interval_tree_remove(&p->itree, &pageflags_root);
g_free(p);
g_free_rcu(p, rcu);
}
if (p_last < last) {
start = p_last + 1;
@ -462,7 +464,7 @@ static bool pageflags_set_clear(target_ulong start, target_ulong last,
p->itree.start = last + 1;
interval_tree_insert(&p->itree, &pageflags_root);
} else {
g_free(p);
g_free_rcu(p, rcu);
goto restart;
}
if (set_flags) {
@ -779,6 +781,7 @@ tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env, target_ulong addr,
#define TBD_MASK (TARGET_PAGE_MASK * TPD_PAGES)
typedef struct TargetPageDataNode {
struct rcu_head rcu;
IntervalTreeNode itree;
char data[TPD_PAGES][TARGET_PAGE_DATA_SIZE] __attribute__((aligned));
} TargetPageDataNode;
@ -801,11 +804,11 @@ void page_reset_target_data(target_ulong start, target_ulong end)
n = next,
next = next ? interval_tree_iter_next(n, start, last) : NULL) {
target_ulong n_start, n_last, p_ofs, p_len;
TargetPageDataNode *t;
TargetPageDataNode *t = container_of(n, TargetPageDataNode, itree);
if (n->start >= start && n->last <= last) {
interval_tree_remove(n, &targetdata_root);
g_free(n);
g_free_rcu(t, rcu);
continue;
}
@ -819,7 +822,6 @@ void page_reset_target_data(target_ulong start, target_ulong end)
n_last = MIN(last, n->last);
p_len = (n_last + 1 - n_start) >> TARGET_PAGE_BITS;
t = container_of(n, TargetPageDataNode, itree);
memset(t->data[p_ofs], 0, p_len * TARGET_PAGE_DATA_SIZE);
}
}