tcg: Split out region.c

Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
master
Richard Henderson 2021-03-09 16:24:14 -06:00
parent bf042e8e52
commit 5ff7258cc6
4 changed files with 613 additions and 544 deletions

View File

@ -2,6 +2,7 @@ tcg_ss = ss.source_set()
tcg_ss.add(files(
'optimize.c',
'region.c',
'tcg.c',
'tcg-common.c',
'tcg-op.c',

572
tcg/region.c Normal file
View File

@ -0,0 +1,572 @@
/*
* Memory region management for Tiny Code Generator for QEMU
*
* Copyright (c) 2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "exec/exec-all.h"
#include "tcg/tcg.h"
#if !defined(CONFIG_USER_ONLY)
#include "hw/boards.h"
#endif
#include "tcg-internal.h"
struct tcg_region_tree {
QemuMutex lock;
GTree *tree;
/* padding to avoid false sharing is computed at run-time */
};
/*
* We divide code_gen_buffer into equally-sized "regions" that TCG threads
* dynamically allocate from as demand dictates. Given appropriate region
* sizing, this minimizes flushes even when some TCG threads generate a lot
* more code than others.
*/
struct tcg_region_state {
QemuMutex lock;
/* fields set at init time */
void *start;
void *start_aligned;
void *end;
size_t n;
size_t size; /* size of one region */
size_t stride; /* .size + guard size */
/* fields protected by the lock */
size_t current; /* current region index */
size_t agg_size_full; /* aggregate size of full regions */
};
static struct tcg_region_state region;
/*
* This is an array of struct tcg_region_tree's, with padding.
* We use void * to simplify the computation of region_trees[i]; each
* struct is found every tree_size bytes.
*/
static void *region_trees;
static size_t tree_size;
/* compare a pointer @ptr and a tb_tc @s */
static int ptr_cmp_tb_tc(const void *ptr, const struct tb_tc *s)
{
if (ptr >= s->ptr + s->size) {
return 1;
} else if (ptr < s->ptr) {
return -1;
}
return 0;
}
static gint tb_tc_cmp(gconstpointer ap, gconstpointer bp)
{
const struct tb_tc *a = ap;
const struct tb_tc *b = bp;
/*
* When both sizes are set, we know this isn't a lookup.
* This is the most likely case: every TB must be inserted; lookups
* are a lot less frequent.
*/
if (likely(a->size && b->size)) {
if (a->ptr > b->ptr) {
return 1;
} else if (a->ptr < b->ptr) {
return -1;
}
/* a->ptr == b->ptr should happen only on deletions */
g_assert(a->size == b->size);
return 0;
}
/*
* All lookups have either .size field set to 0.
* From the glib sources we see that @ap is always the lookup key. However
* the docs provide no guarantee, so we just mark this case as likely.
*/
if (likely(a->size == 0)) {
return ptr_cmp_tb_tc(a->ptr, b);
}
return ptr_cmp_tb_tc(b->ptr, a);
}
static void tcg_region_trees_init(void)
{
size_t i;
tree_size = ROUND_UP(sizeof(struct tcg_region_tree), qemu_dcache_linesize);
region_trees = qemu_memalign(qemu_dcache_linesize, region.n * tree_size);
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_init(&rt->lock);
rt->tree = g_tree_new(tb_tc_cmp);
}
}
static struct tcg_region_tree *tc_ptr_to_region_tree(const void *p)
{
size_t region_idx;
/*
* Like tcg_splitwx_to_rw, with no assert. The pc may come from
* a signal handler over which the caller has no control.
*/
if (!in_code_gen_buffer(p)) {
p -= tcg_splitwx_diff;
if (!in_code_gen_buffer(p)) {
return NULL;
}
}
if (p < region.start_aligned) {
region_idx = 0;
} else {
ptrdiff_t offset = p - region.start_aligned;
if (offset > region.stride * (region.n - 1)) {
region_idx = region.n - 1;
} else {
region_idx = offset / region.stride;
}
}
return region_trees + region_idx * tree_size;
}
void tcg_tb_insert(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_insert(rt->tree, &tb->tc, tb);
qemu_mutex_unlock(&rt->lock);
}
void tcg_tb_remove(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_remove(rt->tree, &tb->tc);
qemu_mutex_unlock(&rt->lock);
}
/*
* Find the TB 'tb' such that
* tb->tc.ptr <= tc_ptr < tb->tc.ptr + tb->tc.size
* Return NULL if not found.
*/
TranslationBlock *tcg_tb_lookup(uintptr_t tc_ptr)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree((void *)tc_ptr);
TranslationBlock *tb;
struct tb_tc s = { .ptr = (void *)tc_ptr };
if (rt == NULL) {
return NULL;
}
qemu_mutex_lock(&rt->lock);
tb = g_tree_lookup(rt->tree, &s);
qemu_mutex_unlock(&rt->lock);
return tb;
}
static void tcg_region_tree_lock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_lock(&rt->lock);
}
}
static void tcg_region_tree_unlock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_unlock(&rt->lock);
}
}
void tcg_tb_foreach(GTraverseFunc func, gpointer user_data)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
g_tree_foreach(rt->tree, func, user_data);
}
tcg_region_tree_unlock_all();
}
size_t tcg_nb_tbs(void)
{
size_t nb_tbs = 0;
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
nb_tbs += g_tree_nnodes(rt->tree);
}
tcg_region_tree_unlock_all();
return nb_tbs;
}
static gboolean tcg_region_tree_traverse(gpointer k, gpointer v, gpointer data)
{
TranslationBlock *tb = v;
tb_destroy(tb);
return FALSE;
}
static void tcg_region_tree_reset_all(void)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
g_tree_foreach(rt->tree, tcg_region_tree_traverse, NULL);
/* Increment the refcount first so that destroy acts as a reset */
g_tree_ref(rt->tree);
g_tree_destroy(rt->tree);
}
tcg_region_tree_unlock_all();
}
static void tcg_region_bounds(size_t curr_region, void **pstart, void **pend)
{
void *start, *end;
start = region.start_aligned + curr_region * region.stride;
end = start + region.size;
if (curr_region == 0) {
start = region.start;
}
if (curr_region == region.n - 1) {
end = region.end;
}
*pstart = start;
*pend = end;
}
static void tcg_region_assign(TCGContext *s, size_t curr_region)
{
void *start, *end;
tcg_region_bounds(curr_region, &start, &end);
s->code_gen_buffer = start;
s->code_gen_ptr = start;
s->code_gen_buffer_size = end - start;
s->code_gen_highwater = end - TCG_HIGHWATER;
}
static bool tcg_region_alloc__locked(TCGContext *s)
{
if (region.current == region.n) {
return true;
}
tcg_region_assign(s, region.current);
region.current++;
return false;
}
/*
* Request a new region once the one in use has filled up.
* Returns true on error.
*/
bool tcg_region_alloc(TCGContext *s)
{
bool err;
/* read the region size now; alloc__locked will overwrite it on success */
size_t size_full = s->code_gen_buffer_size;
qemu_mutex_lock(&region.lock);
err = tcg_region_alloc__locked(s);
if (!err) {
region.agg_size_full += size_full - TCG_HIGHWATER;
}
qemu_mutex_unlock(&region.lock);
return err;
}
/*
* Perform a context's first region allocation.
* This function does _not_ increment region.agg_size_full.
*/
static void tcg_region_initial_alloc__locked(TCGContext *s)
{
bool err = tcg_region_alloc__locked(s);
g_assert(!err);
}
void tcg_region_initial_alloc(TCGContext *s)
{
qemu_mutex_lock(&region.lock);
tcg_region_initial_alloc__locked(s);
qemu_mutex_unlock(&region.lock);
}
/* Call from a safe-work context */
void tcg_region_reset_all(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
qemu_mutex_lock(&region.lock);
region.current = 0;
region.agg_size_full = 0;
for (i = 0; i < n_ctxs; i++) {
TCGContext *s = qatomic_read(&tcg_ctxs[i]);
tcg_region_initial_alloc__locked(s);
}
qemu_mutex_unlock(&region.lock);
tcg_region_tree_reset_all();
}
#ifdef CONFIG_USER_ONLY
static size_t tcg_n_regions(void)
{
return 1;
}
#else
/*
* It is likely that some vCPUs will translate more code than others, so we
* first try to set more regions than max_cpus, with those regions being of
* reasonable size. If that's not possible we make do by evenly dividing
* the code_gen_buffer among the vCPUs.
*/
static size_t tcg_n_regions(void)
{
size_t i;
/* Use a single region if all we have is one vCPU thread */
#if !defined(CONFIG_USER_ONLY)
MachineState *ms = MACHINE(qdev_get_machine());
unsigned int max_cpus = ms->smp.max_cpus;
#endif
if (max_cpus == 1 || !qemu_tcg_mttcg_enabled()) {
return 1;
}
/* Try to have more regions than max_cpus, with each region being >= 2 MB */
for (i = 8; i > 0; i--) {
size_t regions_per_thread = i;
size_t region_size;
region_size = tcg_init_ctx.code_gen_buffer_size;
region_size /= max_cpus * regions_per_thread;
if (region_size >= 2 * 1024u * 1024) {
return max_cpus * regions_per_thread;
}
}
/* If we can't, then just allocate one region per vCPU thread */
return max_cpus;
}
#endif
/*
* Initializes region partitioning.
*
* Called at init time from the parent thread (i.e. the one calling
* tcg_context_init), after the target's TCG globals have been set.
*
* Region partitioning works by splitting code_gen_buffer into separate regions,
* and then assigning regions to TCG threads so that the threads can translate
* code in parallel without synchronization.
*
* In softmmu the number of TCG threads is bounded by max_cpus, so we use at
* least max_cpus regions in MTTCG. In !MTTCG we use a single region.
* Note that the TCG options from the command-line (i.e. -accel accel=tcg,[...])
* must have been parsed before calling this function, since it calls
* qemu_tcg_mttcg_enabled().
*
* In user-mode we use a single region. Having multiple regions in user-mode
* is not supported, because the number of vCPU threads (recall that each thread
* spawned by the guest corresponds to a vCPU thread) is only bounded by the
* OS, and usually this number is huge (tens of thousands is not uncommon).
* Thus, given this large bound on the number of vCPU threads and the fact
* that code_gen_buffer is allocated at compile-time, we cannot guarantee
* that the availability of at least one region per vCPU thread.
*
* However, this user-mode limitation is unlikely to be a significant problem
* in practice. Multi-threaded guests share most if not all of their translated
* code, which makes parallel code generation less appealing than in softmmu.
*/
void tcg_region_init(void)
{
void *buf = tcg_init_ctx.code_gen_buffer;
void *aligned;
size_t size = tcg_init_ctx.code_gen_buffer_size;
size_t page_size = qemu_real_host_page_size;
size_t region_size;
size_t n_regions;
size_t i;
n_regions = tcg_n_regions();
/* The first region will be 'aligned - buf' bytes larger than the others */
aligned = QEMU_ALIGN_PTR_UP(buf, page_size);
g_assert(aligned < tcg_init_ctx.code_gen_buffer + size);
/*
* Make region_size a multiple of page_size, using aligned as the start.
* As a result of this we might end up with a few extra pages at the end of
* the buffer; we will assign those to the last region.
*/
region_size = (size - (aligned - buf)) / n_regions;
region_size = QEMU_ALIGN_DOWN(region_size, page_size);
/* A region must have at least 2 pages; one code, one guard */
g_assert(region_size >= 2 * page_size);
/* init the region struct */
qemu_mutex_init(&region.lock);
region.n = n_regions;
region.size = region_size - page_size;
region.stride = region_size;
region.start = buf;
region.start_aligned = aligned;
/* page-align the end, since its last page will be a guard page */
region.end = QEMU_ALIGN_PTR_DOWN(buf + size, page_size);
/* account for that last guard page */
region.end -= page_size;
/*
* Set guard pages in the rw buffer, as that's the one into which
* buffer overruns could occur. Do not set guard pages in the rx
* buffer -- let that one use hugepages throughout.
*/
for (i = 0; i < region.n; i++) {
void *start, *end;
tcg_region_bounds(i, &start, &end);
/*
* macOS 11.2 has a bug (Apple Feedback FB8994773) in which mprotect
* rejects a permission change from RWX -> NONE. Guard pages are
* nice for bug detection but are not essential; ignore any failure.
*/
(void)qemu_mprotect_none(end, page_size);
}
tcg_region_trees_init();
/*
* Leave the initial context initialized to the first region.
* This will be the context into which we generate the prologue.
* It is also the only context for CONFIG_USER_ONLY.
*/
tcg_region_initial_alloc__locked(&tcg_init_ctx);
}
void tcg_region_prologue_set(TCGContext *s)
{
/* Deduct the prologue from the first region. */
g_assert(region.start == s->code_gen_buffer);
region.start = s->code_ptr;
/* Recompute boundaries of the first region. */
tcg_region_assign(s, 0);
/* Register the balance of the buffer with gdb. */
tcg_register_jit(tcg_splitwx_to_rx(region.start),
region.end - region.start);
}
/*
* Returns the size (in bytes) of all translated code (i.e. from all regions)
* currently in the cache.
* See also: tcg_code_capacity()
* Do not confuse with tcg_current_code_size(); that one applies to a single
* TCG context.
*/
size_t tcg_code_size(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
size_t total;
qemu_mutex_lock(&region.lock);
total = region.agg_size_full;
for (i = 0; i < n_ctxs; i++) {
const TCGContext *s = qatomic_read(&tcg_ctxs[i]);
size_t size;
size = qatomic_read(&s->code_gen_ptr) - s->code_gen_buffer;
g_assert(size <= s->code_gen_buffer_size);
total += size;
}
qemu_mutex_unlock(&region.lock);
return total;
}
/*
* Returns the code capacity (in bytes) of the entire cache, i.e. including all
* regions.
* See also: tcg_code_size()
*/
size_t tcg_code_capacity(void)
{
size_t guard_size, capacity;
/* no need for synchronization; these variables are set at init time */
guard_size = region.stride - region.size;
capacity = region.end + guard_size - region.start;
capacity -= region.n * (guard_size + TCG_HIGHWATER);
return capacity;
}
size_t tcg_tb_phys_invalidate_count(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
size_t total = 0;
for (i = 0; i < n_ctxs; i++) {
const TCGContext *s = qatomic_read(&tcg_ctxs[i]);
total += qatomic_read(&s->tb_phys_invalidate_count);
}
return total;
}

37
tcg/tcg-internal.h Normal file
View File

@ -0,0 +1,37 @@
/*
* Internal declarations for Tiny Code Generator for QEMU
*
* Copyright (c) 2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef TCG_INTERNAL_H
#define TCG_INTERNAL_H 1
#define TCG_HIGHWATER 1024
extern TCGContext **tcg_ctxs;
extern unsigned int n_tcg_ctxs;
bool tcg_region_alloc(TCGContext *s);
void tcg_region_initial_alloc(TCGContext *s);
void tcg_region_prologue_set(TCGContext *s);
#endif /* TCG_INTERNAL_H */

547
tcg/tcg.c
View File

@ -63,6 +63,7 @@
#include "elf.h"
#include "exec/log.h"
#include "tcg-internal.h"
/* Forward declarations for functions declared in tcg-target.c.inc and
used here. */
@ -153,10 +154,8 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct);
static int tcg_out_ldst_finalize(TCGContext *s);
#endif
#define TCG_HIGHWATER 1024
static TCGContext **tcg_ctxs;
static unsigned int n_tcg_ctxs;
TCGContext **tcg_ctxs;
unsigned int n_tcg_ctxs;
TCGv_env cpu_env = 0;
const void *tcg_code_gen_epilogue;
uintptr_t tcg_splitwx_diff;
@ -165,42 +164,6 @@ uintptr_t tcg_splitwx_diff;
tcg_prologue_fn *tcg_qemu_tb_exec;
#endif
struct tcg_region_tree {
QemuMutex lock;
GTree *tree;
/* padding to avoid false sharing is computed at run-time */
};
/*
* We divide code_gen_buffer into equally-sized "regions" that TCG threads
* dynamically allocate from as demand dictates. Given appropriate region
* sizing, this minimizes flushes even when some TCG threads generate a lot
* more code than others.
*/
struct tcg_region_state {
QemuMutex lock;
/* fields set at init time */
void *start;
void *start_aligned;
void *end;
size_t n;
size_t size; /* size of one region */
size_t stride; /* .size + guard size */
/* fields protected by the lock */
size_t current; /* current region index */
size_t agg_size_full; /* aggregate size of full regions */
};
static struct tcg_region_state region;
/*
* This is an array of struct tcg_region_tree's, with padding.
* We use void * to simplify the computation of region_trees[i]; each
* struct is found every tree_size bytes.
*/
static void *region_trees;
static size_t tree_size;
static TCGRegSet tcg_target_available_regs[TCG_TYPE_COUNT];
static TCGRegSet tcg_target_call_clobber_regs;
@ -457,453 +420,6 @@ static const TCGTargetOpDef constraint_sets[] = {
#include "tcg-target.c.inc"
/* compare a pointer @ptr and a tb_tc @s */
static int ptr_cmp_tb_tc(const void *ptr, const struct tb_tc *s)
{
if (ptr >= s->ptr + s->size) {
return 1;
} else if (ptr < s->ptr) {
return -1;
}
return 0;
}
static gint tb_tc_cmp(gconstpointer ap, gconstpointer bp)
{
const struct tb_tc *a = ap;
const struct tb_tc *b = bp;
/*
* When both sizes are set, we know this isn't a lookup.
* This is the most likely case: every TB must be inserted; lookups
* are a lot less frequent.
*/
if (likely(a->size && b->size)) {
if (a->ptr > b->ptr) {
return 1;
} else if (a->ptr < b->ptr) {
return -1;
}
/* a->ptr == b->ptr should happen only on deletions */
g_assert(a->size == b->size);
return 0;
}
/*
* All lookups have either .size field set to 0.
* From the glib sources we see that @ap is always the lookup key. However
* the docs provide no guarantee, so we just mark this case as likely.
*/
if (likely(a->size == 0)) {
return ptr_cmp_tb_tc(a->ptr, b);
}
return ptr_cmp_tb_tc(b->ptr, a);
}
static void tcg_region_trees_init(void)
{
size_t i;
tree_size = ROUND_UP(sizeof(struct tcg_region_tree), qemu_dcache_linesize);
region_trees = qemu_memalign(qemu_dcache_linesize, region.n * tree_size);
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_init(&rt->lock);
rt->tree = g_tree_new(tb_tc_cmp);
}
}
static struct tcg_region_tree *tc_ptr_to_region_tree(const void *p)
{
size_t region_idx;
/*
* Like tcg_splitwx_to_rw, with no assert. The pc may come from
* a signal handler over which the caller has no control.
*/
if (!in_code_gen_buffer(p)) {
p -= tcg_splitwx_diff;
if (!in_code_gen_buffer(p)) {
return NULL;
}
}
if (p < region.start_aligned) {
region_idx = 0;
} else {
ptrdiff_t offset = p - region.start_aligned;
if (offset > region.stride * (region.n - 1)) {
region_idx = region.n - 1;
} else {
region_idx = offset / region.stride;
}
}
return region_trees + region_idx * tree_size;
}
void tcg_tb_insert(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_insert(rt->tree, &tb->tc, tb);
qemu_mutex_unlock(&rt->lock);
}
void tcg_tb_remove(TranslationBlock *tb)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree(tb->tc.ptr);
g_assert(rt != NULL);
qemu_mutex_lock(&rt->lock);
g_tree_remove(rt->tree, &tb->tc);
qemu_mutex_unlock(&rt->lock);
}
/*
* Find the TB 'tb' such that
* tb->tc.ptr <= tc_ptr < tb->tc.ptr + tb->tc.size
* Return NULL if not found.
*/
TranslationBlock *tcg_tb_lookup(uintptr_t tc_ptr)
{
struct tcg_region_tree *rt = tc_ptr_to_region_tree((void *)tc_ptr);
TranslationBlock *tb;
struct tb_tc s = { .ptr = (void *)tc_ptr };
if (rt == NULL) {
return NULL;
}
qemu_mutex_lock(&rt->lock);
tb = g_tree_lookup(rt->tree, &s);
qemu_mutex_unlock(&rt->lock);
return tb;
}
static void tcg_region_tree_lock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_lock(&rt->lock);
}
}
static void tcg_region_tree_unlock_all(void)
{
size_t i;
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
qemu_mutex_unlock(&rt->lock);
}
}
void tcg_tb_foreach(GTraverseFunc func, gpointer user_data)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
g_tree_foreach(rt->tree, func, user_data);
}
tcg_region_tree_unlock_all();
}
size_t tcg_nb_tbs(void)
{
size_t nb_tbs = 0;
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
nb_tbs += g_tree_nnodes(rt->tree);
}
tcg_region_tree_unlock_all();
return nb_tbs;
}
static gboolean tcg_region_tree_traverse(gpointer k, gpointer v, gpointer data)
{
TranslationBlock *tb = v;
tb_destroy(tb);
return FALSE;
}
static void tcg_region_tree_reset_all(void)
{
size_t i;
tcg_region_tree_lock_all();
for (i = 0; i < region.n; i++) {
struct tcg_region_tree *rt = region_trees + i * tree_size;
g_tree_foreach(rt->tree, tcg_region_tree_traverse, NULL);
/* Increment the refcount first so that destroy acts as a reset */
g_tree_ref(rt->tree);
g_tree_destroy(rt->tree);
}
tcg_region_tree_unlock_all();
}
static void tcg_region_bounds(size_t curr_region, void **pstart, void **pend)
{
void *start, *end;
start = region.start_aligned + curr_region * region.stride;
end = start + region.size;
if (curr_region == 0) {
start = region.start;
}
if (curr_region == region.n - 1) {
end = region.end;
}
*pstart = start;
*pend = end;
}
static void tcg_region_assign(TCGContext *s, size_t curr_region)
{
void *start, *end;
tcg_region_bounds(curr_region, &start, &end);
s->code_gen_buffer = start;
s->code_gen_ptr = start;
s->code_gen_buffer_size = end - start;
s->code_gen_highwater = end - TCG_HIGHWATER;
}
static bool tcg_region_alloc__locked(TCGContext *s)
{
if (region.current == region.n) {
return true;
}
tcg_region_assign(s, region.current);
region.current++;
return false;
}
/*
* Request a new region once the one in use has filled up.
* Returns true on error.
*/
static bool tcg_region_alloc(TCGContext *s)
{
bool err;
/* read the region size now; alloc__locked will overwrite it on success */
size_t size_full = s->code_gen_buffer_size;
qemu_mutex_lock(&region.lock);
err = tcg_region_alloc__locked(s);
if (!err) {
region.agg_size_full += size_full - TCG_HIGHWATER;
}
qemu_mutex_unlock(&region.lock);
return err;
}
/*
* Perform a context's first region allocation.
* This function does _not_ increment region.agg_size_full.
*/
static void tcg_region_initial_alloc__locked(TCGContext *s)
{
bool err = tcg_region_alloc__locked(s);
g_assert(!err);
}
#ifndef CONFIG_USER_ONLY
static void tcg_region_initial_alloc(TCGContext *s)
{
qemu_mutex_lock(&region.lock);
tcg_region_initial_alloc__locked(s);
qemu_mutex_unlock(&region.lock);
}
#endif
/* Call from a safe-work context */
void tcg_region_reset_all(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
qemu_mutex_lock(&region.lock);
region.current = 0;
region.agg_size_full = 0;
for (i = 0; i < n_ctxs; i++) {
TCGContext *s = qatomic_read(&tcg_ctxs[i]);
tcg_region_initial_alloc__locked(s);
}
qemu_mutex_unlock(&region.lock);
tcg_region_tree_reset_all();
}
#ifdef CONFIG_USER_ONLY
static size_t tcg_n_regions(void)
{
return 1;
}
#else
/*
* It is likely that some vCPUs will translate more code than others, so we
* first try to set more regions than max_cpus, with those regions being of
* reasonable size. If that's not possible we make do by evenly dividing
* the code_gen_buffer among the vCPUs.
*/
static size_t tcg_n_regions(void)
{
size_t i;
/* Use a single region if all we have is one vCPU thread */
#if !defined(CONFIG_USER_ONLY)
MachineState *ms = MACHINE(qdev_get_machine());
unsigned int max_cpus = ms->smp.max_cpus;
#endif
if (max_cpus == 1 || !qemu_tcg_mttcg_enabled()) {
return 1;
}
/* Try to have more regions than max_cpus, with each region being >= 2 MB */
for (i = 8; i > 0; i--) {
size_t regions_per_thread = i;
size_t region_size;
region_size = tcg_init_ctx.code_gen_buffer_size;
region_size /= max_cpus * regions_per_thread;
if (region_size >= 2 * 1024u * 1024) {
return max_cpus * regions_per_thread;
}
}
/* If we can't, then just allocate one region per vCPU thread */
return max_cpus;
}
#endif
/*
* Initializes region partitioning.
*
* Called at init time from the parent thread (i.e. the one calling
* tcg_context_init), after the target's TCG globals have been set.
*
* Region partitioning works by splitting code_gen_buffer into separate regions,
* and then assigning regions to TCG threads so that the threads can translate
* code in parallel without synchronization.
*
* In softmmu the number of TCG threads is bounded by max_cpus, so we use at
* least max_cpus regions in MTTCG. In !MTTCG we use a single region.
* Note that the TCG options from the command-line (i.e. -accel accel=tcg,[...])
* must have been parsed before calling this function, since it calls
* qemu_tcg_mttcg_enabled().
*
* In user-mode we use a single region. Having multiple regions in user-mode
* is not supported, because the number of vCPU threads (recall that each thread
* spawned by the guest corresponds to a vCPU thread) is only bounded by the
* OS, and usually this number is huge (tens of thousands is not uncommon).
* Thus, given this large bound on the number of vCPU threads and the fact
* that code_gen_buffer is allocated at compile-time, we cannot guarantee
* that the availability of at least one region per vCPU thread.
*
* However, this user-mode limitation is unlikely to be a significant problem
* in practice. Multi-threaded guests share most if not all of their translated
* code, which makes parallel code generation less appealing than in softmmu.
*/
void tcg_region_init(void)
{
void *buf = tcg_init_ctx.code_gen_buffer;
void *aligned;
size_t size = tcg_init_ctx.code_gen_buffer_size;
size_t page_size = qemu_real_host_page_size;
size_t region_size;
size_t n_regions;
size_t i;
n_regions = tcg_n_regions();
/* The first region will be 'aligned - buf' bytes larger than the others */
aligned = QEMU_ALIGN_PTR_UP(buf, page_size);
g_assert(aligned < tcg_init_ctx.code_gen_buffer + size);
/*
* Make region_size a multiple of page_size, using aligned as the start.
* As a result of this we might end up with a few extra pages at the end of
* the buffer; we will assign those to the last region.
*/
region_size = (size - (aligned - buf)) / n_regions;
region_size = QEMU_ALIGN_DOWN(region_size, page_size);
/* A region must have at least 2 pages; one code, one guard */
g_assert(region_size >= 2 * page_size);
/* init the region struct */
qemu_mutex_init(&region.lock);
region.n = n_regions;
region.size = region_size - page_size;
region.stride = region_size;
region.start = buf;
region.start_aligned = aligned;
/* page-align the end, since its last page will be a guard page */
region.end = QEMU_ALIGN_PTR_DOWN(buf + size, page_size);
/* account for that last guard page */
region.end -= page_size;
/*
* Set guard pages in the rw buffer, as that's the one into which
* buffer overruns could occur. Do not set guard pages in the rx
* buffer -- let that one use hugepages throughout.
*/
for (i = 0; i < region.n; i++) {
void *start, *end;
tcg_region_bounds(i, &start, &end);
/*
* macOS 11.2 has a bug (Apple Feedback FB8994773) in which mprotect
* rejects a permission change from RWX -> NONE. Guard pages are
* nice for bug detection but are not essential; ignore any failure.
*/
(void)qemu_mprotect_none(end, page_size);
}
tcg_region_trees_init();
/*
* Leave the initial context initialized to the first region.
* This will be the context into which we generate the prologue.
* It is also the only context for CONFIG_USER_ONLY.
*/
tcg_region_initial_alloc__locked(&tcg_init_ctx);
}
static void tcg_region_prologue_set(TCGContext *s)
{
/* Deduct the prologue from the first region. */
g_assert(region.start == s->code_gen_buffer);
region.start = s->code_ptr;
/* Recompute boundaries of the first region. */
tcg_region_assign(s, 0);
/* Register the balance of the buffer with gdb. */
tcg_register_jit(tcg_splitwx_to_rx(region.start),
region.end - region.start);
}
#ifdef CONFIG_DEBUG_TCG
const void *tcg_splitwx_to_rx(void *rw)
{
@ -988,63 +504,6 @@ void tcg_register_thread(void)
}
#endif /* !CONFIG_USER_ONLY */
/*
* Returns the size (in bytes) of all translated code (i.e. from all regions)
* currently in the cache.
* See also: tcg_code_capacity()
* Do not confuse with tcg_current_code_size(); that one applies to a single
* TCG context.
*/
size_t tcg_code_size(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
size_t total;
qemu_mutex_lock(&region.lock);
total = region.agg_size_full;
for (i = 0; i < n_ctxs; i++) {
const TCGContext *s = qatomic_read(&tcg_ctxs[i]);
size_t size;
size = qatomic_read(&s->code_gen_ptr) - s->code_gen_buffer;
g_assert(size <= s->code_gen_buffer_size);
total += size;
}
qemu_mutex_unlock(&region.lock);
return total;
}
/*
* Returns the code capacity (in bytes) of the entire cache, i.e. including all
* regions.
* See also: tcg_code_size()
*/
size_t tcg_code_capacity(void)
{
size_t guard_size, capacity;
/* no need for synchronization; these variables are set at init time */
guard_size = region.stride - region.size;
capacity = region.end + guard_size - region.start;
capacity -= region.n * (guard_size + TCG_HIGHWATER);
return capacity;
}
size_t tcg_tb_phys_invalidate_count(void)
{
unsigned int n_ctxs = qatomic_read(&n_tcg_ctxs);
unsigned int i;
size_t total = 0;
for (i = 0; i < n_ctxs; i++) {
const TCGContext *s = qatomic_read(&tcg_ctxs[i]);
total += qatomic_read(&s->tb_phys_invalidate_count);
}
return total;
}
/* pool based memory allocation */
void *tcg_malloc_internal(TCGContext *s, int size)
{