From 5ff7258cc649dd5a3752485f285411e3915c9aba Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 9 Mar 2021 16:24:14 -0600 Subject: [PATCH 1/1] tcg: Split out region.c MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Reviewed-by: Luis Pires Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- tcg/meson.build | 1 + tcg/region.c | 572 +++++++++++++++++++++++++++++++++++++++++++++ tcg/tcg-internal.h | 37 +++ tcg/tcg.c | 547 +------------------------------------------ 4 files changed, 613 insertions(+), 544 deletions(-) create mode 100644 tcg/region.c create mode 100644 tcg/tcg-internal.h diff --git a/tcg/meson.build b/tcg/meson.build index 84064a341e..5be3915529 100644 --- a/tcg/meson.build +++ b/tcg/meson.build @@ -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', diff --git a/tcg/region.c b/tcg/region.c new file mode 100644 index 0000000000..6e34fcf775 --- /dev/null +++ b/tcg/region.c @@ -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(®ion.lock); + err = tcg_region_alloc__locked(s); + if (!err) { + region.agg_size_full += size_full - TCG_HIGHWATER; + } + qemu_mutex_unlock(®ion.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(®ion.lock); + tcg_region_initial_alloc__locked(s); + qemu_mutex_unlock(®ion.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(®ion.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(®ion.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(®ion.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(®ion.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(®ion.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; +} diff --git a/tcg/tcg-internal.h b/tcg/tcg-internal.h new file mode 100644 index 0000000000..b1dda343c2 --- /dev/null +++ b/tcg/tcg-internal.h @@ -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 */ diff --git a/tcg/tcg.c b/tcg/tcg.c index eca72990c1..8c43c0f316 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -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(®ion.lock); - err = tcg_region_alloc__locked(s); - if (!err) { - region.agg_size_full += size_full - TCG_HIGHWATER; - } - qemu_mutex_unlock(®ion.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(®ion.lock); - tcg_region_initial_alloc__locked(s); - qemu_mutex_unlock(®ion.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(®ion.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(®ion.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(®ion.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(®ion.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(®ion.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) { -- 2.39.5