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tcg: Allocate code_gen_buffer into struct tcg_region_state

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Do not mess around with setting values within tcg_init_ctx.
Put the values into 'region' directly, which is where they
will live for the lifetime of the program.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-03-10 12:34:27 -06:00
parent 47d590df34
commit 032a4b1ba0
1 changed files with 27 additions and 37 deletions
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64
tcg/region.c
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@ -70,13 +70,12 @@ static size_t tree_size;
bool in_code_gen_buffer(const void *p)
{
const TCGContext *s = &tcg_init_ctx;
/*
* Much like it is valid to have a pointer to the byte past the
* end of an array (so long as you don't dereference it), allow
* a pointer to the byte past the end of the code gen buffer.
*/
return (size_t)(p - s->code_gen_buffer) <= s->code_gen_buffer_size;
return (size_t)(p - region.start_aligned) <= region.total_size;
}
#ifdef CONFIG_DEBUG_TCG
@ -562,8 +561,8 @@ static bool alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
}
qemu_madvise(buf, size, QEMU_MADV_HUGEPAGE);
tcg_ctx->code_gen_buffer = buf;
tcg_ctx->code_gen_buffer_size = size;
region.start_aligned = buf;
region.total_size = size;
return true;
}
#elif defined(_WIN32)
@ -584,8 +583,8 @@ static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
return false;
}
tcg_ctx->code_gen_buffer = buf;
tcg_ctx->code_gen_buffer_size = size;
region.start_aligned = buf;
region.total_size = size;
return true;
}
#else
@ -637,8 +636,8 @@ static bool alloc_code_gen_buffer_anon(size_t size, int prot,
/* Request large pages for the buffer. */
qemu_madvise(buf, size, QEMU_MADV_HUGEPAGE);
tcg_ctx->code_gen_buffer = buf;
tcg_ctx->code_gen_buffer_size = size;
region.start_aligned = buf;
region.total_size = size;
return true;
}
@ -659,8 +658,8 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
return false;
}
/* The size of the mapping may have been adjusted. */
size = tcg_ctx->code_gen_buffer_size;
buf_rx = tcg_ctx->code_gen_buffer;
buf_rx = region.start_aligned;
size = region.total_size;
#endif
buf_rw = qemu_memfd_alloc("tcg-jit", size, 0, &fd, errp);
@ -682,8 +681,8 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
#endif
close(fd);
tcg_ctx->code_gen_buffer = buf_rw;
tcg_ctx->code_gen_buffer_size = size;
region.start_aligned = buf_rw;
region.total_size = size;
tcg_splitwx_diff = buf_rx - buf_rw;
/* Request large pages for the buffer and the splitwx. */
@ -734,7 +733,7 @@ static bool alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
return false;
}
buf_rw = (mach_vm_address_t)tcg_ctx->code_gen_buffer;
buf_rw = (mach_vm_address_t)region.start_aligned;
buf_rx = 0;
ret = mach_vm_remap(mach_task_self(),
&buf_rx,
@ -846,11 +845,8 @@ static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
*/
void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
{
void *buf, *aligned, *end;
size_t total_size;
size_t page_size;
size_t region_size;
size_t n_regions;
size_t i;
bool ok;
@ -858,39 +854,33 @@ void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
splitwx, &error_fatal);
assert(ok);
buf = tcg_init_ctx.code_gen_buffer;
total_size = tcg_init_ctx.code_gen_buffer_size;
page_size = qemu_real_host_page_size;
n_regions = tcg_n_regions(total_size, max_cpus);
/* 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 + total_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 = (total_size - (aligned - buf)) / n_regions;
region.n = tcg_n_regions(region.total_size, max_cpus);
page_size = qemu_real_host_page_size;
region_size = region.total_size / region.n;
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);
region.stride = region_size;
/* Reserve space for guard pages. */
region.size = region_size - page_size;
region.total_size -= page_size;
/*
* The first region will be smaller than the others, via the prologue,
* which has yet to be allocated. For now, the first region begins at
* the page boundary.
*/
region.after_prologue = region.start_aligned;
/* init the region struct */
qemu_mutex_init(&region.lock);
region.n = n_regions;
region.size = region_size - page_size;
region.stride = region_size;
region.after_prologue = buf;
region.start_aligned = aligned;
/* page-align the end, since its last page will be a guard page */
end = QEMU_ALIGN_PTR_DOWN(buf + total_size, page_size);
/* account for that last guard page */
end -= page_size;
total_size = end - aligned;
region.total_size = total_size;
/*
* Set guard pages in the rw buffer, as that's the one into which