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tcg: Add --accel tcg,split-wx property

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Plumb the value through to alloc_code_gen_buffer.  This is not
supported by any os or tcg backend, so for now enabling it will
result in an error.

Reviewed-by: Joelle van Dyne <j@getutm.app>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2020-10-28 20:50:29 -07:00
parent 6bc144237a
commit a35b3e1415
15 changed files with 72 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
accel/tcg/tcg-all.c
View File

@ -38,6 +38,7 @@ struct TCGState {
AccelState parent_obj;
bool mttcg_enabled;
int splitwx_enabled;
unsigned long tb_size;
};
typedef struct TCGState TCGState;
@ -94,6 +95,13 @@ static void tcg_accel_instance_init(Object *obj)
TCGState *s = TCG_STATE(obj);
s->mttcg_enabled = default_mttcg_enabled();
/* If debugging enabled, default "auto on", otherwise off. */
#ifdef CONFIG_DEBUG_TCG
s->splitwx_enabled = -1;
#else
s->splitwx_enabled = 0;
#endif
}
bool mttcg_enabled;
@ -102,7 +110,7 @@ static int tcg_init(MachineState *ms)
{
TCGState *s = TCG_STATE(current_accel());
tcg_exec_init(s->tb_size * 1024 * 1024);
tcg_exec_init(s->tb_size * 1024 * 1024, s->splitwx_enabled);
mttcg_enabled = s->mttcg_enabled;
/*
@ -179,6 +187,18 @@ static void tcg_set_tb_size(Object *obj, Visitor *v,
s->tb_size = value;
}
static bool tcg_get_splitwx(Object *obj, Error **errp)
{
TCGState *s = TCG_STATE(obj);
return s->splitwx_enabled;
}
static void tcg_set_splitwx(Object *obj, bool value, Error **errp)
{
TCGState *s = TCG_STATE(obj);
s->splitwx_enabled = value;
}
static void tcg_accel_class_init(ObjectClass *oc, void *data)
{
AccelClass *ac = ACCEL_CLASS(oc);
@ -196,6 +216,10 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data)
object_class_property_set_description(oc, "tb-size",
"TCG translation block cache size");
object_class_property_add_bool(oc, "split-wx",
tcg_get_splitwx, tcg_set_splitwx);
object_class_property_set_description(oc, "split-wx",
"Map jit pages into separate RW and RX regions");
}
static const TypeInfo tcg_accel_type = {

35
accel/tcg/translate-all.c
View File

@ -1015,13 +1015,19 @@ static inline void *split_cross_256mb(void *buf1, size_t size1)
static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE]
__attribute__((aligned(CODE_GEN_ALIGN)));
static bool alloc_code_gen_buffer(size_t tb_size, Error **errp)
static bool alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
{
void *buf = static_code_gen_buffer;
void *end = static_code_gen_buffer + sizeof(static_code_gen_buffer);
void *buf, *end;
size_t size;
if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported");
return false;
}
/* page-align the beginning and end of the buffer */
buf = static_code_gen_buffer;
end = static_code_gen_buffer + sizeof(static_code_gen_buffer);
buf = QEMU_ALIGN_PTR_UP(buf, qemu_real_host_page_size);
end = QEMU_ALIGN_PTR_DOWN(end, qemu_real_host_page_size);
@ -1050,9 +1056,16 @@ static bool alloc_code_gen_buffer(size_t tb_size, Error **errp)
return true;
}
#elif defined(_WIN32)
static bool alloc_code_gen_buffer(size_t size, Error **errp)
static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{
void *buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
void *buf;
if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported");
return false;
}
buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (buf == NULL) {
error_setg_win32(errp, GetLastError(),
@ -1065,12 +1078,17 @@ static bool alloc_code_gen_buffer(size_t size, Error **errp)
return true;
}
#else
static bool alloc_code_gen_buffer(size_t size, Error **errp)
static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{
int prot = PROT_WRITE | PROT_READ | PROT_EXEC;
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
void *buf;
if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported");
return false;
}
buf = mmap(NULL, size, prot, flags, -1, 0);
if (buf == MAP_FAILED) {
error_setg_errno(errp, errno,
@ -1145,7 +1163,7 @@ static void tb_htable_init(void)
/* Must be called before using the QEMU cpus. 'tb_size' is the size
(in bytes) allocated to the translation buffer. Zero means default
size. */
void tcg_exec_init(unsigned long tb_size)
void tcg_exec_init(unsigned long tb_size, int splitwx)
{
bool ok;
@ -1154,7 +1172,8 @@ void tcg_exec_init(unsigned long tb_size)
page_init();
tb_htable_init();
ok = alloc_code_gen_buffer(size_code_gen_buffer(tb_size), &error_fatal);
ok = alloc_code_gen_buffer(size_code_gen_buffer(tb_size),
splitwx, &error_fatal);
assert(ok);
#if defined(CONFIG_SOFTMMU)

2
bsd-user/main.c
View File

@ -909,7 +909,7 @@ int main(int argc, char **argv)
}
/* init tcg before creating CPUs and to get qemu_host_page_size */
tcg_exec_init(0);
tcg_exec_init(0, false);
cpu_type = parse_cpu_option(cpu_model);
cpu = cpu_create(cpu_type);

3
include/sysemu/tcg.h
View File

@ -8,7 +8,8 @@
#ifndef SYSEMU_TCG_H
#define SYSEMU_TCG_H
void tcg_exec_init(unsigned long tb_size);
void tcg_exec_init(unsigned long tb_size, int splitwx);
#ifdef CONFIG_TCG
extern bool tcg_allowed;
#define tcg_enabled() (tcg_allowed)

2
linux-user/main.c
View File

@ -701,7 +701,7 @@ int main(int argc, char **argv, char **envp)
cpu_type = parse_cpu_option(cpu_model);
/* init tcg before creating CPUs and to get qemu_host_page_size */
tcg_exec_init(0);
tcg_exec_init(0, false);
cpu = cpu_create(cpu_type);
env = cpu->env_ptr;

7
qemu-options.hx
View File

@ -115,6 +115,7 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel,
" igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
" kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n"
" kvm-shadow-mem=size of KVM shadow MMU in bytes\n"
" split-wx=on|off (enable TCG split w^x mapping)\n"
" tb-size=n (TCG translation block cache size)\n"
" thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
SRST
@ -140,6 +141,12 @@ SRST
``kvm-shadow-mem=size``
Defines the size of the KVM shadow MMU.
``split-wx=on|off``
Controls the use of split w^x mapping for the TCG code generation
buffer. Some operating systems require this to be enabled, and in
such a case this will default on. On other operating systems, this
will default off, but one may enable this for testing or debugging.
``tb-size=n``
Controls the size (in MiB) of the TCG translation block cache.

1
tcg/aarch64/tcg-target.h
View File

@ -155,5 +155,6 @@ void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#define TCG_TARGET_NEED_LDST_LABELS
#endif
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif /* AARCH64_TCG_TARGET_H */

1
tcg/arm/tcg-target.h
View File

@ -142,5 +142,6 @@ void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#define TCG_TARGET_NEED_LDST_LABELS
#endif
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/i386/tcg-target.h
View File

@ -235,5 +235,6 @@ static inline void tb_target_set_jmp_target(uintptr_t tc_ptr, uintptr_t jmp_rx,
#define TCG_TARGET_NEED_LDST_LABELS
#endif
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/mips/tcg-target.h
View File

@ -201,6 +201,7 @@ extern bool use_mips32r2_instructions;
#define TCG_TARGET_DEFAULT_MO (0)
#define TCG_TARGET_HAS_MEMORY_BSWAP 1
#define TCG_TARGET_SUPPORT_MIRROR 0
void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);

1
tcg/ppc/tcg-target.h
View File

@ -185,5 +185,6 @@ void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#define TCG_TARGET_NEED_LDST_LABELS
#endif
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/riscv/tcg-target.h
View File

@ -171,5 +171,6 @@ void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_HAS_MEMORY_BSWAP 0
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/s390/tcg-target.h
View File

@ -159,5 +159,6 @@ static inline void tb_target_set_jmp_target(uintptr_t tc_ptr, uintptr_t jmp_rx,
#define TCG_TARGET_NEED_LDST_LABELS
#endif
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/sparc/tcg-target.h
View File

@ -172,5 +172,6 @@ extern bool use_vis3_instructions;
void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
#define TCG_TARGET_NEED_POOL_LABELS
#define TCG_TARGET_SUPPORT_MIRROR 0
#endif

1
tcg/tci/tcg-target.h
View File

@ -198,6 +198,7 @@ void tci_disas(uint8_t opc);
#define TCG_TARGET_DEFAULT_MO (0)
#define TCG_TARGET_HAS_MEMORY_BSWAP 1
#define TCG_TARGET_SUPPORT_MIRROR 0
static inline void tb_target_set_jmp_target(uintptr_t tc_ptr, uintptr_t jmp_rx,
uintptr_t jmp_rw, uintptr_t addr)