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authorRichard Henderson <richard.henderson@linaro.org>2020-10-29 23:49:57 +0000
committerRichard Henderson <richard.henderson@linaro.org>2021-01-07 05:09:42 -1000
commit6f70ddee19ec7837812bda81cec59dc2681df0a9 (patch)
tree5636e5d4a0acd825416d633f8163207236a5ab0c
parenta8c35b2cadfc7bef5221ceee0725493461568528 (diff)
downloadqemu-arm-6f70ddee19ec7837812bda81cec59dc2681df0a9.tar.gz
accel/tcg: Support split-wx for darwin/iOS with vm_remap
Cribbed from code posted by Joelle van Dyne <j@getutm.app>, and rearranged to a cleaner structure. Reviewed-by: Joelle van Dyne <j@getutm.app> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
-rw-r--r--accel/tcg/translate-all.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 3b6804578d..c37718db4d 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1166,9 +1166,71 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
}
#endif /* CONFIG_POSIX */
+#ifdef CONFIG_DARWIN
+#include <mach/mach.h>
+
+extern kern_return_t mach_vm_remap(vm_map_t target_task,
+ mach_vm_address_t *target_address,
+ mach_vm_size_t size,
+ mach_vm_offset_t mask,
+ int flags,
+ vm_map_t src_task,
+ mach_vm_address_t src_address,
+ boolean_t copy,
+ vm_prot_t *cur_protection,
+ vm_prot_t *max_protection,
+ vm_inherit_t inheritance);
+
+static bool alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
+{
+ kern_return_t ret;
+ mach_vm_address_t buf_rw, buf_rx;
+ vm_prot_t cur_prot, max_prot;
+
+ /* Map the read-write portion via normal anon memory. */
+ if (!alloc_code_gen_buffer_anon(size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, errp)) {
+ return false;
+ }
+
+ buf_rw = (mach_vm_address_t)tcg_ctx->code_gen_buffer;
+ buf_rx = 0;
+ ret = mach_vm_remap(mach_task_self(),
+ &buf_rx,
+ size,
+ 0,
+ VM_FLAGS_ANYWHERE,
+ mach_task_self(),
+ buf_rw,
+ false,
+ &cur_prot,
+ &max_prot,
+ VM_INHERIT_NONE);
+ if (ret != KERN_SUCCESS) {
+ /* TODO: Convert "ret" to a human readable error message. */
+ error_setg(errp, "vm_remap for jit splitwx failed");
+ munmap((void *)buf_rw, size);
+ return false;
+ }
+
+ if (mprotect((void *)buf_rx, size, PROT_READ | PROT_EXEC) != 0) {
+ error_setg_errno(errp, errno, "mprotect for jit splitwx");
+ munmap((void *)buf_rx, size);
+ munmap((void *)buf_rw, size);
+ return false;
+ }
+
+ tcg_splitwx_diff = buf_rx - buf_rw;
+ return true;
+}
+#endif /* CONFIG_DARWIN */
+
static bool alloc_code_gen_buffer_splitwx(size_t size, Error **errp)
{
if (TCG_TARGET_SUPPORT_MIRROR) {
+#ifdef CONFIG_DARWIN
+ return alloc_code_gen_buffer_splitwx_vmremap(size, errp);
+#endif
#ifdef CONFIG_POSIX
return alloc_code_gen_buffer_splitwx_memfd(size, errp);
#endif
@@ -1201,6 +1263,11 @@ static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
#ifdef CONFIG_TCG_INTERPRETER
/* The tcg interpreter does not need execute permission. */
prot = PROT_READ | PROT_WRITE;
+#elif defined(CONFIG_DARWIN)
+ /* Applicable to both iOS and macOS (Apple Silicon). */
+ if (!splitwx) {
+ flags |= MAP_JIT;
+ }
#endif
return alloc_code_gen_buffer_anon(size, prot, flags, errp);