| Message ID | 20201214140314.18544-20-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Mirror map JIT memory for TCG | expand |
Guarding MAP_JIT with
if (!splitwx) {
flags |= MAP_JIT;
}
is better because MAP_JIT tells the kernel that we want a RWX mapping
which is not the case. On iOS, special entitlements are needed for
MAP_JIT.
-j
On Mon, Dec 14, 2020 at 6:03 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> 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>
> ---
> accel/tcg/translate-all.c | 65 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 65 insertions(+)
>
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index 1931e65365..17df6c94fa 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 +1263,9 @@ 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). */
> + flags |= MAP_JIT;
> #endif
>
> return alloc_code_gen_buffer_anon(size, prot, flags, errp);
> --
> 2.25.1
>
On 1/4/21 8:02 PM, Joelle van Dyne wrote: > Guarding MAP_JIT with > > if (!splitwx) { > flags |= MAP_JIT; > } > > is better because MAP_JIT tells the kernel that we want a RWX mapping > which is not the case. On iOS, special entitlements are needed for > MAP_JIT. Thanks, fixed. r~
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 1931e65365..17df6c94fa 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 +1263,9 @@ 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). */ + flags |= MAP_JIT; #endif return alloc_code_gen_buffer_anon(size, prot, flags, errp);