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That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, j@getutm.app, laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" We cannot use a real temp file, because we would need to find a filesystem that does not have noexec enabled. However, a memfd is not associated with any filesystem. Signed-off-by: Richard Henderson --- accel/tcg/translate-all.c | 87 +++++++++++++++++++++++++++++++++++---- 1 file changed, 80 insertions(+), 7 deletions(-) diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index 8918a09f10..3e69ebd1d3 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1088,17 +1088,11 @@ static bool alloc_code_gen_buffer(size_t size, int = mirror, Error **errp) return true; } #else -static bool alloc_code_gen_buffer(size_t size, int mirror, Error **errp) +static bool alloc_code_gen_buffer_anon(size_t size, int prot, Error **errp) { - int prot =3D PROT_WRITE | PROT_READ | PROT_EXEC; int flags =3D MAP_PRIVATE | MAP_ANONYMOUS; void *buf; =20 - if (mirror > 0) { - error_setg(errp, "jit split-rwx not supported"); - return false; - } - buf =3D mmap(NULL, size, prot, flags, -1, 0); if (buf =3D=3D MAP_FAILED) { error_setg_errno(errp, errno, @@ -1147,6 +1141,85 @@ static bool alloc_code_gen_buffer(size_t size, int m= irror, Error **errp) tcg_ctx->code_gen_buffer =3D buf; return true; } + +#ifdef CONFIG_LINUX +#include "qemu/memfd.h" + +static bool alloc_code_gen_buffer_mirror_memfd(size_t size, Error **errp) +{ + void *buf_rw, *buf_rx; + int fd; + + fd =3D qemu_memfd_create("tcg-jit", size, false, 0, 0, errp); + if (fd < 0) { + return false; + } + + buf_rw =3D mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (buf_rw =3D=3D MAP_FAILED) { + error_setg_errno(errp, errno, + "allocate %zu bytes for jit buffer", size); + close(fd); + return false; + } + + buf_rx =3D mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_SHARED, fd, 0); + if (buf_rx =3D=3D MAP_FAILED) { + error_setg_errno(errp, errno, + "allocate %zu bytes for jit mirror", size); + munmap(buf_rw, size); + close(fd); + return false; + } + close(fd); + + tcg_ctx->code_gen_buffer =3D buf_rw; + tcg_ctx->code_gen_buffer_size =3D size; + tcg_rx_mirror_diff =3D buf_rx - buf_rw; + + /* Request large pages for the buffer and the mirror. */ + qemu_madvise(buf_rw, size, QEMU_MADV_HUGEPAGE); + qemu_madvise(buf_rx, size, QEMU_MADV_HUGEPAGE); + return true; +} +#endif + +static bool alloc_code_gen_buffer_mirror(size_t size, Error **errp) +{ + if (TCG_TARGET_SUPPORT_MIRROR) { +#ifdef CONFIG_LINUX + return alloc_code_gen_buffer_mirror_memfd(size, errp); +#endif + } + error_setg(errp, "jit split-rwx not supported"); + return false; +} + +static bool alloc_code_gen_buffer(size_t size, int mirror, Error **errp) +{ + if (mirror) { + Error *local_err =3D NULL; + if (alloc_code_gen_buffer_mirror(size, &local_err)) { + return true; + } + /* + * If mirror force-on (1), fail; + * if mirror default-on (-1), fall through to mirror off. + */ + if (mirror > 0) { + error_propagate(errp, local_err); + return false; + } + } + + int prot =3D PROT_READ | PROT_WRITE | PROT_EXEC; +#ifdef CONFIG_TCG_INTERPRETER + /* The tcg interpreter does not need execute permission. */ + prot =3D PROT_READ | PROT_WRITE; +#endif + + return alloc_code_gen_buffer_anon(size, prot, errp); +} #endif /* USE_STATIC_CODE_GEN_BUFFER, WIN32, POSIX */ =20 static bool tb_cmp(const void *ap, const void *bp) --=20 2.25.1