{"id":2232508,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2232508/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260504-feat-mte4-v5-12-232a648e63c6@gmail.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260504-feat-mte4-v5-12-232a648e63c6@gmail.com>","date":"2026-05-04T15:50:45","name":"[v5,12/15] target/arm: tag is not a part of PAuth with MTX","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"b00f11511c5998201aa4a1d0e2de83d25dc5a836","submitter":{"id":91863,"url":"http://patchwork.ozlabs.org/api/1.1/people/91863/?format=json","name":"Gabriel Brookman","email":"brookmangabriel@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260504-feat-mte4-v5-12-232a648e63c6@gmail.com/mbox/","series":[{"id":502688,"url":"http://patchwork.ozlabs.org/api/1.1/series/502688/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=502688","date":"2026-05-04T15:50:33","name":"target/arm: add support for MTE4","version":5,"mbox":"http://patchwork.ozlabs.org/series/502688/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2232508/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2232508/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=ZzuGG8ZD;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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charset=\"utf-8\"","Content-Transfer-Encoding":"7bit","Message-Id":"<20260504-feat-mte4-v5-12-232a648e63c6@gmail.com>","References":"<20260504-feat-mte4-v5-0-232a648e63c6@gmail.com>","In-Reply-To":"<20260504-feat-mte4-v5-0-232a648e63c6@gmail.com>","To":"qemu-devel@nongnu.org","Cc":"Peter Maydell ,\n Gustavo Romero ,\n Richard Henderson , qemu-arm@nongnu.org,\n Laurent Vivier ,\n Gabriel Brookman , Helge Deller ,\n Pierrick Bouvier ,\n Pierrick Bouvier ","X-Mailer":"b4 0.15.2","X-Developer-Signature":"v=1; a=ed25519-sha256; t=1777909867; l=3109;\n i=brookmangabriel@gmail.com; s=20251009; h=from:subject:message-id;\n bh=i7naSFKtsdz7oJ/mLAV3eXUKurGnggfA0UJX9vwXyVE=;\n b=beRiuMoGUh2trILB0UOertQUMc/zy6fknjcq7gSUZHgKun0WCnuuWwBVfNhaJW7+EirEeH2lY\n 1/4idKjmpHAD3FtHMGyqprB+YkcsbXSUDzwf8gwybtQgDXPwEG13OfQ","X-Developer-Key":"i=brookmangabriel@gmail.com; a=ed25519;\n pk=m9TtPDal6WzoHNnQiHHKf8dTrv3DUCPUUTujuo8vNrw=","Received-SPF":"pass client-ip=2607:f8b0:4864:20::82f;\n envelope-from=brookmangabriel@gmail.com; helo=mail-qt1-x82f.google.com","X-Spam_score_int":"-10","X-Spam_score":"-1.1","X-Spam_bar":"-","X-Spam_report":"(-1.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FORGED_GMAIL_RCVD=1,\n FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=no autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"As described in the section on MTX, tag bits should not be used to store\nor compute the PAC when MTX is set. See also Authenticate(),\nInsertPAC(), and Strip().\n\nSigned-off-by: Gabriel Brookman \n---\n target/arm/internals.h | 12 +++++++++++-\n target/arm/tcg/pauth_helper.c | 18 +++++++++++++++++-\n 2 files changed, 28 insertions(+), 2 deletions(-)","diff":"diff --git a/target/arm/internals.h b/target/arm/internals.h\nindex d313d36603..31b7e1c85e 100644\n--- a/target/arm/internals.h\n+++ b/target/arm/internals.h\n@@ -1809,7 +1809,17 @@ static inline uint64_t pauth_ptr_mask(ARMVAParameters param)\n int bot_pac_bit = 64 - param.tsz;\n int top_pac_bit = 64 - 8 * param.tbi;\n \n- return MAKE_64BIT_MASK(bot_pac_bit, top_pac_bit - bot_pac_bit);\n+ uint64_t mask = MAKE_64BIT_MASK(bot_pac_bit, top_pac_bit - bot_pac_bit);\n+\n+ /*\n+ * If mtx is enabled, second nibble is not part of PAC. See\n+ * InsertPAC().\n+ */\n+ if (param.mtx) {\n+ mask &= ~MAKE_64BIT_MASK(56, 4);\n+ }\n+\n+ return mask;\n }\n \n /* Add the cpreg definitions for debug related system registers */\ndiff --git a/target/arm/tcg/pauth_helper.c b/target/arm/tcg/pauth_helper.c\nindex 67c0d59d9e..3d83ca4c3c 100644\n--- a/target/arm/tcg/pauth_helper.c\n+++ b/target/arm/tcg/pauth_helper.c\n@@ -342,9 +342,16 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,\n }\n \n /* Build a pointer with known good extension bits. */\n- top_bit = 64 - 8 * param.tbi;\n+ top_bit = 64 - 8 * (param.tbi || param.mtx);\n bot_bit = 64 - param.tsz;\n ext_ptr = deposit64(ptr, bot_bit, top_bit - bot_bit, ext);\n+ /*\n+ * If mtx is active but not tbi, then the top 4 bits are replaced with the\n+ * ext bit, while leaving bits 56-59 alone. See InsertPAC().\n+ */\n+ if (param.mtx && !param.tbi) {\n+ ext_ptr = deposit64(ext_ptr, 60, 4, ext);\n+ }\n \n pac = pauth_computepac(env, ext_ptr, modifier, *key);\n \n@@ -377,6 +384,11 @@ static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,\n if (param.tbi) {\n ptr &= ~MAKE_64BIT_MASK(bot_bit, 55 - bot_bit + 1);\n pac &= MAKE_64BIT_MASK(bot_bit, 54 - bot_bit + 1);\n+ } else if (param.mtx) {\n+ ptr &= ~(MAKE_64BIT_MASK(60, 4) |\n+ MAKE_64BIT_MASK(bot_bit, 55 - bot_bit + 1));\n+ pac &= MAKE_64BIT_MASK(60, 4) |\n+ MAKE_64BIT_MASK(bot_bit, 54 - bot_bit + 1);\n } else {\n ptr &= MAKE_64BIT_MASK(0, bot_bit);\n pac &= ~(MAKE_64BIT_MASK(55, 1) | MAKE_64BIT_MASK(0, bot_bit));\n@@ -424,6 +436,10 @@ static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,\n cmp_mask = MAKE_64BIT_MASK(bot_bit, top_bit - bot_bit);\n cmp_mask &= ~MAKE_64BIT_MASK(55, 1);\n \n+ if (param.mtx) {\n+ cmp_mask &= ~MAKE_64BIT_MASK(56, 4);\n+ }\n+\n if (pauth_feature >= PauthFeat_2) {\n ARMPauthFeature fault_feature =\n is_combined ? PauthFeat_FPACCOMBINED : PauthFeat_FPAC;\n","prefixes":["v5","12/15"]}