From nobody Tue Sep 23 22:15:43 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1752745898436613.2884422457379; Thu, 17 Jul 2025 02:51:38 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ucLFx-0002sv-1y; Thu, 17 Jul 2025 05:50:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ucL0R-0001pX-Ul; Thu, 17 Jul 2025 05:34:26 -0400 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ucL0P-0001nQ-Sa; Thu, 17 Jul 2025 05:34:23 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 47049137CE9; Thu, 17 Jul 2025 12:34:04 +0300 (MSK) Received: from think4mjt.origo (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id 2B7F62491E3; Thu, 17 Jul 2025 12:34:12 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Peter Maydell , Richard Henderson , Michael Tokarev Subject: [Stable-10.0.3 41/65] target/arm: Don't enforce NSE, NS check for EL3->EL3 returns Date: Thu, 17 Jul 2025 12:33:37 +0300 Message-ID: <20250717093412.728292-2-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1752745899615116600 Content-Type: text/plain; charset="utf-8" From: Peter Maydell In the Arm ARM, rule R_TYTWB that defines illegal exception return cases includes the case: If FEAT_RME is implemented, then if SCR_EL3.{NSE, NS} is {1, 0}, an exception return from EL3 to a lower Exception level Our implementation of this check fails to check that the return is to a lower exception level, so it will incorrectly fire on EL3->EL3 exception returns. Fix the check condition. This requires us to move it further down in the function to a point where we know the new_el value. Fixes: 35aa6715ddcd9 ("target/arm: Catch illegal-exception-return from EL3 = with bad NSE/NS") Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3016 Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20250704165636.261888-1-peter.maydell@linaro.org (cherry picked from commit c563cd7e61d074f58eef413322144461dd243716) Signed-off-by: Michael Tokarev diff --git a/target/arm/tcg/helper-a64.c b/target/arm/tcg/helper-a64.c index 9244848efe..be0935d194 100644 --- a/target/arm/tcg/helper-a64.c +++ b/target/arm/tcg/helper-a64.c @@ -653,15 +653,6 @@ void HELPER(exception_return)(CPUARMState *env, uint64= _t new_pc) spsr &=3D ~PSTATE_SS; } =20 - /* - * FEAT_RME forbids return from EL3 with an invalid security state. - * We don't need an explicit check for FEAT_RME here because we enforce - * in scr_write() that you can't set the NSE bit without it. - */ - if (cur_el =3D=3D 3 && (env->cp15.scr_el3 & (SCR_NS | SCR_NSE)) =3D=3D= SCR_NSE) { - goto illegal_return; - } - new_el =3D el_from_spsr(spsr); if (new_el =3D=3D -1) { goto illegal_return; @@ -673,6 +664,17 @@ void HELPER(exception_return)(CPUARMState *env, uint64= _t new_pc) goto illegal_return; } =20 + /* + * FEAT_RME forbids return from EL3 to a lower exception level + * with an invalid security state. + * We don't need an explicit check for FEAT_RME here because we enforce + * in scr_write() that you can't set the NSE bit without it. + */ + if (cur_el =3D=3D 3 && new_el < 3 && + (env->cp15.scr_el3 & (SCR_NS | SCR_NSE)) =3D=3D SCR_NSE) { + goto illegal_return; + } + if (new_el !=3D 0 && arm_el_is_aa64(env, new_el) !=3D return_to_aa64) { /* Return to an EL which is configured for a different register wi= dth */ goto illegal_return; --=20 2.47.2