From nobody Sun Jun 7 22:18:44 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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; dmarc=pass(p=none dis=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; t=1780753713; cv=none; d=zohomail.com; s=zohoarc; b=DFeuS4ajNWzVwEqUujKhF1tnLe1pDyrRo+n3aoa0q+0qjI0Dt8a61KUX6xhvGwn50yrbfM6/6iPfnjFqa2Pbj+Jfsno4pBPvQFQ+DuQvgJcQmwg8YSOFeunu9HZPQ8MYkPga2vfs7NQYdjybuRrZ+WtsQs/T3nnRrPg4mAPy2RM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1780753713; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=f2lDKcqQ8unO0L5ykgRMFRBw2EOUQnwyumW8J8Iy/4c=; b=Rjg9LosfZzcisNr+wGRieH4Gvd5lR3ercER9v187q8IYaTZ/FctMqiJAw+2xBB3BL13KQnLgzpQBBtCPiZim2nsTZHaXuWQDXrOJXv7oEZUHcKG9JDvmmw6irV91kDpSzoM+SweBUDgT6nv3JElVl9svEStFsU88C9JY1aLONDY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1780753713808279.26389857256254; Sat, 6 Jun 2026 06:48:33 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wVrNX-0002Ru-Qx; Sat, 06 Jun 2026 09:48:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wVnCk-0000Rb-LK for qemu-devel@nongnu.org; Sat, 06 Jun 2026 05:20:34 -0400 Received: from mail-lj1-x235.google.com ([2a00:1450:4864:20::235]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1wVnCi-0003Xp-R4 for qemu-devel@nongnu.org; Sat, 06 Jun 2026 05:20:34 -0400 Received: by mail-lj1-x235.google.com with SMTP id 38308e7fff4ca-3967717c951so29221671fa.1 for ; Sat, 06 Jun 2026 02:20:32 -0700 (PDT) Received: from kali ([82.162.57.219]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-396ac2be11esm29306311fa.27.2026.06.06.02.20.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 06 Jun 2026 02:20:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780737630; x=1781342430; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=f2lDKcqQ8unO0L5ykgRMFRBw2EOUQnwyumW8J8Iy/4c=; b=Et8d8RhwqZFH+Rlsh3wvKpSLcsN78Dz2IylTb9l4BY8OwK+njT5hPLgqpLQoHdqcPW zWTxgkl8kpuG2q7fwDR+v1UHVHQHXHlQOicpU1bLhuPQNe2wUpoxXvhqbOifeu2Y79w/ kAiIpQnbP7tlSy5wbdT/JfQC4cVZrtSFn30z0VMwle02rozDFqKJMo7Gxc9EmStJxupD U7uD0l8vuQ2QIae+luTVu0S8QCXUGlUDD8XGfBJsi1pMr2FJW1tO3/qrTdDvJsnVF6dp aEaSPbizUkHhTKy3mqBGoPm8KNgyPt/q0c5lbrmyHRhudlnQeyjS6BnwmIH4LxK89Exi luKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780737630; x=1781342430; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=f2lDKcqQ8unO0L5ykgRMFRBw2EOUQnwyumW8J8Iy/4c=; b=FHwJd50a6xXDkN5VyhljCmqEECKpCksC6+Nh65YRnUH2rVw7mGQrPaRsjrGGZkJMuM 1l6slDGOZpRwAE+v/NrOF3b7TPOxegdISk2uuqAtJwW7o+wt06+aIvElpTQ2FKtldwKV yqHrPuNBJZm6b3CBhzorGNU1Gw069cLL4Xv6gXvCktF1/f8EcHC6MWBiVxxSZlDuPon4 07uzRho6i1ryARXnSyfk374xnmQpGo+WFcmKxTS3X33D/hpTlvusnOSmRDOkZ6emM5Y3 9p1S4yEKXfP+cwXTksG1uVc/h+KVMEoyH5CfSNDuX+mWmWISBUTOH3IniVmov3m2lg9v Z7/Q== X-Gm-Message-State: AOJu0YydjeTN6cK93MES7tkERagjbb8btRpPM614cO5vsDjOFP6Ke026 /GaJeCtj6ng913u7YnxOU2ioOQ6KUymheEOVvV6d7bjiFMxrsq2SYgaj+W601OLt X-Gm-Gg: Acq92OGrQbuNmc1aaHt5RpdQz4PWFVlraHoOL9tEokWxZXrNqpgKtxcPP/k5LBr7bwf 5R+fixgNZJnS4ql1IYoYBPXbEN2OwRv902LU+EkQVcnkDAOpXAF0sEnhzYUrR5c2yBH2QlpDVE7 s+RArfXqInCEYubqJ3vzcdg1vNNhCUx+aRmrvE3CxuP900XQaRFB6D+8RRZntiUSvUmLzmVlmf+ zJjLdQ7L4Pi+lJ7Wxcv5HRvdX6PfMeyI5RukmX92GQqHCaPfaynJCzO7o9r/HBOGLfRASDmNE26 u2r57XRF3tj4LfaijjBe5KgpXTp+TsqBHW2dmmju+Zbvi8xL1nlJHHjmORLXUvFR+twAHVefIcK z3rrxsN4sgupehlZfIMj1djJ1cGSnVOer6ZIcwNSCRzcEHuOVme4LBQe5ZIgmVeHfQQxZSTTIlq ww84oF+rWeAXOQZGTI9RzHa17oDF0= X-Received: by 2002:a2e:a58b:0:b0:391:1570:b6c6 with SMTP id 38308e7fff4ca-396d07f0a62mr20909731fa.2.1780737630144; Sat, 06 Jun 2026 02:20:30 -0700 (PDT) From: Andrey Polivoda To: qemu-devel@nongnu.org Cc: Andrey Polivoda Subject: [PATCH] target/i386: helper_sysret(): Check that RCX contains a canonical address when emulating an Intel CPU Date: Sat, 6 Jun 2026 19:20:12 +1000 Message-ID: <20260606092022.67929-1-apolivodaa433@gmail.com> X-Mailer: git-send-email 2.53.0 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=lists1p.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::235; envelope-from=apolivodaa433@gmail.com; helo=mail-lj1-x235.google.com X-Spam_score_int: -7 X-Spam_score: -0.8 X-Spam_bar: / X-Spam_report: (-0.8 / 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, FORGED_GMAIL_RCVD=1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Sat, 06 Jun 2026 09:47:42 -0400 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1780753714496158500 Content-Type: text/plain; charset="utf-8" Intel and AMD CPUs implement SYSRETQ instruction differently. One of these differences is whether a canonicality check of the address that will be loaded to RIP is performed: Intel CPUs do this check, AMD CPUs don'= t. Currently, QEMU does not perform this check when emulating Intel CPUs. This patch corrects this by implementing the canonlicality check on a new R= IP value from RCX and performing it only when emulating Intel CPUs. Flags and segment registers' caches are updated only after checking the new= RIP value to ensure that CPU state is not modified in case the #GP(0) exception is raised due to the check failure. Cc: qemu-devel@nongnu.org, Paolo Bonzini , Richard Henderson Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3223 Signed-off-by: Andrey Polivoda --- target/i386/tcg/seg_helper.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/target/i386/tcg/seg_helper.c b/target/i386/tcg/seg_helper.c index 58aac72011..d5c174b7fd 100644 --- a/target/i386/tcg/seg_helper.c +++ b/target/i386/tcg/seg_helper.c @@ -1096,17 +1096,22 @@ void helper_sysret(CPUX86State *env, int dflag) selector =3D (env->star >> 48) & 0xffff; #ifdef TARGET_X86_64 if (env->hflags & HF_LMA_MASK) { - cpu_load_eflags(env, (uint32_t)(env->regs[11]), TF_MASK | AC_MASK - | ID_MASK | IF_MASK | IOPL_MASK | VM_MASK | RF_MAS= K | - NT_MASK); if (dflag =3D=3D 2) { + uint64_t new_rip =3D env->regs[R_ECX]; + if (IS_INTEL_CPU(env)) { + int shift =3D (get_pg_mode(env) & PG_MODE_LA57) ? 56 : 47; + int64_t sext =3D (int64_t)new_rip >> shift; + if (sext !=3D 0 && sext !=3D -1) { + raise_exception_err_ra(env, EXCP0D_GPF, 0, GETPC()); + } + } cpu_x86_load_seg_cache(env, R_CS, (selector + 16) | 3, 0, 0xffffffff, DESC_G_MASK | DESC_P_MASK | DESC_S_MASK | (3 << DESC_DPL_SHIFT) | DESC_CS_MASK | DESC_R_MASK | DESC_A_MAS= K | DESC_L_MASK); - env->eip =3D env->regs[R_ECX]; + env->eip =3D new_rip; } else { cpu_x86_load_seg_cache(env, R_CS, selector | 3, 0, 0xffffffff, @@ -1120,6 +1125,10 @@ void helper_sysret(CPUX86State *env, int dflag) DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK | (3 << DESC_DPL_SHIFT) | DESC_W_MASK | DESC_A_MASK); + + cpu_load_eflags(env, (uint32_t)(env->regs[11]), TF_MASK | AC_MASK + | ID_MASK | IF_MASK | IOPL_MASK | VM_MASK | RF_MAS= K | + NT_MASK); } else #endif { --=20 2.53.0