From nobody Tue Feb 10 08:41:14 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1558564771; cv=none; d=zoho.com; s=zohoarc; b=KXNBzZk102jpoavmz/0FsRgsjNN0cWbTXjjTAv87sickHTWsrEfcGZTT0CJmi6IhjCqm18YhAOjHPctbhYMLbgH8UQzZUX5l+ihMeDu2Oxr790mq+5FUqKW+qUXACEA4tb8gqaf1Qp0bAVW7B7UirLHuDbcjRTzkfkC+dx974rA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1558564771; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=xoXIkCrK3V7BH4MhmjLPxOrcr1ayi9bYK48w1V2yt0Q=; b=hkELPTEwHnoe29OJF8CS4Fy6WtUH8iFbI/J3/QtPgLpifa0i5a2Ve/5tnPOr0eOvE+x7+vQNNgU40WnRFQf5o+K5Q+A3ZwMQXKkr4o0MaYJmezJJqSWAbXhp+KgdPEaiBwV56EC6/wcTXVkgTdR7RrKoB+3yFdESQ6T5yQUOq9c= ARC-Authentication-Results: i=1; mx.zoho.com; dkim=fail; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1558564771769662.6440847793722; Wed, 22 May 2019 15:39:31 -0700 (PDT) Received: from localhost ([127.0.0.1]:52633 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTZtO-0002Ux-Cl for importer@patchew.org; Wed, 22 May 2019 18:39:26 -0400 Received: from eggs.gnu.org ([209.51.188.92]:49952) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTZj5-0003Ab-8u for qemu-devel@nongnu.org; Wed, 22 May 2019 18:28:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hTZj3-0007S7-Vo for qemu-devel@nongnu.org; Wed, 22 May 2019 18:28:47 -0400 Received: from mail-yb1-xb42.google.com ([2607:f8b0:4864:20::b42]:42799) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hTZj3-0007Pp-P9 for qemu-devel@nongnu.org; Wed, 22 May 2019 18:28:45 -0400 Received: by mail-yb1-xb42.google.com with SMTP id a21so1487406ybg.9 for ; Wed, 22 May 2019 15:28:41 -0700 (PDT) Received: from localhost.localdomain ([71.46.56.17]) by smtp.gmail.com with ESMTPSA id q11sm2276453ywg.7.2019.05.22.15.28.40 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 May 2019 15:28:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=xoXIkCrK3V7BH4MhmjLPxOrcr1ayi9bYK48w1V2yt0Q=; b=fTiFpJr6MaizSsFIhcrL8ePFaPoA/fdloKYzsG/NjD6FCXV9MSF96sPiscm/12Hc8P jmolJMzgFClnXxz01bH9J05E0m7TMStGYP2cusMN20WSoWhFUv9j0fgPIrMdd3T3+vaH MwkZCaf7MeB3ZuYovoVTKqs0KMO2dy9kEzQLyhRA62BabiV1jzybnFQ+/WbWodwTT01f HixsX7yoEm+yOeARKsZhcfjtAXPBZQzb0cZlqoujYHixc39jznt+/m+k2rH5/x7fzMKR qRrJXGVVqvW8h2RMt0GAp1vZEyfWsTbgENYXPfmP3/I3TFT6jiwoXOrrEg0g8kz8jwfa 8Zww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=xoXIkCrK3V7BH4MhmjLPxOrcr1ayi9bYK48w1V2yt0Q=; b=g4wZtGPeyxfmjHLS6WKQdtCvp+kwICqR8l3ZwBPeVrxzgUHn6DIxlBHzS6BeOmDcCA D3z05qdef7Z5ri4zYBujLwhm0gXdQG2wv7sV8PZrs0TFUDbGOBgGkareauwntbAfYp4c JKZptozY3zgd86QbYW8CLBkKkfiREvzIid4tDlYDacMcvpb2/YQ44KQNk91hoKDwxOVU gVei4nn59WjLFHPAYYf5LpU3rPQNjtFA9z8c/CG+3OULqQEMBu2HOb0uDdoTGC7LZt/Y ucRt/TOZFdABUJIhPI8Gh9JplX6zNNGi4GXNqtOwVzJ2Er8+bIYRe1jI/OM1HbK5VXib V6Iw== X-Gm-Message-State: APjAAAVXT58C1/JPi8VaLGvp/UVWRasLaxnLdl/8JQ4o7SdCQeEbCq8b njcZBe0XArt7VoLNwlkBpEtcJsce2tw= X-Google-Smtp-Source: APXvYqxN/wUVAAZoaLfQi0YFG74OhQoRtFizsIxcy09LwaRFiRcgzy/YQiT65vAeAzn+LcbLwBMYSg== X-Received: by 2002:a25:dc3:: with SMTP id 186mr22561627ybn.276.1558564121109; Wed, 22 May 2019 15:28:41 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Wed, 22 May 2019 18:28:21 -0400 Message-Id: <20190522222821.23850-17-richard.henderson@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190522222821.23850-1-richard.henderson@linaro.org> References: <20190522222821.23850-1-richard.henderson@linaro.org> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::b42 Subject: [Qemu-devel] [PULL 16/16] tcg/i386: Use MOVDQA for TCG_TYPE_V128 load/store X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This instruction raises #GP, aka SIGSEGV, if the effective address is not aligned to 16-bytes. We have assertions in tcg-op-gvec.c that the offset from ENV is aligned, for vector types <=3D V128. But the offset itself does not validate that the final pointer is aligned -- one must also remember to use the QEMU_ALIGNED() attribute on the vector member within ENV. PowerPC Altivec has vector load/store instructions that silently discard the low 4 bits of the address, making alignment mistakes difficult to discover. Aid that by making the most popular host visibly signal the error. Signed-off-by: Richard Henderson --- tcg/i386/tcg-target.inc.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index 6ec5e60448..c0443da4af 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -1082,14 +1082,24 @@ static void tcg_out_ld(TCGContext *s, TCGType type,= TCGReg ret, } /* FALLTHRU */ case TCG_TYPE_V64: + /* There is no instruction that can validate 8-byte alignment. */ tcg_debug_assert(ret >=3D 16); tcg_out_vex_modrm_offset(s, OPC_MOVQ_VqWq, ret, 0, arg1, arg2); break; case TCG_TYPE_V128: + /* + * The gvec infrastructure is asserts that v128 vector loads + * and stores use a 16-byte aligned offset. Validate that the + * final pointer is aligned by using an insn that will SIGSEGV. + */ tcg_debug_assert(ret >=3D 16); - tcg_out_vex_modrm_offset(s, OPC_MOVDQU_VxWx, ret, 0, arg1, arg2); + tcg_out_vex_modrm_offset(s, OPC_MOVDQA_VxWx, ret, 0, arg1, arg2); break; case TCG_TYPE_V256: + /* + * The gvec infrastructure only requires 16-byte alignment, + * so here we must use an unaligned load. + */ tcg_debug_assert(ret >=3D 16); tcg_out_vex_modrm_offset(s, OPC_MOVDQU_VxWx | P_VEXL, ret, 0, arg1, arg2); @@ -1117,14 +1127,24 @@ static void tcg_out_st(TCGContext *s, TCGType type,= TCGReg arg, } /* FALLTHRU */ case TCG_TYPE_V64: + /* There is no instruction that can validate 8-byte alignment. */ tcg_debug_assert(arg >=3D 16); tcg_out_vex_modrm_offset(s, OPC_MOVQ_WqVq, arg, 0, arg1, arg2); break; case TCG_TYPE_V128: + /* + * The gvec infrastructure is asserts that v128 vector loads + * and stores use a 16-byte aligned offset. Validate that the + * final pointer is aligned by using an insn that will SIGSEGV. + */ tcg_debug_assert(arg >=3D 16); - tcg_out_vex_modrm_offset(s, OPC_MOVDQU_WxVx, arg, 0, arg1, arg2); + tcg_out_vex_modrm_offset(s, OPC_MOVDQA_WxVx, arg, 0, arg1, arg2); break; case TCG_TYPE_V256: + /* + * The gvec infrastructure only requires 16-byte alignment, + * so here we must use an unaligned store. + */ tcg_debug_assert(arg >=3D 16); tcg_out_vex_modrm_offset(s, OPC_MOVDQU_WxVx | P_VEXL, arg, 0, arg1, arg2); --=20 2.17.1