From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 13B53C77B78 for ; Wed, 3 May 2023 07:11:31 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pu6aH-0005ak-Oo; Wed, 03 May 2023 03:07:29 -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 1pu6Zr-0004z3-5i for qemu-devel@nongnu.org; Wed, 03 May 2023 03:07:04 -0400 Received: from mail-wm1-x32a.google.com ([2a00:1450:4864:20::32a]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pu6Zn-0005Z5-Uw for qemu-devel@nongnu.org; Wed, 03 May 2023 03:07:02 -0400 Received: by mail-wm1-x32a.google.com with SMTP id 5b1f17b1804b1-3f19afc4fbfso47405925e9.2 for ; Wed, 03 May 2023 00:06:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1683097618; x=1685689618; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=3lrJF/qXESqdgqxzYXiwMDd8bhgg68V4bNiRRkSEKr0=; b=rCmOgqNAQXzxJaeE44P1uzRxHyYzgGSz+R20lDdTbMbEeULdSML9aJ7Jy6O8YKxeua RQnf0qy6x2T3KLgONhUoeTN+4yxzxYCmkjLYYDEmyxrOC00Doov9XJwAvv4e9n4yTz+N UIzjh+1vq0Sc5IPjn6js4IDLQ6DMzgUj14Bj4AMQo9/2LxS+zeSLTXkTuJVWCDQwuToI Od688Wzlfjnq/rB3ZbOAUHj/WIa/hMG6SK2fYfiZ/JaTD5LsThm60muVfThy19pMhBt4 wDYpshDaeuSWEyNc+S+krKRRhBw0IqUh0YxtwS9RnzX9JkewWWc6QnPtigfy9TX57zYV qv/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683097618; x=1685689618; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=3lrJF/qXESqdgqxzYXiwMDd8bhgg68V4bNiRRkSEKr0=; b=lQtEg7GXKzxolG4Jxo0bKVObRibVAs4pFEfOlvCYQ4+8a9vIN6UPqTSTmFfERD71fz emBGboV2sPK47EfgoN3zNNUe9WnKj+12dAts3PQH0fBcoeYxlbCmvSjOs7yDppaAFPPp uXq45ipjHTgiWB7RsODBiqIn8AEv2zX4zsMcP9NQJe3aG1SGMQa8y8rn8oCWbyli0RXB ik36TtVl6P9hIqlJmW7TGv6DgE3UOFaAE7Mb8kzk9VJ+mC0T0XLrBaTm6uIUqHwvmsjs uEkTxG/PdBPVSH01QMR+rlDbkrZVnfoqL3OMt62HxtMx3z0PPcWHKDzCKTHKWS+mQz9V R2UQ== X-Gm-Message-State: AC+VfDz9QQtD03w9H8Bqh7/iqt1aZyhyjg6nQ59PPT8li/YT/SLz529H hx6Vjq0xjfXYrP64p9oPLQyvd+hHnnwssQMxOZiWeg== X-Google-Smtp-Source: ACHHUZ6HZknxjkIjOTnL/jTJnQK537wsWbM7Yod/9DV9Ne602iFmwSW+LsmqsaVqKJ8hpFb4xRUTJw== X-Received: by 2002:a7b:cd18:0:b0:3f1:9525:7bb6 with SMTP id f24-20020a7bcd18000000b003f195257bb6mr13570542wmj.5.1683097618487; Wed, 03 May 2023 00:06:58 -0700 (PDT) Received: from stoup.Home ([2a02:c7c:74db:8d00:c01d:9d74:b630:9087]) by smtp.gmail.com with ESMTPSA id q3-20020a1cf303000000b003f3157988f8sm921184wmq.26.2023.05.03.00.06.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 May 2023 00:06:58 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: git@xen0n.name, gaosong@loongson.cn, philmd@linaro.org, qemu-arm@nongnu.org, qemu-riscv@nongnu.org, qemu-s390x@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= Subject: [PATCH v4 01/57] include/exec/memop: Add bits describing atomicity Date: Wed, 3 May 2023 08:06:00 +0100 Message-Id: <20230503070656.1746170-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230503070656.1746170-1-richard.henderson@linaro.org> References: <20230503070656.1746170-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::32a; envelope-from=richard.henderson@linaro.org; helo=mail-wm1-x32a.google.com 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, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org These bits may be used to describe the precise atomicity requirements of the guest, which may then be used to constrain the methods by which it may be emulated by the host. For instance, the AArch64 LDP (32-bit) instruction changes semantics with ARMv8.4 LSE2, from MO_64 | MO_ATMAX_4 | MO_ATOM_IFALIGN (64-bits, single-copy atomic only on 4 byte units, nonatomic if not aligned by 4), to MO_64 | MO_ATMAX_SIZE | MO_ATOM_WITHIN16 (64-bits, single-copy atomic within a 16 byte block) The former may be implemented with two 4 byte loads, or a single 8 byte load if that happens to be efficient on the host. The latter may not, and may also require a helper when misaligned. Reviewed-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- include/exec/memop.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/include/exec/memop.h b/include/exec/memop.h index 25d027434a..04e4048f0b 100644 --- a/include/exec/memop.h +++ b/include/exec/memop.h @@ -81,6 +81,42 @@ typedef enum MemOp { MO_ALIGN_32 = 5 << MO_ASHIFT, MO_ALIGN_64 = 6 << MO_ASHIFT, + /* + * MO_ATOM_* describes that atomicity requirements of the operation: + * MO_ATOM_IFALIGN: the operation must be single-copy atomic if and + * only if it is aligned; if unaligned there is no atomicity. + * MO_ATOM_NONE: the operation has no atomicity requirements. + * MO_ATOM_SUBALIGN: the operation is single-copy atomic by parts + * by the alignment. E.g. if the address is 0 mod 4, then each + * 4-byte subobject is single-copy atomic. + * This is the atomicity of IBM Power and S390X processors. + * MO_ATOM_WITHIN16: the operation is single-copy atomic, even if it + * is unaligned, so long as it does not cross a 16-byte boundary; + * if it crosses a 16-byte boundary there is no atomicity. + * This is the atomicity of Arm FEAT_LSE2. + * + * MO_ATMAX_* describes the maximum atomicity unit required: + * MO_ATMAX_SIZE: the entire operation, i.e. MO_SIZE. + * MO_ATMAX_[248]: units of N bytes. + * + * Note the default (i.e. 0) values are single-copy atomic to the + * size of the operation, if aligned. This retains the behaviour + * from before these were introduced. + */ + MO_ATOM_SHIFT = 8, + MO_ATOM_MASK = 0x3 << MO_ATOM_SHIFT, + MO_ATOM_IFALIGN = 0 << MO_ATOM_SHIFT, + MO_ATOM_NONE = 1 << MO_ATOM_SHIFT, + MO_ATOM_SUBALIGN = 2 << MO_ATOM_SHIFT, + MO_ATOM_WITHIN16 = 3 << MO_ATOM_SHIFT, + + MO_ATMAX_SHIFT = 10, + MO_ATMAX_MASK = 0x3 << MO_ATMAX_SHIFT, + MO_ATMAX_SIZE = 0 << MO_ATMAX_SHIFT, + MO_ATMAX_2 = 1 << MO_ATMAX_SHIFT, + MO_ATMAX_4 = 2 << MO_ATMAX_SHIFT, + MO_ATMAX_8 = 3 << MO_ATMAX_SHIFT, + /* Combinations of the above, for ease of use. */ MO_UB = MO_8, MO_UW = MO_16, -- 2.34.1