From nobody Fri Mar 27 04:00:18 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=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1772744155; cv=none; d=zohomail.com; s=zohoarc; b=KXUCmULf7xUOXEne/MXjLm/vB99lzjASOVC08bQZyQku8nd/+ftkZ34XKyG2cOGnz56FuSpO0039izn8ICIoDcheEzt8VviAz3pouY+TsC3+at0c5cJy65nhzcWxG/BHrQ6vpFwXaSMLi7LTa3uplrKWFCwmRtcdU8zONBBe87I= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1772744155; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=QAo6ofbgTbHTQLqhku7tbhHK2r8k4onc7bjEitYzIus=; b=j02bxpOlimJ1SzA+tT30uq6BzjBynkaaygpYzl6S8fmMtoy+fAiUOVL/qhFofMa+wxL3+olfYCXqRsgQA72MuDurPT2oy3Xu2YtbVngTAIrcQsgChO4VomnrRO3Sjpq23kp5SL7vgKc8DQHG6TJlqdJVXVcCt8ThA5Uc+Gi5oIs= 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1772744155604397.68107599949724; Thu, 5 Mar 2026 12:55:55 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vyFjX-0003VX-C6; Thu, 05 Mar 2026 15:55:49 -0500 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 1vyFjJ-0003Po-NS for qemu-devel@nongnu.org; Thu, 05 Mar 2026 15:55:34 -0500 Received: from mail-pf1-x429.google.com ([2607:f8b0:4864:20::429]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1vyFjG-0006g1-VN for qemu-devel@nongnu.org; Thu, 05 Mar 2026 15:55:33 -0500 Received: by mail-pf1-x429.google.com with SMTP id d2e1a72fcca58-829756f3ee9so2100168b3a.2 for ; Thu, 05 Mar 2026 12:55:29 -0800 (PST) Received: from pc.taild8403c.ts.net (216-71-219-44.dyn.novuscom.net. [216.71.219.44]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8297e4fbbd4sm3847454b3a.53.2026.03.05.12.55.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Mar 2026 12:55:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1772744128; x=1773348928; darn=nongnu.org; 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=QAo6ofbgTbHTQLqhku7tbhHK2r8k4onc7bjEitYzIus=; b=eEJ6lrqvaWDexAf+MkjdOpwWITxr9qGWvmFivvipYtWt8SlQAbKxpKPmYxF0a1Kvaf ru+gikDg21xnXPQ2J0996qqbYWnQTpJuprRLj89BBs7vjGl7GfXhE5gjZc+gx5enPbz1 s1SoTdn5UXhn7nxmmwcVAoEHJEdYDMiv3z4Kpso8kkAM+tyUja0hrsTsyKvum2Mb+m5Q n1chEAF3zmhW7EWaGUXkmrHqrlc7yyDJC9UmO3WxWo2jkxjiVDg0s8Tv4p/meTBTGPf1 MNZiGVaZZYAYAMgRMKYPA0xN+m1HJ9kCVkVTQa9cwgPI/pOO//vqTyF2eI+Cyz0qdljy 9Haw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772744128; x=1773348928; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=QAo6ofbgTbHTQLqhku7tbhHK2r8k4onc7bjEitYzIus=; b=nQTHt+st9jyC6P/z6DYTE172hu5+RjKxhp9w/WRTGHAOc4y8+4JwRUepWGPnTPFO2i sSFLYUZWL0pqwMKn2KZk1XbHZLse9+ybnWflIesRvaGmIIC7bfqr6QeiQLSlt1ZPbNNg s0b/XpSmUmnB7AsJNp0v5Ac+oGg3OL+h1c6Eao/mCEx8Ezs4U9Uq+Z4M5w0aFHCqia0q vt7FQUizJlxK/V3Dm86UkGH1ze+ykPVcOSCYrP4Lm3OisiTOCujjWmA5GqAiRtML8v4S O6EfJ+o4G4gsVJabe2wNL+u4gbG43n5X6/DkT+loJB84fJwS9IVBZrh+nYYumeZIbeZo EkzA== X-Gm-Message-State: AOJu0YxG8Qmbcr4529nQzW0c70ZgOlK+syCOivBBrJyBzOBguz1L6vMH ovxmcurgmEj1dqZyCvsOWIeP9CoJNtYGs7RwkqxV6EIIN1JHGVYHEmcp1q4Epba3XQuIXVhmaoe vcIqL X-Gm-Gg: ATEYQzxO/GZG8tRfpluTslKgQFKjzsh3BvRYSo2HYwT+2vr99sAt/Z4P57OJ9Wtgk2T yJhSeQT2kdeP/0CNnmTZz6OXjZupf7SoFA0m0AVtEgUivMATVHRXZ3UPtO8xoz0JGWe1V54Q+CB yfzZQFnsHalhoA0Dpsu+anCEvLSS8VXgBfqaE0clcOy4mnaBIZqsMXwkag/m2XyrYYOJYV6hJe2 QvUI64l3ZaxJGjxZd/sqxmCsTnPiGFjDjGBlIoL98tS3ICe60I8/PuYhFORau31HeDdcEXVLW8J BXZDCjBNakXFO+pjmJHUQ35qqbR45J/2pZuhT1NvvQShGCjMfHY7TNA/9FuB9HH7aZI/gAbicIY NJ75YjjZmcl0erHDoFZeKRl1KJSstUAMCTBhVV04R5qjleExGPm5LyBpOEsCCw42KbhVpwNS9nS 5HJvAHlImt1eELDp8w7oUR3I2DwAlkFiMsq0WJYiUcMPN38X6qvf7RZM0FPG36kw48ilBE1/aBm Jqw X-Received: by 2002:a05:6a00:2184:b0:827:2f06:87af with SMTP id d2e1a72fcca58-82972d4b197mr5770882b3a.64.1772744127836; Thu, 05 Mar 2026 12:55:27 -0800 (PST) From: Pierrick Bouvier To: qemu-devel@nongnu.org, peter.maydell@linaro.org, richard.henderson@linaro.org, pbonzini@redhat.com, stefanha@redhat.com Cc: pierrick.bouvier@linaro.org Subject: [PULL 2/6] hw/virtio: Simplify virtio_access_is_big_endian() Date: Thu, 5 Mar 2026 12:55:16 -0800 Message-ID: <20260305205520.2125218-3-pierrick.bouvier@linaro.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260305205520.2125218-1-pierrick.bouvier@linaro.org> References: <20260305205520.2125218-1-pierrick.bouvier@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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=2607:f8b0:4864:20::429; envelope-from=pierrick.bouvier@linaro.org; helo=mail-pf1-x429.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 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: 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 @linaro.org) X-ZM-MESSAGEID: 1772744156904154100 Thanks to previous refactoring, we can see more easily it is strictly equivalent to always call virtio_vdev_is_big_endian. static inline bool virtio_vdev_is_big_endian(VirtIODevice *vdev) { if (virtio_vdev_is_legacy(vdev)) { assert(vdev->device_endian !=3D VIRTIO_DEVICE_ENDIAN_UNKNOWN); return vdev->device_endian =3D=3D VIRTIO_DEVICE_ENDIAN_BIG; } /* Devices conforming to VIRTIO 1.0 or later are always LE. */ return false; } The key is to understand that vdev->device_endian is initialized as expected. It always contains cpu endianness, and not device endianness, ignoring if device is legacy or not. By default, it's initialized to vdev->device_endian =3D virtio_default_endian(), which matches target default endianness. Then, on virtio_reset, it will be initialized with current_cpu endianness (if there is one current_cpu). void virtio_reset() { ... if (current_cpu) { /* Guest initiated reset */ vdev->device_endian =3D virtio_current_cpu_endian(); } else { /* System reset */ vdev->device_endian =3D virtio_default_endian(); } Now, we can see how existing virtio_access_is_big_endian is equivalent to virtio_vdev_is_big_endian. Let's break the existing function in its 3 variants, and compare that to virtio_vdev_is_big_endian. static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) - #if defined(LEGACY_VIRTIO_IS_BIENDIAN) return virtio_vdev_is_big_endian(vdev); This is the exact replacement we did, so equivalent. - #elif TARGET_BIG_ENDIAN if (!virtio_vdev_is_legacy(vdev)) { return false; } return true; we know target_is_big_endian(), so vdev->device_endian =3D=3D VIRTIO_DEVICE_ENDIAN_BIG. if (virtio_vdev_is_legacy(vdev)) { return VIRTIO_DEVICE_ENDIAN_BIG =3D=3D VIRTIO_DEVICE_ENDIAN_BIG; } return false; It's written in opposite style compared to existing code (if legacy vs if modern), but it's strictly equivalent. - #else return false; we know !target_is_big_endian(), so vdev->device_endian =3D=3D VIRTIO_DEVICE_ENDIAN_LITTLE. if virtio_vdev_is_legacy(vdev) { return VIRTIO_DEVICE_ENDIAN_LITTLE =3D=3D VIRTIO_DEVICE_ENDIAN_BIG; } return false; So it always return false, as expected. Reviewed-by: Philippe Mathieu-Daud=C3=A9 Acked-by: Stefan Hajnoczi Signed-off-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Richard Henderson Link: https://lore.kernel.org/qemu-devel/20260225041948.52929-3-philmd@lina= ro.org Signed-off-by: Pierrick Bouvier --- include/hw/virtio/virtio-access.h | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-a= ccess.h index b8aa7a520f5..e3148c23881 100644 --- a/include/hw/virtio/virtio-access.h +++ b/include/hw/virtio/virtio-access.h @@ -21,23 +21,9 @@ #include "hw/virtio/virtio.h" #include "hw/virtio/virtio-bus.h" =20 -#if defined(TARGET_PPC64) || defined(TARGET_ARM) -#define LEGACY_VIRTIO_IS_BIENDIAN 1 -#endif - static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) { -#if defined(LEGACY_VIRTIO_IS_BIENDIAN) return virtio_vdev_is_big_endian(vdev); -#elif TARGET_BIG_ENDIAN - if (!virtio_vdev_is_legacy(vdev)) { - /* Devices conforming to VIRTIO 1.0 or later are always LE. */ - return false; - } - return true; -#else - return false; -#endif } =20 static inline void virtio_stw_p(VirtIODevice *vdev, void *ptr, uint16_t v) --=20 2.47.3