[{"id":3685075,"web_url":"http://patchwork.ozlabs.org/comment/3685075/","msgid":"<5e440ba1-c029-4e2e-976a-41d35b4dffed@linaro.org>","list_archive_url":null,"date":"2026-05-01T09:36:49","subject":"Re: [PATCH v4 5/7] target/arm: enable event stream on WFE\n instructions","submitter":{"id":72104,"url":"http://patchwork.ozlabs.org/api/people/72104/","name":"Richard Henderson","email":"richard.henderson@linaro.org"},"content":"On 4/30/26 20:44, Alex Bennée wrote:\n> void HELPER(wfe)(CPUARMState *env)\n> {\n> #ifdef CONFIG_USER_ONLY\n> @@ -495,32 +586,44 @@ void HELPER(wfe)(CPUARMState *env)\n> #else\n> /*\n> * WFE (Wait For Event) is a hint instruction.\n> - * For Cortex-M (M-profile), we implement the strict architectural behavior:\n> + *\n> * 1. Check the Event Register (set by SEV or SEVONPEND).\n> * 2. If set, clear it and continue (consume the event).\n> */\n> - if (arm_feature(env, ARM_FEATURE_M)) {\n> - CPUState *cs = env_cpu(env);\n> + CPUState *cs = env_cpu(env);\n> + ARMCPU *cpu = ARM_CPU(cs);\n\nARMCPU *cpu = env_archcpu(env);\n\n> + /* For A-profile we also can be woken by the event stream */\n> + if (arm_feature(env, ARM_FEATURE_AARCH64) && cpu->wfxt_timer) {\n> + int64_t next_event = gt_calc_next_event_stream(env);\n> + if (next_event > 0) {\n> + timer_mod(cpu->wfxt_timer, next_event);\n> + }\n> }\n\nYou shouldn't need the feature test, since we'll only instantiate the timer when the \nfeature is available.\n\n\n\nr~","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256\n header.s=google header.b=xul0yJJ4;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g6Qtp3hZTz1yHZ\n\tfor ; Fri, 01 May 2026 19:37:36 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wIkIt-0000Tn-6L; Fri, 01 May 2026 05:36:59 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wIkIr-0000Tf-9e\n for qemu-devel@nongnu.org; Fri, 01 May 2026 05:36:57 -0400","from mail-pl1-x633.google.com ([2607:f8b0:4864:20::633])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from )\n id 1wIkIp-0003Br-Rz\n for qemu-devel@nongnu.org; Fri, 01 May 2026 05:36:57 -0400","by mail-pl1-x633.google.com with SMTP id\n d9443c01a7336-2adbfab4501so7670105ad.2\n for ; Fri, 01 May 2026 02:36:55 -0700 (PDT)","from [192.168.10.140] ([180.233.125.15])\n by smtp.gmail.com with ESMTPSA id\n d9443c01a7336-2b9caa7e855sm18247605ad.10.2026.05.01.02.36.52\n for \n (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);\n Fri, 01 May 2026 02:36:53 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=linaro.org; s=google; t=1777628214; x=1778233014; darn=nongnu.org;\n h=content-transfer-encoding:in-reply-to:content-language:from\n :references:to:subject:user-agent:mime-version:date:message-id:from\n :to:cc:subject:date:message-id:reply-to;\n bh=cz/ingkOX9rnJiAR0BaZNZlFtqqNJnUoEA+uwl1m/i8=;\n b=xul0yJJ4lYK7UXxN4gX8oOcMn2nQ8rnB685VzKC1mTW5Q3YfMtEhXMQe7+G1V6jfjX\n ak5r03B7ZVM4n5nyVXvU9N5r7ZMhDUN9QaaShVQHEnLQ8dJjEn+TL83OjsVdXSs13FdS\n Pk3fBiXxjjGeItdwTNlMw2dNxbqMtXaJQK2LOZiCLD/HpeyP2hQB8xQCFVhVTpeRL5mB\n K2/tylsH/b4+bB/mHYZiNnO0OiggIx8z8NJaRJRpASD4fhDMm1yEeggy/ZG45Iq/6cOg\n gh2PA1XZVb9Axc9i38WFjp5BI9XEgl/y1QJajXDBwuCSfeZMALYU/Qv+xlSGt+gl7GDV\n H3nw==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1777628214; x=1778233014;\n h=content-transfer-encoding:in-reply-to:content-language:from\n :references:to:subject:user-agent:mime-version:date:message-id\n :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id\n :reply-to;\n bh=cz/ingkOX9rnJiAR0BaZNZlFtqqNJnUoEA+uwl1m/i8=;\n b=KWpAPn/fUCT5KIC1iZ0lrohnn/TcUZFzupl8QSQfgkw3qv6R8dfckf8IWPcKRfhpBr\n 4MQ/42SW+NlJtcw9a5cfEDt6/lpn0aqEi3Sa86UWJOrFMpmhTeNTI/1PiyuLr+xGwUOH\n HJF0MfgTi5ZMBJqgMmZRUjyO0oyvEkB5mIPQXLBI5w41UqQEuu/5UTf2gBHbEoGyvX/6\n gOBUjkbAEzzXTDiK0oxQrsKK/koEnvpE6GPybkVrjwjfTbJn4U4dqmuQvrx+jzWHTkIE\n Y4J/NSX9Ficf+C6GgnymAYlcz37cVWN6FLPPgs/UUtPWjti1f7t7VYL+SSaMDrAS9avd\n YztQ==","X-Gm-Message-State":"AOJu0YxtxL7XoYM3ToailuO4wwztBZWtsgXjTfYZRXEG4S+FNIjFB9iV\n 50dAPNU32BjsaawrO/USe4qnsjxpQ9hmqKRGzoM4U1u+0SDaAiu8LY2khRHLodfIxGN+qh/ypxo\n FwRh5JO4=","X-Gm-Gg":"AeBDieuRR8H0vaozXwAFiiTXsLVIB9sBMwQASnnzJ6GnKtR/oWEvkcVr5IFkKmOnA2J\n 3i872c01lv6iStPr9WT+Mi9dtZ3/TdtOiG9dViP8MBsr5ObQvwbVF79x4KT1vizLFQQm7cV6zw9\n 7IGSzQFsCloUev5QkM/Agf3sRbSjeHGT1ydRQKkffNk2glfjl067JFcUxNVWEtiRNpJkbNTLehl\n mSgj+27miX7L3+9S7RBmsa3+JW3npmADz+lylWuhoVPxE0bEXhFzz8TRU/rBV2I4hqIM8p6wx1p\n N6QAFfour2K5STdl6lkaAlpuxVMbDKdNvQHuL5Gs6hxL268wXKa3RfNjLsBz0suYLhIHGNHnKM6\n 7WI+OUhBro2Mkg581OFhMPZQdIn0CKm7vgPhxzaXbEsNq/4X1fJzVvsemk7N4JGcvpIYYdqBV8H\n ZMrDDU31lm8kdSW1f/8j/jBMfsVQ6i3YNa0bU4ZtD9seApiqh/nzV5","X-Received":"by 2002:a17:903:1af0:b0:2b0:6d33:e7c0 with SMTP id\n d9443c01a7336-2b9a22f6fcfmr65783085ad.1.1777628213871;\n Fri, 01 May 2026 02:36:53 -0700 (PDT)","Message-ID":"<5e440ba1-c029-4e2e-976a-41d35b4dffed@linaro.org>","Date":"Fri, 1 May 2026 19:36:49 +1000","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH v4 5/7] target/arm: enable event stream on WFE\n instructions","To":"qemu-devel@nongnu.org","References":"<20260430104434.1482407-1-alex.bennee@linaro.org>\n <20260430104434.1482407-6-alex.bennee@linaro.org>","From":"Richard Henderson ","Content-Language":"en-US","In-Reply-To":"<20260430104434.1482407-6-alex.bennee@linaro.org>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=2607:f8b0:4864:20::633;\n envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x633.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,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n 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":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}}]