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[109.243.71.234]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48862775412sm5638432f8f.10.2026.09.22.07.50.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Sep 2026 07:50:13 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Authentication-Results: eu.smtp.expurgate.cloud; dkim=pass header.s=20251104 header.d=gmail.com header.i="@gmail.com" header.h="Content-Transfer-Encoding:Content-Type:In-Reply-To:From:Content-Language:References:Cc:To:Subject:User-Agent:MIME-Version:Date:Message-ID" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790088614; x=1790693414; darn=lists.xenproject.org; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to :content-type; bh=HlqJcAaLUHpOAKZ2E3y2oDjiN8GgNL8j6yICFQt86Vg=; b=JPKosG4FduEInV+o5oUTNRPYqCqcN5ZQ/SKZ3ffZ6Q++vCySHJeXY9Dkaz0SEwiFFZ T3h1rlBnadgWSsU+rGDCRY388XPNuAmSMyj3RvHUsgck5vcuE40uLc9+11SruxnofnYN q6Bl9luZa5XUuAM3Mq6GvVMhKb4rIm6OqGgLbGuwIQeEe+FUMFzxewYh6hbQT4Pk/xXZ ZHy7rinaSBr/3XuJBkcoDbGWZqWneJH8KFrBrpCAnIUFU0APml1/vo+4yz5eCRvaU3KY YjGkxYtRs45W9cycQfN5kcjba19zP4sjQllVjbVU1pqIcG17DtxtuslVhFvBvOjxYOn3 y4nQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790088614; x=1790693414; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=HlqJcAaLUHpOAKZ2E3y2oDjiN8GgNL8j6yICFQt86Vg=; b=g0MnpHJKVxxA6TnjjUZgn7JpFNIW4AiUeYSn958C2iy1pOLOsP38ALtfwArKEck9je 2Ws6zmdWa/1RrVOeWeR6Cd2PMfULn0uJjo67JAPGxqaVanId8z3rwarS3tIrTzLswz5M XiTr1fwFe5QanyXlrgUSI7C5g6nThHBiN4CrI7KRcWXA/YTNbgBnlu8wTxMB/be6tYPO cPKVZdCMZBalVupUTNGV/zR7Yi4Oxpm87wYPTgjr16FIy6Pno8LiNC498TVXuPrbYqDW CLejyLDijhceuONVXCs/6zogGiYLmcVeUfVBhfs6MJVLaDRfKdGJ16+rrYFQ1PYhdE7o pX5w== X-Gm-Message-State: AFuF++mvcx0EwuLeP/+zmE8WbS5xelcZ9wn4SCMHldiJjyEZY/wlXidg z/II8XMqkO47UhX20q2o14IsJVgk9nCNWRC89MlQJxaxX4PkfeYMwqyv X-Gm-Gg: AYBFou0dOLfcV5hBenfo8QFVEd07A6azxW+sZ9wRzvEzRQf/ZQv7UR8nhnz1W7EmuJy a68c7UwOOUsB/LL29acCa4eDksf84JYnqkI+8YF1RAK8E6fCmfXIMNG/Je8lo/YLiEaAwaAz16a od2kncNTHKdhSt0QfRAoyPIH/ZQGW+Ki6kAvxpmorD6yhxOK8IKBYv9Kb3QEbw1aPyh1lJH7kuH FTHDHShdv2glP2aBnFvRZF0ltsuUrOc53k5dD1HxYH86OFBBCoisPKHHX2Mlk9qwaqTF70hh9Ar A1eH8JFAtbEs1Z1fMAXkUDIbs+gxf4WXVJp5IS2zpvKVAuVbqFnXYLoBE+VL/Ix/js7zuH0YL1D RpZy7usU9oY0er3Bbv1h9nHfzKLFLKpZBHF3qpo3NvNhA02KVzgWmUwH7l25o60iktCn/NfXwX/ a+9w2XgzoLiva0mXsBG3SzNREiZQxDopvO9fDkbaLPuTB8RCshxjV+ulFBwiHqVcTBy9gW59DrA vKDiYw02G5NNuDMpqgsRYAWRSvkRH7Z+A7GDHv0risKtXtwFg== X-Received: by 2002:a05:600c:46cc:b0:493:f5bf:4dc6 with SMTP id 5b1f17b1804b1-49fc566951dmr197506265e9.7.1790088614004; Tue, 22 Sep 2026 07:50:14 -0700 (PDT) Message-ID: <69cdf366-06bc-4989-b060-935c9e0c8a4e@gmail.com> Date: Tue, 22 Sep 2026 16:50:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/6] xen/riscv: make Zihintpause no longer a required extension To: Baptiste Le Duc Cc: xen-devel@lists.xenproject.org, Jan Beulich , Stefano Stabellini , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Julien Grall , Anthony PERARD , Andrew Cooper , Connor Davis , Alistair Francis , Michal Orzel References: <1789032657.8631fc262581453bbf619ec5b2062170.1a08aa7f23b000c4f3@vates.tech> <1789032898.8631fc262581453bbf619ec5b2062170.1a08aaba10f000c4f3@vates.tech> Content-Language: en-US From: Oleksii Kurochko In-Reply-To: <1789032898.8631fc262581453bbf619ec5b2062170.1a08aaba10f000c4f3@vates.tech> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-purgate-ID: tlsNG-c201ff/1790088614-73EB92A1-82AD5A61/10/73395122804 X-purgate-type: spam X-purgate-size: 954 On 9/10/26 11:34 AM, Baptiste Le Duc wrote: > required_extensions[] panics at boot if Zihintpause is missing, but Xen > never actually depends on it: cpu_relax() only emits the "pause" hint when > the extension is implemented, otherwise it emits `0x0100000F`, a legally > valid FENCE instruction (`FENCE W, 0`) rather than a native NOP. FENCE is > guaranteed by the RISC-V base ISA, so it never raises an illegal > instruction fault. With an empty successor set, it enforces no > memory-ordering constraints and thus architecturally behaves as a NOP. > > Drop it from required_extensions so hardware without Zihintpause > still boots. > > Assisted-by: Claude:claude-opus-5 > Signed-off-by: Baptiste Le Duc > --- > Changes since v1: > - rewrite commit message. > --- > xen/arch/riscv/cpufeature.c | 1 - > 1 file changed, 1 deletion(-) > Please update also booting.txt? Thanks. ~ Oleksii