From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 080861FE44B for ; Mon, 21 Jul 2025 17:20:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753118456; cv=none; b=uwmhBhMzkIJE9SYBGGl7Ck15Igd5T7ZTSi4ctJOb6I9LwXIJ/Nl+iWFKR/bGY4j0jcQgaH6WhKiG6VffnfrPCL5xgkXmQZ4ziFoSZZ3G5CuLm4uxQ15I/KTyhv1BHaohoH6Xzr7vK2HLzPO4Gy0lDSWKkzI6I+cT+hZnM2mWrvc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753118456; c=relaxed/simple; bh=0NlFb+qovKUIq/o0/4pCjyJKfbYaztgHRLswjYbe0qI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=C28VKnkC7hAiiehor5cZLOqWMLK0VV5wEFPQMzW4YDhQpcojk5/6jfGNC1bz99HORtRIv1of3jYaT1o4o70TbChaaC9uHtbbkr3tFxNUqiG7qRJ+GAk12wGvGLbbr5suAOeTHjKuUgjOyYxoeQxJxYhnphN3FYvuiwFqheWPLyw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=M6lAY38n; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="M6lAY38n" Received: from [10.137.184.60] (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 82C482115836; Mon, 21 Jul 2025 10:20:54 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 82C482115836 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1753118454; bh=F0WeBj2bGuuRDUrwwzYEPFuv3oAaANMb0rzB3x/zEGs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=M6lAY38nEFF6SPpxTb0jBP9+abnYKMYir5Krk+urbD9Y4Z3t0/8JxNOMoSNX0fUsO FpNzv3YTYyKxz1aNCxTInjwirrXdr/tAAFV9m67PV5iaHZKfIqy5hqXiBd9RY4hSKN QIvH+QrTMRImtRgveFS0jbwSC3/UPzX3dY5iu3vc= Message-ID: <55e5f8d2-2b81-4883-a9ac-ad1a426c4222@linux.microsoft.com> Date: Mon, 21 Jul 2025 10:20:54 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm64: kvm, smccc: Fix vendor uuid To: Sudeep Holla , Jack Thomson Cc: mark.rutland@arm.com, lpieralisi@kernel.org, arnd@arndb.de, wei.liu@kernel.org, mhklinux@outlook.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, kvmarm@lists.linux.dev, roypat@amazon.com, Jack Thomson References: <20250721130558.50823-1-jackabt.amazon@gmail.com> <20250721-proficient-carrot-cockatoo-393ae1@sudeepholla> Content-Language: en-US From: Roman Kisel In-Reply-To: <20250721-proficient-carrot-cockatoo-393ae1@sudeepholla> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/21/2025 9:15 AM, Sudeep Holla wrote: > (I can't see this original patch in my mailbox, got only Marc's response) > > On Mon, Jul 21, 2025 at 02:05:58PM +0100, Jack Thomson wrote: >> From: Jack Thomson >> >> Commit 13423063c7cb ("arm64: kvm, smccc: Introduce and use API for >> getting hypervisor UUID") replaced the explicit register constants >> with the UUID_INIT macro. However, there is an endian issue, meaning >> the UUID generated and used in the handshake didn't match UUID prior to >> the commit. >> >> The change in UUID causes the SMCCC vendor handshake to fail with older >> guest kernels, meaning devices such as PTP were not available in the >> guest. >> >> This patch updates the parameters to the macro to generate a UUID which >> matches the previous value, and re-establish backwards compatibility >> with older guest kernels. >> > > Nice catch. This is result of classic confusion with UUID and GUID especially > coming from Microsoft who tend to use GUID more. > > Reviewed-by: Sudeep Holla > > This also makes me wonder if the initialisation in arch/arm64/hyperv/mshyperv.c > is also wrong or may be that's correct only MS guys can confirm as I couldn't > find the UUID string for that. MUCH appreciated!! Apologies for that miss in testing of the older kernels. I'll check on our side and will fix what needs fixing. > -- Thank you, Roman