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 83ECAEE36A0 for ; Fri, 13 Feb 2026 09:45:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vqpjm-0004c2-8c; Fri, 13 Feb 2026 04:45:22 -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 1vqpjS-0004WP-62 for qemu-devel@nongnu.org; Fri, 13 Feb 2026 04:45:03 -0500 Received: from linux.microsoft.com ([13.77.154.182]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vqpjO-0006PU-5v for qemu-devel@nongnu.org; Fri, 13 Feb 2026 04:45:00 -0500 Received: from example.com (unknown [167.220.208.59]) by linux.microsoft.com (Postfix) with ESMTPSA id 9912820B7165; Fri, 13 Feb 2026 01:44:52 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9912820B7165 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1770975894; bh=Bd/+xlcSIp5ZfXJ+RSzaxBeMC2mzAriE00zmbk9fB8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mZxEO2y3Z7xsJ4uZgPv4s+Hfysoywsea+BlSKQ0Xx/c6zKbClKK6qDCnSW92FBZTE HTaZpbRJsoiXKLSkwSisG4XeIfl59pfTrQWhXOqonPaN5+lvJTv9qA6xUq6BKDni/r Mb6XyQvSSxwNMD7nwXddJG8Yci7TEkiM8NtLtCng= Date: Fri, 13 Feb 2026 10:44:49 +0100 From: Magnus Kulke To: Mohamed Mediouni Cc: qemu-devel@nongnu.org, Wei Liu , Wei Liu , Zhao Liu , Paolo Bonzini , Magnus Kulke Subject: Re: [PATCH 08/10] target/i386: query mshv accel for supported cpuids Message-ID: References: <20260211155410.203883-1-magnuskulke@linux.microsoft.com> <20260211155410.203883-9-magnuskulke@linux.microsoft.com> <28261EA8-97DB-400F-A85C-4066A1AC425A@unpredictable.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <28261EA8-97DB-400F-A85C-4066A1AC425A@unpredictable.fr> Received-SPF: pass client-ip=13.77.154.182; envelope-from=magnuskulke@linux.microsoft.com; helo=linux.microsoft.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Feb 12, 2026 at 12:35:57AM +0100, Mohamed Mediouni wrote: > > Interesting. For WHPX on Arm, what’s done is creating a stub partition and extract CPUID info from > it (with necessary guest stub code if necessary) but doing it this way like HVF x86 does is intriguing too… > > Is this future-proof or are there catches with this approach? > I think this is a valid approach that we also considered. I assume for MSHV eventually we want to have a MSHV_GET_SUPPORTED_CPUID ioctl, similar to what exists in KVM, so we can make centralize some decisions instead of leaving it up to the VMM. This approach might end up using a dummy partition inside the kernel, but would be an implementation detail.