From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD1EB36E498 for ; Tue, 4 Aug 2026 06:46:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785825963; cv=none; b=al+qozd0YhXCEEoVEEpJvNSnZ6O053zsFI6inXwmw+Zpos73CvNND2w9v7QuiAzqHvlb2sZ7Gg48yM0Q0vFOkReWcM9mxKmyTtHPwi3L96C4qEnsNjyH0Kl0zNGfZE8CpY9/wHAdIj0cq1K2iS6Ih3l2kt/ypC64yvlKbnCfNtU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785825963; c=relaxed/simple; bh=Drw3DEtoh0jJrNSb6k28XkWszIy+b8jHV4xZiKXVVsU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=OSvYa9i7HP0JadMLs3TfwCMjMkV3Fv4yoUkbW21U7N+OuG7I6oFHJjS14EfqWlxODhRIw8ksgQ2BGtxQyJy1OcnbrpHWLdFvOVOXFplQOow5Ov1zzeQ5FPywFqCTWSmhZF6ujymcleT50q9zxUGCvakAn4aWYx9jeRFK3OBz0pU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=MpBZgyLa; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MpBZgyLa" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1785825960; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0Til7dJ+LBxYd932gQSxYw4R3kFQ/CW4QMe0aradBus=; b=MpBZgyLa4EiBQ4k255ZrYhe9h6P14Eb/DAb49Eh/GCNsEpq7tAld34FzOXettWcjn2mBi2 dnrdR311L3ZBUXYm6enusF2JDmetN7aymJ8CivZgx6MMS8k/+1OL3yGnSpYCoGgI+H/GaI 0Ffvt0hnLRLuktQxlEHXR2LauHnDGxY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-247-SV9xW_IvNheFpOtuyKHrYA-1; Tue, 04 Aug 2026 02:45:57 -0400 X-MC-Unique: SV9xW_IvNheFpOtuyKHrYA-1 X-Mimecast-MFC-AGG-ID: SV9xW_IvNheFpOtuyKHrYA_1785825955 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 408171956048; Tue, 4 Aug 2026 06:45:54 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.7]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 51EB641C; Tue, 4 Aug 2026 06:45:53 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id BEBB521E6920; Tue, 04 Aug 2026 08:45:50 +0200 (CEST) From: Markus Armbruster To: Khushit Shah Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org, kvmarm@lists.linux.dev, eric.auger@redhat.com, cohuck@redhat.com, peter.maydell@linaro.org, richard.henderson@linaro.org, maz@kernel.org, oliver.upton@linux.dev, berrange@redhat.com, abologna@redhat.com, jdenemar@redhat.com, gshan@redhat.com, skolothumtho@nvidia.com, sebott@redhat.com, philmd@linaro.org, yangjinqian1@huawei.com, shaju.abraham@nutanix.com, mark.caveayland@nutanix.com, prerna.saxena@nutanix.com Subject: Re: [RFC PATCH v3 16/19] qmp: add query-cpu-props-info command In-Reply-To: <20260716213858.609699-17-khushit.shah@nutanix.com> (Khushit Shah's message of "Thu, 16 Jul 2026 21:38:55 +0000") References: <20260716213858.609699-1-khushit.shah@nutanix.com> <20260716213858.609699-17-khushit.shah@nutanix.com> Date: Tue, 04 Aug 2026 08:45:50 +0200 Message-ID: <878q6m5qox.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 X-Mimecast-MFC-PROC-ID: VDw-cy4bmcu33S1CGY8Hsv2Ajw6vVEXpQnfoOKSAF_k_1785825955 X-Mimecast-Originator: redhat.com Content-Type: text/plain Khushit Shah writes: > Introduce the 'query-cpu-props-info' QMP command. For CPU model > properties it reports the type (boolean or number) and the set of values > supported under the active accelerator and host. > > For numbers the supported values are expressed as a list of inclusive > {min, max} ranges; for booleans as the list of allowed true/false > values. > > The command and its return types (CpuPropertyType, CpuPropertyInfo and > friends) are defined in qapi/machine.json rather than an Arm-specific > schema, since the concept applies to other targets (e.g. x86, riscv) > too. Target that do not implement it return an error. > > The Arm/KVM implementation spins up a scratch "host" vCPU object, > walks its QOM properties: SYSREG_ ID-register fields become 'number' > properties whose ranges come from arm_field_get_supported_values(), > and the advertised feature toggles become 'boolean' properties. > > Signed-off-by: Khushit Shah This explains what the command does and how it's implemented. It's silent on the most important aspect: why do we want the command? What is its intended purpose?