From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 D51B413AD11 for ; Mon, 28 Oct 2024 17:04:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730135086; cv=none; b=Rlp3rB/6Hwv0iipnQUlittCVyfmKchoqbRstHU2nI9gw0Jz10ay1k8PhGIUAXn3Fle2gOIjXnDwZDSPeotYoyaI534ZjXRQxmu7SIvLrheuhmBdN1G94iw+3MHwJ6cCVtW5Nv4JZwApzO/bp/WikM8UV7Ych1KfMW5trZk2bNo0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730135086; c=relaxed/simple; bh=N934Gy15GhKIz42AbfgQ6N7wf/fV+42eBQxpkdE/VNM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TC85cDQkQgUOx9dg3PxWXH9lj5bbcs76QjwDGHIRETK8CUoQMJyc/IGg36sBMfl3fRB4cn3mT8SnFNVhgvwuZmv0PRa9ZhpE6oMwS1gZfyJyZ/fwAzkA7xykEKkRJ2upNFc/dq0X+4Fj6bBNpxQVMIn04jRMU2fy5x2njXccKEU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=coZPHvQX; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="coZPHvQX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730135083; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NQu+8I7Sok3PPSrWFRnNNqhfVgvV3ebDTRz6eG60lgs=; b=coZPHvQXUMrufm+1kPj5OWKECUwEwMBSDoaLF2WoKQyjleqdTn7cWljdmDt/eSECCuw+eM AaRd3n2CsoOzVYLHfHf59YznKl02HVreIPafdj21eTXwgDiSxEYX80Dcf0ZWHVhnFC243O JDVWwbXo5HRkDX/rKP5hjwGNu/4wrnc= 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-328-jh4yBVELOw2Tk0UapQ0TwQ-1; Mon, 28 Oct 2024 13:04:40 -0400 X-MC-Unique: jh4yBVELOw2Tk0UapQ0TwQ-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 DF7481955EB5; Mon, 28 Oct 2024 17:04:37 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.86]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E381B1956088; Mon, 28 Oct 2024 17:04:30 +0000 (UTC) Date: Mon, 28 Oct 2024 17:04:27 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Cc: Eric Auger , eric.auger.pro@gmail.com, cohuck@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, kvmarm@lists.linux.dev, richard.henderson@linaro.org, alex.bennee@linaro.org, maz@kernel.org, oliver.upton@linux.dev, sebott@redhat.com, shameerali.kolothum.thodi@huawei.com, armbru@redhat.com, abologna@redhat.com, jdenemar@redhat.com, shahuang@redhat.com, mark.rutland@arm.com, philmd@linaro.org, pbonzini@redhat.com Subject: Re: [RFC 18/21] arm/cpu: Introduce a customizable kvm host cpu model Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20241025101959.601048-1-eric.auger@redhat.com> <20241025101959.601048-19-eric.auger@redhat.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On Mon, Oct 28, 2024 at 04:48:18PM +0000, Peter Maydell wrote: > On Mon, 28 Oct 2024 at 16:35, Daniel P. Berrangé wrote: > > > > On Mon, Oct 28, 2024 at 04:16:31PM +0000, Peter Maydell wrote: > > > On Fri, 25 Oct 2024 at 14:24, Daniel P. Berrangé wrote: > > > > On Fri, Oct 25, 2024 at 03:18:25PM +0200, Eric Auger wrote: > > > > > On 10/25/24 15:06, Daniel P. Berrangé wrote: > > > > > > Also, is this naming convention really the same one that users > > > > > > will see when they look at /proc/cpuinfo to view features ? It > > > > > No it is not. I do agree that the custom cpu model is very low level. It > > > > > is very well suited to test all series turning ID regs as writable but > > > > > this would require an extra layer that adapts /proc/cpuinfo feature > > > > > level to this regid/field abstraction. > > > > > > > > > > In /cpu/proc you will see somethink like: > > > > > Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp > > > > > asimdhp cpuid asimdrdm lrcpc dcpop asimddp > > > > > > > > Right, IMHO, this is the terminology that QEMU must use in user > > > > facing APIs. > > > > > > /proc/cpuinfo's naming is rather weird for historical > > > reasons (for instance there is only one FEAT_FP16 feature > > > but cpuinfo lists "fphp" and "asimdhp" separately). > > > > There's plenty of wierd history in x86 too. In this > > case I might suggest just picking one of the two > > common names, and ignoring the other. > > > > If we really wanted to, we could alias the 2nd name > > to the first, but its likely not worth the bother. > > Or we could use the standard set of architectural > feature names, and not have the problem at all, and not > have to document what we mean by our nonstandard names. > (cpuinfo names do actually mostly line up with the > standard names, just not 100%. Similarly gcc/clang command > line options are mostly the architectural feature name.) Ah, right, yes. Sorry I mis-understood you originally to be suggesting the same low level names as this patch. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|