From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 430613F8230; Fri, 17 Jul 2026 12:33:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784291596; cv=none; b=UygR87DR9AtQGbPsg1e3w2S/9x4sopht0c+XDYOPY1Uiq31n6ZKoOHs0nQfnovZfKhj1I4jBU/JhNauQU6UlnOudZLD0W/CM7u2Qll26SOyPSPX3w7YVbRNz1MZGLmct/B1JDZE8aIhKEuQB1Q+w+1c8ZxcFX9YJ8zj1itod41g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784291596; c=relaxed/simple; bh=RDpVVg8kFR8tLzOuRdIhEL58jET3NKRROOt/Z0gxSao=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZI2H6N2XsKW49DZHtiMUaIXfAvHhqWRQ7bNLju1VqCFFL73mcXAq89fb6rdUBL7pvySqyEKR/lPjXjW40eSwG/0hozhlZeqrWBbzMSxKL7L5MtOnBWR/LBimfeRGSYZFdRaxREoHf0ca6bWTrafvFZvuC5AvminwMJSOn3tz7Lk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=hMWp8GwJ; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="hMWp8GwJ" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A85021476; Fri, 17 Jul 2026 05:33:07 -0700 (PDT) Received: from [10.57.84.220] (unknown [10.57.84.220]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 467C23F7B4; Fri, 17 Jul 2026 05:33:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784291591; bh=RDpVVg8kFR8tLzOuRdIhEL58jET3NKRROOt/Z0gxSao=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hMWp8GwJzRF5UZIO7llWHBXTN/HLu31bPfKJMWbDqFPVX/ABCDP7Uv8E3nfr/pgz6 mz93o+2LPGP9NgzF7GOkgmnMKpHPVuOlv83VrSes5m+va/CFG+etb0rtKfkR6zbW0B a1EOO8mqxjWKsUm2Nf3s27A0ZKvy/CA6wT5MW1T8= Message-ID: Date: Fri, 17 Jul 2026 13:33:07 +0100 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: [RFC PATCH v1 0/8] Arm Core Local Accelerator Driver Content-Language: en-GB To: Marc Zyngier , Will Deacon Cc: Greg Kroah-Hartman , Arnd Bergmann , Catalin Marinas , Mark Rutland , Jean-Philippe Brucker , Oded Gabbay , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, oupton@kernel.org, hch@infradead.org, jgg@nvidia.com References: <20260717104759.123203-1-ryan.roberts@arm.com> <87ech1rf6n.wl-maz@kernel.org> From: Ryan Roberts In-Reply-To: <87ech1rf6n.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 17/07/2026 13:09, Marc Zyngier wrote: > Thanks Will for roping me in. Sorry - I intentionally didn't include you because last time we spoke you said you were only really interested in discussions on the virt side of things and I didn't want to spam your inbox. Perhaps the wrong decision... > > On Fri, 17 Jul 2026 12:33:17 +0100, > Will Deacon wrote: >> >>> I'm deliberately constraining the scope to bare-metal support for now. >>> Virtualization is something we are considering (and have prototyped), but plan >>> to post a separate RFC for that as follow-up, once we have agreement on >>> direction for the bare-metal driver. >> >> I'd actually like to see what the virtualisation part looks like first >> because doing it as a bolt-on later feels like the wrong approach. The >> structure you have at the moment is remarkably clean, given the >> architectural/CPU interactions (this thing even apparently builds as a >> module, nice!), but I'm unsure how far you can push the separation once >> you need to start hacking at KVM. Maybe the MMU notifiers are enough, >> but I can't tell. > > +1. > > Virtualisation cannot be a "bolt on the side" exercise. It is an > integral part of the arm64 tree, particularly for memory management > and scheduling, all of which have a direct impact on KVM. > > I don't think we can really evaluate anything here without looking at > the full picture. OK understood - as per reply to Will, we'll prioritise doing a version with virt support. Thanks, Ryan > > Thanks, > > M. >