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 889273D6CDA; Mon, 11 May 2026 10:40:09 +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=1778496010; cv=none; b=iA9MVkWqnwXsz0hFij9nJpkqDHH3Fe0Zbht+LiDGbuzbHDofPE2GoWSISunI0qUE+r4icNiE3O92AOSiKk5YB4UXRoiakeXlzuszlw88tnH8Ju1mO2AJ3pwJFQKGtujNYxr8x2FkJh0X7dKh/XFK5URHxw/YdMMrwa2qCfq8/Dk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778496010; c=relaxed/simple; bh=qIBIaoZMw/edt0QBmUc5C+O+459IgUULanpiPn179Hg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C7LT++jCdfnFBcmwj2nG9Mm/GKISIoxS2Y6qbiFek4QYAOnke+Ikmdo+nM1H6l202hKpTougioe6WxxWWj+RE/fGYoJGe3nW01fY4ON/lzLtCi5Gcvq6VRahl3XPFdk78KRLpRy3nUPPxxfnkRTacKOFfMywEKZFVTrB5jfiFtI= 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=AZqdSIPc; 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="AZqdSIPc" 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 75A2E16F2; Mon, 11 May 2026 03:40:03 -0700 (PDT) Received: from J2N7QTR9R3.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F384E3F836; Mon, 11 May 2026 03:40:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1778496008; bh=qIBIaoZMw/edt0QBmUc5C+O+459IgUULanpiPn179Hg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AZqdSIPcNDUt2vsK0aBBMNGq9ftbYQkLtJzZEzpQyfsNIjrAIFSQvILVMNzfskFEI 3FSQiqKU+OjtNIqZZdvzkW0W9FwO3XyBsK96xa0zZ+jH7MmqlpmVwr9Vzdo88s+c3e Y04PU7WiXTlkgUqc0fJH/a8rXBHvUWHvl79a6z4o= Date: Mon, 11 May 2026 11:40:02 +0100 From: Mark Rutland To: Mark Brown Cc: Marc Zyngier , Joey Gouly , Catalin Marinas , Suzuki K Poulose , Will Deacon , Paolo Bonzini , Jonathan Corbet , Shuah Khan , Oliver Upton , Dave Martin , Fuad Tabba , Ben Horgan , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Peter Maydell , Eric Auger Subject: Re: [PATCH v10 01/30] arm64/sysreg: Update SMIDR_EL1 to DDI0601 2025-06 Message-ID: References: <20260306-kvm-arm64-sme-v10-0-43f7683a0fb7@kernel.org> <20260306-kvm-arm64-sme-v10-1-43f7683a0fb7@kernel.org> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sat, May 09, 2026 at 09:43:11AM +0900, Mark Brown wrote: > On Fri, May 08, 2026 at 06:12:01PM +0100, Mark Rutland wrote: > > On Fri, Mar 06, 2026 at 05:00:53PM +0000, Mark Brown wrote: > > > > Update the definition of SMIDR_EL1 in the sysreg definition to reflect the > > > information in DD0601 2025-06. This includes somewhat more generic ways of > > > describing the sharing of SMCUs, more information on supported priorities > > > and provides additional resolution for describing affinity groups. > > > FWIW, these are all in ARM DDI 0487 M.b: > > > https://developer.arm.com/documentation/ddi0487/mb/ > > > Is anything later in the series going to depend on these fields, or > > would everything behave correctly with the existing RES0 field > > definitions? > > We're exposing the affinity fields so there's a build time issue. What I'm asking is what is the rationale for updating these definitions? e.g. * Are we planning to use any of the fields in a specific way in the *host*? * Are we planning to use any of the fields in a specific way in the *guest*? * Is this updated just out of habit? Knowing the rationale would help with review, even if that rationale is just "it seemed nice to use the latest". > > > +Field 55:52 HIP > > > Reading the ARM ARM, HIP is arguably a backwards-incompatible change. > > Yes, I belive people are aware. Ok. Is that considered a problem, or accepted? Which people are aware? > > Do we expect to expose that to VMs, or just hide priorities entirely? I > > suspect we probably want to require that the guest sees > > SMIDR_EL1.SMPS==0, and not care about any of that. > > Currently we're not exposing priority support to guests so we don't need > to worry about it yet. Do we plan to in future? Mark.