From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792594893; b=4djRa0W2nUsP0/O+hA1QZ1ZK9+ZugWSpI7T7ITM0YkBL2WUuW4gSvx0GveRbRJs0FU9J QIKnvCeL+Ri39m2W7QWQpnmL7f1tQjQSlYfoKVWTEiaNa76dHmZecTFCr6QQ/jtSnq5rK Glz4mzbPbL/PfdicjldDiLzPNUy320WQYypEDoBk6i4Z35+4y/aGEPnRbeP8LUNCPsMIi gpuf5jSRqSvvkFxxLKV02hnyUHd/tFOJJVRKvxrsNd/1Ya6XGX1LSLekFkwvCJ/yrSzM8 s6nmK+FaZlfsBWie1CP89tb9jzYPwTxnZx3yyL/rswE7ZQJthYLxPWyVwMNf2BS3D2g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792594893; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=A4guUMc9i9ehpF1G8jQSt60WOuL8gly2/KcblJXhFIY=; b=14jUndmvLiJ9nbv0C6j7Q7s+jLr5XV01Gk+YYpeKgCUC6oyxlqeQS77mqUP3A273AaSq +EET/QFhqO7BbQ8oTHUshIlDhfrlUQM4b0XHNxyF5oOyF0HIcfE4lM6glzHezPrtk96kj aTfDtu0Jm/NGfCkX15Bo+QN8uAtCSfV1CQ4iQqdcY2Vssg/HzlBa3QBWxQqbxc9AjslZv gC95FekYagLnfIqF22HSYOmmnqdokq3heeoMEVXtV2tF5vubt6V7a+wwRA+PRTkvZJj+K a/yX1Pzm2NwaXvTAtpaEL7CW12+Y/yvHf/mat5GjS9gkm6PlI3IABG/Dw+2oxY7p2wA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Xba3Sfr2; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3AA86606A319; Wed, 21 Oct 2026 15:01:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Xba3Sfr2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EC2F1F000C1; Wed, 21 Oct 2026 15:01:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792594892; bh=A4guUMc9i9ehpF1G8jQSt60WOuL8gly2/KcblJXhFIY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Xba3Sfr20Kz5gusDKlhGPB3CawV7BST+aPzpn6mJzugFRMC+iYEF0//1hJzhbhn5B FpgprOld7c3FBThNJEx6YKXfgUWaXn73oa7/WoC6aQu97ASe6/crpYX+EXseyo/tfj nh9yvk54UUA9/Jqpzbb1Y2OvJkbnXn6oqsu8W9B93EawaCC3uz5o9Ns19Bs8dcq66r W5QSNhK3dUxYpMMFtCIdBs6EIFBx8gtGp7sEp5WlZWLmY3fWTPtCxZ1lLjIHPYGeNH rfMdw2Cxm6lDO2ECHr+MtIu10ADMmsFvc0tAIuubT+nmA8XSiOMjp6vT2qvi9uXRN5 +H7iCZ4kynszw== Date: Wed, 21 Oct 2026 16:01:26 +0100 From: "Lorenzo Stoakes (ARM)" To: Marc Zyngier Cc: Fuad Tabba , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Mark Brown , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] KVM: arm64: Sanitise ID_AA64MMFR3_EL1.S1P[IO]E Message-ID: References: <20261020064306.1542865-1-fuad.tabba@linux.dev> <86o6cnywvb.wl-maz@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86o6cnywvb.wl-maz@kernel.org> On Wed, Oct 21, 2026 at 03:03:04PM +0100, Marc Zyngier wrote: > On Tue, 20 Oct 2026 20:30:56 +0100, > Fuad Tabba wrote: > > > > >> @@ -59,6 +59,7 @@ struct reg_feat_map_desc { > > >> const struct reg_bits_to_feat_map feat_map; > > >> const struct reg_bits_to_feat_map *bit_feat_map; > > >> const unsigned int bit_feat_map_sz; > > >> + const unsigned int idreg_idx; > > > > > > This field feels a bit hazardous - 0 is a valid index and now things that > > > don't declare it are setting a valid value. > > > > idreg_idx is only read for the descriptors in idreg_feat_maps[], which > > all come from DECLARE_IDREG_FEAT_MAP(), so the 0 in the others is > > never used. Storing the encoding would work as well, I'll leave that > > one to Marc. > > I don't think we should baby-sit people who hack this code. If you put > something that is not the output of IDREG_IDX(), you get to keep the > pieces. If you use this out of context, it will blow up in your face. That's fair enough, I did worry a bit about identifying the idreg variant vs. not from a reg_feat_map_desc instance though? > > >> +static bool idreg_deps(struct kvm *kvm, const struct reg_feat_map_desc *r) > > >> + for (int i = 0; i < r->bit_feat_map_sz; i++) { > > >> + if ((r->bit_feat_map[i].flags & CALL_FUNC) && > > > > > > What if it isn't a CALL_FUNC feature? > > > > > > Could this loop just be replaced with compute_resx_bits()? > > > > It's skipped, so a dependency written as a plain field match would be > > silently ignored. Both entries today are CALL_FUNC, but > > compute_resx_bits() handles every kind of entry and would also give > > the res1 line something to set. It'd mean moving idreg_deps() below > > it. > > I really do not want to drag compute_resx_bits() into this. None of > that stuff is RESx. It is bad enough that we use the same structures > to represent different type of dependencies. I also want to add new > ways to affect ID registers that really do not fit the RESx handling. I wonder if it's worth breaking out the resx stuff into something separate that both call? As a follow-up obviously. > > > Marc, compute_resx_bits(), the rename and the loop rework are all fine > > by me. If you agree, I can respin with them, or you can fold them in > > when applying, whichever is easier for you. > > I don't care about the name, but I don't want the rest of the proposed > changes. Fine with me ;) the logic all looks fine so these were nits. As you are indifferent on name, do you mind having the two functions one calling another? That is a lot clearer to my eyes. But also not a showstopper, obviously! -- Cheers, Lorenzo