From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F1C54CCD1BE for ; Wed, 22 Oct 2025 07:01:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=9KEBoR2NF5SFNxXTP9ERe3gk24NqRNbTEKVIDs5duuM=; b=P6RKs3SqUpSz7qH8YfLlx1wv+K XIEaiHv3MtQSj+mBDfVwI7cDPTYsh13UK/BsAwbk4qgbhlpg4PD97F482bLo/YRp2AhogRjFOS508 yTVxxoTRz+cmMOy2y5r6vu49AglWWQVX8N7/7li1M/G8qiAeNC/axGTabIA85WqHAhy9VE6O/mQUJ Fm2sYyhlPRA4VLOp9Lq1Dln0iwGbNjlYRitI82fkXKzKKA7s69bfQP/oH3OJh2qzSHFJJyZQh8gPB i5BynABHrpunyXFXkd4GrrMwsfORuxz2ZFJwyAP/Aoi5mybgt1JnyllcGjmCXe/MdV+FEwMSlpae9 8eT9Tntw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBSqb-00000001mGN-0U86; Wed, 22 Oct 2025 07:01:25 +0000 Received: from out-179.mta0.migadu.com ([2001:41d0:1004:224b::b3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBSqW-00000001m6l-2TH6 for linux-arm-kernel@lists.infradead.org; Wed, 22 Oct 2025 07:01:23 +0000 Date: Wed, 22 Oct 2025 00:00:47 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1761116457; 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=9KEBoR2NF5SFNxXTP9ERe3gk24NqRNbTEKVIDs5duuM=; b=kFP9CdYpXFhlbYcBxvLZpwKZovKdHaNAHaCCudWiy6suLIs0ODT5J9cVI2s04HjjfNbudz taiovlVK8FDkQ/YF3Dg6TrgQvASB2YIzETsutcZ331Oxg/BRyCyEec0l/wfjYuHU49Nrpj lI7AtI8dGYdJoVHpT7Gj8RouzUqRxzg= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Joey Gouly , Suzuki K Poulose , Zenghui Yu , Peter Maydell , stable@vger.kernel.org Subject: Re: [PATCH 1/3] KVM: arm64: Make ID_PFR1_EL1.GIC writable Message-ID: References: <20251013083207.518998-1-maz@kernel.org> <20251013083207.518998-2-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251013083207.518998-2-maz@kernel.org> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251022_000120_772381_26178252 X-CRM114-Status: UNSURE ( 8.69 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hey, On Mon, Oct 13, 2025 at 09:32:05AM +0100, Marc Zyngier wrote: > Similarly to ID_AA64PFR0_EL1.GIC, relax ID_PFR1_EL1.GIC to be writable. This looks fine to me, although I do wonder if we should just allow userspace to write whatever value it wants to the 32-bit ID registers and be done with it. Nowhere do we use a 32-bit ID register value as a condition for trap configuration / emulation, so even if the VMM lies to the guest it shouldn't trip up KVM. Thanks, Oliver