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=1793044351; b=3fOwRoyY6sF5Y7TuCA6AKcKMz0rZdlSCB5dmV2AzsYTBKW2WoPBl8XfiRQUmtmfeRZ6h wkNiV6pjynCl1L8rbcHyZgJDpkJXEFe8xSwoUKmgD1z3jcq1IAwyDtmno96OtHpbxuiaO Shsm06JEe+Yy47s3wfLrD6O/z+1KsF7zFOAdzxDYqahMwObC6hYYN63JjLmvEL5/zan6R 5SXjWIaNKMNRRVr0bpw6NhdJ65Yzdgu80WM/4qZTY0P6oIukh/S1HUStJ4uOc5JqUjmDU v6SAEUvYSjRcEr1EUPusICYELjeIK70c17IKOwTsNsKRkRv0JHJq0Cj4PQVR7k8ZM8g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793044351; h=Received:DKIM-Signature:Received:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References:User-Agent:MIME-Version:Content-Type: X-SA-Exim-Connect-IP:X-SA-Exim-Rcpt-To:X-SA-Exim-Mail-From: X-SA-Exim-Scanned; bh=IoO8jhMb7zvyQD2W9noPd0i8Vmj5N2eTxpmHRimEf5s=; b=z6lJ6wqUVmrSMcLXUfGFF/2AxzvTGgQCTPB8EhsdKghdI1DdV1NIir7n1PVdbEUcINCY z+RnTfr2LD5sNjoEHVogJ8jeG620eEMy/OzRJEOLfzPDzWzxxU/y3qnQxxHjCFR5QFraX UWVUO4sRCRj0W0xtg8pkXyoUDNJ4A6R7Tz1WM/rE+TdiIXa+VYkzOzW6V4M28nExcD2Jw 3bWsNvDXHLItMA3geo1PQcVQLY7IlqLbaTjy7F144aOTLwsUpjnU+K+ogzNFmsb6lSZwn C/UtnLuy0KL3qJFcnYRr4WamN3/UMFigU4+zksTvcoFJvbDjuLLb2YG4NIKsiE2kV3A== 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=Dh+lMa57; 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 2B3E5606A31A; Mon, 26 Oct 2026 19:52:30 +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=Dh+lMa57 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA57C1F01825; Mon, 26 Oct 2026 19:52:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793044350; bh=IoO8jhMb7zvyQD2W9noPd0i8Vmj5N2eTxpmHRimEf5s=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Dh+lMa57ctnoQbPT7OdxHHCZrljxrsPpdfG+vxEZI13YMHVbXy6qtk+DCZfdOyFy4 N2TwljPdyHZfAI3mTwwX+b8iU8Z2zoO17BoQShYNMRMjoZBxqCes75qo2DHtS9gMoM Cc58wmExV10KhJuIAULNgA4RkzDuACLlF2KbJUb2psbb9b2pukicYbhg1RMuV2cuDR /+Zxh0hL2q4tUH7bLb5pBAwvwR3yl5B8d89vs8iNbDcxemwB73Dgre6rPTLuaweKa+ XKdlLz3XZ9csWRf+zaaIbXJtuQj9rPph2U/fB+G1AcchVvrclH1NN/a++AaFj8heBy bUgId6+bxkhFA== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1xLQk8-00000007QAT-1I5B; Mon, 26 Oct 2026 19:52:28 +0000 Date: Mon, 26 Oct 2026 19:55:45 +0000 Message-ID: <87qzhc8ce6.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Raghavendra Rao Ananta , Eric Auger , Will Deacon , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] KVM: arm64: vgic-v4: Don't allocate vPEs for a GICv2 VM In-Reply-To: References: <20261026152639.3926498-1-fuad.tabba@linux.dev> <20261026152639.3926498-2-fuad.tabba@linux.dev> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) 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 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oupton@kernel.org, fuad.tabba@linux.dev, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, rananta@google.com, eric.auger@redhat.com, will@kernel.org, tabba@google.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 26 Oct 2026 19:12:23 +0000, Oliver Upton wrote: > > On Mon, Oct 26, 2026 at 03:26:38PM +0000, Fuad Tabba wrote: > > KVM can run a GICv2 VM on a GICv4.0 host whose CPU interface supports > > legacy operation. > > I'm pretty sure there's no IP out there that has GICv4.0 and legacy > mode... My favourite space heater, HiSi D05, says otherwise: 64 A72, GICv4.0. Remember that it is the *CPU* that provides compat mode, and not the GIC. M. -- Jazz isn't dead. It just smells funny.