From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB087328B6; Wed, 27 Nov 2024 15:42:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732722120; cv=none; b=tBl6QTxSs/IY2EBxkDefR4yrkyDBcLNxdzPnz3cO7U+llcof6ON09tIjupNxkvxePoZI6bCAojtILinmZ27Fjq1LzbCri8/eowUCyaojVxh0ZEy5SiX3yG+xdIB29b+6KQZFvgiZ24TZEogGBZSERThhGlAmfdYtdTSXuM9BUQE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732722120; c=relaxed/simple; bh=dZSnAYpZutAuOvaVC5VkHYc0cGR/1sXeOGbZkw59I2w=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=K+3NQtMikTGbYpeZFc5bm42Nd/JuUAO9l723d/wstWTHRMfVDQcwD9vl0OQOrextdXLgb6kvpewuSiEQ4NpBzbKZjCHXWuvg0SkY2qtI/Xe982jMn9t++v2qYksGqCbUxfB5PxRZh59nsDcwHvXd8Jv2mbQNBJF21ZW/fD5bo+o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=keRTqRHW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="keRTqRHW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 488A6C4CED3; Wed, 27 Nov 2024 15:42:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732722120; bh=dZSnAYpZutAuOvaVC5VkHYc0cGR/1sXeOGbZkw59I2w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=keRTqRHWiVSj0heTa4ZVSS1l8dafdIoPicR8WQe/Fr3C/bRoRUQalLEZIJ3cyK7cI cPGIqpGF49rYoTyj2iUzh0hjZ9jeD8moEQZ8j9iD1S2v4EOaWhFdxZ/1dF4DkoahJt GjS0JDpt4tTVrneIyEdrurg6phrKcrr7K03RBBBRS8Jz1j42v5eZQm3UYuuISlbL91 zEynDTl3v/3MTwjQWPeB/+ndzhqWSam97iEd+zF72TjtfY7GKw+//xM4p/1OJdaImF /kqnHl9kKeYhGvFwwVlQ3lYdVhtDY4uiqm4m4YAiRj2X1L3jadW5sEfhQ53T34SLpi 7ftqIEdWt41NQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1tGKAv-00GItK-Un; Wed, 27 Nov 2024 15:41:58 +0000 Date: Wed, 27 Nov 2024 15:41:57 +0000 Message-ID: <868qt4vg3e.wl-maz@kernel.org> From: Marc Zyngier To: Steven Price Cc: Catalin Marinas , Oliver Upton , Will Deacon , Joey Gouly , Suzuki K Poulose , Zenghui Yu , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: arm64: Bump KVM_VCPU_MAX_FEATURES In-Reply-To: References: <20241127145644.421352-1-steven.price@arm.com> <86a5dkvh9o.wl-maz@kernel.org> 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/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: steven.price@arm.com, catalin.marinas@arm.com, oliver.upton@linux.dev, will@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.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 Wed, 27 Nov 2024 15:24:32 +0000, Steven Price wrote: > > On 27/11/2024 15:16, Marc Zyngier wrote: > > On Wed, 27 Nov 2024 14:56:31 +0000, > > Steven Price wrote: > >> > >> When the KVM_ARM_VCPU_HAS_EL2 define was added, the value of > >> KVM_VCPU_MAX_FEATURES wasn't incremented, so that feature has never been > >> in the KVM_VCPU_VALID_FEATURES bit mask. This means the HAS_EL2 feature > >> will never be exposed to user space even if the system supports it. > >> > >> Fixes: 89b0e7de3451 ("KVM: arm64: nv: Introduce nested virtualization VCPU feature") > >> Signed-off-by: Steven Price > >> --- > >> I might be missing something, and it's possible that > >> KVM_ARM_VCPU_HAS_EL2 is deliberately not exposed yet. > > > > This is on purpose. I'm not planning to enable EL2 support until it is > > ready. > > I did suspect that's the case - but it might have been better to knobble > it in system_supported_vcpu_features()/kvm_vcpu_init_check_features() > rather than 'hiding' it in the MAX_FEATURES. But hindsight is a > wonderful thing ;) > > >> However I'm > >> working on v6 of the host CCA series and as part of that want to add a > >> new feature but and bump KVM_VCPU_MAX_FEATURES up to 9. > > > > Well, I guess that defines some ordering then! :D > > Indeed - I'll try to remember to include note about this "dependency" in > my cover letter. We're likely to need a few more rounds for CCA to be > ready, so hopefully NV will naturally be there in time :D Any minute now, according to those impersonating a French physicist... M. -- Without deviation from the norm, progress is not possible.