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 2BF74CD5BCE for ; Thu, 13 Nov 2025 11:42:15 +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:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID: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=XdG50GdO6gAEhJsxfa+nmzU70gs6Qy9WO2otRykW7Bo=; b=eFLGomYuLfhgov6KSBpE2DkSOq NIN86uc7BufB3sXsEwDJpnntGH/y5JeW+ptDFGbJhlxpHIqry1M0mdIj/025xMtYzLVKvrl/fk6/3 +Ju4eF9EYJ5hLcT/iHDqVBS9TwMqIPEOAxROzJsL7/rBzTGSBcNHq5qL7LiY+y6N9a3qG7PiW2Dgm bLU9uNWDarb77RygSfFMCLLuy3/iV/8Vqs1EFRChT3BkshFtPcyN/NBSpFddrXugLaQZJpn2kkZ8l LXvscYOlmBMpjAtxnbgLs5IS3cMi9vVHFBZJtaAXp1xz5GH7zBZj6CinTP4dzMUA8/5SBuFAVlCvz 2P4eqG7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJViM-0000000APPT-18U6; Thu, 13 Nov 2025 11:42:10 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJViK-0000000APPL-2YtB for linux-arm-kernel@lists.infradead.org; Thu, 13 Nov 2025 11:42:08 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 8573660219; Thu, 13 Nov 2025 11:42:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C21CC4CEF8; Thu, 13 Nov 2025 11:42:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763034127; bh=QgHFt6FHIW10WhXSanDVm43md4tZOo1qLvXd9ZzB3AE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Ytsd/mir0Lv9XI9rvJ+l8/nj1mIvaqoya/2pOSw1uoH+DeioGBHDiC66Tx+ZT2lBX hCndMN2VVpgy8VqruA5HYa8MOr4XUrEsVIzC8/k1jdVMM5wWOlFXGl0/k0DsOy7w2b DmNG9Lc24s3U4XgJVRCszq4tNHsW6NPaA5zH3a87YDVZZq/ctX5czwITd7PmZsqdT+ mo9QfdJBIiZjqtOVvP2RCVLi/IZJOlx1osW+6bBJ4KA8JTlA4GUfjRtG162K29Mbt6 pCnUKWKXigCKBNb2ZaL1k9LneO5gfbrTre2pYjf8UbV36kV1ECEt0YzNOI2W08SE5A mj+Q9F+5yZf/Q== 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 4.98.2) (envelope-from ) id 1vJViG-00000004rK3-3hWQ; Thu, 13 Nov 2025 11:42:04 +0000 Date: Thu, 13 Nov 2025 11:42:04 +0000 Message-ID: <86pl9mtb03.wl-maz@kernel.org> From: Marc Zyngier To: Joey Gouly Cc: Marek Szyprowski , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Suzuki K Poulose , Oliver Upton , Zenghui Yu , Christoffer Dall , Volodymyr Babchuk , Yao Yuan Subject: Re: [PATCH v2 04/45] KVM: arm64: Turn vgic-v3 errata traps into a patched-in constant In-Reply-To: <20251113112333.GA1434041@e124191.cambridge.arm.com> References: <20251109171619.1507205-1-maz@kernel.org> <20251109171619.1507205-5-maz@kernel.org> <86seeitd3f.wl-maz@kernel.org> <5a0aac14-6d1f-4941-b0d1-bb60572e7a6e@samsung.com> <20251113112333.GA1434041@e124191.cambridge.arm.com> 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) 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: joey.gouly@arm.com, m.szyprowski@samsung.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, suzuki.poulose@arm.com, oupton@kernel.org, yuzenghui@huawei.com, christoffer.dall@arm.com, Volodymyr_Babchuk@epam.com, yaoyuan@linux.alibaba.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false 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 On Thu, 13 Nov 2025 11:23:33 +0000, Joey Gouly wrote: > I suppose the issue is that the alternatives in vgic_ich_hcr_trap_bits() are > always calculated, even if that function is only used from the gic-v3 code. > Calculating the trap bits reads ICH_VTR_EL2, which needs FEAT_GICv3. Except that we have a bunch of rotten fruits that only have half a GICv3, so relying on FEAT_GICv3 isn't useful if we want to continue supporting these machines in the foreseeable future. The fix for this is, I expect, what I posted at [1]. Thanks, M. [1] https://lore.kernel.org/r/86seeitd3f.wl-maz@kernel.org -- Without deviation from the norm, progress is not possible.