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 9AE5427B34E; Thu, 13 Nov 2025 11:42:07 +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=1763034127; cv=none; b=f4Z1AThmy4gqVwNC8gfUTjzhHN6M58F3lp2ZV5+SsI50Vk1YdMrPXma3YHdrj+vZGj9JQdq2cAmvwib60QzKwFt1U8qaGc/PYpop0lVbb6rG/fT578WtZYI3e8p0vuPGwgdXnlV1un3GqMRxNtdygdDmkh3USLGMTmVBtyiqWfg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763034127; c=relaxed/simple; bh=QgHFt6FHIW10WhXSanDVm43md4tZOo1qLvXd9ZzB3AE=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=Sa2mrmxXEPGrkZT062xHtoSxa0DukBVgslZzKYwl18teXtOWhth27vo2GK/jZeBj/Ko12mg/celVXZ8GVHj1LGV3YKk+1NBWlZUa8NctEAlcnRUXCWHaNfa+5v04+VxN+DVjna8wnOivlQK+twoMzScsgLwf5j2FFOBw1Q6Y+u8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ytsd/mir; 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="Ytsd/mir" 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) Precedence: bulk X-Mailing-List: kvm@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: 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 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.