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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AA9AEB64DC for ; Sun, 9 Jul 2023 14:57:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229591AbjGIO5k (ORCPT ); Sun, 9 Jul 2023 10:57:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230040AbjGIO5i (ORCPT ); Sun, 9 Jul 2023 10:57:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9541E1B4; Sun, 9 Jul 2023 07:57:10 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 065AE60B83; Sun, 9 Jul 2023 14:56:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3ED66C433C7; Sun, 9 Jul 2023 14:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688914574; bh=s/KLEUrpUPS3pZCuQPjKoUSGuWuJeNp/7nLddxJ79rk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CJ8gC1F5cddng7dJg4Ip4ExhBbTtaLPrv7spAw+OKkco6XZTsTv1alvqxJPLPeJE+ GPZbHtz2ssfXahUqVEaQ0JLAMrGMmJetiTLA5iKX5kJ1L7Edf8aNv8PBLlNKBnNFTL p2QAZSFIVDJPgcEyZbHt4ujCv9cNIBDPwYhO2x4FlLY1mSUs9ZVkMEkSScxws+i8r5 ur4nlhF9JtrzooSnWvcG+5d6V76hYOmnfOemy3GXqZz3+LZFsyLtoy/O8kOsDpm7oM GYtTThvTyu9md0EYgFIQdIbuYVQ84uRY0Hidv+zU05YMlbWAdvOvUHtY2UYrVpa5Bp e7ksEuXc6+HvA== Date: Sun, 9 Jul 2023 10:56:13 -0400 From: Sasha Levin To: Mark Brown Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Kristina Martsenko , Catalin Marinas , will@kernel.org, james.morse@arm.com, mark.rutland@arm.com, amit.kachhap@arm.com, maz@kernel.org, anshuman.khandual@arm.com, joey.gouly@arm.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH AUTOSEL 6.4 07/12] arm64: cpufeature: detect FEAT_HCX Message-ID: References: <20230702195057.1787686-1-sashal@kernel.org> <20230702195057.1787686-7-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jul 03, 2023 at 12:51:57PM +0100, Mark Brown wrote: >On Sun, Jul 02, 2023 at 03:50:52PM -0400, Sasha Levin wrote: >> From: Kristina Martsenko >> >> [ Upstream commit b0c756fe996ac930033882ca56410639e5cad1ec ] >> >> Detect if the system has the new HCRX_EL2 register added in ARMv8.7/9.2, >> so that subsequent patches can check for its presence. >> >> KVM currently relies on the register being present on all CPUs (or >> none), so the kernel will panic if that is not the case. Fortunately no >> such systems currently exist, but this can be revisited if they appear. >> Note that the kernel will not panic if CONFIG_KVM is disabled. > >This is a new feature, it's not clear why we'd backport it (especially >since it's a new feature which is a dependency for other features rather >than something that people can use outside of the kernel)? The second paragraph (above) suggested it should be. -- Thanks, Sasha