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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E05EC433ED for ; Thu, 8 Apr 2021 10:33:20 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A738B61158 for ; Thu, 8 Apr 2021 10:33:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A738B61158 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:Cc:To:From :Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wZMM9TM2wFsb6iyF/vJbs+fY/mL88BCKpPhgxQf4Pss=; b=m5ydD8ZVVAbo1bj08Nu9Th+kD yrRRjFqmm1X2IlfRCE6QS5mileV9WbQLvIvNot7cWjM+0XCk7LltMlvO2M6jv03S2Rs889+KB2h7p Z9dxEJfQ4iFpUBFFKiNCmeW8NhWLSF5iM6HgrdqRrB84Effw+hCXorJV4nkbyV71QDcwIqsQ0bfjA Ch5Uc+G9pFMhsRrL9vjLj+WuYHNd+rnEEKDxJddcewYAfCuv6mDjRZCHGT8NPT5hSdnG/a5Po7NmV ZyogM64lpLA/IV5Q5C2P8qPKm2z3g93FHXG91upjNqKGIV+MLAZhj8HFLP5AeWBq9cBzu0vKczf3X vi/X3indA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lURx3-007eMa-LF; Thu, 08 Apr 2021 10:31:54 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lURwx-007eJe-Q5 for linux-arm-kernel@lists.infradead.org; Thu, 08 Apr 2021 10:31:50 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0171261166; Thu, 8 Apr 2021 10:31:46 +0000 (UTC) Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1lURws-006HKW-Pk; Thu, 08 Apr 2021 11:31:42 +0100 MIME-Version: 1.0 Date: Thu, 08 Apr 2021 11:31:42 +0100 From: Marc Zyngier To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, Hector Martin , Arnd Bergmann , Mark Rutland , Catalin Marinas , kernel-team@android.com Subject: Re: [PATCH v2 3/3] arm64: Allow nVHE impaired CPUs to boot without CONFIG_ARM64_VHE In-Reply-To: <20210407211848.GE16198@willie-the-truck> References: <20210330173947.999859-1-maz@kernel.org> <20210330173947.999859-4-maz@kernel.org> <20210407211848.GE16198@willie-the-truck> User-Agent: Roundcube Webmail/1.4.11 Message-ID: <8474e539259346842178f51a26d59d74@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: will@kernel.org, linux-arm-kernel@lists.infradead.org, marcan@marcan.st, arnd@kernel.org, mark.rutland@arm.com, catalin.marinas@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210408_113148_486905_53B710C2 X-CRM114-Status: GOOD ( 20.94 ) 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2021-04-07 22:18, Will Deacon wrote: > On Tue, Mar 30, 2021 at 06:39:47PM +0100, Marc Zyngier wrote: >> CPUs stuck in VHE mode need some additional care if the kernel >> is compiled without CONFIG_ARM64_VHE. >> >> Treat this case as another version of a mismatched boot, and >> prevent KVM from being initialised. The machine will boot in >> some bizarre state, using TPIDR_EL1 instead of TPIDR_EL2, but >> otherwise be functional. >> >> Signed-off-by: Marc Zyngier >> --- >> arch/arm64/include/asm/virt.h | 18 +++++++++++++----- >> arch/arm64/kvm/va_layout.c | 9 +++++++++ >> 2 files changed, 22 insertions(+), 5 deletions(-) > > Hmm, I think we definitely need _something_ here, but it's a bit > annoying > to put ourselves into this weird state just for the sake of one stupid > machine. Which is why I'm not keen at all on this patch, and I'm happy to see the machine die a painful death. We really can't be blamed for terminally buggy HW, which the M1 obviously is. > What if we dropped CONFIG_ARM64_VHE and made the VHE code unconditional > instead? Is there a good reason to allow it to be disabled nowadays? What do we do for the other camp, aka people really wanting to run nVHE without any command line parameter? I can't see why you'd want to do that, but hey, that's only me. I'd be quite happy to see CONFIG_ARM64_VHE go though. Let me know if you want a patch doing that instead. Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel