From patchwork Mon Oct 11 15:38:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 12550365 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D36DC433F5 for ; Mon, 11 Oct 2021 15:39:09 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 25D1660C4B for ; Mon, 11 Oct 2021 15:39:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 25D1660C4B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=STeLYnzJIZwBbdFzjGexLYKH6/fqye90o0kqlJzSeUI=; b=azl38N18KL806J C+VV4lFIQbEBx38HpP7adXavowF/zyQSIKrhFOvEAqvNDIj9oDAhfLrV49nLOsW2ZRGV+Agnjem7r L2ZVe8Qie304J6GTzRvbTHHs22NRkyYyCQBwmCAFiL3DXl0Ic7vfWRIR2vu2ihuZD9XCXCDhx39lU mWSIXknrEUntze3BVsjcUNWvqcbjvGQGiAcFXSNArxNWjEZehQw49PCOg6Qw5G5/KNlPE0V0fpz7P 9uyF7luc7DA2qdKfmX0d6Khcx0UbdKAzeIFvrVlEA5CWRVzYe+87ccSwXaNK6SOmNlTdSyokZoVu8 XICge6DLJdVQigTxEo0g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mZxMa-009wFA-Bg; Mon, 11 Oct 2021 15:37:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mZxMW-009wEB-74 for linux-arm-kernel@lists.infradead.org; Mon, 11 Oct 2021 15:37:13 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A6DB9101E; Mon, 11 Oct 2021 08:37:08 -0700 (PDT) Received: from monolith.cable.virginm.net (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E367F3F694; Mon, 11 Oct 2021 08:37:06 -0700 (PDT) From: Alexandru Elisei To: corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled Date: Mon, 11 Oct 2021 16:38:35 +0100 Message-Id: <20211011153835.291147-1-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211011_083712_324187_318E1390 X-CRM114-Status: GOOD ( 12.24 ) 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 Recent changes to KVM for arm64 has made it impossible for the host to hibernate or use kexec when protected mode is enabled via the kernel command line. There are people who rely on kexec (for example, developers who use kexec as a quick way to test a new kernel), let's document this change in behaviour, so it doesn't catch them by surprise and we have a place to point people to if it does. Signed-off-by: Alexandru Elisei --- Based on the tip of the pkvm/restrict-hypercalls series [1] [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pkvm/restrict-hypercalls Documentation/admin-guide/kernel-parameters.txt | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 91ba391f9b32..741e33fd444a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2372,7 +2372,9 @@ state is kept private from the host. Not valid if the kernel is running in EL2. - Defaults to VHE/nVHE based on hardware support. + Defaults to VHE/nVHE based on hardware support. Setting + mode to "protected" will disable kexec and hibernation + for the host. kvm-arm.vgic_v3_group0_trap= [KVM,ARM] Trap guest accesses to GICv3 group-0