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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 2F9F7C433DB for ; Tue, 29 Dec 2020 16:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E06F220825 for ; Tue, 29 Dec 2020 16:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726634AbgL2QCE (ORCPT ); Tue, 29 Dec 2020 11:02:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726203AbgL2QCE (ORCPT ); Tue, 29 Dec 2020 11:02:04 -0500 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FD52C0613D6 for ; Tue, 29 Dec 2020 08:01:23 -0800 (PST) Received: by mail-wr1-x42c.google.com with SMTP id r3so15060915wrt.2 for ; Tue, 29 Dec 2020 08:01:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=NtCljhLriYtvqTyh0Oi7f3SoeajHUSS/0DAzm3hIGXE=; b=Oz7Ml7QJVCMzwv2c3OvZUVS1nQR+4abLjG0AvTqtcYOBygQ3cV++dq2Q6H5LlAKrJT yiLsX9sMElJJfJRsPvDEaP+TbemQEMjDGRraLIfCVxGD+J1oRK5SOotiiGSBR1h+utFs k3pYH3lbVXXATfVz7oopjMSJzngGXuu/egoKdfuLkxzdA0cJVJK5H1HBZcheS6le/UX2 bR7Wy/OEayCryx50CMsvlN8wahXfGjPH3yP5ucV7N9nK9AGU3X/DyctWqEyNDF6LCIEA 4b7vbgmlTU4v2FSk5RCmiSPrrdDZY0nYjL0nBX3BHVA/0Xyyv+6JRgMuPGWQUtZ8JJrL yrYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=NtCljhLriYtvqTyh0Oi7f3SoeajHUSS/0DAzm3hIGXE=; b=qRDyY+Tn3HQhniXXSbcDly2Fa5osVfKiI/R7smY12dx8+ASsJrigir7zIFdnuj+FfH nFkq97raG5+EIV+GtoM+Ee2e7vhVUfUvu6nTLQW8aYbku6WO8LURFh1QsbQhqRSbe20r ZsiTgf2lsGPhthPgg30/VjEAhtyExd5qnU74kp8PJjmROcANVqWoEDz0B6VChuS5Xfzg POrlwvIAS6vTuZHc7Yp9WCQpp23tFM7OypbglBzX7fK3Pg0/fajehUv9PkQ7dJDGFGuJ azyGe1dMwdGj89eVD0+L5kuZG4Gjl/fU6KXLo6WxRVu+V75bUKporPjkrDqqmzI6qmKs u2+w== X-Gm-Message-State: AOAM533HeTMe3/yKA6GOCbyP3Ngc5UI+malMCqz/oRNseoBsDY+jZpUU pFj1IDN2t3W9iPixcaJCwCRzeg== X-Google-Smtp-Source: ABdhPJw9Ayoh9M0GtPyVtC0R8Y+dAZ8drQfvlYeo93ZmkqUpL9igbq4DREd39sZg1DlSlN4TeaAUKw== X-Received: by 2002:adf:8290:: with SMTP id 16mr54668406wrc.27.1609257682161; Tue, 29 Dec 2020 08:01:22 -0800 (PST) Received: from localhost ([2a01:4b00:8523:2d03:b0e4:997:fb3:e517]) by smtp.gmail.com with ESMTPSA id l5sm61284118wrv.44.2020.12.29.08.01.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 29 Dec 2020 08:01:20 -0800 (PST) From: David Brazdil To: kvmarm@lists.cs.columbia.edu Cc: Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Catalin Marinas , Will Deacon , Mark Rutland , Lorenzo Pieralisi , Sudeep Holla , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com, David Brazdil Subject: [PATCH] KVM: arm64: Allow PSCI SYSTEM_OFF/RESET to return Date: Tue, 29 Dec 2020 16:00:59 +0000 Message-Id: <20201229160059.64135-1-dbrazdil@google.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The KVM/arm64 PSCI relay assumes that SYSTEM_OFF and SYSTEM_RESET should not return, as dictated by the PSCI spec. However, there is firmware out there which breaks this assumption, leading to a hyp panic. Make KVM more robust to broken firmware by allowing these to return. Signed-off-by: David Brazdil --- arch/arm64/kvm/hyp/nvhe/psci-relay.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c index e3947846ffcb..8e7128cb7667 100644 --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c @@ -77,12 +77,6 @@ static unsigned long psci_forward(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 2), cpu_reg(host_ctxt, 3)); } -static __noreturn unsigned long psci_forward_noreturn(struct kvm_cpu_context *host_ctxt) -{ - psci_forward(host_ctxt); - hyp_panic(); /* unreachable */ -} - static unsigned int find_cpu_id(u64 mpidr) { unsigned int i; @@ -251,10 +245,13 @@ static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_ case PSCI_0_2_FN_MIGRATE_INFO_TYPE: case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU: return psci_forward(host_ctxt); + /* + * SYSTEM_OFF/RESET should not return according to the spec. + * Allow it so as to stay robust to broken firmware. + */ case PSCI_0_2_FN_SYSTEM_OFF: case PSCI_0_2_FN_SYSTEM_RESET: - psci_forward_noreturn(host_ctxt); - unreachable(); + return psci_forward(host_ctxt); case PSCI_0_2_FN64_CPU_SUSPEND: return psci_cpu_suspend(func_id, host_ctxt); case PSCI_0_2_FN64_CPU_ON: -- 2.29.2.729.g45daf8777d-goog