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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B7F2CC433DB for ; Fri, 26 Feb 2021 18:13:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72C8264F17 for ; Fri, 26 Feb 2021 18:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229752AbhBZSNi (ORCPT ); Fri, 26 Feb 2021 13:13:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:54278 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229571AbhBZSNd (ORCPT ); Fri, 26 Feb 2021 13:13:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D7B7B64E85; Fri, 26 Feb 2021 18:12:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614363173; bh=nAk4WrgY8B1ZZvvFfv8YJ7MnbT4maSdfShrZmvw4D64=; h=From:To:Cc:Subject:Date:From; b=oRVWGsLXznLVXC6SDWZGUxWKLSP5iTK6CsaJ6BXqEDc/NllJ8K40KI/TxRQPsinkB 3+JjvMXwYe5xM4nRSRWg92AmWm6FkR0+QPL2cg1ehaH8LO+Dj6wBBh2NnGuTMXQHC/ 6+MJJJUtJlKOsnwgcW1TqZ5EUg6n4PfpmJzMTkhiibEoxkK81AC38RSDSpwzAoHk3m aNWV4oY0kKviXBM1bFZMclEl1ZkvB81TLxFmmkIVjZGVg65UOOXyNkE/JlciG9/iRX 2b8PB8XAbpGkod0dKqAlwP5tHrnaJjQpZBLA5OL2aJjM2B58Wc+Woxwu8g7wBf5ksk IKha1ce9e8GVQ== From: Will Deacon To: kvmarm@lists.cs.columbia.edu, maz@kernel.org Cc: linux-arm-kernel@lists.infradead.org, kernel-team@android.com, Will Deacon , Andrew Scull , stable@vger.kernel.org, Quentin Perret Subject: [PATCH] KVM: arm64: Avoid corrupting vCPU context register in guest exit Date: Fri, 26 Feb 2021 18:12:11 +0000 Message-Id: <20210226181211.14542-1-will@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Commit 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest context") tracks the currently running vCPU, clearing the pointer to NULL on exit from a guest. Unfortunately, the use of 'set_loaded_vcpu' clobbers x1 to point at the kvm_hyp_ctxt instead of the vCPU context, causing the subsequent RAS code to go off into the weeds when it saves the DISR assuming that the CPU context is embedded in a struct vCPU. Leave x1 alone and use x3 as a temporary register instead when clearing the vCPU on the guest exit path. Cc: Marc Zyngier Cc: Andrew Scull Cc: Fixes: 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest context") Suggested-by: Quentin Perret Signed-off-by: Will Deacon --- This was pretty awful to debug! arch/arm64/kvm/hyp/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index b0afad7a99c6..0c66a1d408fd 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -146,7 +146,7 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) // Now restore the hyp regs restore_callee_saved_regs x2 - set_loaded_vcpu xzr, x1, x2 + set_loaded_vcpu xzr, x2, x3 alternative_if ARM64_HAS_RAS_EXTN // If we have the RAS extensions we can consume a pending error -- 2.30.1.766.gb4fecdf3b7-goog