From patchwork Fri Mar 5 18:52:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 394267 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 5BEB2C4332D for ; Fri, 5 Mar 2021 18:53:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BBCD650A1 for ; Fri, 5 Mar 2021 18:53:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229493AbhCESxZ (ORCPT ); Fri, 5 Mar 2021 13:53:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:58224 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229595AbhCESxC (ORCPT ); Fri, 5 Mar 2021 13:53:02 -0500 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 C71D260200; Fri, 5 Mar 2021 18:53:01 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lIFZM-00HYFA-3M; Fri, 05 Mar 2021 18:53:00 +0000 From: Marc Zyngier To: Paolo Bonzini Cc: Alexandru Elisei , Andre Przywara , Andrew Scull , Catalin Marinas , Christoffer Dall , Howard Zhang , Jia He , Mark Rutland , Quentin Perret , Shameerali Kolothum Thodi , Suzuki K Poulose , Will Deacon , James Morse , Julien Thierry , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/8] KVM: arm64: Avoid corrupting vCPU context register in guest exit Date: Fri, 5 Mar 2021 18:52:48 +0000 Message-Id: <20210305185254.3730990-3-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210305185254.3730990-1-maz@kernel.org> References: <87eegtzbch.wl-maz@kernel.org> <20210305185254.3730990-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, andre.przywara@arm.com, ascull@google.com, catalin.marinas@arm.com, christoffer.dall@arm.com, Howard.Zhang@arm.com, justin.he@arm.com, mark.rutland@arm.com, qperret@google.com, shameerali.kolothum.thodi@huawei.com, suzuki.poulose@arm.com, will@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Will Deacon 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 Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210226181211.14542-1-will@kernel.org --- 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