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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0270C41535 for ; Mon, 7 Feb 2022 11:49:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1388470AbiBGLnp (ORCPT ); Mon, 7 Feb 2022 06:43:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1385754AbiBGLc1 (ORCPT ); Mon, 7 Feb 2022 06:32:27 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E47ACC0401C2; Mon, 7 Feb 2022 03:32:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A5EF4B80EC3; Mon, 7 Feb 2022 11:32:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF268C004E1; Mon, 7 Feb 2022 11:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644233544; bh=yXOodRqUYTtTkw1TE/eivAQOedKt74N5rdHbQhj10b0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1aeLTRz5CW7uScQNfnVmbne2QRbmRhBq0bJm3cpnwMcSiQmrNWAWAGgtJd2vszXG1 3eAo1SsMVlOvg0RPAFXedS3b9XFJxVYWgH+czJLMhgJoiYz0wfPhDpufenASrxbXcH Inthf4/Z5KdezFpsLYpZHR+cujcG1b90BZVTbJ1c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steven Price , James Morse , Marc Zyngier Subject: [PATCH 5.16 045/126] KVM: arm64: Avoid consuming a stale esr value when SError occur Date: Mon, 7 Feb 2022 12:06:16 +0100 Message-Id: <20220207103805.675591778@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220207103804.053675072@linuxfoundation.org> References: <20220207103804.053675072@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: James Morse commit 1c71dbc8a179d99dd9bb7e7fc1888db613cf85de upstream. When any exception other than an IRQ occurs, the CPU updates the ESR_EL2 register with the exception syndrome. An SError may also become pending, and will be synchronised by KVM. KVM notes the exception type, and whether an SError was synchronised in exit_code. When an exception other than an IRQ occurs, fixup_guest_exit() updates vcpu->arch.fault.esr_el2 from the hardware register. When an SError was synchronised, the vcpu esr value is used to determine if the exception was due to an HVC. If so, ELR_EL2 is moved back one instruction. This is so that KVM can process the SError first, and re-execute the HVC if the guest survives the SError. But if an IRQ synchronises an SError, the vcpu's esr value is stale. If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2, causing an unrelated guest instruction to be executed twice. Check ARM_EXCEPTION_CODE() before messing with ELR_EL2, IRQs don't update this register so don't need to check. Fixes: defe21f49bc9 ("KVM: arm64: Move PC rollback on SError to HYP") Cc: stable@vger.kernel.org Reported-by: Steven Price Signed-off-by: James Morse Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220127122052.1584324-3-james.morse@arm.com Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kvm/hyp/include/hyp/switch.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -446,7 +446,8 @@ static inline bool fixup_guest_exit(stru if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ) vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR); - if (ARM_SERROR_PENDING(*exit_code)) { + if (ARM_SERROR_PENDING(*exit_code) && + ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ) { u8 esr_ec = kvm_vcpu_trap_get_class(vcpu); /*