From patchwork Mon Sep 13 13:16:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 510364 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 D5E11C433F5 for ; Mon, 13 Sep 2021 14:45:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C115E60FDA for ; Mon, 13 Sep 2021 14:45:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345342AbhIMOrK (ORCPT ); Mon, 13 Sep 2021 10:47:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:60204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348299AbhIMOpH (ORCPT ); Mon, 13 Sep 2021 10:45:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 91E0763226; Mon, 13 Sep 2021 13:58:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631541484; bh=lLyRquFGoi3tfA7vBHxudAkqITHw5IE3d1c2ikUzxis=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fqQJEXT3LK/uv+ox1nYgEakxghGCk/vIgLO1A5d6UF9JDVZU0EdxmwULg1Dt+A4hF Cxg93SUOJufUC4qgnjDN2SX3uBavORhXt06g7bAO1PiGnFDi0NVcSX/7zC0BdctQIi EciBZDyqM5NngLXFAfFO+DqONuKRB6tg6YAaVkr0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jim Mattson , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.14 316/334] KVM: nVMX: Unconditionally clear nested.pi_pending on nested VM-Enter Date: Mon, 13 Sep 2021 15:16:10 +0200 Message-Id: <20210913131124.117806401@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson commit f7782bb8d818d8f47c26b22079db10599922787a upstream. Clear nested.pi_pending on nested VM-Enter even if L2 will run without posted interrupts enabled. If nested.pi_pending is left set from a previous L2, vmx_complete_nested_posted_interrupt() will pick up the stale flag and exit to userspace with an "internal emulation error" due the new L2 not having a valid nested.pi_desc. Arguably, vmx_complete_nested_posted_interrupt() should first check for posted interrupts being enabled, but it's also completely reasonable that KVM wouldn't screw up a fundamental flag. Not to mention that the mere existence of nested.pi_pending is a long-standing bug as KVM shouldn't move the posted interrupt out of the IRR until it's actually processed, e.g. KVM effectively drops an interrupt when it performs a nested VM-Exit with a "pending" posted interrupt. Fixing the mess is a future problem. Prior to vmx_complete_nested_posted_interrupt() interpreting a null PI descriptor as an error, this was a benign bug as the null PI descriptor effectively served as a check on PI not being enabled. Even then, the new flow did not become problematic until KVM started checking the result of kvm_check_nested_events(). Fixes: 705699a13994 ("KVM: nVMX: Enable nested posted interrupt processing") Fixes: 966eefb89657 ("KVM: nVMX: Disable vmcs02 posted interrupts if vmcs12 PID isn't mappable") Fixes: 47d3530f86c0 ("KVM: x86: Exit to userspace when kvm_check_nested_events fails") Cc: stable@vger.kernel.org Cc: Jim Mattson Signed-off-by: Sean Christopherson Message-Id: <20210810144526.2662272-1-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx/nested.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2223,12 +2223,11 @@ static void prepare_vmcs02_early(struct ~PIN_BASED_VMX_PREEMPTION_TIMER); /* Posted interrupts setting is only taken from vmcs12. */ - if (nested_cpu_has_posted_intr(vmcs12)) { + vmx->nested.pi_pending = false; + if (nested_cpu_has_posted_intr(vmcs12)) vmx->nested.posted_intr_nv = vmcs12->posted_intr_nv; - vmx->nested.pi_pending = false; - } else { + else exec_control &= ~PIN_BASED_POSTED_INTR; - } pin_controls_set(vmx, exec_control); /*