From patchwork Sat Jul 23 00:51:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12926997 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 E56E5CCA489 for ; Sat, 23 Jul 2022 00:51:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235934AbiGWAvr (ORCPT ); Fri, 22 Jul 2022 20:51:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235033AbiGWAvp (ORCPT ); Fri, 22 Jul 2022 20:51:45 -0400 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA65B101F3 for ; Fri, 22 Jul 2022 17:51:44 -0700 (PDT) Received: by mail-pj1-x104a.google.com with SMTP id r6-20020a17090a2e8600b001f0768a1af1so5003472pjd.8 for ; Fri, 22 Jul 2022 17:51:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=dDbBsniYzHp/DkWFlMs8orp7Z4WhIFDdPFs5eLnWS08=; b=WyABck1LPPvjC6je72o/2E18L+yh/Fefg4gzXmU5uIknt5PWWm5Juk50jGnGUtiQnX hL+pyIBGmbbkOSj3PqffyytipWE5zL2OikSniX+VkGUBtgsE/QHMIORPqtS+ULO3Zsaa ip8JF1lShaoow/UOoWUm2xuTcdwdRR7wAlhiAa4RLE45hJ8wce19sHdZdHdllfSkLK6V LOqw13njtxrvL89XeQ7yv0bKFbXteI/wBieQBJ+L+BYTKD4Dbm0ODZNY2jIuJxf9MG75 61waSCk9Pa1sLCf7zN07XU0d1YcML5jhU8F//+FbyNdZvfCA6QT4vDmCl3tA8S74YScj PyoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=dDbBsniYzHp/DkWFlMs8orp7Z4WhIFDdPFs5eLnWS08=; b=jToQvEF37ZknlaCFL/j5qXp2SoblLqeDxWR0wLzSv2tgIwPsuI9M65iV1B37FQxd1Q B/+nzd+708AfbE2XVdDX+F7BNQusv9pGXuFifHRWHbVjRWM3ljTtYzFri9CVZFczK2Zf MUURzlVa67uhC4NHPhKyocwQNjNxM8xE+NOSud5TvCIjKdR/oPdIWxnaXbVrNP/m61tu HVl7RwOe4oq8dQ59RBnHlize5Cb3R3DrydsI7LiCuzE6LIApJrKUaX6dqj6OVMBzz5XV u+F6xdryLKe7zMAE7h2wNMF1A0YrWgCBKg/Nx+biDWZbwQk+NgPiSmxNqDZZFfcVsPKl vtQA== X-Gm-Message-State: AJIora9cxWNhSU5/wcELqGvVkUdtJprxTXqDJEUoC/UN9urj5S6s+HvX SvfgtWScDhW5ZQHFmUhXqdNL/OK3EoU= X-Google-Smtp-Source: AGRyM1uJ5QTu58N+K9iKE/YpRT81L0TBA2fMLg0Trw/QkA46BeeOGxKp1UHrTTFXsIZm7jzXx47C/bCpyX4= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:7784:b0:1ef:c0fe:968c with SMTP id v4-20020a17090a778400b001efc0fe968cmr19848862pjk.26.1658537504313; Fri, 22 Jul 2022 17:51:44 -0700 (PDT) Reply-To: Sean Christopherson Date: Sat, 23 Jul 2022 00:51:14 +0000 In-Reply-To: <20220723005137.1649592-1-seanjc@google.com> Message-Id: <20220723005137.1649592-2-seanjc@google.com> Mime-Version: 1.0 References: <20220723005137.1649592-1-seanjc@google.com> X-Mailer: git-send-email 2.37.1.359.gd136c6c3e2-goog Subject: [PATCH v4 01/24] KVM: nVMX: Unconditionally purge queued/injected events on nested "exit" From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Maxim Levitsky , Oliver Upton , Peter Shier Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Drop pending exceptions and events queued for re-injection when leaving nested guest mode, even if the "exit" is due to VM-Fail, SMI, or forced by host userspace. Failure to purge events could result in an event belonging to L2 being injected into L1. This _should_ never happen for VM-Fail as all events should be blocked by nested_run_pending, but it's possible if KVM, not the L1 hypervisor, is the source of VM-Fail when running vmcs02. SMI is a nop (barring unknown bugs) as recognition of SMI and thus entry to SMM is blocked by pending exceptions and re-injected events. Forced exit is definitely buggy, but has likely gone unnoticed because userspace probably follows the forced exit with KVM_SET_VCPU_EVENTS (or some other ioctl() that purges the queue). Fixes: 4f350c6dbcb9 ("kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Reviewed-by: Jim Mattson Reviewed-by: Maxim Levitsky --- arch/x86/kvm/vmx/nested.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index b9425b142028..a980d9cbee60 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4255,14 +4255,6 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, nested_vmx_abort(vcpu, VMX_ABORT_SAVE_GUEST_MSR_FAIL); } - - /* - * Drop what we picked up for L2 via vmx_complete_interrupts. It is - * preserved above and would only end up incorrectly in L1. - */ - vcpu->arch.nmi_injected = false; - kvm_clear_exception_queue(vcpu); - kvm_clear_interrupt_queue(vcpu); } /* @@ -4602,6 +4594,17 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason, WARN_ON_ONCE(nested_early_check); } + /* + * Drop events/exceptions that were queued for re-injection to L2 + * (picked up via vmx_complete_interrupts()), as well as exceptions + * that were pending for L2. Note, this must NOT be hoisted above + * prepare_vmcs12(), events/exceptions queued for re-injection need to + * be captured in vmcs12 (see vmcs12_save_pending_event()). + */ + vcpu->arch.nmi_injected = false; + kvm_clear_exception_queue(vcpu); + kvm_clear_interrupt_queue(vcpu); + vmx_switch_vmcs(vcpu, &vmx->vmcs01); /* Update any VMCS fields that might have changed while L2 ran */