From nobody Tue Dec 16 21:35:35 2025 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 5A758EE49A6 for ; Fri, 25 Aug 2023 01:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238995AbjHYBqa (ORCPT ); Thu, 24 Aug 2023 21:46:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238424AbjHYBpw (ORCPT ); Thu, 24 Aug 2023 21:45:52 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6826119A2 for ; Thu, 24 Aug 2023 18:45:36 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-c8f360a07a2so490058276.2 for ; Thu, 24 Aug 2023 18:45:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1692927935; x=1693532735; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=n7Gx8G07oVDQESvSj0fHPYOAdbAFRD7QyHdI7Awfk+Q=; b=0aSp4kNGD1/BX/bcgBsNHRwqRtg0WUUVF2KI4HnIt1W8kSOqTsMsunXF6sKqc1lePN zD5JTXnXRKrT3e4M1KGt35cYVMWj2C37LHxI8mzPFWqG0rCMp+aOIfFNUyWSlFUxc2jb nLYXyu+bRDKVnaLQGLdJ9yvqA0cltYcfZFB2nNwtiu0AyhrCo5BLedrqxMSheMuhK1h5 cqmDRHLK63UeTLJywqr/KOOrEF4rL4pzAiUSkSW2rsLzr3UR4iDqWLd6XU0jQxduqBnm PgPSe5P2sdrVKNc6rLDEtt1fA6wmKVvmwCXJXCBNAzTDTPOuWtT1Vo9ELSi9riXORgsu GW+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692927935; x=1693532735; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=n7Gx8G07oVDQESvSj0fHPYOAdbAFRD7QyHdI7Awfk+Q=; b=eO3OXr6Qif+DX92cRRBAvBOnNBSmJM/8Xvd/CJNHTAobD0KEznHBVd++ForhBakiaO dS5HtccjDqlop30fmtsAerTe2w2L/cEQBr0IG8YKo19jlZY5SDV6tFSodKr6kkd8St7J g5MDGEfpb+gJeZmas8M1gdD0qCOtWCF/hD14O8edcXJNOA/tfJtda2eoX624Js0CtyV7 niXbqydttwfXH3cf1KImwJ2JZGDclSz8gNBrlRjoXUJjkGVXxOW5RCfRT6I3EjE64pMv sCyoc4uJnrnU2WKAnlxDH2RJb7QbW+mboaf5is9I59elyG0GCsCj0VpPUFgXiUun9TfX xSaw== X-Gm-Message-State: AOJu0YzKyb+KcTQil3B3czt5lwn5icZLW6U10GQ75hWv3Hgm6UzFUVQC 5q2hOK1Mc44Zan2CpT0OyUe4TLbGFK0= X-Google-Smtp-Source: AGHT+IFCXCroBTtRaWtWSiSvA6Ehy34meR1vhXagG3zkvhYbnr3Cu2pBSL1uq6RbjpkAcAl4kxpPXT21/v0= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:290:b0:d48:c04:f256 with SMTP id v16-20020a056902029000b00d480c04f256mr326480ybh.11.1692927935742; Thu, 24 Aug 2023 18:45:35 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 24 Aug 2023 18:45:32 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.42.0.rc2.253.gd59a3bf2b4-goog Message-ID: <20230825014532.2846714-1-seanjc@google.com> Subject: [PATCH] KVM: VMX: Refresh available regs and IDT vectoring info before NMI handling From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Like Xu Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Reset the mask of available "registers" and refresh the IDT vectoring info snapshot in vmx_vcpu_enter_exit(), before KVM potentially handles a an NMI VM-Exit. One of the "registers" that KVM VMX lazily loads is the vmcs.VM_EXIT_INTR_INFO field, which is holds the vector+type on "exception or NMI" VM-Exits, i.e. is needed to identify NMIs. Clearing the available registers bitmask after handling NMIs results in KVM querying info from the last VM-Exit that read vmcs.VM_EXIT_INTR_INFO, and leads to both missed NMIs and spurious NMIs in the host. Opportunistically grab vmcs.IDT_VECTORING_INFO_FIELD early in the VM-Exit path too, e.g. to guard against similar consumption of stale data. The field is read on every "normal" VM-Exit, and there's no point in delaying the inevitable. Reported-by: Like Xu Fixes: 11df586d774f ("KVM: VMX: Handle NMI VM-Exits in noinstr region") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Reviewed-by: Paolo Bonzini --- Like, this is lightly tested, any testing you can provide would be much appreciated. I definitely want to get coverage for this in selftests and/or KUT, but I'm very short on cycles right now. arch/x86/kvm/vmx/vmx.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e6849f780dba..d2b78ab7a9f2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7222,13 +7222,20 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_= vcpu *vcpu, flags); =20 vcpu->arch.cr2 =3D native_read_cr2(); + vcpu->arch.regs_avail &=3D ~VMX_REGS_LAZY_LOAD_SET; + + vmx->idt_vectoring_info =3D 0; =20 vmx_enable_fb_clear(vmx); =20 - if (unlikely(vmx->fail)) + if (unlikely(vmx->fail)) { vmx->exit_reason.full =3D 0xdead; - else - vmx->exit_reason.full =3D vmcs_read32(VM_EXIT_REASON); + goto out; + } + + vmx->exit_reason.full =3D vmcs_read32(VM_EXIT_REASON); + if (likely(!vmx->exit_reason.failed_vmentry)) + vmx->idt_vectoring_info =3D vmcs_read32(IDT_VECTORING_INFO_FIELD); =20 if ((u16)vmx->exit_reason.basic =3D=3D EXIT_REASON_EXCEPTION_NMI && is_nmi(vmx_get_intr_info(vcpu))) { @@ -7237,6 +7244,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vc= pu *vcpu, kvm_after_interrupt(vcpu); } =20 +out: guest_state_exit_irqoff(); } =20 @@ -7358,8 +7366,6 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) loadsegment(es, __USER_DS); #endif =20 - vcpu->arch.regs_avail &=3D ~VMX_REGS_LAZY_LOAD_SET; - pt_guest_exit(vmx); =20 kvm_load_host_xsave_state(vcpu); @@ -7376,17 +7382,12 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcp= u) vmx->nested.nested_run_pending =3D 0; } =20 - vmx->idt_vectoring_info =3D 0; - if (unlikely(vmx->fail)) return EXIT_FASTPATH_NONE; =20 if (unlikely((u16)vmx->exit_reason.basic =3D=3D EXIT_REASON_MCE_DURING_VM= ENTRY)) kvm_machine_check(); =20 - if (likely(!vmx->exit_reason.failed_vmentry)) - vmx->idt_vectoring_info =3D vmcs_read32(IDT_VECTORING_INFO_FIELD); - trace_kvm_exit(vcpu, KVM_ISA_VMX); =20 if (unlikely(vmx->exit_reason.failed_vmentry)) base-commit: fff2e47e6c3b8050ca26656693caa857e3a8b740 --=20 2.42.0.rc2.253.gd59a3bf2b4-goog