From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60721351C1C for ; Thu, 1 Oct 2026 00:46:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790815596; cv=none; b=G7HDWlEm/yOMYv4oAOaBDlDXhS+Xo8SGfXRfOC+FwSZnbIGrUhewETjmyFHk2x7xQENPuceFuKVPePw/4+WVUYs3/b9ho4tYcK+oK8IuGuochZtgf0iHoXTY8GOhwxvTbNEO89dw+P1w4zJogDUvv0DnmRTNfXwEQ9R4zVg30Mk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790815596; c=relaxed/simple; bh=uf8I7s1+24jGWy8mkKdk7Hu3Uf4I4ZzvX6kAT5SAvFQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=usfY2o1IooWKxSZA4orfLrUg74uO64RZ2n5oFUQ4MwOqVI62csWcRoz/wXHkMkBuYQ724VpGtsZreJOWRLV0bALJYtaKMUiki0xBWfPxpemrwrHBN1xKVHCSVtt9XIPWsSl5hlxVOyyH6mdjjiB60BmB+q6+IUwL3QKwgG9IenY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L48XSBhU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L48XSBhU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2C3F1F000FF; Thu, 1 Oct 2026 00:46:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790815595; bh=fca2JWqmaQb+0SrKATVLsQ7hwXwJUEvIbjv6G5X2tNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=L48XSBhU/dcSatlOH2vkqEQx3oT6/wFFElYbV9B6WOAOCtNe4Q62GBilKDcKZlpIm 0QzyLtHmPXZqlRXZYlivTV/WE+a9TawDlIAQ24O1pj4QZ35lYl1k+domWGiCRkZmnB rWi+rZH21ZUka85OVxWV82GrFJrK7puGzIKKGM885w7f9jCqlRLax3Y1Xq6Pyok6mq 2OYlji096AnGD/bBSY9mbuEUHsRhO2WY/2jLCaeFTiTaG2lxZCW3vfXYTT8Vi74Cf0 4G+JjKAx38GiKX4qgjcOsea0wCHJTAS43ou0chlPyZPlY5MvzqgOhqjGGiaj+tTSVE IXoxl8l4JRJlg== From: Sasha Levin To: stable@vger.kernel.org Cc: Sean Christopherson , Jinwoo Lee , Stefan Teodorescu , Sasha Levin Subject: [PATCH 5.15.y 2/2] KVM: x86: Fill kvm_run exit fields in common get_nested_state_pages() error paths Date: Wed, 30 Sep 2026 20:46:32 -0400 Message-ID: <20261001004632.2232201-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261001004632.2232201-1-sashal@kernel.org> References: <2026092940-distress-hardship-4b3d@gregkh> <20261001004632.2232201-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sean Christopherson [ Upstream commit c1214f293d77c6e425a379f90d09bdb4815993a8 ] Fill kvm_run with "internal error, emulation" in the common error handling paths for getting nested state pages, as requiring each check to manually fill kvm_run is error prone and requires a non-trivial amount of copy+paste. Specifically, both SVM and VMX fail to fill kvm_run if load_pdptrs() fails, and SVM fails to fill kvm_run if kvm_hv_verify_vp_assist() fails. If those flows fail, the *best* case scenario is that KVM will exit to userspace with KVM_EXIT_UNKNOWN. The worst case scenario is that KVM exits with a stale exit_reason and confuses userspace. Note, SVM never exits to userspace if something goes sideways when dealing with vmcb12 assets while emulating VMRUN, i.e. lack of SVM-specific code is not a bug. Fixes: 0f85722341b0 ("KVM: nVMX: delay loading of PDPTRs to KVM_REQ_GET_NESTED_STATE_PAGES") Fixes: 232f75d3b4b5 ("KVM: nSVM: call nested_svm_load_cr3 on nested state load") Fixes: 3f4a812edf5c ("KVM: nSVM: hyper-v: Enable L2 TLB flush") Cc: stable@vger.kernel.org Reported-by: Jinwoo Lee Closes: https://lore.kernel.org/all/20260813043932.3214460-1-rkskek9254@gmail.com Reported-by: Stefan Teodorescu Link: https://patch.msgid.link/20260921211608.1030158-3-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Sasha Levin --- arch/x86/kvm/svm/nested.c | 7 +------ arch/x86/kvm/vmx/nested.c | 15 +++++---------- arch/x86/kvm/x86.c | 3 +++ 3 files changed, 9 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 08f30b5ebe30f..7b3f0d506a986 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1439,13 +1439,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu) if (CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, vcpu->arch.cr3))) return false; - if (!nested_svm_merge_msrpm(vcpu)) { - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = - KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; + if (!nested_svm_merge_msrpm(vcpu)) return false; - } return true; } diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 1b87dded131dc..dbd16e08da396 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3222,10 +3222,6 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu) } else { pr_debug_ratelimited("%s: no backing 'struct page' for APIC-access address in vmcs12\n", __func__); - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = - KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; return false; } } @@ -3289,11 +3285,6 @@ static bool vmx_get_nested_state_pages(struct kvm_vcpu *vcpu) if (!nested_get_evmcs_page(vcpu)) { pr_debug_ratelimited("%s: enlightened vmptrld failed\n", __func__); - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = - KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; - return false; } @@ -3681,8 +3672,12 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) vmentry_failed: vcpu->arch.nested_run_pending = 0; - if (status == NVMX_VMENTRY_KVM_INTERNAL_ERROR) + if (status == NVMX_VMENTRY_KVM_INTERNAL_ERROR) { + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + vcpu->run->internal.ndata = 0; return 0; + } if (status == NVMX_VMENTRY_VMEXIT) return 1; WARN_ON_ONCE(status != NVMX_VMENTRY_VMFAIL); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aa459fb327682..f0223a8beac31 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9779,6 +9779,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) } if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) { if (unlikely(!kvm_nested_call(get_nested_state_pages)(vcpu))) { + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + vcpu->run->internal.ndata = 0; kvm_make_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu); r = 0; goto out; -- 2.53.0