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 D3379371049 for ; Wed, 30 Sep 2026 15:39:39 +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=1790782786; cv=none; b=V5/LpT6xet6bZUVtiLDBrxzvpc0qjI9GT2jeT7DxxssryYt8MZ0wSM5LBbUwAh7OrJWjN0Utlw6I49ideqCwlIWwRXc6nmUYf6/yh+0m3blvnjQijvFWetnA6tantn9dnEhoIndHg/3Qb9tfPHnCa/q/SDvqqgJSSPpEMAihLEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790782786; c=relaxed/simple; bh=ki2X6+DtnMsJieEPdsXvdbeJkx3AUGXDfrqmJp3OaoI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QFIwi2jb0jxMFEmXkuBxqpo0NN8bzA9y0VQJgcDQa4DqUe+jFBacXCEd+WENGjhlek+ecpBv8zB1ruKqlN/8LMPpAUkQGqfSr5HR9GyoMakLrAUW0giw8Gc2zT+uPe35ZaXb4sh2euTbZO1EmvzBVUZlkPWYmFPD9VhMTfSmpZg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QkzqkdIb; 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="QkzqkdIb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C26881F00899; Wed, 30 Sep 2026 15:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790782779; bh=PUNPxBEkyU53xYqHLxpj4W1RhgHwTMFo1PYKKuwydBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QkzqkdIbXkwtxavHJv30d3So2Snc1QrTtvRQUTlIc5EjEcPySuvSo2fjCG4so3nNW haqFK47aXehpoyge6hUm4BfZyr2s3sc/FlavcWnfODHfEKdEKvVMVTxKRoalnTgPPp U10jWcl3p4tQbrAPsZ3cweUbpFLKeauqfVNIHQIULL6SWPyfTkFCtpHL3J/rI+l+kL BBfjvgfsmHd3TNRRO6J9Hai6dWQRXKHpa0zcAL0eDAKrBuE/RphI/PbjuNzVTN0bV2 kGO95IJ1HsuAKUgTw2MZkG4BTfbjYDdCjsNWvGl0OvfdEoUZQzG6m3ooUaUx96+1lw jvhbRUfPb9nMA== From: Sasha Levin To: stable@vger.kernel.org Cc: Sean Christopherson , Jinwoo Lee , Stefan Teodorescu , Sasha Levin Subject: [PATCH 6.18.y 4/4] KVM: x86: Fill kvm_run exit fields in common get_nested_state_pages() error paths Date: Wed, 30 Sep 2026 11:39:34 -0400 Message-ID: <20260930153934.2895211-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260930153934.2895211-1-sashal@kernel.org> References: <2026092938-celibate-sarcastic-e56f@gregkh> <20260930153934.2895211-1-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 c765ea1dff69c..a6b92819318b8 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1953,13 +1953,8 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu) 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; - } if (kvm_hv_verify_vp_assist(vcpu)) return false; diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index cb44ae23728b3..890ee82af35d6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3492,10 +3492,6 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu) } else { pr_debug_ratelimited("%s: no backing 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; } } @@ -3566,11 +3562,6 @@ 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; } #endif @@ -3956,8 +3947,12 @@ 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 69d48df5d1d89..c86b828ca578a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10708,6 +10708,9 @@ 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