From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 41DE33EDE44; Tue, 12 May 2026 17:51:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608291; cv=none; b=VsXNx9BHvnCIlNV6cryGurWyfzyylguiGKd6647d+8fZ8orooBCf5QdwuzZpVTU7aMXq3q1WfgDqQb5ocxduqPnqktKLskq6bUUwoyWdVocx2gkTOLu0nDhY6Xq59MdzTb95xWTG44DLkW9D3skMXsS6SBNMtUWte3sZQb3BQLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608291; c=relaxed/simple; bh=kwckheeuVwRKsdQMIqoAYK43WdH3vbwbo+ckrQsvEv8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FHYVqs+3P+MnV+r3R9Mfi39ZcLbDgtxLY6tXOikmvYTd9YlwFtC0E/q1EWldMbtEF2v5isf+TTMJd7/uRfgxY90a85vCe98e+lPi5Znwy3VU0WezSr9GQVyxoxG8UM1pwx4OU7ZDcvUfXO+v7QIGqLa06XYW+zg2dbxL9ym2tlo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ePqG9K4l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ePqG9K4l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1AB8C2BCB0; Tue, 12 May 2026 17:51:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778608291; bh=kwckheeuVwRKsdQMIqoAYK43WdH3vbwbo+ckrQsvEv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ePqG9K4lJm2HN5JTZN84K1hPuEkyg03ZT5fbVxOhnUTDK+PEFj68uSyHgZ5RX48jN YStPp04fl66vKJkfoA3Nbco4t+uIqiqxhn7kbAkgaPFU4n36JAMQiOh9cDxGcxphjR oDxGOvDFJXaOgBOaOuaHicR0xB4g5olKB03VWvLI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paolo Bonzini Subject: [PATCH 6.18 022/270] KVM: SVM: check validity of VMCB controls when returning from SMM Date: Tue, 12 May 2026 19:37:03 +0200 Message-ID: <20260512173938.925077719@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173938.452574370@linuxfoundation.org> References: <20260512173938.452574370@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Bonzini commit be5fa8737d42c5ba16d2ea72c23681f8abbb07e8 upstream. The VMCB12 is stored in guest memory and can be mangled while in SMM; it is then reloaded by svm_leave_smm(), but it is not checked again for validity. Move the cached vmcb12 control and save consistency checks out of svm_set_nested_state() and into a helper, and reuse it in svm_leave_smm(). Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/nested.c | 12 ++++++++++-- arch/x86/kvm/svm/svm.c | 4 ++++ arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 15 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -484,6 +484,15 @@ void nested_copy_vmcb_save_to_cache(stru __nested_copy_vmcb_save_to_cache(&svm->nested.save, save); } +int nested_svm_check_cached_vmcb12(struct kvm_vcpu *vcpu) +{ + if (!nested_vmcb_check_save(vcpu) || + !nested_vmcb_check_controls(vcpu)) + return -EINVAL; + + return 0; +} + /* * Synchronize fields that are written by the processor, so that * they can be copied back into the vmcb12. @@ -990,8 +999,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vc nested_copy_vmcb_control_to_cache(svm, &vmcb12->control); nested_copy_vmcb_save_to_cache(svm, &vmcb12->save); - if (!nested_vmcb_check_save(vcpu) || - !nested_vmcb_check_controls(vcpu)) { + if (nested_svm_check_cached_vmcb12(vcpu) < 0) { vmcb12->control.exit_code = SVM_EXIT_ERR; vmcb12->control.exit_code_hi = -1u; vmcb12->control.exit_info_1 = 0; --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4885,6 +4885,10 @@ static int svm_leave_smm(struct kvm_vcpu vmcb12 = map.hva; nested_copy_vmcb_control_to_cache(svm, &vmcb12->control); nested_copy_vmcb_save_to_cache(svm, &vmcb12->save); + + if (nested_svm_check_cached_vmcb12(vcpu) < 0) + goto unmap_save; + ret = enter_svm_guest_mode(vcpu, smram64->svm_guest_vmcb_gpa, vmcb12, false); if (ret) --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -782,6 +782,7 @@ static inline int nested_svm_simple_vmex int nested_svm_exit_handled(struct vcpu_svm *svm); int nested_svm_check_permissions(struct kvm_vcpu *vcpu); +int nested_svm_check_cached_vmcb12(struct kvm_vcpu *vcpu); int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr, bool has_error_code, u32 error_code); int nested_svm_exit_special(struct vcpu_svm *svm);