From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 459741F583D for ; Fri, 23 Jan 2026 22:15:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769206546; cv=none; b=fkEZtFXwWYwrUnfqvJuAb9RBPd6yxl2Irll4ioqjfjVHYmpV9yxDz3UJ9UB+WNGJ77r1nW9JHBAofaRoH54lcqqtQyxIqsr3tXoFeFQG2pweYzM76Nf8QuWxLHsyxmV9ptBCmmcIv+OLI25Q1IfoQX/Y7R5W044+DoAALZ0cjJU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769206546; c=relaxed/simple; bh=mME44fj5sKRvocaLJiXWIy8v/tVDcJq4u+E+ifHxorU=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=Dgnlt8HHThSocu4ebs36FY23ToNhuSNT5byF4s/SvMK1Csea/mxkWaTSdlD82e7X4xFUprv2nDcLQmAqdG70Umt8cD5e2Kbabtg7ELClxf91VvkKkBoJCCFWF1Zs3tkARh09arplyQnbanlSftVk72hnH+rPhWQ3mUGeJW+MvGE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=w1fQTLTj; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="w1fQTLTj" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-c617e59845dso1526261a12.1 for ; Fri, 23 Jan 2026 14:15:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769206544; x=1769811344; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=5YUi5HBifyma3b53VcD8N5rMKKrP+86iMqVIaX6eOVo=; b=w1fQTLTj4ZCbdwuZZFbSpzsI5ESV/qNHeXwHNlwgkdzRMWI0joA7jMfmL+5InF+vOl Joc4aZchapFBL/SJZjhtN51q+4KsgsrVrSidpbf0u7t0RLjok5Ire/DDnIhHWPJ5tcl6 ibs+8S64LsGRs3uRnsGRQlJ3fmB1dwGcM0E9l4ysuNTM/n0LZEwqeIhiKfbgrtyo4CWg 6PQ2XbDpkfJp+t6UX2mI8ueX3D+z6g2nbvRg63BYUhpIH4pr4ML1Hw4rrb3fAPpykgb6 tkOnRzl310/syAeBkkuUcgzdq89m6yfZ1SjFv03azDVbfvNx6YvbDd4mP0UOT0bZWWUL I2mw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769206544; x=1769811344; 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=5YUi5HBifyma3b53VcD8N5rMKKrP+86iMqVIaX6eOVo=; b=LGMBqMYK5GimTJCHwrfW5vRkLexOJOpUfEf6mlIQsotaMMLy4YzDp93H6v76xWb9sy 4ihI3sIAcPUWqFt1wdmG8cCZ1RHdxRyiz8VRKmGYzfhI1akNVU3qfBSx6f233/g9zLlb sPb92rQ+azuLeB5F9evn1rxJ6ptnDj3haDURmXOJum4HinodAsmgjSUMqiSCJVFxsuNh ZZK1p6GNvYmi17HymiBhzBXuTES+0iaue3aUcKR7PinSHPmLccrKLLyLRJ4hIuVEmU2H Du7iy1jli4Q1BkKMqDws0HWxaXqRjp+v0kABjA5PcpJp5JmGV8+KKYzu+zaBQoUmRsBQ 1w1w== X-Forwarded-Encrypted: i=1; AJvYcCVoxCWh5Zi/hnDcPTFGnZL2z6h+BbSjwurpi+K0llJZs+ZiC432/CHqbBJtADSqmwLAjAvU/Jr1NqPRc2g=@vger.kernel.org X-Gm-Message-State: AOJu0YzYf1q7kSDrtZ3ypOoK/OlGjQb7jwGoW4tDq0JUnApuMPQ2Av1I 1Lqp32HsC6n0KpOsIWSRuQryKtYwMAlzXKO1HkRKrYoKrOFnvAUrVkT/TmixljRA1paJijbBzcO 8wbJHjA== X-Received: from pgbfe1.prod.google.com ([2002:a05:6a02:2881:b0:c0e:3bf6:b8e2]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:7489:b0:387:9522:b667 with SMTP id adf61e73a8af0-38e6f828589mr4873706637.78.1769206544521; Fri, 23 Jan 2026 14:15:44 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 23 Jan 2026 14:15:39 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog Message-ID: <20260123221542.2498217-1-seanjc@google.com> Subject: [PATCH 0/3] KVM: x86: CET vs. nVMX fix and hardening From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Mathias Krause , John Allen , Rick Edgecombe , Chao Gao , Binbin Wu , Xiaoyao Li , Jim Mattson Content-Type: text/plain; charset="UTF-8" Fix a bug where KVM will clear IBT and SHSTK bits after nested VMX MSRs have been configured, e.g. if the kernel is built with CONFIG_X86_CET=y but CONFIG_X86_KERNEL_IBT=n. The late clearing results in kvm-intel.ko refusing to load as the CPU compatible checks generate their VMCS configs with IBT=n and SHSTK=n, ultimately causing a mismatch on the CET entry and exit controls. Patch 2 hardens against similar bugs in the future by added a flag and WARNs to yell if KVM sets or clear feature flags outside of the dedicated flow. Patch 3 adds (very, very) long overdue printing of the mistmatching offsets in the VMCS configs. Sean Christopherson (3): KVM: x86: Finalize kvm_cpu_caps setup from {svm,vmx}_set_cpu_caps() KVM: x86: Harden against unexpected adjustments to kvm_cpu_caps KVM: VMX: Print out "bad" offsets+value on VMCS config mismatch arch/x86/kvm/cpuid.c | 29 +++++++++++++++++++++++++++-- arch/x86/kvm/cpuid.h | 7 ++++++- arch/x86/kvm/svm/svm.c | 4 +++- arch/x86/kvm/vmx/vmx.c | 20 ++++++++++++++++++-- arch/x86/kvm/x86.c | 14 -------------- arch/x86/kvm/x86.h | 2 ++ 6 files changed, 56 insertions(+), 20 deletions(-) base-commit: e81f7c908e1664233974b9f20beead78cde6343a -- 2.52.0.457.g6b5491de43-goog