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 A7F5031A56C for ; Mon, 16 Mar 2026 15:25:03 +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=1773674703; cv=none; b=iqhu9ubWe82vr9ft0PtNHewRF5xPFt60wcC7uZxJBavPKGnnmYlX886AMRNEI5AeoFacuVriBVJuckRBn0+/gDnFFNuYsLLAT3vqmrx+dwH5T/F9MAOiYx2wKbBZnQANoPK8cIEr3PBIsviFSeBEhzT7BHCbAr3gEmMHDb+L89E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773674703; c=relaxed/simple; bh=nD8N7W3AGTFR95AJYctw3fIQBUHyARgWy0tcEOsA/hk=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=Vkn4+r5hxfladlBKPPuGeKd32myiGxSyK7g0ar9n0IiiMBIjePDkqypksvd54F28BQu4KbS1U9b44znrEFroR+mstJQomktcRq11vhLaCpyAFdu9onG1tNPOVNYhmAG4+x33ZEKxTRC1CyzEI4udw5OBksOdzvsmw/3WvuUk1kg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jslYp0oG; 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="jslYp0oG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E855AC19421; Mon, 16 Mar 2026 15:25:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773674703; bh=nD8N7W3AGTFR95AJYctw3fIQBUHyARgWy0tcEOsA/hk=; h=Subject:To:Cc:From:Date:From; b=jslYp0oGKOBaxqj0UVJ1yjcmcDvThA7sUCLHxHNDsYMZVe9Zc1B+dPWFEO4bpDRvn wl4JGJVXbhhM+pdkGjq55MsWDT6pImT+ojGzRNnAWwmsJUglsaqojaafZ5rNT90nbq ih2FHt2GsjsWFC3o9mTg+NKEtNMuMzaQ18p6c8u8= Subject: FAILED: patch "[PATCH] KVM: x86: Introduce KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM" failed to apply to 6.12-stable tree To: jmattson@google.com,pbonzini@redhat.com,seanjc@google.com Cc: From: Date: Mon, 16 Mar 2026 16:24:59 +0100 Message-ID: <2026031659-scroll-setting-4687@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x e2ffe85b6d2bb7780174b87aa4468a39be17eb81 # git commit -s git send-email --to '' --in-reply-to '2026031659-scroll-setting-4687@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e2ffe85b6d2bb7780174b87aa4468a39be17eb81 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Thu, 5 Feb 2026 15:15:26 -0800 Subject: [PATCH] KVM: x86: Introduce KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM Add KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM to allow L1 to set FREEZE_IN_SMM in vmcs12's GUEST_IA32_DEBUGCTL field, as permitted prior to commit 6b1dd26544d0 ("KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest"). Enable the quirk by default for backwards compatibility (like all quirks); userspace can disable it via KVM_CAP_DISABLE_QUIRKS2 for consistency with the constraints on WRMSR(IA32_DEBUGCTL). Note that the quirk only bypasses the consistency check. The vmcs02 bit is still owned by the host, and PMCs are not frozen during virtualized SMM. In particular, if a host administrator decides that PMCs should not be frozen during physical SMM, then L1 has no say in the matter. Fixes: 095686e6fcb4 ("KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter") Cc: stable@vger.kernel.org Signed-off-by: Jim Mattson Link: https://patch.msgid.link/20260205231537.1278753-1-jmattson@google.com [sean: tag for stable@, clean-up and fix goofs in the comment and docs] Signed-off-by: Sean Christopherson [Rename quirk. - Paolo] Signed-off-by: Paolo Bonzini diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 6f85e1b321dd..19365b284395 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8543,6 +8543,14 @@ KVM_X86_QUIRK_IGNORE_GUEST_PAT By default, on Intel platforms, KVM ignores guest software, for example if it does not expose a bochs graphics device (which is known to have had a buggy driver). + +KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM By default, KVM relaxes the consistency + check for GUEST_IA32_DEBUGCTL in vmcs12 + to allow FREEZE_IN_SMM to be set. When + this quirk is disabled, KVM requires this + bit to be cleared. Note that the vmcs02 + bit is still completely controlled by the + host, regardless of the quirk setting. =================================== ============================================ 7.32 KVM_CAP_MAX_VCPU_ID diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ff07c45e3c73..6e4e3ef9b8c7 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2485,7 +2485,8 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS | \ KVM_X86_QUIRK_SLOT_ZAP_ALL | \ KVM_X86_QUIRK_STUFF_FEATURE_MSRS | \ - KVM_X86_QUIRK_IGNORE_GUEST_PAT) + KVM_X86_QUIRK_IGNORE_GUEST_PAT | \ + KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM) #define KVM_X86_CONDITIONAL_QUIRKS \ (KVM_X86_QUIRK_CD_NW_CLEARED | \ diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 846a63215ce1..0d4538fa6c31 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -476,6 +476,7 @@ struct kvm_sync_regs { #define KVM_X86_QUIRK_SLOT_ZAP_ALL (1 << 7) #define KVM_X86_QUIRK_STUFF_FEATURE_MSRS (1 << 8) #define KVM_X86_QUIRK_IGNORE_GUEST_PAT (1 << 9) +#define KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM (1 << 10) #define KVM_STATE_NESTED_FORMAT_VMX 0 #define KVM_STATE_NESTED_FORMAT_SVM 1 diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 248635da6766..603c98de2cc8 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3300,10 +3300,24 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu, if (CC(vmcs12->guest_cr4 & X86_CR4_CET && !(vmcs12->guest_cr0 & X86_CR0_WP))) return -EINVAL; - if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) && - (CC(!kvm_dr7_valid(vmcs12->guest_dr7)) || - CC(!vmx_is_valid_debugctl(vcpu, vmcs12->guest_ia32_debugctl, false)))) - return -EINVAL; + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) { + u64 debugctl = vmcs12->guest_ia32_debugctl; + + /* + * FREEZE_IN_SMM is not virtualized, but allow L1 to set it in + * vmcs12's DEBUGCTL under a quirk for backwards compatibility. + * Note that the quirk only relaxes the consistency check. The + * vmcc02 bit is still under the control of the host. In + * particular, if a host administrator decides to clear the bit, + * then L1 has no say in the matter. + */ + if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM)) + debugctl &= ~DEBUGCTLMSR_FREEZE_IN_SMM; + + if (CC(!kvm_dr7_valid(vmcs12->guest_dr7)) || + CC(!vmx_is_valid_debugctl(vcpu, debugctl, false))) + return -EINVAL; + } if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) && CC(!kvm_pat_valid(vmcs12->guest_ia32_pat)))