From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793819861; b=zajai15pXuF/bvASRz5H0UGXiHeIh/d8O1srrATxGVN6PQRbS2Vdos+4s5p2rG9tvz+n St1gCYkG16UC1K8gQ1/T49MPK0y0QJdw0m9W7rWjBT6ewO+3iB09uPI/fdMMy34QALSwf G0dOBsxBWg18eFfVxej8SmrljEkD8zoknqORHPWJaXJ7BwmnSqROcWsgIXqkSw31rlb6B Brs69fy/94N1ggF+sb+PsNJpunAdpRciXhRwxtgDIiHysxSoHYNooD2jmbWfA9LAmBo51 H1eb7A1fqjcNDj7zftBy1eeoMaMM30FuH2r0/bdPmJTbIFcJl7ZV47lKHHZfMDL1p/w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793819861; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=cUbaEnicdrmdCt2rZSq1W7ahNhAdiLVNHf3YRP9cPYM=; b=NtIbavYRsAkJ5Kw4X7v0ZhYvgijKQ8L913g0ioXgnFb524g33Ve0MFHpbDNmN4J/ubhc 41KEIQTyMyVE6XUjk01xMNZwvJnJ3woBdJsHkRzHIbzpGlHUZMByeOLvboM9x594He3u5 JlpAPrCyc/eVIJq2CEcZf3jN+mMRfBnz1RDhDo+xS3rAkIj8cOTlRiXrJJq4VMXpO2Crl pD/8e74EdBf/pC3w93zPRNb28ecykQ5neXqPc43+O5U73GVeLoyDvwFcZyQMNbYnhgwwj ES/CJGFTUkkyDrW2UkYbn/SfN6LrnQiSqSvotJfxtgGT4oMHUK7cAsDO29B+TszWw9Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=U+tCwQRX; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C1FF60A3832 for ; Wed, 4 Nov 2026 19:17:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=U+tCwQRX Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7FB01F0093A; Wed, 4 Nov 2026 19:17:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793819861; bh=cUbaEnicdrmdCt2rZSq1W7ahNhAdiLVNHf3YRP9cPYM=; h=Subject:To:Cc:From:Date; b=U+tCwQRXnuUenobmOJrhkV7Xr/V/Es7RNWYU6hV7L3vioit54Jsa3yqXFU68erm7/ FkRutr/+TU3EjocXkTJw95eLXm9NfKM64VtOwwV40uwmHgBpR1quIX9UxxjqI6X6qZ deq+sQNC8lGLQxNUV2Mck98eOQ5DCthVcWqQpzJc= Subject: FAILED: patch "[PATCH] KVM: nSVM: Reject KVM_SET_NESTED_STATE if L1 has EFER.LMA=1" failed to apply to 6.6-stable tree To: seanjc@google.com,fane@google.com,yosry@kernel.org Cc: From: Date: Wed, 04 Nov 2026 14:17:38 -0500 Message-ID: <2026110438-espionage-padding-358f@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 5dc500a354cc8e109df678076ae3488094649468 # git commit -s git send-email --to '' --in-reply-to '2026110438-espionage-padding-358f@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5dc500a354cc8e109df678076ae3488094649468 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 2 Sep 2026 16:20:24 -0700 Subject: [PATCH] KVM: nSVM: Reject KVM_SET_NESTED_STATE if L1 has EFER.LMA=1 && EFER.LME=0 Reject KVM_SET_NESTED_STATE if the incoming L1 host state has what is effectively an impossible EFER combination of LMA=1 but LME=0, i.e. if the state says long mode is active but not enabled. Unlike VMX, SVM doesn't have an explicit consistent check for the illegal combination; presumably hardware simply ignores EFER.LMA if EFER.LME=0. Unfortunately, KVM doesn't ignore EFER.LMA in this case and consumes the illegal state when constructing the shadow MMU for L2. E.g. if userspace also clears CR4.PAE, then kvm_calc_cpu_role() will compute a role with 4 or 5 levels of paging, but shadow_mmu_init_context() will wire up the MMU to use the paging32 template, which maxes out its levels at 2. Note, the "real badness" is effectively the same as what happened with the nVMX bug fixed by commit 112e66017bff ("KVM: nVMX: add missing consistency checks for CR0 and CR4"). Unfortunately, the sanity check added by commit 72e2fb24a0b0 ("KVM: x86/mmu: Bug the VM if a vCPU ends up in long mode without PAE enabled") doesn't work for this case, since L2 state is active at the time of the page fault, but it's L1 that has the bad state. Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE") Cc: stable@vger.kernel.org Cc: Yosry Ahmed Reported-by: Stefan Teodorescu Link: https://patch.msgid.link/20260902232028.2767071-2-seanjc@google.com Signed-off-by: Sean Christopherson diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 73f37b050d0a..49fb10ad1f9f 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -2028,6 +2028,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, if (!(save->cr0 & X86_CR0_PG) || !(save->cr0 & X86_CR0_PE) || (save->rflags & X86_EFLAGS_VM) || + ((save->efer & EFER_LMA) && !(save->efer & EFER_LME)) || !nested_vmcb_check_save(vcpu, &save_cached, false)) goto out_free;