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 852712DCF7D for ; Mon, 30 Mar 2026 09:45:53 +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=1774863953; cv=none; b=KsGA9TUF7cBUYoP+0FhvyZcK95UFPzwTu1kNZNwNcucv6ob7qDrQWvh0a7CisurQsHzgqAXc3hdZbz+71j6xp++BxTOcajFTWwk/AA0bgcrxHBTD5huFvbwo3YXK61nTSNtgaraR03VM7HSS2r6YRd0e1Qk4tcjway8XstXFqjA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774863953; c=relaxed/simple; bh=f+WAQt3NP/I5njpAZe7BU0BdA85Lcp049iIeJSqHS54=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=W0XMIlKOB5jb95BJK/o1c3QEFgwOGk+UuaLBx5hHZbw19k/G+QkFn7siGkvmtX6hrREodHPOtDkLH6s99bcIp0P70WHk4zZ9FjGgUPHdc95134oQv/OXPNcdox7zbplkk5Bdrldo09uH4SlAZBMzr13Eu/bOEkcqHDgI36BhU3w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nC5rMuG5; 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="nC5rMuG5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 755AFC4CEF7; Mon, 30 Mar 2026 09:45:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774863953; bh=f+WAQt3NP/I5njpAZe7BU0BdA85Lcp049iIeJSqHS54=; h=Subject:To:Cc:From:Date:From; b=nC5rMuG58Pk5nAHH/t9Zc4VZyzzyggVtVkDtdzNi1U/5vyK+cZkAnOmflQVpDCH6y almcXGDyvimMq9lPcADRy4YWb54fq+MvbpCKlgNGG32u26Snp4DxiOPVDxNa7+Md9v 38GuA3Y/Koyc3iB0YEqofcTyxEPry6b0iQ4AUNiw= Subject: FAILED: patch "[PATCH] KVM: x86/mmu: Drop/zap existing present SPTE even when" failed to apply to 6.1-stable tree To: seanjc@google.com,bkov@amazon.com,fgriffo@amazon.co.uk Cc: From: Date: Mon, 30 Mar 2026 11:45:49 +0200 Message-ID: <2026033049-dial-everyone-46da@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 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x aad885e774966e97b675dfe928da164214a71605 # git commit -s git send-email --to '' --in-reply-to '2026033049-dial-everyone-46da@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From aad885e774966e97b675dfe928da164214a71605 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 5 Mar 2026 17:28:04 -0800 Subject: [PATCH] KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE When installing an emulated MMIO SPTE, do so *after* dropping/zapping the existing SPTE (if it's shadow-present). While commit a54aa15c6bda3 was right about it being impossible to convert a shadow-present SPTE to an MMIO SPTE due to a _guest_ write, it failed to account for writes to guest memory that are outside the scope of KVM. E.g. if host userspace modifies a shadowed gPTE to switch from a memslot to emulted MMIO and then the guest hits a relevant page fault, KVM will install the MMIO SPTE without first zapping the shadow-present SPTE. ------------[ cut here ]------------ is_shadow_present_pte(*sptep) WARNING: arch/x86/kvm/mmu/mmu.c:484 at mark_mmio_spte+0xb2/0xc0 [kvm], CPU#0: vmx_ept_stale_r/4292 Modules linked in: kvm_intel kvm irqbypass CPU: 0 UID: 1000 PID: 4292 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:mark_mmio_spte+0xb2/0xc0 [kvm] Call Trace: mmu_set_spte+0x237/0x440 [kvm] ept_page_fault+0x535/0x7f0 [kvm] kvm_mmu_do_page_fault+0xee/0x1f0 [kvm] kvm_mmu_page_fault+0x8d/0x620 [kvm] vmx_handle_exit+0x18c/0x5a0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm] kvm_vcpu_ioctl+0x2d5/0x980 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb5/0x730 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47fa3f ---[ end trace 0000000000000000 ]--- Reported-by: Alexander Bulekov Debugged-by: Alexander Bulekov Suggested-by: Fred Griffoul Fixes: a54aa15c6bda3 ("KVM: x86/mmu: Handle MMIO SPTEs directly in mmu_set_spte()") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index b922a8b00057..98406d6aa2d6 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3044,12 +3044,6 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, bool prefetch = !fault || fault->prefetch; bool write_fault = fault && fault->write; - if (unlikely(is_noslot_pfn(pfn))) { - vcpu->stat.pf_mmio_spte_created++; - mark_mmio_spte(vcpu, sptep, gfn, pte_access); - return RET_PF_EMULATE; - } - if (is_shadow_present_pte(*sptep)) { if (prefetch && is_last_spte(*sptep, level) && pfn == spte_to_pfn(*sptep)) @@ -3073,6 +3067,14 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, was_rmapped = 1; } + if (unlikely(is_noslot_pfn(pfn))) { + vcpu->stat.pf_mmio_spte_created++; + mark_mmio_spte(vcpu, sptep, gfn, pte_access); + if (flush) + kvm_flush_remote_tlbs_gfn(vcpu->kvm, gfn, level); + return RET_PF_EMULATE; + } + wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, *sptep, prefetch, false, host_writable, &spte);