From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DFA6FCA5FA2 for ; Mon, 28 Sep 2026 12:29:12 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4htgbW1mwZz2yCL; Mon, 28 Sep 2026 22:29:11 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=148.163.158.5 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790598551; cv=none; b=hty1KR90WhqfxvnAXdwnv/35yJDONwz0WWobwH+Zwyo7UnxgNzBGYeNmmXM/Cq/SGNMkrhIFpEw4QstwTSNV+o3gOfNL1ZoBHJ0W1yMa+x7ZxV0CmbZu3eCnUuEdrcRJacZm9Wekw0drx8brQdp69NsP0LHhOnZv/Hg/pIcczSkYXARG3TEQD/J116pdrSYNsmgmBuVlUD65uCljnnr6tlnxHHf+QUDf0V5SwdCs0NleTD8F4lM5DR/UEPauneQR4pWDYlkn1pH2qtJ2qDdILbLVH1MnTOVKWd5qUDRzgdz5xzDRjyW5cm0rjJrMT14v6zRK2WFNWd1TnLk8SsSsRA== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790598551; c=relaxed/relaxed; bh=owG7PdSKZiKgNxplioX22//h+Uijuj+ymNAWo5x5JvU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GqyTPDkNPAkitW1peFSmcWU32sLOb4H5OXZRGXwtzUQqPXkX1wU66dHXgiNgf1mG8FoYm79tcNHtdWrbY1XgmXJGx0Nx+Nq5RhWVt/yrrTbEG9GQbQrEOhXz/uNPme/Mh+iqV/9JePMh3Yt9+QX6UI7QDArcDJNvnry+LBVBEGVBfNGOQnG5g9Pjf29U17LZI/Hu77w5T4GJFuudJ31+LDSMeUUsDpK1ButuCkgfR7Fy83s/aD+P1KWjX7tZhkSTKhKlt76rV4XLLM/DxKGE8V8IBgbfTO6XcnnJEeI61Ra15ms8vPE/+50S8zKLYLaMmts7gy3UF5Nc4emIwUw+iw== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=QVYJq9eg; dkim-atps=neutral; spf=pass (client-ip=148.163.158.5; helo=mx0b-001b2d01.pphosted.com; envelope-from=amachhiw@linux.ibm.com; receiver=lists.ozlabs.org) smtp.mailfrom=linux.ibm.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=QVYJq9eg; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0b-001b2d01.pphosted.com; envelope-from=amachhiw@linux.ibm.com; receiver=lists.ozlabs.org) Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4htgbV17Y7z2y25 for ; Mon, 28 Sep 2026 22:29:09 +1000 (AEST) Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 68SBZf7Z1011358; Mon, 28 Sep 2026 12:28:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=owG7Pd SKZiKgNxplioX22//h+Uijuj+ymNAWo5x5JvU=; b=QVYJq9egZVRifNhq0yuY5n kk4+ptY78TN0zQZbhDrC8Fsr0sk16X1kMvPWDRIuipAQd1z72V8KglxgT10okusz BZqVT6DNG7CpIT2GatJxLrTnpQT9o2iusc6NW8Hbpe46TrBYvxRp13p+iYj+OwZ+ ycK3j0zmoe0euUNbpu6l6ZDq9e/Y4zGg15WNnJi7iNfPlHZrSHuyfTLCJUc71StK Qp3WO4tnT3ex1kW5oOAw211HHSI+nYg214SnNqvGj5XfvPw7LWovQgzeaFjaNe4s ZvC0x1Ef3TE/d6UAwN4+AgeHk1qGIqTZzGO8p6VcGQBZoSEJJTLy7W5a6wFH4WXQ == Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4gx5pt0u76-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 28 Sep 2026 12:28:58 +0000 (GMT) Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.18.1.11/8.18.1.11) with ESMTP id 68SBHXFC057256; Mon, 28 Sep 2026 12:28:57 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 4gxu2y4wq4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Sep 2026 12:28:57 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 68SCSrGu44171746 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 28 Sep 2026 12:28:53 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AC89F20049; Mon, 28 Sep 2026 12:28:53 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9FB2920040; Mon, 28 Sep 2026 12:28:49 +0000 (GMT) Received: from localhost.localdomain (unknown [9.124.213.32]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 28 Sep 2026 12:28:49 +0000 (GMT) From: Amit Machhiwal To: Madhavan Srinivasan , linuxppc-dev@lists.ozlabs.org Cc: Amit Machhiwal , Nicholas Piggin , Michael Ellerman , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Gautam Menghani , Harsh Prateek Bora , R Nageswara Sastry , Alexander Graf , linux-hardening@vger.kernel.org, stable@vger.kernel.org, Avi Kivity Subject: [RESEND PATCH 1/3] KVM: PPC: Book3S HV: Add SRCU protection for virtual-mode HPT hcalls Date: Mon, 28 Sep 2026 17:58:35 +0530 Message-ID: <20260928122837.8782-2-amachhiw@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260928122837.8782-1-amachhiw@linux.ibm.com> References: <20260928122837.8782-1-amachhiw@linux.ibm.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: 3P-6-2inoYiuy8O40xxiZ5nxXx1QNZCK X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTI4MDA0OCBTYWx0ZWRfX+JQT7bDB8FLj L/mqathAbjbsc4DFCxidldFlr4qtWymFylSCO7INLGnn36F2ehCj0QnTOlvCHixm+RYaHR5bM0E E4I5wGIEQYhY2GEGMScEBwrIMV+6io40VMlI8sWGqumr+Tm+tdmGfieWyyJ3gil625k0Ga7o4MR wMJJm3EVtDrspxLncjeqQzRH8wlGVsJk3PTHqQC6LtpBEaGnGqtdEd6MLc4thl416ZgNsdNvHet 3+pw9K+/BZwAEv96m0NbbGZ7CPbizVwI5fQUfdVX7z1RmjBG6pQ5PO2I/yhpQ6xgoFIBXo2ocap RZqlD/OcIf2xwyZLi2ALLSOguj7lAhSUxhYoHqD1kdI0Ya9p5OuG9AjDh4W5z1babz5n/b1k5h2 CMa4jVLNO0c/5uW1gW6azs8IO8KupsInFH8lrZqIVUxgalYRjnE8XF/Zv8Rb//UOghuaix3AtvU oHiJA4Yee08GHBqKqeQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwOTI4MDA0OCBTYWx0ZWRfX8ecEBfn5VE+V LAUgNIKha7N876jOdh+xiwuMH8ETH7Yi1RhjU6W+d4N/5etH536hF2HIIGCR7YutUIvkO7ddOOO C7AQuT975F/Mka62I47gI2AiDzO8LSg= X-Authority-Analysis: v=2.4 cv=EY5d0/mC c=1 sm=1 tr=0 ts=6aba5d8a cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=VnNF1IyMAAAA:8 a=DgxhUou5BkHipWTGidQA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: sfttyqefxfBBC0_OfzdDIgTUBo49ixiS X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-28_03,2026-09-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 suspectscore=0 adultscore=0 clxscore=1015 malwarescore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609280048 The virtual-mode HPT hcall handlers (H_ENTER, H_REMOVE, H_BULK_REMOVE, H_CLEAR_REF, H_CLEAR_MOD) call into book3s_hv_rm_mmu.c, which accesses memslots via kvm_memslots_raw(). kvm_memslots_raw() uses rcu_dereference_raw_check() to bypass SRCU lockdep annotation checking. This is safe in real mode because the entire guest entry/exit is wrapped in srcu_read_lock/unlock inside kvmppc_run_core() and kvmhv_run_single_vcpu(). However, since commit 6165d5dd99db ("KVM: PPC: Book3S HV: add virtual mode handlers for HPT hcalls and page faults"), these same handlers are also executed in virtual mode via kvmppc_pseries_do_hcall(), which runs after SRCU has already been released on guest exit. A concurrent KVM_SET_USER_MEMORY_REGION deletion or move can therefore call synchronize_srcu_expedited() — which does not wait for this thread — and then kfree(slot) and vfree(slot->arch.rmap) while the hcall handler still holds a raw pointer to the memslot. lock_rmap() then writes to freed vmalloc memory, leading to use-after-free and memory corruption. Because kvm_memslots_raw() suppresses lockdep checks, this race is entirely silent. Fix this by factoring out the 7 HPT hcall handlers (H_REMOVE, H_ENTER, H_READ, H_CLEAR_MOD, H_CLEAR_REF, H_PROTECT, H_BULK_REMOVE) into a helper function, kvmppc_pseries_do_hpt_hcall(), and wrapping its call site in srcu_read_lock(&kvm->srcu) / srcu_read_unlock(&kvm->srcu, idx). Targeting only the HPT hcalls avoids wrapping non-HPT hcalls that sleep (such as H_CONFER, H_REGISTER_VPA, H_PAGE_INIT) or handlers that already acquire SRCU internally (such as H_RTAS). Fixes: 6165d5dd99db ("KVM: PPC: Book3S HV: add virtual mode handlers for HPT hcalls and page faults") Cc: stable@vger.kernel.org # v5.14+ Suggested-by: Ritesh Harjani (IBM) Signed-off-by: Amit Machhiwal --- arch/powerpc/kvm/book3s_hv.c | 70 ++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 35 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index dbac3573b2c8..aa51968e206a 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1159,6 +1159,38 @@ static long kvmppc_h_rpt_invalidate(struct kvm_vcpu *vcpu, return H_SUCCESS; } +static long kvmppc_pseries_do_hpt_hcall(struct kvm_vcpu *vcpu, unsigned long req) +{ + switch (req) { + case H_REMOVE: + return kvmppc_h_remove(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5), + kvmppc_get_gpr(vcpu, 6)); + case H_ENTER: + return kvmppc_h_enter(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5), + kvmppc_get_gpr(vcpu, 6), + kvmppc_get_gpr(vcpu, 7)); + case H_READ: + return kvmppc_h_read(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5)); + case H_CLEAR_MOD: + return kvmppc_h_clear_mod(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5)); + case H_CLEAR_REF: + return kvmppc_h_clear_ref(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5)); + case H_PROTECT: + return kvmppc_h_protect(vcpu, kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5), + kvmppc_get_gpr(vcpu, 6)); + case H_BULK_REMOVE: + return kvmppc_h_bulk_remove(vcpu); + } + + return H_FUNCTION; +} + int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; @@ -1174,47 +1206,15 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) switch (req) { case H_REMOVE: - ret = kvmppc_h_remove(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5), - kvmppc_get_gpr(vcpu, 6)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_ENTER: - ret = kvmppc_h_enter(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5), - kvmppc_get_gpr(vcpu, 6), - kvmppc_get_gpr(vcpu, 7)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_READ: - ret = kvmppc_h_read(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_CLEAR_MOD: - ret = kvmppc_h_clear_mod(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_CLEAR_REF: - ret = kvmppc_h_clear_ref(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_PROTECT: - ret = kvmppc_h_protect(vcpu, kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5), - kvmppc_get_gpr(vcpu, 6)); - if (ret == H_TOO_HARD) - return RESUME_HOST; - break; case H_BULK_REMOVE: - ret = kvmppc_h_bulk_remove(vcpu); + idx = srcu_read_lock(&kvm->srcu); + ret = kvmppc_pseries_do_hpt_hcall(vcpu, req); + srcu_read_unlock(&kvm->srcu, idx); if (ret == H_TOO_HARD) return RESUME_HOST; break; -- 2.54.0 (Apple Git-157)