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 0EAB5CA6007 for ; Wed, 7 Oct 2026 18:21:52 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4j0M0F4wTyz30NF; Thu, 08 Oct 2026 05:21:49 +1100 (AEDT) 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=1791397309; cv=none; b=E0t+rXAd3TMqhspHVWzZkbtpr/fjTzfOHGawUmk35ey5/Q6i+LqadDiQz1mE30wMts/TxH5mzp/V+APISdFL2V3RH6imV7gMU1W6vKjalgO2aWX3H0JIaea8tUZak98elnmxsKkrwzBXZrLXX9qTZBmYXUNndxcimXkI+qDfZeNqbToOVcA24HPYm7Xb8RJNoaaIqe6xd47MPRsnmJOpyzZQvNkehszoIj7EL2T4ZkhO6MJ4okCUf9XxpA09Fbx99UNs1c5JhGWG7KP1g7nT7EKZ8pzFVPud9ePA2ZR1Hz+l3UnxoSvj3SUAYX0nhsPj+mnRUGT2DOaMP+EmiBgEUw== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1791397309; c=relaxed/relaxed; bh=5PT3FwA4ChHnjEa+xr3xDXd780D+F0Ni80fRcedI2C0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=B7NzWdf6O3QZBi+dWCgh10/QfYcP0F7uOGs6v7c+4ubxq6+t/sHkXEkVrDJZLfRNHRzt+6mlRCAXhljul66eaJaQvZv9xAyegiSmRk9lry7SLPOEOGfO6KS2NROKyghzGLgTKso4xBkGhv1f3XD1GzULkuCYRTAeJbtujUJOTOLfATF8a4GOsvoZE4exf6MH7lW0nPBq9Gphbw/1g8F6vTC51pBC3+QV2ZePqSkEfhV21HWFebSWEj0DhFDv7NS9JAOFnPftBGzBhUk9s1OXQK37jV5S6pqFmijZ75zq13GcMD+zSFPER/7V4j6egi45sRUScQ1CFXLtT944t77eUA== 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=QVUg9VHg; 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=QVUg9VHg; 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 4j0M0C6Bbzz30Bd for ; Thu, 08 Oct 2026 05:21:47 +1100 (AEDT) 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 697F6Lwt2849847; Wed, 7 Oct 2026 18:21:37 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=5PT3Fw A4ChHnjEa+xr3xDXd780D+F0Ni80fRcedI2C0=; b=QVUg9VHgql1MnxIWOoczA9 t83WpozkKRY4aD982oVcgkG91j+/8arYIjABC9walIvm51wzSXU+qOAp7eYa0nLa /0OhUSlIkfwQ7T7PbHTMSpeg5Co9xZyGj0JAOzN7Ta+YBPMXxlTPSaKF/8FH6l2d YKoEl9lsvnS7ol0vr90d4ueW3SMWOJGZ9rsLo9q2Uz9sOsLvt1zrLfAUI8TU7Vi4 L2N5IBTJh8iwg5/S7yzADiaZ/ykSSkyG1g4rYldMhljAJPO2GXBvPd0A+QXLGjYr /jC63UsFm9/DqGeOOv9uvIbIloUJ1wUsGj46wfTL4r5k1QrSQSpNIg2tXXcWsYaw == Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4h2sbve3vt-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 07 Oct 2026 18:21:36 +0000 (GMT) Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.18.1.11/8.18.1.11) with ESMTP id 697IHYrN2245348; Wed, 7 Oct 2026 18:21:36 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4h58d5m419-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Oct 2026 18:21:36 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 697ILUor17105400 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 7 Oct 2026 18:21:30 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EEFCC20040; Wed, 7 Oct 2026 18:21:29 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 81CCB2004D; Wed, 7 Oct 2026 18:21:25 +0000 (GMT) Received: from localhost.localdomain (unknown [9.39.25.208]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 7 Oct 2026 18:21:25 +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: [PATCH v4 1/3] KVM: PPC: Book3S HV: Add SRCU protection for virtual-mode HPT hcalls Date: Wed, 7 Oct 2026 23:51:13 +0530 Message-ID: <20261007182116.12479-2-amachhiw@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261007182116.12479-1-amachhiw@linux.ibm.com> References: <20261007182116.12479-1-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: w8sOdD_9Q_XMQzvlEmbz-UBTd3Ctkjrr X-Authority-Analysis: v=2.4 cv=KJHPn1Fo c=1 sm=1 tr=0 ts=6ac68db1 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=660iZSQnnn4A: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: QTIGVwiSTBXUnKCONl30bYo-JJZbtQbw X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDA3MDA3MiBTYWx0ZWRfX1YsBmj/13ue/ VRtJ1topMdxoZkK8ZkTY/MTyaH9qiiajgyHAPEgIMQOMimhC/gWRPI1CFbhq/f6dRhvQI5Y5vjc ia/v22zsYkyRZ1jZjW0V/DLL6LhGB/mOyLHJ2XC5fWGgxNsGp8VyPKfF2JrRWOruTyez9bYktm1 PWcZ+pO2cPWOn3Kig9OqsC3KRw5PjEDXOEDNOT1CHeWnfkPuHj0a0i8u9Ms0ztWVpdDmwyTyQvi XagX6oBNRxaJCxLtGD5HXzwoYfyf7YIdrq1j5Vyvw+wxpZan6qD7WfWT1XgfsDEK9deVUEYaouH 8s3EQahMpXk2TfgPb64ITtLj5hJSml37zFhTCcFHO6Ee+OfpSpB0Z0mlsEtR0hVZOTLVO1l/Uqm U9HTuFLB3V+Qxetjx1h4/L/IlCl8XyMVtY0/T872MCFGURP830h9LyK7BvsezGS24RRY5laZiBY n1A7ZJS/8PeABLo5/pQ== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDA3MDA3MiBTYWx0ZWRfX7rkf/yDvQuVd vR7GjA9JB161OOyiy+iFU60pV2/x/lfCLv0QOqbJm8MIf8FCVeuAh10Nrh2THvUAkvz2RAweMfz 3ak5qQzuLNr2prdxNwCujO6tHtEhKq4= 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=2026-10-07_05,2026-10-06_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 spamscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 impostorscore=0 adultscore=0 clxscore=1015 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2610070072 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) Reviewed-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 de05d721edc4..46dd550115a4 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)