From nobody Sat Feb 7 07:01:38 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 15156437918971005.3828148194381; Wed, 10 Jan 2018 20:09:51 -0800 (PST) Received: from localhost ([::1]:38099 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZUBS-0007Gw-Nd for importer@patchew.org; Wed, 10 Jan 2018 23:09:42 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54892) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZUAS-0006nH-S7 for qemu-devel@nongnu.org; Wed, 10 Jan 2018 23:08:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZUAP-0005Gr-ND for qemu-devel@nongnu.org; Wed, 10 Jan 2018 23:08:40 -0500 Received: from ozlabs.ru ([107.173.13.209]:49080) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZUAP-0005F8-Hq; Wed, 10 Jan 2018 23:08:37 -0500 Received: from vpl1.ozlabs.ibm.com (localhost [IPv6:::1]) by ozlabs.ru (Postfix) with ESMTP id 2A4953A6000A; Wed, 10 Jan 2018 23:08:16 -0500 (EST) From: Alexey Kardashevskiy To: qemu-devel@nongnu.org Date: Thu, 11 Jan 2018 15:08:32 +1100 Message-Id: <20180111040832.28383-1-aik@ozlabs.ru> X-Mailer: git-send-email 2.11.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 107.173.13.209 Subject: [Qemu-devel] [PATCH qemu] target/ppc: Yet another fix for KVM-HV HPTE accessors X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexey Kardashevskiy , qemu-ppc@nongnu.org, David Gibson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" As stated in the 1ad9f0a464fe commit log, the returned entries are not a while PTEG. It was not a problem before 1ad9f0a464fe as it would read a single record assuming it contains a whole PTEG but now the code tries reading the entire PTEG and "if ((n - i) < invalid)" produces negative values which then are converted to size_t for memset() and that throws seg fault. This fixes the math. While here, fix the last @i increment as well. Fixes: 1ad9f0a464fe "target/ppc: Fix KVM-HV HPTE accessors" Signed-off-by: Alexey Kardashevskiy --- Record #0: (gdb) p *hdr $13 =3D { index =3D , n_valid =3D 0x1, n_invalid =3D 0x6 } Record #1: (gdb) p *hdr $18 =3D { index =3D , n_valid =3D 0x2, n_invalid =3D 0x6 } i.e. in the second iteration of the loop right before "if ((n - i) < invalid)": (gdb) p n $16 =3D 0x8 (gdb) p i $17 =3D 0x9 and @invalid becomes -1. --- target/ppc/kvm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c index 0566af7..c2dea81 100644 --- a/target/ppc/kvm.c +++ b/target/ppc/kvm.c @@ -2657,21 +2657,24 @@ void kvmppc_read_hptes(ppc_hash_pte64_t *hptes, hwa= ddr ptex, int n) =20 hdr =3D (struct kvm_get_htab_header *)buf; while ((i < n) && ((char *)hdr < (buf + rc))) { - int invalid =3D hdr->n_invalid; + int invalid =3D hdr->n_invalid, valid =3D hdr->n_valid; =20 if (hdr->index !=3D (ptex + i)) { hw_error("kvmppc_read_hptes: Unexpected HPTE index %"PRIu32 " !=3D (%"HWADDR_PRIu" + %d", hdr->index, ptex, i= ); } =20 - memcpy(hptes + i, hdr + 1, HASH_PTE_SIZE_64 * hdr->n_valid); - i +=3D hdr->n_valid; + if (n - i < valid) { + valid =3D n - i; + } + memcpy(hptes + i, hdr + 1, HASH_PTE_SIZE_64 * valid); + i +=3D valid; =20 if ((n - i) < invalid) { invalid =3D n - i; } memset(hptes + i, 0, invalid * HASH_PTE_SIZE_64); - i +=3D hdr->n_invalid; + i +=3D invalid; =20 hdr =3D (struct kvm_get_htab_header *) ((char *)(hdr + 1) + HASH_PTE_SIZE_64 * hdr->n_valid); --=20 2.11.0