From nobody Thu Nov 13 22:02:51 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1583419078; cv=none; d=zohomail.com; s=zohoarc; b=Qws4ZLfhnw+GRU3YEDB6vPav97o1W0R+oopxHZWh+97yVRFKvg828COaVZ5SCmtL03cSngvPLEbLrWpFCSDRGGsYelb6BQnSJ/ph9XU9S8f5Y3SNswMKM4ON3p21gljwBSBRxaYwHGKjS1M5rkxJkV5A77EFin6WkVb93+sZ7ks= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1583419078; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=6BRQjN964Dr4w6axvvjVY5gJygw5QYBcf+sSZYLkYQo=; b=iv/dBh+OnsvpTHuGeqnwgHp1loxtIQSiYiyNB7sXLFnSHtzHzwhuQEE6/BxM4MdGGQgEL62wacpUZA22MVaBrjCSrqtuCNZ/C+J3Uo57HIJyCsWUzR5M4/1uwqpze04q32u0/+0RK4SFqgYQUhY3XXQc+ynwR6WDdxpBi8DSagc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1583419078974366.2551500825946; Thu, 5 Mar 2020 06:37:58 -0800 (PST) Received: from localhost ([::1]:50380 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rdN-0002AC-Ul for importer@patchew.org; Thu, 05 Mar 2020 09:37:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35671) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rXg-0008Og-Rw for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j9rXf-00038z-KR for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:04 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45764 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j9rXf-00038h-GG for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:03 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-471-wPRTW4a-PxqCROMY29kVpQ-1; Thu, 05 Mar 2020 09:31:59 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6DEE913E4; Thu, 5 Mar 2020 14:31:58 +0000 (UTC) Received: from t480s.redhat.com (ovpn-120-166.rdu2.redhat.com [10.10.120.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E63790538; Thu, 5 Mar 2020 14:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583418723; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6BRQjN964Dr4w6axvvjVY5gJygw5QYBcf+sSZYLkYQo=; b=aHfteZn8LZaK9Rf95BGcSEQMlZBAYnx/sJYNL9l5xltLqrctHEcTwOFkjVyQV+a6tdF2aN mvAfRM+W59Oi79Qm1dscGpgnZaohdu6uC5Pr6nuWkz1WuPBO9wBciUohnLFGafRP0B4SaP Qx/BKi472UavW3cISkNr3QaxwVnFvwI= X-MC-Unique: wPRTW4a-PxqCROMY29kVpQ-1 From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v4 07/15] util/mmap-alloc: Factor out calculation of the pagesize for the guard page Date: Thu, 5 Mar 2020 15:29:37 +0100 Message-Id: <20200305142945.216465-8-david@redhat.com> In-Reply-To: <20200305142945.216465-1-david@redhat.com> References: <20200305142945.216465-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S . Tsirkin" , Igor Kotrasinski , David Hildenbrand , "Dr . David Alan Gilbert" , Peter Xu , Greg Kurz , Murilo Opsfelder Araujo , Igor Mammedov , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Let's factor out calculating the size of the guard page and rename the variable to make it clearer that this pagesize only applies to the guard page. Reviewed-by: Peter Xu Cc: "Michael S. Tsirkin" Cc: Murilo Opsfelder Araujo Cc: Greg Kurz Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Cc: Igor Mammedov Signed-off-by: David Hildenbrand Acked-by: Murilo Opsfelder Araujo --- util/mmap-alloc.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 27dcccd8ec..f0277f9fad 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -82,17 +82,27 @@ size_t qemu_mempath_getpagesize(const char *mem_path) return qemu_real_host_page_size; } =20 +static inline size_t mmap_guard_pagesize(int fd) +{ +#if defined(__powerpc64__) && defined(__linux__) + /* Mappings in the same segment must share the same page size */ + return qemu_fd_getpagesize(fd); +#else + return qemu_real_host_page_size; +#endif +} + void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared, bool is_pmem) { + const size_t guard_pagesize =3D mmap_guard_pagesize(fd); int flags; int map_sync_flags =3D 0; int guardfd; size_t offset; - size_t pagesize; size_t total; void *guardptr; void *ptr; @@ -113,8 +123,7 @@ void *qemu_ram_mmap(int fd, * anonymous memory is OK. */ flags =3D MAP_PRIVATE; - pagesize =3D qemu_fd_getpagesize(fd); - if (fd =3D=3D -1 || pagesize =3D=3D qemu_real_host_page_size) { + if (fd =3D=3D -1 || guard_pagesize =3D=3D qemu_real_host_page_size) { guardfd =3D -1; flags |=3D MAP_ANONYMOUS; } else { @@ -123,7 +132,6 @@ void *qemu_ram_mmap(int fd, } #else guardfd =3D -1; - pagesize =3D qemu_real_host_page_size; flags =3D MAP_PRIVATE | MAP_ANONYMOUS; #endif =20 @@ -135,7 +143,7 @@ void *qemu_ram_mmap(int fd, =20 assert(is_power_of_2(align)); /* Always align to host page size */ - assert(align >=3D pagesize); + assert(align >=3D guard_pagesize); =20 flags =3D MAP_FIXED; flags |=3D fd =3D=3D -1 ? MAP_ANONYMOUS : 0; @@ -189,8 +197,8 @@ void *qemu_ram_mmap(int fd, * a guard page guarding against potential buffer overflows. */ total -=3D offset; - if (total > size + pagesize) { - munmap(ptr + size + pagesize, total - size - pagesize); + if (total > size + guard_pagesize) { + munmap(ptr + size + guard_pagesize, total - size - guard_pagesize); } =20 return ptr; @@ -198,15 +206,8 @@ void *qemu_ram_mmap(int fd, =20 void qemu_ram_munmap(int fd, void *ptr, size_t size) { - size_t pagesize; - if (ptr) { /* Unmap both the RAM block and the guard page */ -#if defined(__powerpc64__) && defined(__linux__) - pagesize =3D qemu_fd_getpagesize(fd); -#else - pagesize =3D qemu_real_host_page_size; -#endif - munmap(ptr, size + pagesize); + munmap(ptr, size + mmap_guard_pagesize(fd)); } } --=20 2.24.1