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 X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F51FC35247 for ; Mon, 3 Feb 2020 18:36:10 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E15572082E for ; Mon, 3 Feb 2020 18:36:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TKqPiHsO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E15572082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45832 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iygZt-0004WK-3u for qemu-devel@archiver.kernel.org; Mon, 03 Feb 2020 13:36:09 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59750) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iygWI-00085r-Py for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iygWH-0001tE-Cx for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:26 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:31025 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iygWH-0001pT-5Y for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580754743; 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=uvHeRWBrLxpLh5CubflKqh/5Wa9JFfhXcBP4obYJe6k=; b=TKqPiHsOiOoG32f0sfr/RKu07Cnc1ybf0ehD+Fe3gLpgGNPagV2WHdtZMejY58XwvgQBJZ Fu09IXylAmOz+t4Yj9ijBWhUWXWd0xuiAGnGrbHX7iWGqqnU4g2qhG7ofsBjJL4jRGCMjr 3DMr5bJ2hUNSkB5RCd01Y+WNmDWFf0U= 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-43-fg9lsnfdOPu6brdhN-Beiw-1; Mon, 03 Feb 2020 13:32:16 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9501B800D48; Mon, 3 Feb 2020 18:32:15 +0000 (UTC) Received: from t480s.redhat.com (ovpn-117-77.ams2.redhat.com [10.36.117.77]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11B965D9CA; Mon, 3 Feb 2020 18:32:05 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v1 08/13] util/mmap-alloc: Prepare for resizable mmaps Date: Mon, 3 Feb 2020 19:31:20 +0100 Message-Id: <20200203183125.164879-9-david@redhat.com> In-Reply-To: <20200203183125.164879-1-david@redhat.com> References: <20200203183125.164879-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: fg9lsnfdOPu6brdhN-Beiw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII 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: 207.211.31.81 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" , David Hildenbrand , "Dr . David Alan Gilbert" , Greg Kurz , Murilo Opsfelder Araujo , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When shrinking a mmap we want to re-reserve the already populated area. When growing a memory region, we want to populate starting with a given fd_offset. Prepare by allowing to pass these parameters. Also, let's make sure we always process full pages, to avoid unmapping/remapping pages that are already in use when growing/shrinking. (existing callers seem to guarantee this, but that's not obvious) Cc: "Michael S. Tsirkin" Cc: Greg Kurz Cc: Murilo Opsfelder Araujo Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Signed-off-by: David Hildenbrand --- util/mmap-alloc.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index f043ccb0ab..63ad6893b7 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -83,12 +83,12 @@ size_t qemu_mempath_getpagesize(const char *mem_path) } =20 /* - * Reserve a new memory region of the requested size to be used for mappin= g - * from the given fd (if any). + * Reserve a new memory region of the requested size or re-reserve parts + * of an existing region to be used for mapping from the given fd (if any)= . */ -static void *mmap_reserve(size_t size, int fd) +static void *mmap_reserve(void *ptr, size_t size, int fd) { - int flags =3D MAP_PRIVATE; + int flags =3D MAP_PRIVATE | (ptr ? MAP_FIXED : 0); =20 #if defined(__powerpc64__) && defined(__linux__) /* @@ -111,19 +111,23 @@ static void *mmap_reserve(size_t size, int fd) flags |=3D MAP_ANONYMOUS; #endif =20 - return mmap(0, size, PROT_NONE, flags, fd, 0); + return mmap(ptr, size, PROT_NONE, flags, fd, 0); } =20 /* * Populate memory in a reserved region from the given fd (if any). */ -static void *mmap_populate(void *ptr, size_t size, int fd, bool shared, - bool is_pmem) +static void *mmap_populate(void *ptr, size_t size, int fd, size_t fd_offse= t, + bool shared, bool is_pmem) { int map_sync_flags =3D 0; int flags =3D MAP_FIXED; void *new_ptr; =20 + if (fd =3D=3D -1) { + fd_offset =3D 0; + } + flags |=3D fd =3D=3D -1 ? MAP_ANONYMOUS : 0; flags |=3D shared ? MAP_SHARED : MAP_PRIVATE; if (shared && is_pmem) { @@ -131,7 +135,7 @@ static void *mmap_populate(void *ptr, size_t size, int = fd, bool shared, } =20 new_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags | map_sync_f= lags, - fd, 0); + fd, fd_offset); if (new_ptr =3D=3D MAP_FAILED && map_sync_flags) { if (errno =3D=3D ENOTSUP) { char *proc_link =3D g_strdup_printf("/proc/self/fd/%d", fd); @@ -153,7 +157,7 @@ static void *mmap_populate(void *ptr, size_t size, int = fd, bool shared, * If mmap failed with MAP_SHARED_VALIDATE | MAP_SYNC, we will try * again without these flags to handle backwards compatibility. */ - new_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, fd, 0); + new_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, fd, fd_= offset); } return new_ptr; } @@ -178,13 +182,16 @@ void *qemu_ram_mmap(int fd, size_t offset, total; void *ptr, *guardptr; =20 + /* we can only map whole pages */ + size =3D QEMU_ALIGN_UP(size, pagesize); + /* * Note: this always allocates at least one extra page of virtual addr= ess * space, even if size is already aligned. */ total =3D size + align; =20 - guardptr =3D mmap_reserve(total, fd); + guardptr =3D mmap_reserve(0, total, fd); if (guardptr =3D=3D MAP_FAILED) { return MAP_FAILED; } @@ -195,7 +202,7 @@ void *qemu_ram_mmap(int fd, =20 offset =3D QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guar= dptr; =20 - ptr =3D mmap_populate(guardptr + offset, size, fd, shared, is_pmem); + ptr =3D mmap_populate(guardptr + offset, size, fd, 0, shared, is_pmem)= ; if (ptr =3D=3D MAP_FAILED) { munmap(guardptr, total); return MAP_FAILED; @@ -221,6 +228,9 @@ void qemu_ram_munmap(int fd, void *ptr, size_t size) { const size_t pagesize =3D mmap_pagesize(fd); =20 + /* we can only map whole pages */ + size =3D QEMU_ALIGN_UP(size, pagesize); + if (ptr) { /* Unmap both the RAM block and the guard page */ munmap(ptr, size + pagesize); --=20 2.24.1