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 B2FAEC4BA24 for ; Thu, 27 Feb 2020 10:23:39 +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 7EE2024672 for ; Thu, 27 Feb 2020 10:23:39 +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="gYOH2ziz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7EE2024672 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]:56682 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7GKQ-0004FQ-Hi for qemu-devel@archiver.kernel.org; Thu, 27 Feb 2020 05:23:38 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40176) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7GBW-0003qG-Cf for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j7GBT-0000VR-TW for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:26 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:23104 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 1j7GBT-0000Su-P7 for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582798463; 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=4mZwnvyZhERJne67+bQOssfXKczt9eVEF1mwFB9tgoM=; b=gYOH2ziz+UPzecHZgJuepa/tcHp/QfIVmWn91CBn/L/u3bbbM75YaeAOMcEDUXEiJ4utHi 0nTPl09cQfngCig5VhzDKLXW4RsyB+F6V7CBNPu93BC1FA7wXK400/Bq5y/ES+b+cQkk5q cirJbgcmqmvUQCWFXDf6FQaUYIhfRlw= 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-244-pNJ7hmV9Mcae-qUqDXsgjQ-1; Thu, 27 Feb 2020 05:14:22 -0500 X-MC-Unique: pNJ7hmV9Mcae-qUqDXsgjQ-1 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 AF9DD107B7D7; Thu, 27 Feb 2020 10:14:20 +0000 (UTC) Received: from t480s.redhat.com (ovpn-116-36.ams2.redhat.com [10.36.116.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 60B916E3EE; Thu, 27 Feb 2020 10:14:07 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v3 10/15] util/mmap-alloc: Prepare for resizeable mmaps Date: Thu, 27 Feb 2020 11:12:00 +0100 Message-Id: <20200227101205.5616-11-david@redhat.com> In-Reply-To: <20200227101205.5616-1-david@redhat.com> References: <20200227101205.5616-1-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-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] X-Received-From: 205.139.110.120 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" , Richard Henderson , 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+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. Add some asserts. Reviewed-by: Richard Henderson Reviewed-by: Peter Xu Cc: Igor Kotrasinski Cc: Murilo Opsfelder Araujo Cc: "Michael S. Tsirkin" Cc: Greg Kurz Cc: Murilo Opsfelder Araujo Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Cc: Igor Mammedov Signed-off-by: David Hildenbrand --- util/mmap-alloc.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 73179f36d6..c6a6075215 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 *populated_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 populated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, - flags | map_sync_flags, fd, 0); + flags | map_sync_flags, fd, fd_offset); if (populated_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 +157,8 @@ 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. */ - populated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, f= d, 0); + populated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, f= d, + fd_offset); } return populated_ptr; } @@ -175,16 +180,19 @@ void *qemu_ram_mmap(int fd, bool is_pmem) { const size_t guard_pagesize =3D mmap_guard_pagesize(fd); + const size_t pagesize =3D qemu_fd_getpagesize(fd); size_t offset, total; void *ptr, *guardptr; =20 + g_assert(QEMU_IS_ALIGNED(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(NULL, total, fd); if (guardptr =3D=3D MAP_FAILED) { return MAP_FAILED; } @@ -195,7 +203,7 @@ 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; @@ -219,6 +227,10 @@ void *qemu_ram_mmap(int fd, =20 void qemu_ram_munmap(int fd, void *ptr, size_t size) { + const size_t pagesize =3D qemu_fd_getpagesize(fd); + + g_assert(QEMU_IS_ALIGNED(size, pagesize)); + if (ptr) { /* Unmap both the RAM block and the guard page */ munmap(ptr, size + mmap_guard_pagesize(fd)); --=20 2.24.1