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,URIBL_BLOCKED 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 92229C3F2CD for ; Thu, 5 Mar 2020 14:40:24 +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 5B70A20848 for ; Thu, 5 Mar 2020 14:40:24 +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="X4ORHxKo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B70A20848 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]:50416 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rfj-0005eE-Hl for qemu-devel@archiver.kernel.org; Thu, 05 Mar 2020 09:40:23 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35789) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rXx-0000QZ-IX for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j9rXw-0003O4-6l for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:21 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:41326 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 1j9rXw-0003N6-2N for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583418739; 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=2eknTrxrpZwJTyM4q9bbVp/0nK/Ipyt3w1hOhR5L378=; b=X4ORHxKooLCqQOKeU5fnoQlYaaRZRXXf8jDe/OObYv1TqkiM3nclYqWP29wa4JWW45K4Jo BQpIa9i+XkaZsJuLJzvPCutqD2Cq91qaaiFlRFOoM5PL2jP60qg2TZizcM/oS4r1l0eeeX D90GLfeArConvQcr5ZbLAxj05nkX7xQ= 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-27-nFi3yssxP-akRBGnaTv5rQ-1; Thu, 05 Mar 2020 09:32:16 -0500 X-MC-Unique: nFi3yssxP-akRBGnaTv5rQ-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 B40EA1005510; Thu, 5 Mar 2020 14:32:14 +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 9743F91D7A; Thu, 5 Mar 2020 14:32:09 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v4 10/15] util/mmap-alloc: Prepare for resizeable mmaps Date: Thu, 5 Mar 2020 15:29:40 +0100 Message-Id: <20200305142945.216465-11-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-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: 207.211.31.120 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 activated area. When growing a memory region, we want to activate 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 8f40ef4fed..2767caa33b 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 activated 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__) /* @@ -111,20 +111,24 @@ 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 /* * Activate memory in a reserved region from the given fd (if any), to mak= e * it accessible. */ -static void *mmap_activate(void *ptr, size_t size, int fd, bool shared, - bool is_pmem) +static void *mmap_activate(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 *activated_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) { @@ -132,7 +136,7 @@ static void *mmap_activate(void *ptr, size_t size, int = fd, bool shared, } =20 activated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, - flags | map_sync_flags, fd, 0); + flags | map_sync_flags, fd, fd_offset); if (activated_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); @@ -154,7 +158,8 @@ static void *mmap_activate(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. */ - activated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, f= d, 0); + activated_ptr =3D mmap(ptr, size, PROT_READ | PROT_WRITE, flags, f= d, + fd_offset); } return activated_ptr; } @@ -176,16 +181,19 @@ 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; } @@ -196,7 +204,7 @@ void *qemu_ram_mmap(int fd, =20 offset =3D QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guar= dptr; =20 - ptr =3D mmap_activate(guardptr + offset, size, fd, shared, is_pmem); + ptr =3D mmap_activate(guardptr + offset, size, fd, 0, shared, is_pmem)= ; if (ptr =3D=3D MAP_FAILED) { munmap(guardptr, total); return MAP_FAILED; @@ -220,6 +228,10 @@ 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