From nobody Thu Sep 19 02:13:20 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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 (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1549272873130354.21811501990226; Mon, 4 Feb 2019 01:34:33 -0800 (PST) Received: from localhost ([127.0.0.1]:39429 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gqae6-0002Tg-4t for importer@patchew.org; Mon, 04 Feb 2019 04:34:30 -0500 Received: from eggs.gnu.org ([209.51.188.92]:39256) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gqa9v-0001av-1f for qemu-devel@nongnu.org; Mon, 04 Feb 2019 04:03:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gqa9n-0000jE-VI for qemu-devel@nongnu.org; Mon, 04 Feb 2019 04:03:18 -0500 Received: from ozlabs.org ([2401:3900:2:1::2]:34469) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gqa9n-0000GT-46; Mon, 04 Feb 2019 04:03:11 -0500 Received: by ozlabs.org (Postfix, from userid 1007) id 43tMCC26fjz9sPc; Mon, 4 Feb 2019 20:01:40 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1549270903; bh=JBVZse8IGPqfsMcYrSN0cgqFVkyCtbmg0RiC1KWiVbI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jq8vETQH8FSA6mMYtIKYGcpjcNx6FKPNHEN2R1V6k89u4jNbv/g1APN+8dSpnxXqC uTaXKni/q7JyHJ9bULaZbC/wbpjbWU1KSdmVIZDLYfy91KWSWsNxYtYq5QmTp++LHI /7yoo1QdTylsMnEoGXaIEGY5ZBTZVj0WtSE1LAk0= From: David Gibson To: peter.maydell@linaro.org Date: Mon, 4 Feb 2019 20:01:23 +1100 Message-Id: <20190204090124.26191-37-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190204090124.26191-1-david@gibson.dropbear.id.au> References: <20190204090124.26191-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2401:3900:2:1::2 Subject: [Qemu-devel] [PULL 36/37] mmap-alloc: unfold qemu_ram_mmap() 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: lvivier@redhat.com, qemu-devel@nongnu.org, groug@kaod.org, spopovyc@redhat.com, qemu-ppc@nongnu.org, clg@kaod.org, Murilo Opsfelder Araujo , David Gibson 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" From: Murilo Opsfelder Araujo Unfold parts of qemu_ram_mmap() for the sake of understanding, moving declarations to the top, and keeping architecture-specifics in the ifdef-else blocks. No changes in the function behaviour. Give ptr and ptr1 meaningful names: ptr -> guardptr : pointer to the PROT_NONE guard region ptr1 -> ptr : pointer to the mapped memory returned to caller Signed-off-by: Murilo Opsfelder Araujo Reviewed-by: Greg Kurz Signed-off-by: David Gibson --- util/mmap-alloc.c | 53 ++++++++++++++++++++++++++++++----------------- 1 file changed, 34 insertions(+), 19 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index fd329eccd8..f71ea038c8 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -77,11 +77,19 @@ size_t qemu_mempath_getpagesize(const char *mem_path) =20 void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) { + int flags; + int guardfd; + size_t offset; + size_t total; + void *guardptr; + void *ptr; + /* * Note: this always allocates at least one extra page of virtual addr= ess * space, even if size is already aligned. */ - size_t total =3D size + align; + total =3D size + align; + #if defined(__powerpc64__) && defined(__linux__) /* On ppc64 mappings in the same segment (aka slice) must share the sa= me * page size. Since we will be re-allocating part of this segment @@ -91,16 +99,22 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, = bool shared) * We do this unless we are using the system page size, in which case * anonymous memory is OK. */ - int anonfd =3D fd =3D=3D -1 || qemu_fd_getpagesize(fd) =3D=3D getpages= ize() ? -1 : fd; - int flags =3D anonfd =3D=3D -1 ? MAP_ANONYMOUS : MAP_NORESERVE; - void *ptr =3D mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0= ); + flags =3D MAP_PRIVATE; + if (fd =3D=3D -1 || qemu_fd_getpagesize(fd) =3D=3D getpagesize()) { + guardfd =3D -1; + flags |=3D MAP_ANONYMOUS; + } else { + guardfd =3D fd; + flags |=3D MAP_NORESERVE; + } #else - void *ptr =3D mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -= 1, 0); + guardfd =3D -1; + flags =3D MAP_PRIVATE | MAP_ANONYMOUS; #endif - size_t offset; - void *ptr1; =20 - if (ptr =3D=3D MAP_FAILED) { + guardptr =3D mmap(0, total, PROT_NONE, flags, guardfd, 0); + + if (guardptr =3D=3D MAP_FAILED) { return MAP_FAILED; } =20 @@ -108,19 +122,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align= , bool shared) /* Always align to host page size */ assert(align >=3D getpagesize()); =20 - offset =3D QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; - ptr1 =3D mmap(ptr + offset, size, PROT_READ | PROT_WRITE, - MAP_FIXED | - (fd =3D=3D -1 ? MAP_ANONYMOUS : 0) | - (shared ? MAP_SHARED : MAP_PRIVATE), - fd, 0); - if (ptr1 =3D=3D MAP_FAILED) { - munmap(ptr, total); + flags =3D MAP_FIXED; + flags |=3D fd =3D=3D -1 ? MAP_ANONYMOUS : 0; + flags |=3D shared ? MAP_SHARED : MAP_PRIVATE; + offset =3D QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guar= dptr; + + ptr =3D mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, f= d, 0); + + if (ptr =3D=3D MAP_FAILED) { + munmap(guardptr, total); return MAP_FAILED; } =20 if (offset > 0) { - munmap(ptr, offset); + munmap(guardptr, offset); } =20 /* @@ -129,10 +144,10 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align= , bool shared) */ total -=3D offset; if (total > size + getpagesize()) { - munmap(ptr1 + size + getpagesize(), total - size - getpagesize()); + munmap(ptr + size + getpagesize(), total - size - getpagesize()); } =20 - return ptr1; + return ptr; } =20 void qemu_ram_munmap(void *ptr, size_t size) --=20 2.20.1