From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34318) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoqbR-0003wl-JR for qemu-devel@nongnu.org; Wed, 21 Oct 2015 06:26:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZoqbI-0005vc-U5 for qemu-devel@nongnu.org; Wed, 21 Oct 2015 06:26:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33458) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoqbI-0005uW-EK for qemu-devel@nongnu.org; Wed, 21 Oct 2015 06:26:32 -0400 Date: Wed, 21 Oct 2015 13:26:27 +0300 From: "Michael S. Tsirkin" Message-ID: <1445423133-5119-3-git-send-email-mst@redhat.com> References: <1445423133-5119-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1445423133-5119-1-git-send-email-mst@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 02/38] exec: factor out duplicate mmap code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , =?us-ascii?B?PT9VVEYtOD9xP01hcmMtQW5kcj1DMz1BOT0yMEx1cmVhdT89?= , Thibaut Collet , Paolo Bonzini Anonymous and file-backed RAM allocation are now almost exactly the same. Reduce code duplication by moving RAM mmap code out of oslib-posix.c and exec.c. Reported-by: Marc-Andr=E9 Lureau Signed-off-by: Michael S. Tsirkin Reviewed-by: Paolo Bonzini Acked-by: Paolo Bonzini Tested-by: Thibaut Collet --- include/qemu/mmap-alloc.h | 10 +++++++ exec.c | 47 +++++++------------------------ util/mmap-alloc.c | 71 +++++++++++++++++++++++++++++++++++++++++= ++++++ util/oslib-posix.c | 28 +++---------------- util/Makefile.objs | 1 + 5 files changed, 96 insertions(+), 61 deletions(-) create mode 100644 include/qemu/mmap-alloc.h create mode 100644 util/mmap-alloc.c diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h new file mode 100644 index 0000000..56388e6 --- /dev/null +++ b/include/qemu/mmap-alloc.h @@ -0,0 +1,10 @@ +#ifndef QEMU_MMAP_ALLOC +#define QEMU_MMAP_ALLOC + +#include "qemu-common.h" + +void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared); + +void qemu_ram_munmap(void *ptr, size_t size); + +#endif diff --git a/exec.c b/exec.c index 7d90a52..4505dc7 100644 --- a/exec.c +++ b/exec.c @@ -55,6 +55,9 @@ #include "exec/ram_addr.h" =20 #include "qemu/range.h" +#ifndef _WIN32 +#include "qemu/mmap-alloc.h" +#endif =20 //#define DEBUG_SUBPAGE =20 @@ -84,9 +87,9 @@ static MemoryRegion io_mem_unassigned; */ #define RAM_RESIZEABLE (1 << 2) =20 -/* An extra page is mapped on top of this RAM. +/* RAM is backed by an mmapped file. */ -#define RAM_EXTRA (1 << 3) +#define RAM_FILE (1 << 3) #endif =20 struct CPUTailQ cpus =3D QTAILQ_HEAD_INITIALIZER(cpus); @@ -1188,13 +1191,10 @@ static void *file_ram_alloc(RAMBlock *block, char *filename; char *sanitized_name; char *c; - void *ptr; - void *area =3D NULL; + void *area; int fd; uint64_t hpagesize; - uint64_t total; Error *local_err =3D NULL; - size_t offset; =20 hpagesize =3D gethugepagesize(path, &local_err); if (local_err) { @@ -1238,7 +1238,6 @@ static void *file_ram_alloc(RAMBlock *block, g_free(filename); =20 memory =3D ROUND_UP(memory, hpagesize); - total =3D memory + hpagesize; =20 /* * ftruncate is not supported by hugetlbfs in older @@ -1250,40 +1249,14 @@ static void *file_ram_alloc(RAMBlock *block, perror("ftruncate"); } =20 - ptr =3D mmap(0, total, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, - -1, 0); - if (ptr =3D=3D MAP_FAILED) { - error_setg_errno(errp, errno, - "unable to allocate memory range for hugepages"= ); - close(fd); - goto error; - } - - offset =3D QEMU_ALIGN_UP((uintptr_t)ptr, hpagesize) - (uintptr_t)ptr= ; - - area =3D mmap(ptr + offset, memory, PROT_READ | PROT_WRITE, - (block->flags & RAM_SHARED ? MAP_SHARED : MAP_PRIVATE) | - MAP_FIXED, - fd, 0); + area =3D qemu_ram_mmap(fd, memory, hpagesize, block->flags & RAM_SHA= RED); if (area =3D=3D MAP_FAILED) { error_setg_errno(errp, errno, "unable to map backing store for hugepages"); - munmap(ptr, total); close(fd); goto error; } =20 - if (offset > 0) { - munmap(ptr, offset); - } - ptr +=3D offset; - total -=3D offset; - - if (total > memory + getpagesize()) { - munmap(ptr + memory + getpagesize(), - total - memory - getpagesize()); - } - if (mem_prealloc) { os_mem_prealloc(fd, area, memory); } @@ -1601,7 +1574,7 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size= , MemoryRegion *mr, new_block->used_length =3D size; new_block->max_length =3D size; new_block->flags =3D share ? RAM_SHARED : 0; - new_block->flags |=3D RAM_EXTRA; + new_block->flags |=3D RAM_FILE; new_block->host =3D file_ram_alloc(new_block, size, mem_path, errp); if (!new_block->host) { @@ -1703,8 +1676,8 @@ static void reclaim_ramblock(RAMBlock *block) xen_invalidate_map_cache_entry(block->host); #ifndef _WIN32 } else if (block->fd >=3D 0) { - if (block->flags & RAM_EXTRA) { - munmap(block->host, block->max_length + getpagesize()); + if (block->flags & RAM_FILE) { + qemu_ram_munmap(block->host, block->max_length); } else { munmap(block->host, block->max_length); } diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c new file mode 100644 index 0000000..1394269 --- /dev/null +++ b/util/mmap-alloc.c @@ -0,0 +1,71 @@ +/* + * Support for RAM backed by mmaped host memory. + * + * Copyright (c) 2015 Red Hat, Inc. + * + * Authors: + * Michael S. Tsirkin + * + * This work is licensed under the terms of the GNU GPL, version 2 or + * later. See the COPYING file in the top-level directory. + */ +#include +#include +#include +#include + +void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared) +{ + /* + * Note: this always allocates at least one extra page of virtual ad= dress + * space, even if size is already aligned. + */ + size_t total =3D size + align; + void *ptr =3D mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE,= -1, 0); + size_t offset =3D QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)= ptr; + void *ptr1; + + if (ptr =3D=3D MAP_FAILED) { + return NULL; + } + + /* Make sure align is a power of 2 */ + assert(!(align & (align - 1))); + /* Always align to host page size */ + assert(align >=3D getpagesize()); + + 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); + return NULL; + } + + ptr +=3D offset; + total -=3D offset; + + if (offset > 0) { + munmap(ptr - offset, offset); + } + + /* + * Leave a single PROT_NONE page allocated after the RAM block, to s= erve as + * a guard page guarding against potential buffer overflows. + */ + if (total > size + getpagesize()) { + munmap(ptr + size + getpagesize(), total - size - getpagesize())= ; + } + + return ptr; +} + +void qemu_ram_munmap(void *ptr, size_t size) +{ + if (ptr) { + /* Unmap both the RAM block and the guard page */ + munmap(ptr, size + getpagesize()); + } +} diff --git a/util/oslib-posix.c b/util/oslib-posix.c index a0fcdc2..892d2d8 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -72,6 +72,8 @@ extern int daemon(int, int); #include #endif =20 +#include + int qemu_get_thread_id(void) { #if defined(__linux__) @@ -128,10 +130,7 @@ void *qemu_memalign(size_t alignment, size_t size) void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) { size_t align =3D QEMU_VMALLOC_ALIGN; - size_t total =3D size + align; - void *ptr =3D mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE,= -1, 0); - size_t offset =3D QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)= ptr; - void *ptr1; + void *ptr =3D qemu_ram_mmap(-1, size, align, false); =20 if (ptr =3D=3D MAP_FAILED) { return NULL; @@ -141,23 +140,6 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t *ali= gnment) *alignment =3D align; } =20 - ptr1 =3D mmap(ptr + offset, size, PROT_READ | PROT_WRITE, - MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); - if (ptr1 =3D=3D MAP_FAILED) { - munmap(ptr, total); - return NULL; - } - - ptr +=3D offset; - total -=3D offset; - - if (offset > 0) { - munmap(ptr - offset, offset); - } - if (total > size + getpagesize()) { - munmap(ptr + size + getpagesize(), total - size - getpagesize())= ; - } - trace_qemu_anon_ram_alloc(size, ptr); return ptr; } @@ -171,9 +153,7 @@ void qemu_vfree(void *ptr) void qemu_anon_ram_free(void *ptr, size_t size) { trace_qemu_anon_ram_free(ptr, size); - if (ptr) { - munmap(ptr, size + getpagesize()); - } + qemu_ram_munmap(ptr, size); } =20 void qemu_set_block(int fd) diff --git a/util/Makefile.objs b/util/Makefile.objs index 114d657..f011b81 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -1,6 +1,7 @@ util-obj-y =3D osdep.o cutils.o unicode.o qemu-timer-common.o util-obj-$(CONFIG_WIN32) +=3D oslib-win32.o qemu-thread-win32.o event_no= tifier-win32.o util-obj-$(CONFIG_POSIX) +=3D oslib-posix.o qemu-thread-posix.o event_no= tifier-posix.o qemu-openpty.o +util-obj-$(CONFIG_POSIX) +=3D mmap-alloc.o util-obj-y +=3D envlist.o path.o module.o util-obj-$(call lnot,$(CONFIG_INT128)) +=3D host-utils.o util-obj-y +=3D bitmap.o bitops.o hbitmap.o --=20 MST