On Thu, Sep 24, 2015 at 02:44:41PM +0300, Michael S. Tsirkin wrote: > 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. > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Och forgot to commit. Wil send a fixed v2. > --- > > This is on top of the patchset: > add mitigation against buffer overflows > > include/qemu/mmap-alloc.h | 10 +++++++++ > exec.c | 38 +++++--------------------------- > util/mmap-alloc.c | 56 > +++++++++++++++++++++++++++++++++++++++++++++++ > util/oslib-posix.c | 28 ++++-------------------- > util/Makefile.objs | 2 +- > 5 files changed, 77 insertions(+), 57 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..3400e14 > --- /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); > + > +void qemu_ram_munmap(void *ptr, size_t size); > + > +#endif > diff --git a/exec.c b/exec.c > index 7d90a52..dd8d40a 100644 > --- a/exec.c > +++ b/exec.c > @@ -84,9 +84,9 @@ static MemoryRegion io_mem_unassigned; > */ > #define RAM_RESIZEABLE (1 << 2) > > -/* 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 > > struct CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus); > @@ -1250,40 +1250,14 @@ static void *file_ram_alloc(RAMBlock *block, > perror("ftruncate"); > } > > - ptr = mmap(0, total, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, > - -1, 0); > - if (ptr == MAP_FAILED) { > - error_setg_errno(errp, errno, > - "unable to allocate memory range for hugepages"); > - close(fd); > - goto error; > - } > - > - offset = QEMU_ALIGN_UP((uintptr_t)ptr, hpagesize) - (uintptr_t)ptr; > - > - area = mmap(ptr + offset, memory, PROT_READ | PROT_WRITE, > - (block->flags & RAM_SHARED ? MAP_SHARED : MAP_PRIVATE) | > - MAP_FIXED, > - fd, 0); > + area = qemu_ram_mmap(fd, memory, hpagesize); > if (area == MAP_FAILED) { > error_setg_errno(errp, errno, > "unable to map backing store for hugepages"); > - munmap(ptr, total); > close(fd); > goto error; > } > > - if (offset > 0) { > - munmap(ptr, offset); > - } > - ptr += offset; > - total -= offset; > - > - if (total > memory + getpagesize()) { > - munmap(ptr + memory + getpagesize(), > - total - memory - getpagesize()); > - } > - > if (mem_prealloc) { > os_mem_prealloc(fd, area, memory); > } > @@ -1601,7 +1575,7 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, > MemoryRegion *mr, > new_block->used_length = size; > new_block->max_length = size; > new_block->flags = share ? RAM_SHARED : 0; > - new_block->flags |= RAM_EXTRA; > + new_block->flags |= RAM_FILE; > new_block->host = file_ram_alloc(new_block, size, > mem_path, errp); > if (!new_block->host) { > @@ -1703,8 +1677,8 @@ static void reclaim_ramblock(RAMBlock *block) > xen_invalidate_map_cache_entry(block->host); > #ifndef _WIN32 > } else if (block->fd >= 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..6ea1f33 > --- /dev/null > +++ b/util/mmap-alloc.c > @@ -0,0 +1,56 @@ > +/* > + * Support for RAM backed by mmaped host memory. > + * > + * Copyright (c) 2015 Red Hat, Inc. > + * > + * Authors: > + * Michael S. Tsirkin <m...@redhat.com> > + * > + * 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 <qemu/mmap-alloc.h> > +#include <sys/types.h> > +#include <sys/mman.h> > + > +void *qemu_ram_mmap(int fd, size_t size, size_t align) > +{ > + size_t total = size + align; > + void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, > 0); > + size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; > + void *ptr1; > + > + if (ptr == MAP_FAILED) { > + return NULL; > + } > + > + if (alignment) { > + *alignment = align; > + } > + > + ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, > + MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, fd, 0); > + if (ptr1 == MAP_FAILED) { > + munmap(ptr, total); > + return NULL; > + } > + > + ptr += offset; > + total -= offset; > + > + if (offset > 0) { > + munmap(ptr - offset, offset); > + } > + if (total > size + getpagesize()) { > + munmap(ptr + size + getpagesize(), total - size - getpagesize()); > + } > + > + return ptr; > +} > + > +void qemu_ram_munmap(void *ptr) > +{ > + if (ptr) { > + munmap(ptr, size + getpagesize()); > + } > +} > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index a0fcdc2..72a6bc1 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -72,6 +72,8 @@ extern int daemon(int, int); > #include <sys/sysctl.h> > #endif > > +#include <qemu/mmap-alloc.h> > + > 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 = QEMU_VMALLOC_ALIGN; > - size_t total = size + align; > - void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, > 0); > - size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; > - void *ptr1; > + void *ptr = qemu_ram_mmap(-1, size, align); > > if (ptr == MAP_FAILED) { > return NULL; > @@ -141,23 +140,6 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t > *alignment) > *alignment = align; > } > > - ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, > - MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); > - if (ptr1 == MAP_FAILED) { > - munmap(ptr, total); > - return NULL; > - } > - > - ptr += offset; > - total -= 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); > } > > void qemu_set_block(int fd) > diff --git a/util/Makefile.objs b/util/Makefile.objs > index 114d657..372e037 100644 > --- a/util/Makefile.objs > +++ b/util/Makefile.objs > @@ -1,6 +1,6 @@ > util-obj-y = osdep.o cutils.o unicode.o qemu-timer-common.o > util-obj-$(CONFIG_WIN32) += oslib-win32.o qemu-thread-win32.o > event_notifier-win32.o > -util-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o > event_notifier-posix.o qemu-openpty.o > +util-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o > event_notifier-posix.o qemu-openpty.o mmap-alloc.o > util-obj-y += envlist.o path.o module.o > util-obj-$(call lnot,$(CONFIG_INT128)) += host-utils.o > util-obj-y += bitmap.o bitops.o hbitmap.o > -- > MST