From 437fd90c0250dee670290f9b714253671a990160 Mon Sep 17 00:00:00 2001 From: José Pekkarinen Date: Wed, 18 May 2016 13:18:31 +0300 Subject: These changes are the raw update to qemu-2.6. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Collission happened in the following patches: migration: do cleanup operation after completion(738df5b9) Bug fix.(1750c932f86) kvmclock: add a new function to update env->tsc.(b52baab2) The code provided by the patches was already in the upstreamed version. Change-Id: I3cc11841a6a76ae20887b2e245710199e1ea7f9a Signed-off-by: José Pekkarinen --- qemu/util/mmap-alloc.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 qemu/util/mmap-alloc.c (limited to 'qemu/util/mmap-alloc.c') diff --git a/qemu/util/mmap-alloc.c b/qemu/util/mmap-alloc.c new file mode 100644 index 000000000..0b4cc7f7f --- /dev/null +++ b/qemu/util/mmap-alloc.c @@ -0,0 +1,110 @@ +/* + * 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 "qemu/osdep.h" +#include +#include + +#define HUGETLBFS_MAGIC 0x958458f6 + +#ifdef CONFIG_LINUX +#include +#endif + +size_t qemu_fd_getpagesize(int fd) +{ +#ifdef CONFIG_LINUX + struct statfs fs; + int ret; + + if (fd != -1) { + do { + ret = fstatfs(fd, &fs); + } while (ret != 0 && errno == EINTR); + + if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) { + return fs.f_bsize; + } + } +#endif + + return getpagesize(); +} + +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 address + * space, even if size is already aligned. + */ + size_t total = size + align; +#if defined(__powerpc64__) && defined(__linux__) + /* On ppc64 mappings in the same segment (aka slice) must share the same + * page size. Since we will be re-allocating part of this segment + * from the supplied fd, we should make sure to use the same page size, to + * this end we mmap the supplied fd. In this case, set MAP_NORESERVE to + * avoid allocating backing store memory. + * We do this unless we are using the system page size, in which case + * anonymous memory is OK. + */ + int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : fd; + int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE; + void *ptr = mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0); +#else + void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); +#endif + size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; + void *ptr1; + + if (ptr == MAP_FAILED) { + return MAP_FAILED; + } + + /* Make sure align is a power of 2 */ + assert(!(align & (align - 1))); + /* Always align to host page size */ + assert(align >= getpagesize()); + + ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, + MAP_FIXED | + (fd == -1 ? MAP_ANONYMOUS : 0) | + (shared ? MAP_SHARED : MAP_PRIVATE), + fd, 0); + if (ptr1 == MAP_FAILED) { + munmap(ptr, total); + return MAP_FAILED; + } + + ptr += offset; + total -= offset; + + if (offset > 0) { + munmap(ptr - offset, offset); + } + + /* + * Leave a single PROT_NONE page allocated after the RAM block, to serve 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()); + } +} -- cgit 1.2.3-korg