--- /dev/null
+/*
+ * mmap support for qemu
+ *
+ * Copyright (c) 2003 - 2008 Fabrice Bellard
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "qemu.h"
+#include "qemu-common.h"
+#include "bsd-mman.h"
+
+//#define DEBUG_MMAP
+
+#if defined(CONFIG_USE_NPTL)
+pthread_mutex_t mmap_mutex;
+static int __thread mmap_lock_count;
+
+void mmap_lock(void)
+{
+ if (mmap_lock_count++ == 0) {
+ pthread_mutex_lock(&mmap_mutex);
+ }
+}
+
+void mmap_unlock(void)
+{
+ if (--mmap_lock_count == 0) {
+ pthread_mutex_unlock(&mmap_mutex);
+ }
+}
+
+/* Grab lock to make sure things are in a consistent state after fork(). */
+void mmap_fork_start(void)
+{
+ if (mmap_lock_count)
+ abort();
+ pthread_mutex_lock(&mmap_mutex);
+}
+
+void mmap_fork_end(int child)
+{
+ if (child)
+ pthread_mutex_init(&mmap_mutex, NULL);
+ else
+ pthread_mutex_unlock(&mmap_mutex);
+}
+#else
+/* We aren't threadsafe to start with, so no need to worry about locking. */
+void mmap_lock(void)
+{
+}
+
+void mmap_unlock(void)
+{
+}
+#endif
+
+/* NOTE: all the constants are the HOST ones, but addresses are target. */
+int target_mprotect(abi_ulong start, abi_ulong len, int prot)
+{
+ abi_ulong end, host_start, host_end, addr;
+ int prot1, ret;
+
+#ifdef DEBUG_MMAP
+ printf("mprotect: start=0x" TARGET_FMT_lx
+ " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len,
+ prot & PROT_READ ? 'r' : '-',
+ prot & PROT_WRITE ? 'w' : '-',
+ prot & PROT_EXEC ? 'x' : '-');
+#endif
+
+ if ((start & ~TARGET_PAGE_MASK) != 0)
+ return -EINVAL;
+ len = TARGET_PAGE_ALIGN(len);
+ end = start + len;
+ if (end < start)
+ return -EINVAL;
+ prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
+ if (len == 0)
+ return 0;
+
+ mmap_lock();
+ host_start = start & qemu_host_page_mask;
+ host_end = HOST_PAGE_ALIGN(end);
+ if (start > host_start) {
+ /* handle host page containing start */
+ prot1 = prot;
+ for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
+ prot1 |= page_get_flags(addr);
+ }
+ if (host_end == host_start + qemu_host_page_size) {
+ for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+ prot1 |= page_get_flags(addr);
+ }
+ end = host_end;
+ }
+ ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
+ if (ret != 0)
+ goto error;
+ host_start += qemu_host_page_size;
+ }
+ if (end < host_end) {
+ prot1 = prot;
+ for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+ prot1 |= page_get_flags(addr);
+ }
+ ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
+ prot1 & PAGE_BITS);
+ if (ret != 0)
+ goto error;
+ host_end -= qemu_host_page_size;
+ }
+
+ /* handle the pages in the middle */
+ if (host_start < host_end) {
+ ret = mprotect(g2h(host_start), host_end - host_start, prot);
+ if (ret != 0)
+ goto error;
+ }
+ page_set_flags(start, start + len, prot | PAGE_VALID);
+ mmap_unlock();
+ return 0;
+error:
+ mmap_unlock();
+ return ret;
+}
+
+/* map an incomplete host page */
+static int mmap_frag(abi_ulong real_start,
+ abi_ulong start, abi_ulong end,
+ int prot, int flags, int fd, abi_ulong offset)
+{
+ abi_ulong real_end, addr;
+ void *host_start;
+ int prot1, prot_new;
+
+ real_end = real_start + qemu_host_page_size;
+ host_start = g2h(real_start);
+
+ /* get the protection of the target pages outside the mapping */
+ prot1 = 0;
+ for(addr = real_start; addr < real_end; addr++) {
+ if (addr < start || addr >= end)
+ prot1 |= page_get_flags(addr);
+ }
+
+ if (prot1 == 0) {
+ /* no page was there, so we allocate one */
+ void *p = mmap(host_start, qemu_host_page_size, prot,
+ flags | MAP_ANON, -1, 0);
+ if (p == MAP_FAILED)
+ return -1;
+ prot1 = prot;
+ }
+ prot1 &= PAGE_BITS;
+
+ prot_new = prot | prot1;
+ if (!(flags & MAP_ANON)) {
+ /* msync() won't work here, so we return an error if write is
+ possible while it is a shared mapping */
+ if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
+ (prot & PROT_WRITE))
+ return -1;
+
+ /* adjust protection to be able to read */
+ if (!(prot1 & PROT_WRITE))
+ mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
+
+ /* read the corresponding file data */
+ pread(fd, g2h(start), end - start, offset);
+
+ /* put final protection */
+ if (prot_new != (prot1 | PROT_WRITE))
+ mprotect(host_start, qemu_host_page_size, prot_new);
+ } else {
+ /* just update the protection */
+ if (prot_new != prot1) {
+ mprotect(host_start, qemu_host_page_size, prot_new);
+ }
+ }
+ return 0;
+}
+
+#if defined(__CYGWIN__)
+/* Cygwin doesn't have a whole lot of address space. */
+static abi_ulong mmap_next_start = 0x18000000;
+#else
+static abi_ulong mmap_next_start = 0x40000000;
+#endif
+
+unsigned long last_brk;
+
+/* find a free memory area of size 'size'. The search starts at
+ 'start'. If 'start' == 0, then a default start address is used.
+ Return -1 if error.
+*/
+/* page_init() marks pages used by the host as reserved to be sure not
+ to use them. */
+static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
+{
+ abi_ulong addr, addr1, addr_start;
+ int prot;
+ unsigned long new_brk;
+
+ new_brk = (unsigned long)sbrk(0);
+ if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
+ /* This is a hack to catch the host allocating memory with brk().
+ If it uses mmap then we loose.
+ FIXME: We really want to avoid the host allocating memory in
+ the first place, and maybe leave some slack to avoid switching
+ to mmap. */
+ page_set_flags(last_brk & TARGET_PAGE_MASK,
+ TARGET_PAGE_ALIGN(new_brk),
+ PAGE_RESERVED);
+ }
+ last_brk = new_brk;
+
+ size = HOST_PAGE_ALIGN(size);
+ start = start & qemu_host_page_mask;
+ addr = start;
+ if (addr == 0)
+ addr = mmap_next_start;
+ addr_start = addr;
+ for(;;) {
+ prot = 0;
+ for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr1);
+ }
+ if (prot == 0)
+ break;
+ addr += qemu_host_page_size;
+ /* we found nothing */
+ if (addr == addr_start)
+ return (abi_ulong)-1;
+ }
+ if (start == 0)
+ mmap_next_start = addr + size;
+ return addr;
+}
+
+/* NOTE: all the constants are the HOST ones */
+abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
+ int flags, int fd, abi_ulong offset)
+{
+ abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
+ unsigned long host_start;
+
+ mmap_lock();
+#ifdef DEBUG_MMAP
+ {
+ printf("mmap: start=0x" TARGET_FMT_lx
+ " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=",
+ start, len,
+ prot & PROT_READ ? 'r' : '-',
+ prot & PROT_WRITE ? 'w' : '-',
+ prot & PROT_EXEC ? 'x' : '-');
+ if (flags & MAP_FIXED)
+ printf("MAP_FIXED ");
+ if (flags & MAP_ANON)
+ printf("MAP_ANON ");
+ switch(flags & TARGET_BSD_MAP_FLAGMASK) {
+ case MAP_PRIVATE:
+ printf("MAP_PRIVATE ");
+ break;
+ case MAP_SHARED:
+ printf("MAP_SHARED ");
+ break;
+ default:
+ printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK);
+ break;
+ }
+ printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset);
+ }
+#endif
+
+ if (offset & ~TARGET_PAGE_MASK) {
+ errno = EINVAL;
+ goto fail;
+ }
+
+ len = TARGET_PAGE_ALIGN(len);
+ if (len == 0)
+ goto the_end;
+ real_start = start & qemu_host_page_mask;
+
+ if (!(flags & MAP_FIXED)) {
+ abi_ulong mmap_start;
+ void *p;
+ host_offset = offset & qemu_host_page_mask;
+ host_len = len + offset - host_offset;
+ host_len = HOST_PAGE_ALIGN(host_len);
+ mmap_start = mmap_find_vma(real_start, host_len);
+ if (mmap_start == (abi_ulong)-1) {
+ errno = ENOMEM;
+ goto fail;
+ }
+ /* Note: we prefer to control the mapping address. It is
+ especially important if qemu_host_page_size >
+ qemu_real_host_page_size */
+ p = mmap(g2h(mmap_start),
+ host_len, prot, flags | MAP_FIXED, fd, host_offset);
+ if (p == MAP_FAILED)
+ goto fail;
+ /* update start so that it points to the file position at 'offset' */
+ host_start = (unsigned long)p;
+ if (!(flags & MAP_ANON))
+ host_start += offset - host_offset;
+ start = h2g(host_start);
+ } else {
+ int flg;
+ target_ulong addr;
+
+ if (start & ~TARGET_PAGE_MASK) {
+ errno = EINVAL;
+ goto fail;
+ }
+ end = start + len;
+ real_end = HOST_PAGE_ALIGN(end);
+
+ for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
+ flg = page_get_flags(addr);
+ if (flg & PAGE_RESERVED) {
+ errno = ENXIO;
+ goto fail;
+ }
+ }
+
+ /* worst case: we cannot map the file because the offset is not
+ aligned, so we read it */
+ if (!(flags & MAP_ANON) &&
+ (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
+ /* msync() won't work here, so we return an error if write is
+ possible while it is a shared mapping */
+ if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
+ (prot & PROT_WRITE)) {
+ errno = EINVAL;
+ goto fail;
+ }
+ retaddr = target_mmap(start, len, prot | PROT_WRITE,
+ MAP_FIXED | MAP_PRIVATE | MAP_ANON,
+ -1, 0);
+ if (retaddr == -1)
+ goto fail;
+ pread(fd, g2h(start), len, offset);
+ if (!(prot & PROT_WRITE)) {
+ ret = target_mprotect(start, len, prot);
+ if (ret != 0) {
+ start = ret;
+ goto the_end;
+ }
+ }
+ goto the_end;
+ }
+
+ /* handle the start of the mapping */
+ if (start > real_start) {
+ if (real_end == real_start + qemu_host_page_size) {
+ /* one single host page */
+ ret = mmap_frag(real_start, start, end,
+ prot, flags, fd, offset);
+ if (ret == -1)
+ goto fail;
+ goto the_end1;
+ }
+ ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
+ prot, flags, fd, offset);
+ if (ret == -1)
+ goto fail;
+ real_start += qemu_host_page_size;
+ }
+ /* handle the end of the mapping */
+ if (end < real_end) {
+ ret = mmap_frag(real_end - qemu_host_page_size,
+ real_end - qemu_host_page_size, real_end,
+ prot, flags, fd,
+ offset + real_end - qemu_host_page_size - start);
+ if (ret == -1)
+ goto fail;
+ real_end -= qemu_host_page_size;
+ }
+
+ /* map the middle (easier) */
+ if (real_start < real_end) {
+ void *p;
+ unsigned long offset1;
+ if (flags & MAP_ANON)
+ offset1 = 0;
+ else
+ offset1 = offset + real_start - start;
+ p = mmap(g2h(real_start), real_end - real_start,
+ prot, flags, fd, offset1);
+ if (p == MAP_FAILED)
+ goto fail;
+ }
+ }
+ the_end1:
+ page_set_flags(start, start + len, prot | PAGE_VALID);
+ the_end:
+#ifdef DEBUG_MMAP
+ printf("ret=0x" TARGET_FMT_lx "\n", start);
+ page_dump(stdout);
+ printf("\n");
+#endif
+ mmap_unlock();
+ return start;
+fail:
+ mmap_unlock();
+ return -1;
+}
+
+int target_munmap(abi_ulong start, abi_ulong len)
+{
+ abi_ulong end, real_start, real_end, addr;
+ int prot, ret;
+
+#ifdef DEBUG_MMAP
+ printf("munmap: start=0x%lx len=0x%lx\n", start, len);
+#endif
+ if (start & ~TARGET_PAGE_MASK)
+ return -EINVAL;
+ len = TARGET_PAGE_ALIGN(len);
+ if (len == 0)
+ return -EINVAL;
+ mmap_lock();
+ end = start + len;
+ real_start = start & qemu_host_page_mask;
+ real_end = HOST_PAGE_ALIGN(end);
+
+ if (start > real_start) {
+ /* handle host page containing start */
+ prot = 0;
+ for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ if (real_end == real_start + qemu_host_page_size) {
+ for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ end = real_end;
+ }
+ if (prot != 0)
+ real_start += qemu_host_page_size;
+ }
+ if (end < real_end) {
+ prot = 0;
+ for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ if (prot != 0)
+ real_end -= qemu_host_page_size;
+ }
+
+ ret = 0;
+ /* unmap what we can */
+ if (real_start < real_end) {
+ ret = munmap(g2h(real_start), real_end - real_start);
+ }
+
+ if (ret == 0)
+ page_set_flags(start, start + len, 0);
+ mmap_unlock();
+ return ret;
+}
+
+int target_msync(abi_ulong start, abi_ulong len, int flags)
+{
+ abi_ulong end;
+
+ if (start & ~TARGET_PAGE_MASK)
+ return -EINVAL;
+ len = TARGET_PAGE_ALIGN(len);
+ end = start + len;
+ if (end < start)
+ return -EINVAL;
+ if (end == start)
+ return 0;
+
+ start &= qemu_host_page_mask;
+ return msync(g2h(start), end - start, flags);
+}
Code Review / kvmfornfv.git / blobdiff