{
void *want = g2h(ARM_COMMPAGE & -qemu_host_page_size);
void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
if (addr == MAP_FAILED) {
perror("Allocating guest commpage");
}
}
+/**
+ * pgd_find_hole_fallback: potential mmap address
+ * @guest_size: size of available space
+ * @brk: location of break
+ * @align: memory alignment
+ *
+ * This is a fallback method for finding a hole in the host address
+ * space if we don't have the benefit of being able to access
+ * /proc/self/map. It can potentially take a very long time as we can
+ * only dumbly iterate up the host address space seeing if the
+ * allocation would work.
+ */
+static uintptr_t pgd_find_hole_fallback(uintptr_t guest_size, uintptr_t brk,
+ long align, uintptr_t offset)
+{
+ uintptr_t base;
+
+ /* Start (aligned) at the bottom and work our way up */
+ base = ROUND_UP(mmap_min_addr, align);
+
+ while (true) {
+ uintptr_t align_start, end;
+ align_start = ROUND_UP(base, align);
+ end = align_start + guest_size + offset;
+
+ /* if brk is anywhere in the range give ourselves some room to grow. */
+ if (align_start <= brk && brk < end) {
+ base = brk + (16 * MiB);
+ continue;
+ } else if (align_start + guest_size < align_start) {
+ /* we have run out of space */
+ return -1;
+ } else {
+ int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE | MAP_FIXED;
+ void * mmap_start = mmap((void *) align_start, guest_size,
+ PROT_NONE, flags, -1, 0);
+ if (mmap_start != MAP_FAILED) {
+ munmap((void *) align_start, guest_size);
+ return (uintptr_t) mmap_start + offset;
+ }
+ base += qemu_host_page_size;
+ }
+ }
+}
+
/* Return value for guest_base, or -1 if no hole found. */
static uintptr_t pgb_find_hole(uintptr_t guest_loaddr, uintptr_t guest_size,
- long align)
+ long align, uintptr_t offset)
{
GSList *maps, *iter;
uintptr_t this_start, this_end, next_start, brk;
/* Read brk after we've read the maps, which will malloc. */
brk = (uintptr_t)sbrk(0);
+ if (!maps) {
+ return pgd_find_hole_fallback(guest_size, brk, align, offset);
+ }
+
/* The first hole is before the first map entry. */
this_start = mmap_min_addr;
this_end = ((MapInfo *)iter->data)->start;
next_start = ((MapInfo *)iter->data)->end;
- align_start = ROUND_UP(this_start, align);
+ align_start = ROUND_UP(this_start + offset, align);
/* Skip holes that are too small. */
if (align_start >= this_end) {
{
uintptr_t loaddr = orig_loaddr;
uintptr_t hiaddr = orig_hiaddr;
+ uintptr_t offset = 0;
uintptr_t addr;
if (hiaddr != orig_hiaddr) {
if (ARM_COMMPAGE) {
/*
* Extend the allocation to include the commpage.
- * For a 64-bit host, this is just 4GiB; for a 32-bit host,
- * the address arithmetic will wrap around, but the difference
- * will produce the correct allocation size.
+ * For a 64-bit host, this is just 4GiB; for a 32-bit host we
+ * need to ensure there is space bellow the guest_base so we
+ * can map the commpage in the place needed when the address
+ * arithmetic wraps around.
*/
if (sizeof(uintptr_t) == 8 || loaddr >= 0x80000000u) {
- hiaddr = (uintptr_t)4 << 30;
+ hiaddr = (uintptr_t) 4 << 30;
} else {
- loaddr = ARM_COMMPAGE & -align;
+ offset = -(ARM_COMMPAGE & -align);
}
}
- addr = pgb_find_hole(loaddr, hiaddr - loaddr, align);
+ addr = pgb_find_hole(loaddr, hiaddr - loaddr, align, offset);
if (addr == -1) {
/*
* If ARM_COMMPAGE, there *might* be a non-consecutive allocation
* just above that, and maximises the positive guest addresses.
*/
commpage = ARM_COMMPAGE & -align;
- addr = pgb_find_hole(commpage, -commpage, align);
+ addr = pgb_find_hole(commpage, -commpage, align, 0);
assert(addr != -1);
guest_base = addr;
}
static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr,
abi_ulong guest_hiaddr, long align)
{
- const int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
+ int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
void *addr, *test;
if (guest_hiaddr > reserved_va) {
/* Widen the "image" to the entire reserved address space. */
pgb_static(image_name, 0, reserved_va, align);
+#ifdef MAP_FIXED_NOREPLACE
+ flags |= MAP_FIXED_NOREPLACE;
+#endif
+
/* Reserve the memory on the host. */
assert(guest_base != 0);
test = g2h(0);
addr = mmap(test, reserved_va, PROT_NONE, flags, -1, 0);
if (addr == MAP_FAILED) {
error_report("Unable to reserve 0x%lx bytes of virtual address "
- "space for use as guest address space (check your "
+ "space (%s) for use as guest address space (check your "
"virtual memory ulimit setting or reserve less "
- "using -R option)", reserved_va);
+ "using -R option)", reserved_va, strerror(errno));
exit(EXIT_FAILURE);
}
assert(addr == test);
projects / mirror_qemu.git / blobdiff