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-rw-r--r--linux-user/elfload.c59
-rw-r--r--linux-user/main.c35
-rw-r--r--linux-user/qemu.h6
3 files changed, 56 insertions, 44 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index cbc7617..819fdd5 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -332,9 +332,17 @@ enum
ARM_HWCAP_ARM_VFPv3D16 = 1 << 13,
};
-#define TARGET_HAS_GUEST_VALIDATE_BASE
-/* We want the opportunity to check the suggested base */
-bool guest_validate_base(unsigned long guest_base)
+#define TARGET_HAS_VALIDATE_GUEST_SPACE
+/* Return 1 if the proposed guest space is suitable for the guest.
+ * Return 0 if the proposed guest space isn't suitable, but another
+ * address space should be tried.
+ * Return -1 if there is no way the proposed guest space can be
+ * valid regardless of the base.
+ * The guest code may leave a page mapped and populate it if the
+ * address is suitable.
+ */
+static int validate_guest_space(unsigned long guest_base,
+ unsigned long guest_size)
{
unsigned long real_start, test_page_addr;
@@ -342,6 +350,15 @@ bool guest_validate_base(unsigned long guest_base)
* commpage at 0xffff0fxx
*/
test_page_addr = guest_base + (0xffff0f00 & qemu_host_page_mask);
+
+ /* If the commpage lies within the already allocated guest space,
+ * then there is no way we can allocate it.
+ */
+ if (test_page_addr >= guest_base
+ && test_page_addr <= (guest_base + guest_size)) {
+ return -1;
+ }
+
/* Note it needs to be writeable to let us initialise it */
real_start = (unsigned long)
mmap((void *)test_page_addr, qemu_host_page_size,
@@ -1418,9 +1435,10 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
return sp;
}
-#ifndef TARGET_HAS_GUEST_VALIDATE_BASE
+#ifndef TARGET_HAS_VALIDATE_GUEST_SPACE
/* If the guest doesn't have a validation function just agree */
-bool guest_validate_base(unsigned long guest_base)
+static int validate_guest_space(unsigned long guest_base,
+ unsigned long guest_size)
{
return 1;
}
@@ -1439,7 +1457,7 @@ unsigned long init_guest_space(unsigned long host_start,
/* If just a starting address is given, then just verify that
* address. */
if (host_start && !host_size) {
- if (guest_validate_base(host_start)) {
+ if (validate_guest_space(host_start, host_size) == 1) {
return host_start;
} else {
return (unsigned long)-1;
@@ -1456,6 +1474,8 @@ unsigned long init_guest_space(unsigned long host_start,
/* Otherwise, a non-zero size region of memory needs to be mapped
* and validated. */
while (1) {
+ unsigned long real_size = host_size;
+
/* Do not use mmap_find_vma here because that is limited to the
* guest address space. We are going to make the
* guest address space fit whatever we're given.
@@ -1466,9 +1486,28 @@ unsigned long init_guest_space(unsigned long host_start,
return (unsigned long)-1;
}
- if ((real_start == current_start)
- && guest_validate_base(real_start - guest_start)) {
- break;
+ /* Ensure the address is properly aligned. */
+ if (real_start & ~qemu_host_page_mask) {
+ munmap((void *)real_start, host_size);
+ real_size = host_size + qemu_host_page_size;
+ real_start = (unsigned long)
+ mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0);
+ if (real_start == (unsigned long)-1) {
+ return (unsigned long)-1;
+ }
+ real_start = HOST_PAGE_ALIGN(real_start);
+ }
+
+ /* Check to see if the address is valid. */
+ if (!host_start || real_start == current_start) {
+ int valid = validate_guest_space(real_start - guest_start,
+ real_size);
+ if (valid == 1) {
+ break;
+ } else if (valid == -1) {
+ return (unsigned long)-1;
+ }
+ /* valid == 0, so try again. */
}
/* That address didn't work. Unmap and try a different one.
@@ -1490,6 +1529,8 @@ unsigned long init_guest_space(unsigned long host_start,
}
}
+ qemu_log("Reserved 0x%lx bytes of guest address space\n", host_size);
+
return real_start;
}
diff --git a/linux-user/main.c b/linux-user/main.c
index 9d921aa..63c1249 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3516,39 +3516,16 @@ int main(int argc, char **argv, char **envp)
*/
guest_base = HOST_PAGE_ALIGN(guest_base);
- if (reserved_va) {
- void *p;
- int flags;
-
- flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
- if (have_guest_base) {
- flags |= MAP_FIXED;
- }
- p = mmap((void *)guest_base, reserved_va, PROT_NONE, flags, -1, 0);
- if (p == MAP_FAILED) {
+ if (reserved_va || have_guest_base) {
+ guest_base = init_guest_space(guest_base, reserved_va, 0,
+ have_guest_base);
+ if (guest_base == (unsigned long)-1) {
fprintf(stderr, "Unable to reserve guest address space\n");
exit(1);
}
- guest_base = (unsigned long)p;
- /* Make sure the address is properly aligned. */
- if (guest_base & ~qemu_host_page_mask) {
- munmap(p, reserved_va);
- p = mmap((void *)guest_base, reserved_va + qemu_host_page_size,
- PROT_NONE, flags, -1, 0);
- if (p == MAP_FAILED) {
- fprintf(stderr, "Unable to reserve guest address space\n");
- exit(1);
- }
- guest_base = HOST_PAGE_ALIGN((unsigned long)p);
- }
- qemu_log("Reserved 0x%lx bytes of guest address space\n", reserved_va);
- mmap_next_start = reserved_va;
- }
- if (reserved_va || have_guest_base) {
- if (!guest_validate_base(guest_base)) {
- fprintf(stderr, "Guest base/Reserved VA rejected by guest code\n");
- exit(1);
+ if (reserved_va) {
+ mmap_next_start = reserved_va;
}
}
#endif /* CONFIG_USE_GUEST_BASE */
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 7d4e23e..69b27d7 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -204,12 +204,6 @@ int get_osversion(void);
void fork_start(void);
void fork_end(int child);
-/* Return true if the proposed guest_base is suitable for the guest.
- * The guest code may leave a page mapped and populate it if the
- * address is suitable.
- */
-bool guest_validate_base(unsigned long guest_base);
-
/* Creates the initial guest address space in the host memory space using
* the given host start address hint and size. The guest_start parameter
* specifies the start address of the guest space. guest_base will be the