Alex,
the current s390x qemu memory layout is
0x1000000: guest start
0x80000000: qemu binary
which limits the amount of available memory to <2GB.
This patch moves the guest pages to 32GB to not collide with the binary
and to leave some space for the program break of qemu.
Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com>
Make sure that big guests (e.g. 4 GB do not collide with the binary)
--- qemu-kvm.orig/exec.c 2011-05-04 09:25:22.411957322 +0200
+++ qemu-kvm/exec.c 2011-05-10 14:45:28.158409982 +0200
@@ -2900,10 +2900,14 @@
#endif
} else {
#if defined(TARGET_S390X) && defined(CONFIG_KVM)
- /* XXX S390 KVM requires the topmost vma of the RAM to be < 256GB
*/
- new_block->host = mmap((void*)0x1000000, size,
+ /* S390 KVM requires the topmost vma of the RAM to be smaller than
+ an system defined value, which is at least 256GB. Larger systems
+ have larger values. We put the guest between the end of data
+ segment (system break) and this value. We use 32GB as a base to
+ have enough room for the system break to grow. */
+ new_block->host = mmap((void*)0x800000000, size,
PROT_EXEC|PROT_READ|PROT_WRITE,
- MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+ MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1,
0);
#else
new_block->host = qemu_vmalloc(size);
#endif
