| Message ID | 4DC93446.3000807@de.ibm.com |
|---|---|
| State | New |
| Headers | show |
On 10.05.2011, at 14:49, Christian Borntraeger wrote: > 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 <borntraeger@de.ibm.com> Thanks, applied to the s390-next tree. Also, please dont't address me directly in the patch description, as that one's supposed to go to the public :). Alex
--- 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
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 <borntraeger@de.ibm.com> Make sure that big guests (e.g. 4 GB do not collide with the binary)