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authorDominik Dingel <dingel@linux.vnet.ibm.com>2014-12-01 19:24:42 +0300
committerChristian Borntraeger <borntraeger@de.ibm.com>2015-12-15 19:08:21 +0300
commita3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2 (patch)
tree1e8fd0810ebeb5331a8cb3ec700b023a17162aaa /arch/s390/mm
parent8335713ad08caf2c3dfcb5bc2c93d7e0276142d4 (diff)
downloadlinux-a3a92c31bf0b57ad0ca7f092a6f3a57168ba9ae2.tar.xz
KVM: s390: fix mismatch between user and in-kernel guest limit
While the userspace interface requests the maximum size the gmap code expects to get a maximum address. This error resulted in bigger page tables than necessary for some guest sizes, e.g. a 2GB guest used 3 levels instead of 2. At the same time we introduce KVM_S390_NO_MEM_LIMIT, which allows in a bright future that a guest spans the complete 64 bit address space. We also switch to TASK_MAX_SIZE for the initial memory size, this is a cosmetic change as the previous size also resulted in a 4 level pagetable creation. Reported-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/pgtable.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 54ef3bc01b43..63b039899a5e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -133,7 +133,7 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
/**
* gmap_alloc - allocate a guest address space
* @mm: pointer to the parent mm_struct
- * @limit: maximum size of the gmap address space
+ * @limit: maximum address of the gmap address space
*
* Returns a guest address space structure.
*/
@@ -402,7 +402,7 @@ int gmap_map_segment(struct gmap *gmap, unsigned long from,
if ((from | to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || from + len < from || to + len < to ||
- from + len > TASK_MAX_SIZE || to + len > gmap->asce_end)
+ from + len - 1 > TASK_MAX_SIZE || to + len - 1 > gmap->asce_end)
return -EINVAL;
flush = 0;