diff options
| author | Avi Kivity <avi@redhat.com> | 2009-04-24 16:05:14 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-05-08 15:44:59 -0700 |
| commit | 9de29923f93cc3d56c76130f729ddaa5c48ea4b7 (patch) | |
| tree | 1ad70997474dc240ed4b400776994e01ba6b329d | |
| parent | 64e1b00c974ddeae6a60ebb02e1c487371905cea (diff) | |
KVM: MMU: Fix off-by-one calculating large page count
upstream commit: 99894a799f09cf9e28296bb16e75bd5830fd2c4e
The large page initialization code concludes there are two large pages spanned
by a slot covering 1 (small) page starting at gfn 1. This is incorrect, and
also results in incorrect write_count initialization in some cases (base = 1,
npages = 513 for example).
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
| -rw-r--r-- | virt/kvm/kvm_main.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6723411ead55..e02c48ba2224 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -964,6 +964,7 @@ int __kvm_set_memory_region(struct kvm *kvm, int r; gfn_t base_gfn; unsigned long npages; + int largepages; unsigned long i; struct kvm_memory_slot *memslot; struct kvm_memory_slot old, new; @@ -1039,11 +1040,8 @@ int __kvm_set_memory_region(struct kvm *kvm, new.userspace_addr = 0; } if (npages && !new.lpage_info) { - int largepages = npages / KVM_PAGES_PER_HPAGE; - if (npages % KVM_PAGES_PER_HPAGE) - largepages++; - if (base_gfn % KVM_PAGES_PER_HPAGE) - largepages++; + largepages = 1 + (base_gfn + npages - 1) / KVM_PAGES_PER_HPAGE; + largepages -= base_gfn / KVM_PAGES_PER_HPAGE; new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info)); |