diff options
| author | Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> | 2010-04-13 22:47:24 +0900 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-05-17 12:17:41 +0300 |
| commit | 660c22c425cbe14badfb3b0a0206862577701ab7 (patch) | |
| tree | 272889023481c810eebe54ab5343e634f0cd50bc | |
| parent | 020df0794f5764e742feaa718be88b8f1b4ce04f (diff) | |
KVM: limit the number of pages per memory slot
This patch limits the number of pages per memory slot to make
us free from extra care about type issues.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| -rw-r--r-- | include/linux/kvm_host.h | 6 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 11 |
2 files changed, 12 insertions, 5 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 169d07758ee5..55830638aeb1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -105,6 +105,12 @@ struct kvm_vcpu { struct kvm_vcpu_arch arch; }; +/* + * Some of the bitops functions do not support too long bitmaps. + * This number must be determined not to exceed such limits. + */ +#define KVM_MEM_MAX_NR_PAGES ((1UL << 31) - 1) + struct kvm_memory_slot { gfn_t base_gfn; unsigned long npages; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 55a5d4804499..d6351a34b297 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -557,6 +557,10 @@ int __kvm_set_memory_region(struct kvm *kvm, base_gfn = mem->guest_phys_addr >> PAGE_SHIFT; npages = mem->memory_size >> PAGE_SHIFT; + r = -EINVAL; + if (npages > KVM_MEM_MAX_NR_PAGES) + goto out; + if (!npages) mem->flags &= ~KVM_MEM_LOG_DIRTY_PAGES; @@ -1187,13 +1191,10 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn) memslot = gfn_to_memslot_unaliased(kvm, gfn); if (memslot && memslot->dirty_bitmap) { unsigned long rel_gfn = gfn - memslot->base_gfn; - unsigned long *p = memslot->dirty_bitmap + - rel_gfn / BITS_PER_LONG; - int offset = rel_gfn % BITS_PER_LONG; /* avoid RMW */ - if (!generic_test_le_bit(offset, p)) - generic___set_le_bit(offset, p); + if (!generic_test_le_bit(rel_gfn, memslot->dirty_bitmap)) + generic___set_le_bit(rel_gfn, memslot->dirty_bitmap); } } |