Eric Lee / linux-smarc-t335x-v3.2

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Commit 87bf6e7de1134f48681fd2ce4b7c1ec45458cb6d

Authored by Takuya Yoshikawa
Committed by Avi Kivity
1 parent 77662e0028

KVM: fix the handling of dirty bitmaps to avoid overflows 

Int is not long enough to store the size of a dirty bitmap.

This patch fixes this problem with the introduction of a wrapper
function to calculate the sizes of dirty bitmaps.

Note: in mark_page_dirty(), we have to consider the fact that
  __set_bit() takes the offset as int, not long.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Showing 5 changed files with 24 additions and 13 deletions Side-by-side Diff

arch/ia64/kvm/kvm-ia64.c
Diff comments   View file @ 87bf6e7
... ... @@ -1802,7 +1802,8 @@
1802 1802 {
1803 1803 struct kvm_memory_slot *memslot;
1804 1804 int r, i;
1805   - long n, base;
  1805 + long base;
  1806 + unsigned long n;
1806 1807 unsigned long *dirty_bitmap = (unsigned long *)(kvm->arch.vm_base +
1807 1808 offsetof(struct kvm_vm_data, kvm_mem_dirty_log));
1808 1809  
... ... @@ -1815,7 +1816,7 @@
1815 1816 if (!memslot->dirty_bitmap)
1816 1817 goto out;
1817 1818  
1818   - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  1819 + n = kvm_dirty_bitmap_bytes(memslot);
1819 1820 base = memslot->base_gfn / BITS_PER_LONG;
1820 1821  
1821 1822 for (i = 0; i < n/sizeof(long); ++i) {
... ... @@ -1831,7 +1832,7 @@
1831 1832 struct kvm_dirty_log *log)
1832 1833 {
1833 1834 int r;
1834   - int n;
  1835 + unsigned long n;
1835 1836 struct kvm_memory_slot *memslot;
1836 1837 int is_dirty = 0;
1837 1838  
... ... @@ -1850,7 +1851,7 @@
1850 1851 if (is_dirty) {
1851 1852 kvm_flush_remote_tlbs(kvm);
1852 1853 memslot = &kvm->memslots->memslots[log->slot];
1853   - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  1854 + n = kvm_dirty_bitmap_bytes(memslot);
1854 1855 memset(memslot->dirty_bitmap, 0, n);
1855 1856 }
1856 1857 r = 0;
arch/powerpc/kvm/book3s.c
Diff comments   View file @ 87bf6e7
... ... @@ -1004,7 +1004,8 @@
1004 1004 struct kvm_vcpu *vcpu;
1005 1005 ulong ga, ga_end;
1006 1006 int is_dirty = 0;
1007   - int r, n;
  1007 + int r;
  1008 + unsigned long n;
1008 1009  
1009 1010 mutex_lock(&kvm->slots_lock);
1010 1011  
... ... @@ -1022,7 +1023,7 @@
1022 1023 kvm_for_each_vcpu(n, vcpu, kvm)
1023 1024 kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
1024 1025  
1025   - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  1026 + n = kvm_dirty_bitmap_bytes(memslot);
1026 1027 memset(memslot->dirty_bitmap, 0, n);
1027 1028 }
1028 1029  
... ... @@ -2612,8 +2612,9 @@
2612 2612 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
2613 2613 struct kvm_dirty_log *log)
2614 2614 {
2615   - int r, n, i;
  2615 + int r, i;
2616 2616 struct kvm_memory_slot *memslot;
  2617 + unsigned long n;
2617 2618 unsigned long is_dirty = 0;
2618 2619 unsigned long *dirty_bitmap = NULL;
2619 2620  
... ... @@ -2628,7 +2629,7 @@
2628 2629 if (!memslot->dirty_bitmap)
2629 2630 goto out;
2630 2631  
2631   - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  2632 + n = kvm_dirty_bitmap_bytes(memslot);
2632 2633  
2633 2634 r = -ENOMEM;
2634 2635 dirty_bitmap = vmalloc(n);
include/linux/kvm_host.h
Diff comments   View file @ 87bf6e7
... ... @@ -119,6 +119,11 @@
119 119 int user_alloc;
120 120 };
121 121  
  122 +static inline unsigned long kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot)
  123 +{
  124 + return ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  125 +}
  126 +
122 127 struct kvm_kernel_irq_routing_entry {
123 128 u32 gsi;
124 129 u32 type;
... ... @@ -648,7 +648,7 @@
648 648  
649 649 /* Allocate page dirty bitmap if needed */
650 650 if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
651   - unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;
  651 + unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(&new);
652 652  
653 653 new.dirty_bitmap = vmalloc(dirty_bytes);
654 654 if (!new.dirty_bitmap)
... ... @@ -768,7 +768,7 @@
768 768 {
769 769 struct kvm_memory_slot *memslot;
770 770 int r, i;
771   - int n;
  771 + unsigned long n;
772 772 unsigned long any = 0;
773 773  
774 774 r = -EINVAL;
... ... @@ -780,7 +780,7 @@
780 780 if (!memslot->dirty_bitmap)
781 781 goto out;
782 782  
783   - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
  783 + n = kvm_dirty_bitmap_bytes(memslot);
784 784  
785 785 for (i = 0; !any && i < n/sizeof(long); ++i)
786 786 any = memslot->dirty_bitmap[i];
787 787  
... ... @@ -1186,10 +1186,13 @@
1186 1186 memslot = gfn_to_memslot_unaliased(kvm, gfn);
1187 1187 if (memslot && memslot->dirty_bitmap) {
1188 1188 unsigned long rel_gfn = gfn - memslot->base_gfn;
  1189 + unsigned long *p = memslot->dirty_bitmap +
  1190 + rel_gfn / BITS_PER_LONG;
  1191 + int offset = rel_gfn % BITS_PER_LONG;
1189 1192  
1190 1193 /* avoid RMW */
1191   - if (!generic_test_le_bit(rel_gfn, memslot->dirty_bitmap))
1192   - generic___set_le_bit(rel_gfn, memslot->dirty_bitmap);
  1194 + if (!generic_test_le_bit(offset, p))
  1195 + generic___set_le_bit(offset, p);
1193 1196 }
1194 1197 }
1195 1198