On 12.04.2010, at 12:35, Takuya Yoshikawa wrote:
> This patch fixes a bug found by Avi during the review process
> of my dirty bitmap related work.
>
> To ppc and ia64 people:
> The fix is really simple but touches all architectures using
> dirty bitmaps. So please check this will not suffer your part.
>
> ===
>
> 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@xxxxxxxxxxxxx>
> ---
> arch/ia64/kvm/kvm-ia64.c | 9 +++++----
> arch/powerpc/kvm/book3s.c | 5 +++--
> arch/x86/kvm/x86.c | 5 +++--
> include/linux/kvm_host.h | 5 +++++
> virt/kvm/kvm_main.c | 13 ++++++++-----
> 5 files changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
> index b0ed80c..566aff6 100644
> --- a/arch/ia64/kvm/kvm-ia64.c
> +++ b/arch/ia64/kvm/kvm-ia64.c
> @@ -1806,7 +1806,8 @@ static int kvm_ia64_sync_dirty_log(struct kvm *kvm,
> {
> struct kvm_memory_slot *memslot;
> int r, i;
> - long n, base;
> + long base;
> + unsigned long n;
> unsigned long *dirty_bitmap = (unsigned long *)(kvm->arch.vm_base +
> offsetof(struct kvm_vm_data, kvm_mem_dirty_log));
>
> @@ -1819,7 +1820,7 @@ static int kvm_ia64_sync_dirty_log(struct kvm *kvm,
> if (!memslot->dirty_bitmap)
> goto out;
>
> - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
> + n = kvm_dirty_bitmap_bytes(memslot);
> base = memslot->base_gfn / BITS_PER_LONG;
>
> for (i = 0; i < n/sizeof(long); ++i) {
> @@ -1835,7 +1836,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> struct kvm_dirty_log *log)
> {
> int r;
> - int n;
> + unsigned long n;
> struct kvm_memory_slot *memslot;
> int is_dirty = 0;
>
> @@ -1854,7 +1855,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> if (is_dirty) {
> kvm_flush_remote_tlbs(kvm);
> memslot = &kvm->memslots->memslots[log->slot];
> - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
> + n = kvm_dirty_bitmap_bytes(memslot);
> memset(memslot->dirty_bitmap, 0, n);
> }
> r = 0;
> diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
> index a7ab2ea..4ac7b15 100644
> --- a/arch/powerpc/kvm/book3s.c
> +++ b/arch/powerpc/kvm/book3s.c
> @@ -1118,7 +1118,8 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> struct kvm_vcpu *vcpu;
> ulong ga, ga_end;
> int is_dirty = 0;
> - int r, n;
> + int r;
> + unsigned long n;
>
> mutex_lock(&kvm->slots_lock);
>
> @@ -1136,7 +1137,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> kvm_for_each_vcpu(n, vcpu, kvm)
> kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
>
> - n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
> + n = kvm_dirty_bitmap_bytes(memslot);
Looks like a pretty mechanical change, so no objections from me.
Alex
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