On 11/14/2011 11:23 AM, Takuya Yoshikawa wrote:
> Needed for the next patch which uses this number to decide how to write
> protect a slot.
>
> /* If nothing is dirty, don't bother messing with page tables. */
> - if (is_dirty) {
> + if (memslot->nr_dirty_pages) {
> struct kvm_memslots *slots, *old_slots;
> unsigned long *dirty_bitmap;
>
> @@ -3504,6 +3500,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> goto out;
> memcpy(slots, kvm->memslots, sizeof(struct kvm_memslots));
> slots->memslots[log->slot].dirty_bitmap = dirty_bitmap;
> + slots->memslots[log->slot].nr_dirty_pages = 0;
> slots->generation++;
>
> #endif /* !CONFIG_S390 */
> @@ -1491,7 +1492,8 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot,
> if (memslot && memslot->dirty_bitmap) {
> unsigned long rel_gfn = gfn - memslot->base_gfn;
>
> - __set_bit_le(rel_gfn, memslot->dirty_bitmap);
> + if (!__test_and_set_bit_le(rel_gfn, memslot->dirty_bitmap))
> + memslot->nr_dirty_pages++;
> }
> }
>
The two assignments to ->nr_dirty_pages can race, no? Nothing protects it.
btw mark_page_dirty() itself seems to assume mmu_lock protection that
doesn't exist. Marcelo?
--
error compiling committee.c: too many arguments to function
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