On 3/29/2016 3:35 PM, Paolo Bonzini wrote:
>
>
> On 28/03/2016 08:59, Michael S. Tsirkin wrote:
>>>> + qemu_mutex_lock_balloon_bitmap();
>>>> for (;;) {
>>>> size_t offset = 0;
>>>> uint32_t pfn;
>>>> elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
>>>> if (!elem) {
>>>> + qemu_mutex_unlock_balloon_bitmap();
>>>> return;
>>>> }
>>>>
>>>> @@ -242,6 +245,7 @@ static void virtio_balloon_handle_output(VirtIODevice
>>>> *vdev, VirtQueue *vq)
>>>> addr = section.offset_within_region;
>>>> balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
>>>> !!(vq == s->dvq));
>>>> + qemu_balloon_bitmap_update(addr, !!(vq == s->dvq));
>>>> memory_region_unref(section.mr);
>>>> }
>>>>
>> So the assumption here is that offset_within_region equals
>> ram ptr if region is get_system_memory.
>>
>> And I'm not sure that's always right.
>>
>> Paolo?
>
> Indeed. It is correct for the main system RAM, but hot-plugged RAM
> would also have a zero-based section.offset_within_region. You need to
> add memory_region_get_ram_addr(section.mr), just like the call to
> balloon_page adds memory_region_get_ram_ptr(section.mr).
>
> Paolo
>
Thanks, that's useful.
I am only interested in the offset from memory region base.
Would below guest PA to host offset work, as we do in
address_space_translate_internal()?
(Guest pa - section.offset_within_address_space +
section.offset_within_region)
- Jitendra
