Re: [Qemu-devel] vhost-user: broken mem regions

[Nikolay Nikolaev]

On Wed, Jun 25, 2014 at 7:44 PM, Paolo Bonzini <address@hidden> wrote:
>> nregions: 4
>> region:
>>       gpa = 0x100000000
>>       size = 3221225472
>>       ua = 0x2aab6ac00000
>
> High memory, above 3 gigabytes.
>
>> region:
>>       gpa = 0xFFFC0000
>>       size = 262144
>>       ua = 0x7fc13d200000
>
> This is the BIOS.  There shouldn't be any FD for this one, it
> is not allocated in hugetlbfs.
>
>> region:
>>       gpa = 0x0
>>       size = 655360
>>       ua = 0x2aaaaac00000
>> region:
>>       gpa = 0xC0000
>>       size = 3220439040
>>       ua = 0x2aaaaacc0000
>
> Together, it's the first 3 GB of memory.
>
> I understand now what you mean.  Yeah, the format should be changed
> to include the offset (why does vhost-user need the ua at all?
The vring addresses are QEMU UA addresses. Of course vhost-user can
translate them to guest physical before sending the message.
> perhaps the offset can replace the ua).
>
>> BTW Any idea what to do with region 2, it doesn’t look like the one belonging
>> to the same place, but qemu_get_ram_fd() returns same FD for it.
>
> This must be a bug.  I would have expected qemu_get_ram_fd to return -1
> here, so no descriptor should be passed to vhost-user.
>
> Paolo