Re: [Qemu-devel] physical memory address in guest (from his point of view)

[Catalin Vasile]

On Fri, Apr 24, 2015 at 12:05 PM, Paolo Bonzini <address@hidden> wrote:
>
>
> On 24/04/2015 10:46, Catalin Vasile wrote:
>> Does a physical memory address in a guest points to the same memory as qemu?
>> For example: if I have a physical pointer 0x34 in the guest, does it
>> point to the same location that qemu points with 0x34 address?
>
> No.  QEMU converts guest pointers (which are just uint64_t) to host
> pointers using address_space_map/address_space_unmap.
>
> Paolo
That being said. Does a message that passes from guest to a backend
need to pass through qemu everytime?
I'm trying to understand how virtio virtqueues work. Namely I'm trying
to pass as data itself a pointer in which the backend will write,
namely use copy_to_user() if the backend is a kernel module.