diff options
| author | Damjan Marion <damarion@cisco.com> | 2014-06-26 23:01:32 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2014-06-29 19:39:40 +0300 |
| commit | 3fd74b84076488ae44ba5f3cfed22ff056c5199c (patch) | |
| tree | 5780453adca5f1b8f6ad52b572d06330c323f873 /docs/specs | |
| parent | 12d6e4640ce28d002e96d58c31cd5e7256258626 (diff) | |
vhost-user: fix regions provied with VHOST_USER_SET_MEM_TABLE message
Old code was affected by memory gaps which resulted in buffer pointers
pointing to address outside of the mapped regions.
Here we are introducing following changes:
- new function qemu_get_ram_block_host_ptr() returns host pointer
to the ram block, it is needed to calculate offset of specific
region in the host memory
- new field mmap_offset is added to the VhostUserMemoryRegion. It
contains offset where specific region starts in the mapped memory.
As there is stil no wider adoption of vhost-user agreement was made
that we will not bump version number due to this change
- other fileds in VhostUserMemoryRegion struct are not changed, as
they are all needed for usermode app implementation
- region data is not taken from ram_list.blocks anymore, instead we
use region data which is alredy calculated for use in vhost-net
- Now multiple regions can have same FD and user applicaton can call
mmap() multiple times with the same FD but with different offset
(user needs to take care for offset page alignment)
Signed-off-by: Damjan Marion <damarion@cisco.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Damjan Marion <damarion@cisco.com>
Diffstat (limited to 'docs/specs')
| -rw-r--r-- | docs/specs/vhost-user.txt | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index 2641390244..6abb6977ff 100644 --- a/docs/specs/vhost-user.txt +++ b/docs/specs/vhost-user.txt @@ -78,13 +78,14 @@ Depending on the request type, payload can be: Padding: 32-bit A region is: - --------------------------------------- - | guest address | size | user address | - --------------------------------------- + ----------------------------------------------------- + | guest address | size | user address | mmap offset | + ----------------------------------------------------- Guest address: a 64-bit guest address of the region Size: a 64-bit size User address: a 64-bit user address + mmmap offset: 64-bit offset where region starts in the mapped memory In QEMU the vhost-user message is implemented with the following struct: |