Found with clang static analysis:
lib/librte_vhost/vhost_user.c:996:3: warning:
Value stored to 'ret' is never read
ret = vhost_user_get_vring_base(dev, &msg.payload.state);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Setting up the mapping from GPA (guest physical address) to HPA (guest
physical address) could be very time consuming when the guest memory is
backened with small pages (4K). The bigger the guest memory, the longer
it takes. This could lead a very long vhost-user negotiation.
Since the mapping is only needed in zero copy mode so far, we could
avoid such time consuming settup when zero copy is turned off (which is
the default case).
It's actually a workaround, a right fix might be to start a new thread,
and hide the big latency there.
Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
Cc: stable@dpdk.org
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
REPLY_ACK features provide a generic way for QEMU to ensure both
completion and success of a request.
As described in vhost-user spec in QEMU repository, QEMU sets
VHOST_USER_NEED_REPLY flag (bit 3) when expecting a reply_ack from
the backend. Backend must reply with 0 for success or non-zero
otherwise when flag is set.
Currently, only VHOST_USER_SET_MEM_TABLE request implements reply_ack,
in order to synchronize mapping updates.
This patch enables REPLY_ACK feature generally, but only checks error
code for VHOST_USER_SET_MEM_TABLE.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
When reg_size < page_size the function read in
rte_mem_virt2phy would not return, because
host_user_addr is invalid.
Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
Cc: stable@dpdk.org
Signed-off-by: Haifeng Lin <haifeng.lin@huawei.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
The basic idea is to shadow the used ring update: update them into a
local buffer first, and then flush them all to the virtio used vring
at once in the end.
And since we do avail ring reservation before enqueuing data, we would
know which and how many descs will be used. Which means we could update
the shadow used ring at the reservation time. It also introduce another
slight advantage: we don't need access the desc->flag any more inside
copy_mbuf_to_desc_mergeable().
Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Jianbo Liu <jianbo.liu@linaro.org>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
The basic idea of dequeue zero copy is, instead of copying data from
the desc buf, here we let the mbuf reference the desc buf addr directly.
Doing so, however, has one major issue: we can't update the used ring
at the end of rte_vhost_dequeue_burst. Because we don't do the copy
here, an update of the used ring would let the driver to reclaim the
desc buf. As a result, DPDK might reference a stale memory region.
To update the used ring properly, this patch does several tricks:
- when mbuf references a desc buf, refcnt is added by 1.
This is to pin lock the mbuf, so that a mbuf free from the DPDK
won't actually free it, instead, refcnt is subtracted by 1.
- We chain all those mbuf together (by tailq)
And we check it every time on the rte_vhost_dequeue_burst entrance,
to see if the mbuf is freed (when refcnt equals to 1). If that
happens, it means we are the last user of this mbuf and we are
safe to update the used ring.
- "struct zcopy_mbuf" is introduced, to associate an mbuf with the
right desc idx.
Dequeue zero copy is introduced for performance reason, and some rough
tests show about 50% perfomance boost for packet size 1500B. For small
packets, (e.g. 64B), it actually slows a bit down (well, it could up to
15%). That is expected because this patch introduces some extra works,
and it outweighs the benefit from saving few bytes copy.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Qian Xu <qian.q.xu@intel.com>
So far, we retrieve both the used ring and avail ring idx by the var
last_used_idx; it won't be a problem because the used ring is updated
immediately after those avail entries are consumed.
But that's not true when dequeue zero copy is enabled, that used ring is
updated only when the mbuf is consumed. Thus, we need use another var to
note the last avail ring idx we have consumed.
Therefore, last_avail_idx is introduced.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Qian Xu <qian.q.xu@intel.com>
So that we can convert a guest physical address to host physical
address, which will be used in later Tx zero copy implementation.
MAP_POPULATE is set while mmaping guest memory regions, to make
sure the page tables are setup and then rte_mem_virt2phy() could
yield proper physical address.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Qian Xu <qian.q.xu@intel.com>
Due to history reason (that vhost-cuse comes before vhost-user), some
fields for maintaining the vhost-user memory mappings (such as mmapped
address and size, with those we then can unmap on destroy) are kept in
"orig_region_map" struct, a structure that is defined only in vhost-user
source file.
The right way to go is to remove the structure and move all those fields
into virtio_memory_region struct. But we simply can't do that before,
because it breaks the ABI.
Now, thanks to the ABI refactoring, it's never been a blocking issue
any more. And here it goes: this patch removes orig_region_map and
redefines virtio_memory_region, to include all necessary info.
With that, we can simplify the guest/host address convert a bit.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Qian Xu <qian.q.xu@intel.com>
No need to use a pointer to store/retrieve features.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Invoke get_device() at the beginning of vhost_user_msg_handler, so that
we could check the return value once. Which could save tons of duplicate
get-and-check device.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Some functions are with prefix "user_", while others with "vhost_".
Making them all starting with "vhost_user_" to unify the function names.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Due to history reason (that we have 2 vhost implementations), some
messages are handled in two calls: vhost specific implementation
handles it first and then invoke the common one to do another handling.
We have one implementation only now, we could write one method for
each message. Here fold those common handles to corresponding vhost
user handler.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
The code structure is a bit messy now. For example, vhost-user message
handling is spread to three different files:
vhost-net-user.c virtio-net.c virtio-net-user.c
Where, vhost-net-user.c is the entrance to handle all those messages
and then invoke the right method for a specific message. Some of them
are stored at virtio-net.c, while others are stored at virtio-net-user.c.
The truth is all of them should be in one file, vhost_user.c.
So this patch refactors the source code structure: mainly on renaming
files and moving code from one file to another file that is more suitable
for storing it. Thus, no functional changes are made.
After the refactor, the code structure becomes to:
- socket.c handles all vhost-user socket file related stuff, such
as, socket file creation for server mode, reconnection
for client mode.
- vhost.c mainly on stuff like vhost device creation/destroy/reset.
Most of the vhost API implementation are there, too.
- vhost_user.c all stuff about vhost-user messages handling goes there.
- virtio_net.c all stuff about virtio-net should go there. It has virtio
net Rx/Tx implementation only so far: it's just a rename
from vhost_rxtx.c
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
