[dpdk-dev] [RFC 2/2] vhost: support vhost-user request only handled by external backend
Maxime Coquelin
maxime.coquelin at redhat.com
Thu Feb 28 09:46:26 CET 2019
On 2/27/19 2:15 PM, Ilya Maximets wrote:
> On 27.02.2019 13:02, Maxime Coquelin wrote:
>> External backends may have specific requests to handle, and so
>> we don't want the vhost-user lib to handle these requests as
>> errors.
>>
>> This patch also catch the case where a request is neither handled
>> by the external backend nor by the vhost library.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>> lib/librte_vhost/vhost_user.c | 28 +++++++++++++++-------------
>> 1 file changed, 15 insertions(+), 13 deletions(-)
>>
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index 36c0c676d..bae5ef1cc 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -1924,27 +1924,29 @@ vhost_user_msg_handler(int vid, int fd)
>> }
>>
>> ret = read_vhost_message(fd, &msg);
>> - if (ret <= 0 || msg.request.master >= VHOST_USER_MAX) {
>> + if (ret <= 0) {
>> if (ret < 0)
>> RTE_LOG(ERR, VHOST_CONFIG,
>> "vhost read message failed\n");
>> - else if (ret == 0)
>> + else
>> RTE_LOG(INFO, VHOST_CONFIG,
>> "vhost peer closed\n");
>> - else
>> - RTE_LOG(ERR, VHOST_CONFIG,
>> - "vhost read incorrect message\n");
>>
>> return -1;
>> }
>>
>> ret = 0;
>> - if (msg.request.master != VHOST_USER_IOTLB_MSG)
>> - RTE_LOG(INFO, VHOST_CONFIG, "read message %s\n",
>> - vhost_message_str[msg.request.master]);
>> - else
>> - RTE_LOG(DEBUG, VHOST_CONFIG, "read message %s\n",
>> - vhost_message_str[msg.request.master]);
>> + request = msg.request.master;
>> + if (request < VHOST_USER_MAX && vhost_message_str[req]) {
>> + if (request != VHOST_USER_IOTLB_MSG)
>> + RTE_LOG(INFO, VHOST_CONFIG, "read message %s\n",
>> + vhost_message_str[request]);
>> + else if (
>> + RTE_LOG(DEBUG, VHOST_CONFIG, "read message %s\n",
>> + vhost_message_str[request]);
>
> There is no need for the 'if' without the body.
Oops, indeed. I was pretty sure I did compile test it, but looking at
the history I didn't.
>> + } else {
>> + RTE_LOG(INFO, VHOST_CONFIG, "External request %d\n", request);
>
> External requests could be annoying. Maybe we'll need to move them under DBG ?
> I'm not sure.
Fair point. I'll change to DBG.
>> + }
>>
>> ret = vhost_user_check_and_alloc_queue_pair(dev, &msg);
>> if (ret < 0) {
>> @@ -1960,7 +1962,7 @@ vhost_user_msg_handler(int vid, int fd)
>> * inactive, so it is safe. Otherwise taking the access_lock
>> * would cause a dead lock.
>> */
>> - switch (msg.request.master) {
>> + switch (request) {
>> case VHOST_USER_SET_FEATURES:
>> case VHOST_USER_SET_PROTOCOL_FEATURES:
>> case VHOST_USER_SET_OWNER:
>> @@ -1985,6 +1987,7 @@ vhost_user_msg_handler(int vid, int fd)
>>
>> }
>>
>> + ret = RTE_VHOST_MSG_RESULT_ERR;
>
> This will break the 'vhost_crypto', because it has no 'pre_msg_handler'
> and master will skip to 'post_msg_handler', but it will not be called
> because current status is ERR.
Thanks for catching it.
> Maybe it's easier to introduce RTE_VHOST_MSG_RESULT_NOT_HANDLED and convert
> it to ERR before the reply ?
> This will require changing the pre_msg_handlers to return
> RTE_VHOST_MSG_RESULT_NOT_HANDLED if message wasn't recognized.
> And we'll possibly be able to drop the 'skip_master' in this case.
Ok, that means breaking the API, but it is still experimental so not a
blocker.
I like the idea because it would also make it possible to add some debug
prints.
I'll post new iteration this morning.
Thanks,
Maxime
>> if (dev->extern_ops.pre_msg_handle) {
>> ret = (*dev->extern_ops.pre_msg_handle)(dev->vid,
>> (void *)&msg, &skip_master);
>> @@ -1997,7 +2000,6 @@ vhost_user_msg_handler(int vid, int fd)
>> goto skip_to_post_handle;
>> }
>>
>> - request = msg.request.master;
>> if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {
>> if (!vhost_message_handlers[request])
>> goto skip_to_post_handle;
>>
More information about the dev
mailing list