| Message ID | 20210413123954.3396314-1-arseny.krasnov@kaspersky.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | virtio/vsock: introduce SOCK_SEQPACKET support | expand |
On Tue, Apr 13, 2021 at 03:39:51PM +0300, Arseny Krasnov wrote: > This patchset implements support of SOCK_SEQPACKET for virtio >transport. > As SOCK_SEQPACKET guarantees to save record boundaries, so to >do it, new bit for field 'flags' was added: SEQ_EOR. This bit is >set to 1 in last RW packet of message. > Now as packets of one socket are not reordered neither on vsock >nor on vhost transport layers, such bit allows to restore original >message on receiver's side. If user's buffer is smaller than message >length, when all out of size data is dropped. > Maximum length of datagram is not limited as in stream socket, >because same credit logic is used. Difference with stream socket is >that user is not woken up until whole record is received or error >occurred. Implementation also supports 'MSG_TRUNC' flags. > Tests also implemented. > > Thanks to stsp2@yandex.ru for encouragements and initial design >recommendations. > > Arseny Krasnov (19): > af_vsock: update functions for connectible socket > af_vsock: separate wait data loop > af_vsock: separate receive data loop > af_vsock: implement SEQPACKET receive loop > af_vsock: implement send logic for SEQPACKET > af_vsock: rest of SEQPACKET support > af_vsock: update comments for stream sockets > virtio/vsock: set packet's type in virtio_transport_send_pkt_info() > virtio/vsock: simplify credit update function API > virtio/vsock: defines and constants for SEQPACKET > virtio/vsock: dequeue callback for SOCK_SEQPACKET > virtio/vsock: add SEQPACKET receive logic > virtio/vsock: rest of SOCK_SEQPACKET support > virtio/vsock: enable SEQPACKET for transport > vhost/vsock: enable SEQPACKET for transport > vsock/loopback: enable SEQPACKET for transport > vsock_test: add SOCK_SEQPACKET tests > virtio/vsock: update trace event for SEQPACKET > af_vsock: serialize writes to shared socket > > drivers/vhost/vsock.c | 31 +- > include/linux/virtio_vsock.h | 11 + > include/net/af_vsock.h | 8 + > .../events/vsock_virtio_transport_common.h | 5 +- > include/uapi/linux/virtio_vsock.h | 9 + > net/vmw_vsock/af_vsock.c | 470 +++++++++++------ > net/vmw_vsock/virtio_transport.c | 17 + > net/vmw_vsock/virtio_transport_common.c | 167 ++++-- > net/vmw_vsock/vsock_loopback.c | 12 + > tools/testing/vsock/util.c | 32 +- > tools/testing/vsock/util.h | 3 + > tools/testing/vsock/vsock_test.c | 63 +++ > 12 files changed, 625 insertions(+), 203 deletions(-) > > v7 -> v8: > General changelog: > - whole idea is simplified: channel now considered reliable, > so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. > Only thing that is used to mark end of message is bit in > 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet > with such bit set to 1 means, that this is last packet of > message. > > - POSIX MSG_EOR support is removed, as there is no exact > description how it works. It would be nice to support it, I'll try to see if I can find anything. I just reviewed the series. I think the most important things to fix are the `seqpacket_allow` stored in the struct virtio_transport that is wrong IMHO, and use cpu_to_le32()/le32_to_cpu() to access the flags. I also left some other comments around. Thanks, Stefano > > - all changes to 'include/uapi/linux/virtio_vsock.h' moved > to dedicated patch, as these changes linked with patch to > spec. > > - patch 'virtio/vsock: SEQPACKET feature bit support' now merged > to 'virtio/vsock: setup SEQPACKET ops for transport'. > > - patch 'vhost/vsock: SEQPACKET feature bit support' now merged > to 'vhost/vsock: setup SEQPACKET ops for transport'. > > Per patch changelog: > see every patch after '---' line. > > v6 -> v7: > General changelog: > - virtio transport callback for message length now removed > from transport. Length of record is returned by dequeue > callback. > > - function which tries to get message length now returns 0 > when rx queue is empty. Also length of current message in > progress is set to 0, when message processed or error > happens. > > - patches for virtio feature bit moved after patches with > transport ops. > > Per patch changelog: > see every patch after '---' line. > > v5 -> v6: > General changelog: > - virtio transport specific callbacks which send SEQ_BEGIN or > SEQ_END now hidden inside virtio transport. Only enqueue, > dequeue and record length callbacks are provided by transport. > > - virtio feature bit for SEQPACKET socket support introduced: > VIRTIO_VSOCK_F_SEQPACKET. > > - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to > 'msg_id' and used as id. > > Per patch changelog: > - 'af_vsock: separate wait data loop': > 1) Commit message updated. > 2) 'prepare_to_wait()' moved inside while loop(thanks to > Jorgen Hansen). > Marked 'Reviewed-by' with 1), but as 2) I removed R-b. > > - 'af_vsock: separate receive data loop': commit message > updated. > Marked 'Reviewed-by' with that fix. > > - 'af_vsock: implement SEQPACKET receive loop': style fixes. > > - 'af_vsock: rest of SEQPACKET support': > 1) 'module_put()' added when transport callback check failed. > 2) Now only 'seqpacket_allow()' callback called to check > support of SEQPACKET by transport. > > - 'af_vsock: update comments for stream sockets': commit message > updated. > Marked 'Reviewed-by' with that fix. > > - 'virtio/vsock: set packet's type in send': > 1) Commit message updated. > 2) Parameter 'type' from 'virtio_transport_send_credit_update()' > also removed in this patch instead of in next. > > - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET > related state wrapped to special struct. > > - 'virtio/vsock: update trace event for SEQPACKET': format strings > now not broken by new lines. > > v4 -> v5: > - patches reorganized: > 1) Setting of packet's type in 'virtio_transport_send_pkt_info()' > is moved to separate patch. > 2) Simplifying of 'virtio_transport_send_credit_update()' is > moved to separate patch and before main virtio/vsock patches. > - style problem fixed > - in 'af_vsock: separate receive data loop' extra 'release_sock()' > removed > - added trace event fields for SEQPACKET > - in 'af_vsock: separate wait data loop': > 1) 'vsock_wait_data()' removed 'goto out;' > 2) Comment for invalid data amount is changed. > - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer > check is moved after 'try_module_get()' > - in 'af_vsock: update comments for stream sockets', 'connect-oriented' > replaced with 'connection-oriented' > - in 'loopback/vsock: setup SEQPACKET ops for transport', > 'loopback/vsock' replaced with 'vsock/loopback' > > v3 -> v4: > - SEQPACKET specific metadata moved from packet header to payload > and called 'virtio_vsock_seq_hdr' > - record integrity check: > 1) SEQ_END operation was added, which marks end of record. > 2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented > on every marker send. > - af_vsock.c: socket operations for STREAM and SEQPACKET call same > functions instead of having own "gates" differs only by names: > 'vsock_seqpacket/stream_getsockopt()' now replaced with > 'vsock_connectible_getsockopt()'. > - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that > record ready. There is no need to return number of copied bytes, > because case when record received successfully is checked at virtio > transport layer, when SEQ_END is processed. Also user doesn't need > number of copied bytes, because 'recv()' from SEQPACKET could return > error, length of users's buffer or length of whole record(both are > known in af_vsock.c). > - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved > to separate functions because now both called from several places. > - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport' > pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV' > if failed to use transport. > - tools/testing/vsock/vsock_test.c: rename tests > > v2 -> v3: > - patches reorganized: split for prepare and implementation patches > - local variables are declared in "Reverse Christmas tree" manner > - virtio_transport_common.c: valid leXX_to_cpu() for vsock header > fields access > - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code > between stream and seqpacket sockets. > - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored. > - af_vsock.c: 'vsock_wait_data()' refactored. > > v1 -> v2: > - patches reordered: af_vsock.c related changes now before virtio vsock > - patches reorganized: more small patches, where +/- are not mixed > - tests for SOCK_SEQPACKET added > - all commit messages updated > - af_vsock.c: 'vsock_pre_recv_check()' inlined to > 'vsock_connectible_recvmsg()' > - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport > was not found > - virtio_transport_common.c: transport callback for seqpacket dequeue > - virtio_transport_common.c: simplified > 'virtio_transport_recv_connected()' > - virtio_transport_common.c: send reset on socket and packet type > mismatch. > >Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com> > >-- >2.25.1 >
On 21.04.2021 12:52, Stefano Garzarella wrote: > On Tue, Apr 13, 2021 at 03:39:51PM +0300, Arseny Krasnov wrote: >> This patchset implements support of SOCK_SEQPACKET for virtio >> transport. >> As SOCK_SEQPACKET guarantees to save record boundaries, so to >> do it, new bit for field 'flags' was added: SEQ_EOR. This bit is >> set to 1 in last RW packet of message. >> Now as packets of one socket are not reordered neither on vsock >> nor on vhost transport layers, such bit allows to restore original >> message on receiver's side. If user's buffer is smaller than message >> length, when all out of size data is dropped. >> Maximum length of datagram is not limited as in stream socket, >> because same credit logic is used. Difference with stream socket is >> that user is not woken up until whole record is received or error >> occurred. Implementation also supports 'MSG_TRUNC' flags. >> Tests also implemented. >> >> Thanks to stsp2@yandex.ru for encouragements and initial design >> recommendations. >> >> Arseny Krasnov (19): >> af_vsock: update functions for connectible socket >> af_vsock: separate wait data loop >> af_vsock: separate receive data loop >> af_vsock: implement SEQPACKET receive loop >> af_vsock: implement send logic for SEQPACKET >> af_vsock: rest of SEQPACKET support >> af_vsock: update comments for stream sockets >> virtio/vsock: set packet's type in virtio_transport_send_pkt_info() >> virtio/vsock: simplify credit update function API >> virtio/vsock: defines and constants for SEQPACKET >> virtio/vsock: dequeue callback for SOCK_SEQPACKET >> virtio/vsock: add SEQPACKET receive logic >> virtio/vsock: rest of SOCK_SEQPACKET support >> virtio/vsock: enable SEQPACKET for transport >> vhost/vsock: enable SEQPACKET for transport >> vsock/loopback: enable SEQPACKET for transport >> vsock_test: add SOCK_SEQPACKET tests >> virtio/vsock: update trace event for SEQPACKET >> af_vsock: serialize writes to shared socket >> >> drivers/vhost/vsock.c | 31 +- >> include/linux/virtio_vsock.h | 11 + >> include/net/af_vsock.h | 8 + >> .../events/vsock_virtio_transport_common.h | 5 +- >> include/uapi/linux/virtio_vsock.h | 9 + >> net/vmw_vsock/af_vsock.c | 470 +++++++++++------ >> net/vmw_vsock/virtio_transport.c | 17 + >> net/vmw_vsock/virtio_transport_common.c | 167 ++++-- >> net/vmw_vsock/vsock_loopback.c | 12 + >> tools/testing/vsock/util.c | 32 +- >> tools/testing/vsock/util.h | 3 + >> tools/testing/vsock/vsock_test.c | 63 +++ >> 12 files changed, 625 insertions(+), 203 deletions(-) >> >> v7 -> v8: >> General changelog: >> - whole idea is simplified: channel now considered reliable, >> so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. >> Only thing that is used to mark end of message is bit in >> 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet >> with such bit set to 1 means, that this is last packet of >> message. >> >> - POSIX MSG_EOR support is removed, as there is no exact >> description how it works. > It would be nice to support it, I'll try to see if I can find anything. > > I just reviewed the series. I think the most important things to fix are > the `seqpacket_allow` stored in the struct virtio_transport that is > wrong IMHO, and use cpu_to_le32()/le32_to_cpu() to access the flags. Thank You, i'll prepare next version. Main question is: does this approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered good? In this case it will be easier to prepare final version, because it is smaller and more simple than previous logic. Also patch to spec will be smaller. > > I also left some other comments around. > > Thanks, > Stefano > >> - all changes to 'include/uapi/linux/virtio_vsock.h' moved >> to dedicated patch, as these changes linked with patch to >> spec. >> >> - patch 'virtio/vsock: SEQPACKET feature bit support' now merged >> to 'virtio/vsock: setup SEQPACKET ops for transport'. >> >> - patch 'vhost/vsock: SEQPACKET feature bit support' now merged >> to 'vhost/vsock: setup SEQPACKET ops for transport'. >> >> Per patch changelog: >> see every patch after '---' line. >> >> v6 -> v7: >> General changelog: >> - virtio transport callback for message length now removed >> from transport. Length of record is returned by dequeue >> callback. >> >> - function which tries to get message length now returns 0 >> when rx queue is empty. Also length of current message in >> progress is set to 0, when message processed or error >> happens. >> >> - patches for virtio feature bit moved after patches with >> transport ops. >> >> Per patch changelog: >> see every patch after '---' line. >> >> v5 -> v6: >> General changelog: >> - virtio transport specific callbacks which send SEQ_BEGIN or >> SEQ_END now hidden inside virtio transport. Only enqueue, >> dequeue and record length callbacks are provided by transport. >> >> - virtio feature bit for SEQPACKET socket support introduced: >> VIRTIO_VSOCK_F_SEQPACKET. >> >> - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to >> 'msg_id' and used as id. >> >> Per patch changelog: >> - 'af_vsock: separate wait data loop': >> 1) Commit message updated. >> 2) 'prepare_to_wait()' moved inside while loop(thanks to >> Jorgen Hansen). >> Marked 'Reviewed-by' with 1), but as 2) I removed R-b. >> >> - 'af_vsock: separate receive data loop': commit message >> updated. >> Marked 'Reviewed-by' with that fix. >> >> - 'af_vsock: implement SEQPACKET receive loop': style fixes. >> >> - 'af_vsock: rest of SEQPACKET support': >> 1) 'module_put()' added when transport callback check failed. >> 2) Now only 'seqpacket_allow()' callback called to check >> support of SEQPACKET by transport. >> >> - 'af_vsock: update comments for stream sockets': commit message >> updated. >> Marked 'Reviewed-by' with that fix. >> >> - 'virtio/vsock: set packet's type in send': >> 1) Commit message updated. >> 2) Parameter 'type' from 'virtio_transport_send_credit_update()' >> also removed in this patch instead of in next. >> >> - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET >> related state wrapped to special struct. >> >> - 'virtio/vsock: update trace event for SEQPACKET': format strings >> now not broken by new lines. >> >> v4 -> v5: >> - patches reorganized: >> 1) Setting of packet's type in 'virtio_transport_send_pkt_info()' >> is moved to separate patch. >> 2) Simplifying of 'virtio_transport_send_credit_update()' is >> moved to separate patch and before main virtio/vsock patches. >> - style problem fixed >> - in 'af_vsock: separate receive data loop' extra 'release_sock()' >> removed >> - added trace event fields for SEQPACKET >> - in 'af_vsock: separate wait data loop': >> 1) 'vsock_wait_data()' removed 'goto out;' >> 2) Comment for invalid data amount is changed. >> - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer >> check is moved after 'try_module_get()' >> - in 'af_vsock: update comments for stream sockets', 'connect-oriented' >> replaced with 'connection-oriented' >> - in 'loopback/vsock: setup SEQPACKET ops for transport', >> 'loopback/vsock' replaced with 'vsock/loopback' >> >> v3 -> v4: >> - SEQPACKET specific metadata moved from packet header to payload >> and called 'virtio_vsock_seq_hdr' >> - record integrity check: >> 1) SEQ_END operation was added, which marks end of record. >> 2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented >> on every marker send. >> - af_vsock.c: socket operations for STREAM and SEQPACKET call same >> functions instead of having own "gates" differs only by names: >> 'vsock_seqpacket/stream_getsockopt()' now replaced with >> 'vsock_connectible_getsockopt()'. >> - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that >> record ready. There is no need to return number of copied bytes, >> because case when record received successfully is checked at virtio >> transport layer, when SEQ_END is processed. Also user doesn't need >> number of copied bytes, because 'recv()' from SEQPACKET could return >> error, length of users's buffer or length of whole record(both are >> known in af_vsock.c). >> - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved >> to separate functions because now both called from several places. >> - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport' >> pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV' >> if failed to use transport. >> - tools/testing/vsock/vsock_test.c: rename tests >> >> v2 -> v3: >> - patches reorganized: split for prepare and implementation patches >> - local variables are declared in "Reverse Christmas tree" manner >> - virtio_transport_common.c: valid leXX_to_cpu() for vsock header >> fields access >> - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code >> between stream and seqpacket sockets. >> - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored. >> - af_vsock.c: 'vsock_wait_data()' refactored. >> >> v1 -> v2: >> - patches reordered: af_vsock.c related changes now before virtio vsock >> - patches reorganized: more small patches, where +/- are not mixed >> - tests for SOCK_SEQPACKET added >> - all commit messages updated >> - af_vsock.c: 'vsock_pre_recv_check()' inlined to >> 'vsock_connectible_recvmsg()' >> - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport >> was not found >> - virtio_transport_common.c: transport callback for seqpacket dequeue >> - virtio_transport_common.c: simplified >> 'virtio_transport_recv_connected()' >> - virtio_transport_common.c: send reset on socket and packet type >> mismatch. >> >> Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com> >> >> -- >> 2.25.1 >> >
On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >On 21.04.2021 12:52, Stefano Garzarella wrote: >> On Tue, Apr 13, 2021 at 03:39:51PM +0300, Arseny Krasnov wrote: >>> v7 -> v8: >>> General changelog: >>> - whole idea is simplified: channel now considered reliable, >>> so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. >>> Only thing that is used to mark end of message is bit in >>> 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet >>> with such bit set to 1 means, that this is last packet of >>> message. >>> >>> - POSIX MSG_EOR support is removed, as there is no exact >>> description how it works. >> It would be nice to support it, I'll try to see if I can find anything. >> >> I just reviewed the series. I think the most important things to fix are >> the `seqpacket_allow` stored in the struct virtio_transport that is >> wrong IMHO, and use cpu_to_le32()/le32_to_cpu() to access the flags. > >Thank You, i'll prepare next version. Main question is: does this >approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >good? In this case it will be easier to prepare final version, because >is smaller and more simple than previous logic. Also patch to spec >will be smaller. Yes, it's definitely much better than before. The only problem I see is that we add some overhead per fragment (header). We could solve that with the mergeable buffers that Jiang is considering for DGRAM. If we have that support, I think we could reuse it here as well, but it might be a next step. Thanks, Stefano
On 22.04.2021 11:46, Stefano Garzarella wrote: > On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >> On 21.04.2021 12:52, Stefano Garzarella wrote: >>> On Tue, Apr 13, 2021 at 03:39:51PM +0300, Arseny Krasnov wrote: >>>> v7 -> v8: >>>> General changelog: >>>> - whole idea is simplified: channel now considered reliable, >>>> so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. >>>> Only thing that is used to mark end of message is bit in >>>> 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet >>>> with such bit set to 1 means, that this is last packet of >>>> message. >>>> >>>> - POSIX MSG_EOR support is removed, as there is no exact >>>> description how it works. >>> It would be nice to support it, I'll try to see if I can find anything. >>> >>> I just reviewed the series. I think the most important things to fix are >>> the `seqpacket_allow` stored in the struct virtio_transport that is >>> wrong IMHO, and use cpu_to_le32()/le32_to_cpu() to access the flags. >> Thank You, i'll prepare next version. Main question is: does this >> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >> good? In this case it will be easier to prepare final version, because >> is smaller and more simple than previous logic. Also patch to spec >> will be smaller. > Yes, it's definitely much better than before. > > The only problem I see is that we add some overhead per fragment > (header). We could solve that with the mergeable buffers that Jiang is > considering for DGRAM. If we are talking about receive, i think, i can reuse merge logic for stream sockets, the only difference is that buffers are mergeable until previous EOR(e.g. previous message) bit is found in rx queue. > > If we have that support, I think we could reuse it here as well, but it > might be a next step. > > Thanks, > Stefano > >
On Thu, Apr 22, 2021 at 12:40:17PM +0300, Arseny Krasnov wrote: >On 22.04.2021 11:46, Stefano Garzarella wrote: >> On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >>> Thank You, i'll prepare next version. Main question is: does this >>> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >>> good? In this case it will be easier to prepare final version, because >>> is smaller and more simple than previous logic. Also patch to spec >>> will be smaller. >> Yes, it's definitely much better than before. >> >> The only problem I see is that we add some overhead per fragment >> (header). We could solve that with the mergeable buffers that Jiang is >> considering for DGRAM. > >If we are talking about receive, i think, i can reuse merge logic for Yep, for TX the guest can potentially enqueue a big buffer. Maybe it's still worth keeping a maximum size and fragmenting as we do now. > >stream sockets, the only difference is that buffers are mergeable >until previous EOR(e.g. previous message) bit is found in rx queue. > I got a little lost. Can you elaborate more? Thanks, Stefano
On 22.04.2021 13:02, Stefano Garzarella wrote: > On Thu, Apr 22, 2021 at 12:40:17PM +0300, Arseny Krasnov wrote: >> On 22.04.2021 11:46, Stefano Garzarella wrote: >>> On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >>>> Thank You, i'll prepare next version. Main question is: does this >>>> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >>>> good? In this case it will be easier to prepare final version, because >>>> is smaller and more simple than previous logic. Also patch to spec >>>> will be smaller. >>> Yes, it's definitely much better than before. >>> >>> The only problem I see is that we add some overhead per fragment >>> (header). We could solve that with the mergeable buffers that Jiang is >>> considering for DGRAM. >> If we are talking about receive, i think, i can reuse merge logic for > Yep, for TX the guest can potentially enqueue a big buffer. > Maybe it's still worth keeping a maximum size and fragmenting as we do > now. > >> stream sockets, the only difference is that buffers are mergeable >> until previous EOR(e.g. previous message) bit is found in rx queue. >> > I got a little lost. > Can you elaborate more? I'm talking about 'virtio_transport_recv_enqueue()': it tries to copy data of new packet to buffer of tail packet in rx queue. In case of SEQPACKET i can reuse it, just adding logic that check EOR bit of tail packet. > > Thanks, > Stefano > >
On Thu, Apr 22, 2021 at 01:29:54PM +0300, Arseny Krasnov wrote: > >On 22.04.2021 13:02, Stefano Garzarella wrote: >> On Thu, Apr 22, 2021 at 12:40:17PM +0300, Arseny Krasnov wrote: >>> On 22.04.2021 11:46, Stefano Garzarella wrote: >>>> On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >>>>> Thank You, i'll prepare next version. Main question is: does this >>>>> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >>>>> good? In this case it will be easier to prepare final version, because >>>>> is smaller and more simple than previous logic. Also patch to spec >>>>> will be smaller. >>>> Yes, it's definitely much better than before. >>>> >>>> The only problem I see is that we add some overhead per fragment >>>> (header). We could solve that with the mergeable buffers that Jiang is >>>> considering for DGRAM. >>> If we are talking about receive, i think, i can reuse merge logic for >> Yep, for TX the guest can potentially enqueue a big buffer. >> Maybe it's still worth keeping a maximum size and fragmenting as we do >> now. >> >>> stream sockets, the only difference is that buffers are mergeable >>> until previous EOR(e.g. previous message) bit is found in rx queue. >>> >> I got a little lost. >> Can you elaborate more? > >I'm talking about 'virtio_transport_recv_enqueue()': it tries to copy > >data of new packet to buffer of tail packet in rx queue. In case of > >SEQPACKET i can reuse it, just adding logic that check EOR bit of > >tail packet. This might be a good idea. It doesn't save us the transmitted header though, but at least it saves us from queuing it. Even if with SEQPACKET I don't expect small packets, since it's the driver that divides them and I think it does everything to use the maximum available. Instead the mergeable buffers I was referring to are based on the virito-net feature VIRTIO_NET_F_MRG_RXBUF. Jiang is investigating whether we can reuse them for DGRAM. Thanks, Stefano
On 22.04.2021 13:48, Stefano Garzarella wrote: > On Thu, Apr 22, 2021 at 01:29:54PM +0300, Arseny Krasnov wrote: >> On 22.04.2021 13:02, Stefano Garzarella wrote: >>> On Thu, Apr 22, 2021 at 12:40:17PM +0300, Arseny Krasnov wrote: >>>> On 22.04.2021 11:46, Stefano Garzarella wrote: >>>>> On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >>>>>> Thank You, i'll prepare next version. Main question is: does this >>>>>> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >>>>>> good? In this case it will be easier to prepare final version, because >>>>>> is smaller and more simple than previous logic. Also patch to spec >>>>>> will be smaller. >>>>> Yes, it's definitely much better than before. >>>>> >>>>> The only problem I see is that we add some overhead per fragment >>>>> (header). We could solve that with the mergeable buffers that Jiang is >>>>> considering for DGRAM. >>>> If we are talking about receive, i think, i can reuse merge logic for >>> Yep, for TX the guest can potentially enqueue a big buffer. >>> Maybe it's still worth keeping a maximum size and fragmenting as we do >>> now. >>> >>>> stream sockets, the only difference is that buffers are mergeable >>>> until previous EOR(e.g. previous message) bit is found in rx queue. >>>> >>> I got a little lost. >>> Can you elaborate more? >> I'm talking about 'virtio_transport_recv_enqueue()': it tries to copy >> >> data of new packet to buffer of tail packet in rx queue. In case of >> >> SEQPACKET i can reuse it, just adding logic that check EOR bit of >> >> tail packet. > This might be a good idea. > It doesn't save us the transmitted header though, but at least it saves > us from queuing it. > Even if with SEQPACKET I don't expect small packets, since it's the > driver that divides them and I think it does everything to use the > maximum available. > > Instead the mergeable buffers I was referring to are based on the > virito-net feature VIRTIO_NET_F_MRG_RXBUF. > Jiang is investigating whether we can reuse them for DGRAM. Understand, thank you > > Thanks, > Stefano > >
This patchset implements support of SOCK_SEQPACKET for virtio transport. As SOCK_SEQPACKET guarantees to save record boundaries, so to do it, new bit for field 'flags' was added: SEQ_EOR. This bit is set to 1 in last RW packet of message. Now as packets of one socket are not reordered neither on vsock nor on vhost transport layers, such bit allows to restore original message on receiver's side. If user's buffer is smaller than message length, when all out of size data is dropped. Maximum length of datagram is not limited as in stream socket, because same credit logic is used. Difference with stream socket is that user is not woken up until whole record is received or error occurred. Implementation also supports 'MSG_TRUNC' flags. Tests also implemented. Thanks to stsp2@yandex.ru for encouragements and initial design recommendations. Arseny Krasnov (19): af_vsock: update functions for connectible socket af_vsock: separate wait data loop af_vsock: separate receive data loop af_vsock: implement SEQPACKET receive loop af_vsock: implement send logic for SEQPACKET af_vsock: rest of SEQPACKET support af_vsock: update comments for stream sockets virtio/vsock: set packet's type in virtio_transport_send_pkt_info() virtio/vsock: simplify credit update function API virtio/vsock: defines and constants for SEQPACKET virtio/vsock: dequeue callback for SOCK_SEQPACKET virtio/vsock: add SEQPACKET receive logic virtio/vsock: rest of SOCK_SEQPACKET support virtio/vsock: enable SEQPACKET for transport vhost/vsock: enable SEQPACKET for transport vsock/loopback: enable SEQPACKET for transport vsock_test: add SOCK_SEQPACKET tests virtio/vsock: update trace event for SEQPACKET af_vsock: serialize writes to shared socket drivers/vhost/vsock.c | 31 +- include/linux/virtio_vsock.h | 11 + include/net/af_vsock.h | 8 + .../events/vsock_virtio_transport_common.h | 5 +- include/uapi/linux/virtio_vsock.h | 9 + net/vmw_vsock/af_vsock.c | 470 +++++++++++------ net/vmw_vsock/virtio_transport.c | 17 + net/vmw_vsock/virtio_transport_common.c | 167 ++++-- net/vmw_vsock/vsock_loopback.c | 12 + tools/testing/vsock/util.c | 32 +- tools/testing/vsock/util.h | 3 + tools/testing/vsock/vsock_test.c | 63 +++ 12 files changed, 625 insertions(+), 203 deletions(-) v7 -> v8: General changelog: - whole idea is simplified: channel now considered reliable, so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. Only thing that is used to mark end of message is bit in 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet with such bit set to 1 means, that this is last packet of message. - POSIX MSG_EOR support is removed, as there is no exact description how it works. - all changes to 'include/uapi/linux/virtio_vsock.h' moved to dedicated patch, as these changes linked with patch to spec. - patch 'virtio/vsock: SEQPACKET feature bit support' now merged to 'virtio/vsock: setup SEQPACKET ops for transport'. - patch 'vhost/vsock: SEQPACKET feature bit support' now merged to 'vhost/vsock: setup SEQPACKET ops for transport'. Per patch changelog: see every patch after '---' line. v6 -> v7: General changelog: - virtio transport callback for message length now removed from transport. Length of record is returned by dequeue callback. - function which tries to get message length now returns 0 when rx queue is empty. Also length of current message in progress is set to 0, when message processed or error happens. - patches for virtio feature bit moved after patches with transport ops. Per patch changelog: see every patch after '---' line. v5 -> v6: General changelog: - virtio transport specific callbacks which send SEQ_BEGIN or SEQ_END now hidden inside virtio transport. Only enqueue, dequeue and record length callbacks are provided by transport. - virtio feature bit for SEQPACKET socket support introduced: VIRTIO_VSOCK_F_SEQPACKET. - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to 'msg_id' and used as id. Per patch changelog: - 'af_vsock: separate wait data loop': 1) Commit message updated. 2) 'prepare_to_wait()' moved inside while loop(thanks to Jorgen Hansen). Marked 'Reviewed-by' with 1), but as 2) I removed R-b. - 'af_vsock: separate receive data loop': commit message updated. Marked 'Reviewed-by' with that fix. - 'af_vsock: implement SEQPACKET receive loop': style fixes. - 'af_vsock: rest of SEQPACKET support': 1) 'module_put()' added when transport callback check failed. 2) Now only 'seqpacket_allow()' callback called to check support of SEQPACKET by transport. - 'af_vsock: update comments for stream sockets': commit message updated. Marked 'Reviewed-by' with that fix. - 'virtio/vsock: set packet's type in send': 1) Commit message updated. 2) Parameter 'type' from 'virtio_transport_send_credit_update()' also removed in this patch instead of in next. - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET related state wrapped to special struct. - 'virtio/vsock: update trace event for SEQPACKET': format strings now not broken by new lines. v4 -> v5: - patches reorganized: 1) Setting of packet's type in 'virtio_transport_send_pkt_info()' is moved to separate patch. 2) Simplifying of 'virtio_transport_send_credit_update()' is moved to separate patch and before main virtio/vsock patches. - style problem fixed - in 'af_vsock: separate receive data loop' extra 'release_sock()' removed - added trace event fields for SEQPACKET - in 'af_vsock: separate wait data loop': 1) 'vsock_wait_data()' removed 'goto out;' 2) Comment for invalid data amount is changed. - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer check is moved after 'try_module_get()' - in 'af_vsock: update comments for stream sockets', 'connect-oriented' replaced with 'connection-oriented' - in 'loopback/vsock: setup SEQPACKET ops for transport', 'loopback/vsock' replaced with 'vsock/loopback' v3 -> v4: - SEQPACKET specific metadata moved from packet header to payload and called 'virtio_vsock_seq_hdr' - record integrity check: 1) SEQ_END operation was added, which marks end of record. 2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented on every marker send. - af_vsock.c: socket operations for STREAM and SEQPACKET call same functions instead of having own "gates" differs only by names: 'vsock_seqpacket/stream_getsockopt()' now replaced with 'vsock_connectible_getsockopt()'. - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that record ready. There is no need to return number of copied bytes, because case when record received successfully is checked at virtio transport layer, when SEQ_END is processed. Also user doesn't need number of copied bytes, because 'recv()' from SEQPACKET could return error, length of users's buffer or length of whole record(both are known in af_vsock.c). - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved to separate functions because now both called from several places. - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport' pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV' if failed to use transport. - tools/testing/vsock/vsock_test.c: rename tests v2 -> v3: - patches reorganized: split for prepare and implementation patches - local variables are declared in "Reverse Christmas tree" manner - virtio_transport_common.c: valid leXX_to_cpu() for vsock header fields access - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code between stream and seqpacket sockets. - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored. - af_vsock.c: 'vsock_wait_data()' refactored. v1 -> v2: - patches reordered: af_vsock.c related changes now before virtio vsock - patches reorganized: more small patches, where +/- are not mixed - tests for SOCK_SEQPACKET added - all commit messages updated - af_vsock.c: 'vsock_pre_recv_check()' inlined to 'vsock_connectible_recvmsg()' - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport was not found - virtio_transport_common.c: transport callback for seqpacket dequeue - virtio_transport_common.c: simplified 'virtio_transport_recv_connected()' - virtio_transport_common.c: send reset on socket and packet type mismatch. Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>