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2019-02-18vhost: VPP stalls with vhost performing control plane actionsSteven Luong3-214/+259
Symptom ------- With NDR traffic blasting at VPP, bringing up a new VM with vhost connection to VPP causes packet drops. I am able to recreate this problem easily using a simple setup like this. TREX-------------- switch ---- VPP |---------------| |-------| Cause ----- The reason for the packet drops is due to vhost holding onto the worker barrier lock for too long in vhost_user_socket_read(). There are quite a few of system calls inside the routine. At the end of the routine, it unconditionally calls vhost_user_update_iface_state() for all message types. vhost_user_update_iface_state() also unconditionally calls vhost_user_rx_thread_placement() and vhost_user_tx_thread_placement(). vhost_user_rx_thread_placement scraps out all existing cpu/queue mappings for the interface and creates brand new cpu/queue mappings for the interface. This process is very disruptive and very expensive. In my opinion, this area of code needs a makeover. Fixes ----- * vhost_user_socket_read() is rewritten that it should not hold onto the worker barrier lock for system calls, or at least minimize the need for doing it. * Remove the call to vhost_user_update_iface_state as a default route at the end of vhost_user_socket_read(). There is only a couple of message types which really need to call vhost_user_update_iface_state(). We put the call to those message types which need it. * Remove vhost_user_rx_thread_placement() and vhost_user_tx_thread_placement from vhost_user_update_iface_state(). There is no need to repetatively change the cpu/queue mappings. * vhost_user_rx_thread_placement() is actually quite expensive. It should be called only once per queue for the interface. There is no need to scrap the existing cpu/queue mappings and create new cpu/queue mappings when the additional queues becomes active/enable. * Change to create the cpu/queue mappings for the first RX when the interface is created. Dont remove the cpu/queue mapping when the interface is disconnected. Remove the cpu/queue mapping only when the interface is deleted. The create vhost user interface CLI also has some very expensive system calls if the command is entered with the optional keyword "server" As a bonus, This patch makes the create vhost user interface binary-api and CLI thread safe. Do the protection for the small amount of code which is thread unsafe. Change-Id: I4a19cbf7e9cc37ea01286169882e5603e6d7eb77 Signed-off-by: Steven Luong <sluong@cisco.com>
2019-01-23virtio: fix kick race issue [VPP-1489]Damjan Marion3-10/+29
Change-Id: I25b2a28513821bc5eab9ac6890a3964d412b0399 Signed-off-by: Damjan Marion <damarion@cisco.com> (cherry picked from commit e40231b1ecf4b49faaa9ce7b615a7d867104825b)
2018-10-02vhost-user: add support for vlib_log APIJerome Tollet4-177/+129
Change-Id: I0af68f6b41d0024aa64b93a8b18e2d179bf939b0 Signed-off-by: Jerome Tollet <jtollet@cisco.com> Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-10-02vhost-user: Interface state updatesJuraj Sloboda4-16/+29
Fix inconsistencies between admin and link interface states Admin down should imply link down: link_up = admin_up && link_ready Change-Id: I4d668d82d035b5d2ae508727f34f1722a0c3e677 Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
2018-10-02vhost_user: Fix setting MTU using uninitialized variableJuraj Sloboda1-2/+1
Change-Id: I0caa5fd584e3785f237d08f3d3be23e9bfee7605 Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
2018-09-20vhost: show vhost may display garbage after the interface nameSteven1-2/+3
DBGvpp# show vhost-user Virtio vhost-user interfaces Global: coalesce frames 32 time 1e-3 number of rx virtqueues in interrupt mode: 0 Interface: VirtualEthernet0/0/0�?x�D (ifindex 3) The fix is to use format_vnet_hw_if_index_name rather than hi->name. The former format the name with %v rather than %s Change-Id: If4d275e1eb249cf87b2d6b796b42f24769f9e3e3 Signed-off-by: Steven <sluong@cisco.com>
2018-09-20vhost-user: Add disable feature support in apiMohsin Kazmi2-2/+16
Two flags to disable mergable rx buffers and indirect descriptors are added to api. Change-Id: Iba0ee9c48d19dfc3d3420a3fdaf44a1a1d325e99 Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
2018-09-12vhost: Fix VPP crash when reloading VM with mixed-type ports [VPP-1406]Yichen Wang2-1/+15
When VM is having mixed type of vhost-user and SRIOV ports, QEMU (RedHat v2.10) will not send disconnect signal to VPP, and just gives the new memory region directly. VPP is not able to handle new memory region mapping without disconnect signal first, which will result in a SEGV. The fix will handle the VM reboot scenario without explict disconnect signal from QEMU. The fix is to invalidate the avail, desc, and used pointers in the txvq when the new memory regions are received. This is because these pointers are not valid anymore with the new memory regions. In the input node, check to make sure the avail pointer is valid and punt if not. Change-Id: Ieb8b427b202f4442a58907dab1661d63a03650de Signed-off-by: Yichen Wang <yicwang@cisco.com>
2018-08-13Multiarch handling in different constructor macrosDamjan Marion2-5/+0
This significantly reduces need for ... in multiarch code. Simply constructor macros will jost create static unused entry if CLIB_MARCH_VARIANT is defined and that will be optimized out by compiler. Change-Id: I17d1c4ac0c903adcfadaa4a07de1b854c7ab14ac Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-08-11Multiversioning: Device (tx) function constructorMohsin Kazmi1-18/+3
Change-Id: I39f87ca161c891fb22462a23188982fef7c3243f Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
2018-07-11avoid using thread local storage for thread indexDamjan Marion3-3/+3
It is cheaper to get thread index from vlib_main_t if available... Change-Id: I4582e160d06d9d7fccdc54271912f0635da79b50 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-07-08vhost: Add multi-versioning supportMohsin Kazmi6-1534/+1667
It also refactors the vhost code which was in one big file vhost-user.c. Receive side code is in vhost_user_input.c and Transmit side code is in vhost_user_output.c Change-Id: I1b539b5008685889723e228265786a2a3e9f3a78 Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
2018-06-27gcc8 and Wstringop-truncationMarco Varlese1-2/+2
gcc8 introduced a new warning (Wstringop-truncation) which in our case is being treated as error. Disabling the warning globally might introduce bugs related to string truncation which are not desired by the developer (e.g. bug). Instead, this patch disables the warning only for those occurences which have been verified to be non-bugs but the desired behaviour as per developer will. Change-Id: I0f04ff6b4fad44061e80a65af633fd7e0148a0c5 Signed-off-by: Marco Varlese <marco.varlese@suse.com>
2018-06-11MTU: Software interface / Per-protocol MTU supportOle Troan1-2/+1
This patch separates setting of hardware interfaec and software interface MTU. Software MTU is L2 payload MTU (i.e. not including L2 header). Per-protocol MTU for IPv4, IPv6 and MPLS can also be set. Currently only IP4, IP6 are enabled in adjacency / rewrite code. Documentation in src/vnet/MTU.md Change-Id: Iee2fd6f0bbc8210748dd8e073ab9fab87d323690 Signed-off-by: Ole Troan <ot@cisco.com>
2018-05-28itf: Fix admin up down for AF_PACKET and vhost-userMohsin Kazmi1-6/+4
Change-Id: I84327197d59c72d0d046dd2cb4071bf74af6fc28 Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
2018-05-10vppinfra: use count_trailing_zeros in sparse_vec_indexDamjan Marion1-6/+6
It is much cheaper to use ctzll than to do shift,subtract and mask in likely case when we are looking for 1st set bit in the uword. Change-Id: I31954081571978878c7098bafad0c85a91755fa2 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-04-17vhost: show vhost-user <interface> may crash [VPP-1242]Steven1-0/+7
show vhost-user <interface> may cause a crash if interface is semi-bogus. Semi-bogus means it is a known vpp interface which has a hw_if_index, but it is bogus because it is not a vhost-user interface. The fix is to add a check to reject non vhost-user interface for the command. Change-Id: I63f1e8bfbf46f5ec4c30f9fb3546982b63cd7cc5 Signed-off-by: Steven <sluong@cisco.com>
2018-04-13Revert "MTU: Setting of MTU on software interface (instead of hardware ↵Damjan Marion1-2/+2
interface)" This reverts commit 70083ee74c3141bbefb185525315f1b34497dcaa. Reverting as this patch is causing following crash: 0: /home/damarion/cisco/vpp3/build-data/../src/vnet/devices/devices.h:131 (vnet_get_device_input_thread_index) assertion `queue_id < vec_len (hw->input_node_thread_index_by_queue)' fails Aborted Change-Id: Ie2a365032110b1f67be7a9d832885b9899813d39 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-04-13MTU: Setting of MTU on software interface (instead of hardware interface)Ole Troan1-2/+2
Change-Id: I98bd454a761a1032738a21edeb0fe847e801f901 Signed-off-by: Ole Troan <ot@cisco.com>
2018-03-30tapv2: Sporadic SIGABRT in ethernet_input [VPP-1183]Steven1-3/+3
virtio_free_rx_buffers uses the wrong slot in the vring to get the buffer index. It uses desc_next. It should be last_used_idx which is the slot number for the first valid descriptor. Change-Id: I6b62b794f06869fbffffce45430b8b2e37b1266c Signed-off-by: Steven <sluong@cisco.com>
2018-02-19virtio: add missing tx lock when running multithreadedDamjan Marion2-0/+6
Change-Id: I373f429c53c6f66ad38322addcfaccddb7761392 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-02-08virtio: reset vnet header on txDamjan Marion1-0/+3
Change-Id: Ib04a8787038fb536470a04d99fdc165102edfb5a Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-02-08vhostuser: Fix vhostuser file descriptor leakHaiyang Tan1-4/+13
In the case that vhostuser server accepted more than one client connection, 'vui->clib_file_index' will be overwritten directly without release the possible existed resource, so file descriptor leak occurs Change-Id: I89d08133dae31a12a815df2631334dbf0aefeb1e Signed-off-by: Haiyang Tan <haiyang.tan.dev@gmail.com>
2018-02-07vhost: Added ARMV8 NEON version of function map_guest_mem()Nitin Saxena1-0/+69
(VPP-1085) The NEON implementation searches particular address in VHOST_MEMORY_MAX_NREGIONS regions. Searching two regions at a time. Change-Id: Icc3c6746bc98e3a1fa71424e51b64f62efbfdc74 Signed-off-by: Nitin Saxena <nitin.saxena@cavium.com>
2018-02-06vlib: epoll on worker threadsDamjan Marion2-0/+4
This patch teaches worer threads to sleep and to be waken up by kernel if there is activity on file desctiptors assigned to that thread. It also adds counters to epoll file descriptors and new debug cli 'show unix file'. Change-Id: Iaf67869f4aa88ff5b0a08982e1c08474013107c4 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-02-05vhost_user: code cleanupHaiyang Tan1-4/+4
1. Replace the magic number '-1' with MAP_FAILED 2. On x86 platform, QEMU uses vhostuser required the memory back-end is file based, the file could be tmpfs(4K page size) or hugetlbfs(2M or 1G page size) Change-Id: If1818cb6833728d641f68e4d4a3bc645e70f2ee6 Signed-off-by: Haiyang Tan <haiyang.tan.dev@gmail.com>
2018-01-30VPP-899: Run VPP under SELinuxBilly McFall1-13/+17
Add an SELinux profile such that VPP can run under SELinux on RPM based platforms. The SELinux Policy is currently only implemented for RPM packages, specifically, Fedora, CentOS and RHEL. Doxygen User Documentation has been included (selinux_doc.md). Once some discussion on file locations has completed (see vpp-devlist), updates to the Debug CLI documentation will also need to be updated. Additional changes: Patch Set 2: - Rework selinux_doc.md such that each line is only 80 characters instead of each sentence on a line. Made additonal minor chnages to the text. - Update vHost Debug CLI documentation to reflex new socket location. Cleaned up some text from when I originally wrote it, to better reflex proper use. - Update exec Debug CLI documentation to be more inline with suggested helptext, added text regarding recommended script file location. - For Debian builds, create the /var/log/vpp/ directory. I don't use Debian very much, so please pay extra attention to build-data/platforms.mk and build-root/deb/debian/.gitignore. - Per discussion on VPP call, changed the default log location to /var/log/vpp/vpp.log. - Changed the socket location for vHost in AutoConfig to /var/run/vpp/. Patch Set 3: - Update selinux_doc.md based on comments. Change-Id: I400520dc33f1ca51012d09ef8fe5a7b7b96c631e Signed-off-by: Billy McFall <bmcfall@redhat.com>
2018-01-23VPPAPIGEN: vppapigen replacement in Python PLY.Ole Troan1-1/+1
This is a version of the VPP API generator in Python PLY. It supports the existing language, and has a plugin architecture for generators. Currently C and JSON are supported. Changes: - vl_api_version to option version = "major.minor.patch" - enum support - Added error checking and reporting - import support (removed the C pre-processor) - services (tying request/reply together) Version: option version = "1.0.0"; Enum: enum colours { RED, BLUE = 50, }; define foo { vl_api_colours_t colours; }; Services: service { rpc foo returns foo_reply; rpc foo_dump returns stream foo_details; rpc want_stats returns want_stats_reply events ip4_counters, ip6_counters; }; Future planned features: - unions - bool, text - array support (including length) - proto3 output plugin - Refactor C/C++ generator as a plugin - Refactor Java generator as a plugin Change-Id: Ifa289966c790e1b1a8e2938a91e69331e3a58bdf Signed-off-by: Ole Troan <ot@cisco.com>
2018-01-21vhost_user: 'nregions' saves the actual number of mapped guest physical ↵Haiyang Tan1-1/+2
address area This patch fixed the VMA leak that if mapping one of guest physical address area get failed. Change-Id: I07b0b9a932209561d6ff2b2dd08a111ea5db2209 Signed-off-by: Haiyang Tan <haiyang.tan.dev@gmail.com>
2018-01-18vlib: add vlib_buffer_alloc_to_ring APIDamjan Marion2-11/+4
Change-Id: I4e2804754b443f5f41fb25eed8334908c4a70f84 Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-01-16tapv2: deleting tap interface may leak buffers (VPP-1124)Steven3-9/+32
Buffers may be allocated for indirect descriptors by tx thread and they are freed when tx thread is invoked in the next invocation. This is to allow the recipient (kernel) to have a chance to process them. But if the tap interface is deleted, the tx thread may not yet be called to clean up the indirect descriptors' buffers. In that case, we need to remove them without waiting for the tx thread to be called. Failure to do so may cause buffers leak when the tap interface is deleted. For the RX ring, leakage also exists for vring->buffers when the interface is removed. Change-Id: I3df313a0e60334776b19daf51a9f5bf20dfdc489 Signed-off-by: Steven <sluong@cisco.com> (cherry picked from commit d8a998e74b815dd3725dfcd80080e4e540940236)
2018-01-11api: remove transport specific code from handlersFlorin Coras1-11/+12
This does not update api client code. In other words, if the client assumes the transport is shmem based, this patch does not change that. Furthermore, code that checks queue size, for tail dropping, is not updated. Done for the following apis: Plugins - acl - gtpu - memif - nat - pppoe VNET - bfd - bier - tapv2 - vhost user - dhcp - flow - geneve - ip - punt - ipsec/ipsec-gre - l2 - l2tp - lisp-cp/one-cp - lisp-gpe - map - mpls - policer - session - span - udp - tap - vxlan/vxlan-gpe - interface VPP - api/api.c OAM - oam_api.c Stats - stats.c Change-Id: I0e33ecefb2bdab0295698c0add948068a5a83345 Signed-off-by: Florin Coras <fcoras@cisco.com>
2018-01-09api: refactor vlibmemoryFlorin Coras1-6/+4
- separate client/server code for both memory and socket apis - separate memory api code from generic vlib api code - move unix_shared_memory_fifo to svm and rename to svm_fifo_t - overall declutter Change-Id: I90cdd98ff74d0787d58825b914b0f1eafcfa4dc2 Signed-off-by: Florin Coras <fcoras@cisco.com>
2017-12-14tap_v2: include host-side parameters in the dump binary APIMilan Lenco4-0/+15
Change-Id: I097a738b96a304621520f1842dcac7dbf61a8e3f Signed-off-by: Milan Lenco <milan.lenco@pantheon.tech>
2017-12-08tapv2: multiple improvementsDamjan Marion2-2/+3
- change interface naming scheme - rework netlink code - add option to set link address, namespace Change-Id: Icf667babb3077a07617b0b87c45c957e345cb4d1 Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-12-04tap_v2: move code to vnet/devices/tapDamjan Marion5-1068/+0
virtio backend stays in vnet/devices/virtio Change-Id: Idbf04f1c645a809ed408670ba330662859fe9309 Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-12-04tap_v2: coverity strikes, again!Steven1-2/+3
fd is not close when IOCTL encounters an error which causes resource leak. The fix is to initialize fd to -1. At return, close fd if it has a valid value. Change-Id: I53c4f5c71ca0f556fb6586f5849e7cb622632d8f Signed-off-by: Steven <sluong@cisco.com>
2017-12-04virtio: zero data structs in virtio_vring_initDamjan Marion1-3/+3
Change-Id: I877cf1abb062a90f428c3ec0cab5c6e9dad0ca82 Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-12-02tap_v2: multiple improvementsDamjan Marion5-60/+168
- add support for assigning tap interface to the bridge - add support for assigning tap interface host side ip4 and ip6 address - host namespace can be specified as PID (pid:12345) or full path to file - automatically bring linux interface up Change-Id: I1cf7c3cad9a740e430cc1b9c2bb0aad0ba4cc8d8 Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-12-01virtio: fix coverity warningsSteven1-1/+1
Fix 3 coverity warnings 1. api_format.c: init net_ns = 0 and remove its corresponding vec_add and vec_free 2. netlink.c (reported in tap.c before the code was removed): resource leaked due to fd is not close 3. tap.c: subtract 1 for size when calling strncpy to accommodate the terminated NULL character Change-Id: Iff4e66604862f0c06dac227b8cfd48d3979e41a5 Signed-off-by: Steven <sluong@cisco.com>
2017-11-30tap_v2: move netlink code to separate fileDamjan Marion1-76/+2
Change-Id: Ib091875f77ea99421aec0947fd17833c4e6d2ec2 Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-11-30virtio: fast TAP interfaces with vhost-net backendDamjan Marion9-0/+1953
Change-Id: Ided667356d5c6fb9648eb34685aabd6b16a598b7 Signed-off-by: Damjan Marion <damarion@cisco.com> Signed-off-by: Steven Luong <sluong@cisco.com>
2017-10-14vhost: crash under heavy traffic condition due to memory corruption (VPP-1016)Steven1-2/+33
With heavy traffic, tx code path may crash due to memory corruption Thread 5 "vpp_wk_2" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fff3995c700 (LWP 2505)] 0x00007ffff73675e8 in vhost_user_if_input (vm=0x7fffb5f5bf9c, vum=0x7ffff7882a40 <vhost_user_main>, vui=0x7fffb65570c4, qid=0, node=0x7fffb6577dac, mode=VNET_HW_INTERFACE_RX_MODE_POLLING) at /home/sluong/vpp-master/vpp/build-data/../src/vnet/devices/virtio/vhost-user.c:1610 1610 bi_current = (vum->cpus[thread_index].rx_buffers) [vum->cpus[thread_index].rx_buffers_len]; (gdb) p vum->cpus[thread_index].rx_buffers_len $2 = 793212607 (gdb) Apparently, some code accidentally wrote the bad value in rx_buffers_len. rx_buffers_len should never be greater than 1024 since that is how many buffers we request each time. After debugging many hours, I discovered that the memory corruption happens in the tx code path right here on line 2176. { vhost_copy_t *cpy = &vum->cpus[thread_index].copy[copy_len]; copy_len++; cpy->len = bytes_left; cpy->len = (cpy->len > buffer_len) ? buffer_len : cpy->len; cpy->dst = buffer_map_addr; cpy->src = (uword) vlib_buffer_get_current (current_b0) + current_b0->current_length - bytes_left; (gdb) p cpy $3 = (vhost_copy_t *) 0x7fffb554077c (gdb) p copy_len $4 = 1025 (gdb) p &vum->cpus[3].rx_buffers_len $8 = (u32 *) 0x7fffb5540784 copy_len is picking up the index entry 1024 before it was incremented. copy array has only 1024 members (0 - 1023 are valid). The assignment here in cpy surely causes memory corruption. It is only discovered later when the memory location that it corrupted is used. The condition for the crash is to transmit jumbo frames under heavy volume. Since ring size is 1024, with one packet taking up one index for frame size (less 2048), it does not cause overflow. With jumbo frames, it requires multiple indices for one packet, it can cause the overflow under heavy traffic. The fix is to do copy out when we have 1000 entries in the array to avoid overflow. Change-Id: Iefbc739b8e80470f1cf13123113f8331ffcd0eb2 Signed-off-by: Steven <sluong@cisco.com>
2017-10-09vppapigen: support per-file (major,minor,patch) version stampsDave Barach1-0/+2
Add one of these statements to foo.api: vl_api_version 1.2.3 to generate a version tuple stanza in foo.api.h: /****** Version tuple *****/ vl_api_version_tuple(foo, 1, 2, 3) Change-Id: Ic514439e4677999daa8463a94f948f76b132ff15 Signed-off-by: Dave Barach <dave@barachs.net> Signed-off-by: Ole Troan <ot@cisco.com>
2017-10-09fix buffer allocation for sparse jumbo frames in vhostPierre Pfister1-1/+3
A bug was reported where a jumbo packet would stay in vhost queue forever or until a large enough number of other packets arrived in the queue too. This is due to a bug in vhost input node buffer allocation. The fix is to make sure that vhost always allocates at least enough buffers for one single big packet. '40' is used to account for 65kB frames. Change-Id: I1d293028854165083e30cd798fab9d4140230b78 Signed-off-by: Pierre Pfister <ppfister@cisco.com> (cherry picked from commit 67700d41169ac37d21c400949a316750eabad969)
2017-10-04[aarch64] Fixes CLI crashes on dpaa2 platform.Christophe Fontaine1-1/+1
- always use 'va_args' as pointer in all format_* functions - u32 for all 'indent' params as it's declaration was inconsistent Change-Id: Ic5799309a6b104c9b50fec309cba789c8da99e79 Signed-off-by: Christophe Fontaine <christophe.fontaine@enea.com>
2017-09-22vhost-user: fix link-up statusYoann Desmouceaux1-1/+1
When changing the admin state of a vhost-user interface, do not put it in link-up mode if the interface is not actually ready. Change-Id: Idbc631a7126efa79d199909f9e7656d21bd412ca Signed-off-by: Yoann Desmouceaux <ydesmouc@cisco.com>
2017-09-09move unix_file_* code to vppinfraDamjan Marion2-32/+32
This will allow us to use this code in client libraries without vlib. Change-Id: I8557b752496841ba588aa36b6082cbe2cd1867fe Signed-off-by: Damjan Marion <damarion@cisco.com>
2017-08-31vhost: Disallow interrupt mode config if driver opts out interrupt supportSteven2-3/+9
According to the spec, supporting interrupt mode from the driver is optional, not a must. When interrupt mode is configured on the interface, we should check to make sure that the driver didn't opt out for the kickfd support and reject the configuration if it did. Change-Id: I7d3dbaddde65458e1a6a802754a3768ae8685a0e Signed-off-by: Steven <sluong@cisco.com>
2017-08-30vhost: Cache qsz_mask instead of qsz in vhost_user_vring_tSteven2-32/+28
In the data path, we grab qsz from vhost_user_vring_t to compute qsz_mask and store it in a stack variable to use on many occasions. We never use qsz for any meaningful purpose. It is more useful to cache qsz_mask in vhost_user_vring_t to avoid the needless computation in the data path. Change-Id: Idf4d94a9754d5c75c899f1f4f59602275b9904a6 Signed-off-by: Steven <sluong@cisco.com>