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Message-ID: <ce166660-15a2-92ac-f736-179a8bc2adde@salutedevices.com>
Date:   Mon, 9 Oct 2023 23:24:18 +0300
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Subject: Re: [PATCH net-next v3 10/12] test/vsock: MSG_ZEROCOPY flag tests
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To:     Stefano Garzarella <sgarzare@redhat.com>
CC:     Stefan Hajnoczi <stefanha@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Bobby Eshleman <bobby.eshleman@bytedance.com>,
        <kvm@vger.kernel.org>, <virtualization@lists.linux-foundation.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <kernel@sberdevices.ru>, <oxffffaa@gmail.com>
References: <20231007172139.1338644-1-avkrasnov@salutedevices.com>
 <20231007172139.1338644-11-avkrasnov@salutedevices.com>
 <q3246d73b2u6lquey2b5ie4xzmsoe6lqqq6nqaq6drne2lx6tt@fpe6gdvuqzll>
From:   Arseniy Krasnov <avkrasnov@salutedevices.com>
In-Reply-To: <q3246d73b2u6lquey2b5ie4xzmsoe6lqqq6nqaq6drne2lx6tt@fpe6gdvuqzll>
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On 09.10.2023 18:17, Stefano Garzarella wrote:
> On Sat, Oct 07, 2023 at 08:21:37PM +0300, Arseniy Krasnov wrote:
>> This adds three tests for MSG_ZEROCOPY feature:
>> 1) SOCK_STREAM tx with different buffers.
>> 2) SOCK_SEQPACKET tx with different buffers.
>> 3) SOCK_STREAM test to read empty error queue of the socket.
>>
>> Patch also works as preparation for the next patches for tools in this
>> patchset: vsock_perf and vsock_uring_test:
>> 1) Adds several new functions to util.c - they will be also used by
>>   vsock_uring_test.
>> 2) Adds two new functions for MSG_ZEROCOPY handling to a new header
>>   file - such header will be shared between vsock_test, vsock_perf and
>>   vsock_uring_test, thus avoiding code copy-pasting.
>>
>> Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>> ---
>> Changelog:
>> v1 -> v2:
>>  * Move 'SOL_VSOCK' and 'VSOCK_RECVERR' from 'util.c' to 'util.h'.
>> v2 -> v3:
>>  * Patch was reworked. Now it is also preparation patch (see commit
>>    message). Shared stuff for 'vsock_perf' and tests is placed to a
>>    new header file, while shared code between current test tool and
>>    future uring test is placed to the 'util.c'. I think, that making
>>    this patch as preparation allows to reduce number of changes in the
>>    next patches in this patchset.
>>  * Make 'struct vsock_test_data' private by placing it to the .c file.
>>    Also add comments to this struct to clarify sense of its fields.
>>
>> tools/testing/vsock/Makefile              |   2 +-
>> tools/testing/vsock/msg_zerocopy_common.h |  92 ++++++
>> tools/testing/vsock/util.c                | 110 +++++++
>> tools/testing/vsock/util.h                |   5 +
>> tools/testing/vsock/vsock_test.c          |  16 +
>> tools/testing/vsock/vsock_test_zerocopy.c | 367 ++++++++++++++++++++++
>> tools/testing/vsock/vsock_test_zerocopy.h |  15 +
>> 7 files changed, 606 insertions(+), 1 deletion(-)
>> create mode 100644 tools/testing/vsock/msg_zerocopy_common.h
>> create mode 100644 tools/testing/vsock/vsock_test_zerocopy.c
>> create mode 100644 tools/testing/vsock/vsock_test_zerocopy.h
>>
>> diff --git a/tools/testing/vsock/Makefile b/tools/testing/vsock/Makefile
>> index 21a98ba565ab..1a26f60a596c 100644
>> --- a/tools/testing/vsock/Makefile
>> +++ b/tools/testing/vsock/Makefile
>> @@ -1,7 +1,7 @@
>> # SPDX-License-Identifier: GPL-2.0-only
>> all: test vsock_perf
>> test: vsock_test vsock_diag_test
>> -vsock_test: vsock_test.o timeout.o control.o util.o
>> +vsock_test: vsock_test.o vsock_test_zerocopy.o timeout.o control.o util.o
>> vsock_diag_test: vsock_diag_test.o timeout.o control.o util.o
>> vsock_perf: vsock_perf.o
>>
>> diff --git a/tools/testing/vsock/msg_zerocopy_common.h b/tools/testing/vsock/msg_zerocopy_common.h
>> new file mode 100644
>> index 000000000000..ce89f1281584
>> --- /dev/null
>> +++ b/tools/testing/vsock/msg_zerocopy_common.h
>> @@ -0,0 +1,92 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +#ifndef MSG_ZEROCOPY_COMMON_H
>> +#define MSG_ZEROCOPY_COMMON_H
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <sys/types.h>
>> +#include <sys/socket.h>
>> +#include <linux/errqueue.h>
>> +
>> +#ifndef SOL_VSOCK
>> +#define SOL_VSOCK    287
>> +#endif
>> +
>> +#ifndef VSOCK_RECVERR
>> +#define VSOCK_RECVERR    1
>> +#endif
>> +
>> +static void enable_so_zerocopy(int fd)
>> +{
>> +    int val = 1;
>> +
>> +    if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val))) {
>> +        perror("setsockopt");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +}
>> +
>> +static void vsock_recv_completion(int fd, const bool *zerocopied) __maybe_unused;
> 
> To avoid this, maybe we can implement those functions in .c file and
> link the object.
> 
> WDYT?
> 
> Ah, here (cc (GCC) 13.2.1 20230728 (Red Hat 13.2.1-1)) the build is
> failing:
> 
> In file included from vsock_perf.c:23:
> msg_zerocopy_common.h: In function ‘vsock_recv_completion’:
> msg_zerocopy_common.h:29:67: error: expected declaration specifiers before ‘__maybe_unused’
>    29 | static void vsock_recv_completion(int fd, const bool *zerocopied) __maybe_unused;
>       |                                                                   ^~~~~~~~~~~~~~
> msg_zerocopy_common.h:31:1: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘{’ token
>    31 | {
>       | ^
> 
>> +static void vsock_recv_completion(int fd, const bool *zerocopied)
>> +{
>> +    struct sock_extended_err *serr;
>> +    struct msghdr msg = { 0 };
>> +    char cmsg_data[128];
>> +    struct cmsghdr *cm;
>> +    ssize_t res;
>> +
>> +    msg.msg_control = cmsg_data;
>> +    msg.msg_controllen = sizeof(cmsg_data);
>> +
>> +    res = recvmsg(fd, &msg, MSG_ERRQUEUE);
>> +    if (res) {
>> +        fprintf(stderr, "failed to read error queue: %zi\n", res);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    cm = CMSG_FIRSTHDR(&msg);
>> +    if (!cm) {
>> +        fprintf(stderr, "cmsg: no cmsg\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (cm->cmsg_level != SOL_VSOCK) {
>> +        fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (cm->cmsg_type != VSOCK_RECVERR) {
>> +        fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    serr = (void *)CMSG_DATA(cm);
>> +    if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
>> +        fprintf(stderr, "serr: wrong origin: %u\n", serr->ee_origin);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (serr->ee_errno) {
>> +        fprintf(stderr, "serr: wrong error code: %u\n", serr->ee_errno);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    /* This flag is used for tests, to check that transmission was
>> +     * performed as expected: zerocopy or fallback to copy. If NULL
>> +     * - don't care.
>> +     */
>> +    if (!zerocopied)
>> +        return;
>> +
>> +    if (*zerocopied && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
>> +        fprintf(stderr, "serr: was copy instead of zerocopy\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (!*zerocopied && !(serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
>> +        fprintf(stderr, "serr: was zerocopy instead of copy\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +}
>> +
>> +#endif /* MSG_ZEROCOPY_COMMON_H */
>> diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
>> index 6779d5008b27..b1770edd8cc1 100644
>> --- a/tools/testing/vsock/util.c
>> +++ b/tools/testing/vsock/util.c
>> @@ -11,10 +11,12 @@
>> #include <stdio.h>
>> #include <stdint.h>
>> #include <stdlib.h>
>> +#include <string.h>
>> #include <signal.h>
>> #include <unistd.h>
>> #include <assert.h>
>> #include <sys/epoll.h>
>> +#include <sys/mman.h>
>>
>> #include "timeout.h"
>> #include "control.h"
>> @@ -444,3 +446,111 @@ unsigned long hash_djb2(const void *data, size_t len)
>>
>>     return hash;
>> }
>> +
>> +size_t iovec_bytes(const struct iovec *iov, size_t iovnum)
>> +{
>> +    size_t bytes;
>> +    int i;
>> +
>> +    for (bytes = 0, i = 0; i < iovnum; i++)
>> +        bytes += iov[i].iov_len;
>> +
>> +    return bytes;
>> +}
>> +
>> +unsigned long iovec_hash_djb2(const struct iovec *iov, size_t iovnum)
>> +{
>> +    unsigned long hash;
>> +    size_t iov_bytes;
>> +    size_t offs;
>> +    void *tmp;
>> +    int i;
>> +
>> +    iov_bytes = iovec_bytes(iov, iovnum);
>> +
>> +    tmp = malloc(iov_bytes);
>> +    if (!tmp) {
>> +        perror("malloc");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    for (offs = 0, i = 0; i < iovnum; i++) {
>> +        memcpy(tmp + offs, iov[i].iov_base, iov[i].iov_len);
>> +        offs += iov[i].iov_len;
>> +    }
>> +
>> +    hash = hash_djb2(tmp, iov_bytes);
>> +    free(tmp);
>> +
>> +    return hash;
>> +}
>> +
>> +struct iovec *iovec_from_test_data(const struct iovec *test_iovec, int iovnum)
> 
> From the name this function seems related to vsock_test_data, so I'd
> suggest to move this and free_iovec_test_data() in vsock_test_zerocopy.c
> 
>> +{
>> +    struct iovec *iovec;
>> +    int i;
>> +
>> +    iovec = malloc(sizeof(*iovec) * iovnum);
>> +    if (!iovec) {
>> +        perror("malloc");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    for (i = 0; i < iovnum; i++) {
>> +        iovec[i].iov_len = test_iovec[i].iov_len;
>> +
>> +        iovec[i].iov_base = mmap(NULL, iovec[i].iov_len,
>> +                     PROT_READ | PROT_WRITE,
>> +                     MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE,
>> +                     -1, 0);
>> +        if (iovec[i].iov_base == MAP_FAILED) {
>> +            perror("mmap");
>> +            exit(EXIT_FAILURE);
>> +        }
>> +
>> +        if (test_iovec[i].iov_base != MAP_FAILED)
>> +            iovec[i].iov_base += (uintptr_t)test_iovec[i].iov_base;
>> +    }
>> +
>> +    /* Unmap "invalid" elements. */
>> +    for (i = 0; i < iovnum; i++) {
>> +        if (test_iovec[i].iov_base == MAP_FAILED) {
>> +            if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
>> +                perror("munmap");
>> +                exit(EXIT_FAILURE);
>> +            }
>> +        }
>> +    }
>> +
>> +    for (i = 0; i < iovnum; i++) {
>> +        int j;
>> +
>> +        if (test_iovec[i].iov_base == MAP_FAILED)
>> +            continue;
>> +
>> +        for (j = 0; j < iovec[i].iov_len; j++)
>> +            ((uint8_t *)iovec[i].iov_base)[j] = rand() & 0xff;
>> +    }
>> +
>> +    return iovec;
>> +}
>> +
>> +void free_iovec_test_data(const struct iovec *test_iovec,
>> +              struct iovec *iovec, int iovnum)
>> +{
>> +    int i;
>> +
>> +    for (i = 0; i < iovnum; i++) {
>> +        if (test_iovec[i].iov_base != MAP_FAILED) {
>> +            if (test_iovec[i].iov_base)
>> +                iovec[i].iov_base -= (uintptr_t)test_iovec[i].iov_base;
>> +
>> +            if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
>> +                perror("munmap");
>> +                exit(EXIT_FAILURE);
>> +            }
>> +        }
>> +    }
>> +
>> +    free(iovec);
>> +}
>> diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
>> index e5407677ce05..4cacb8d804c1 100644
>> --- a/tools/testing/vsock/util.h
>> +++ b/tools/testing/vsock/util.h
>> @@ -53,4 +53,9 @@ void list_tests(const struct test_case *test_cases);
>> void skip_test(struct test_case *test_cases, size_t test_cases_len,
>>            const char *test_id_str);
>> unsigned long hash_djb2(const void *data, size_t len);
>> +size_t iovec_bytes(const struct iovec *iov, size_t iovnum);
>> +unsigned long iovec_hash_djb2(const struct iovec *iov, size_t iovnum);
>> +struct iovec *iovec_from_test_data(const struct iovec *test_iovec, int iovnum);
>> +void free_iovec_test_data(const struct iovec *test_iovec,
>> +              struct iovec *iovec, int iovnum);
>> #endif /* UTIL_H */
>> diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>> index da4cb819a183..c1f7bc9abd22 100644
>> --- a/tools/testing/vsock/vsock_test.c
>> +++ b/tools/testing/vsock/vsock_test.c
>> @@ -21,6 +21,7 @@
>> #include <poll.h>
>> #include <signal.h>
>>
>> +#include "vsock_test_zerocopy.h"
>> #include "timeout.h"
>> #include "control.h"
>> #include "util.h"
>> @@ -1269,6 +1270,21 @@ static struct test_case test_cases[] = {
>>         .run_client = test_stream_shutrd_client,
>>         .run_server = test_stream_shutrd_server,
>>     },
>> +    {
>> +        .name = "SOCK_STREAM MSG_ZEROCOPY",
>> +        .run_client = test_stream_msgzcopy_client,
>> +        .run_server = test_stream_msgzcopy_server,
>> +    },
>> +    {
>> +        .name = "SOCK_SEQPACKET MSG_ZEROCOPY",
>> +        .run_client = test_seqpacket_msgzcopy_client,
>> +        .run_server = test_seqpacket_msgzcopy_server,
>> +    },
>> +    {
>> +        .name = "SOCK_STREAM MSG_ZEROCOPY empty MSG_ERRQUEUE",
>> +        .run_client = test_stream_msgzcopy_empty_errq_client,
>> +        .run_server = test_stream_msgzcopy_empty_errq_server,
>> +    },
>>     {},
>> };
>>
>> diff --git a/tools/testing/vsock/vsock_test_zerocopy.c b/tools/testing/vsock/vsock_test_zerocopy.c
>> new file mode 100644
>> index 000000000000..af14efdf334b
>> --- /dev/null
>> +++ b/tools/testing/vsock/vsock_test_zerocopy.c
>> @@ -0,0 +1,367 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* MSG_ZEROCOPY feature tests for vsock
>> + *
>> + * Copyright (C) 2023 SberDevices.
>> + *
>> + * Author: Arseniy Krasnov <avkrasnov@salutedevices.com>
>> + */
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <sys/mman.h>
>> +#include <unistd.h>
>> +#include <poll.h>
>> +#include <linux/errqueue.h>
>> +#include <linux/kernel.h>
>> +#include <errno.h>
>> +
>> +#include "control.h"
>> +#include "vsock_test_zerocopy.h"
>> +#include "msg_zerocopy_common.h"
>> +
>> +#define PAGE_SIZE        4096
> 
> In some tests I saw `sysconf(_SC_PAGESIZE)` is used,
> e.g. in selftests/ptrace/peeksiginfo.c:
> 
> #ifndef PAGE_SIZE
> #define PAGE_SIZE sysconf(_SC_PAGESIZE)
> #endif
> 
> WDYT?

Only small problem with that - in this case I can't use PAGE_SIZE
as array initializer. I think to add some reserved constant value
to designate that iov element must be size of page, then use this
value as initializer and handle it during test iov creating...

Thanks, Arseniy

> 
>> +
>> +#define VSOCK_TEST_DATA_MAX_IOV 3
>> +
>> +struct vsock_test_data {
>> +    /* This test case if for SOCK_STREAM only. */
>> +    bool stream_only;
>> +    /* Data must be zerocopied. This field is checked against
>> +     * field 'ee_code' of the 'struct sock_extended_err', which
>> +     * contains bit to detect that zerocopy transmission was
>> +     * fallbacked to copy mode.
>> +     */
>> +    bool zerocopied;
>> +    /* Enable SO_ZEROCOPY option on the socket. Without enabled
>> +     * SO_ZEROCOPY, every MSG_ZEROCOPY transmission will behave
>> +     * like without MSG_ZEROCOPY flag.
>> +     */
>> +    bool so_zerocopy;
>> +    /* 'errno' after 'sendmsg()' call. */
>> +    int sendmsg_errno;
>> +    /* Number of valid elements in 'vecs'. */
>> +    int vecs_cnt;
>> +    /* Array how to allocate buffers for test.
>> +     * 'iov_base' == NULL -> valid buf: mmap('iov_len').
>> +     *
>> +     * 'iov_base' == MAP_FAILED -> invalid buf:
>> +     *               mmap('iov_len'), then munmap('iov_len').
>> +     *               'iov_base' still contains result of
>> +     *               mmap().
>> +     *
>> +     * 'iov_base' == number -> unaligned valid buf:
>> +     *               mmap('iov_len') + number.
>> +     */
>> +    struct iovec vecs[VSOCK_TEST_DATA_MAX_IOV];
>> +};
>> +
>> +static struct vsock_test_data test_data_array[] = {
>> +    /* Last element has non-page aligned size. */
>> +    {
>> +        .zerocopied = true,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 3,
>> +        {
>> +            { NULL, PAGE_SIZE },
>> +            { NULL, PAGE_SIZE },
>> +            { NULL, 200 }
>> +        }
>> +    },
>> +    /* All elements have page aligned base and size. */
>> +    {
>> +        .zerocopied = true,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 3,
>> +        {
>> +            { NULL, PAGE_SIZE },
>> +            { NULL, PAGE_SIZE * 2 },
>> +            { NULL, PAGE_SIZE * 3 }
>> +        }
>> +    },
>> +    /* All elements have page aligned base and size. But
>> +     * data length is bigger than 64Kb.
>> +     */
>> +    {
>> +        .zerocopied = true,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 3,
>> +        {
>> +            { NULL, PAGE_SIZE * 16 },
>> +            { NULL, PAGE_SIZE * 16 },
>> +            { NULL, PAGE_SIZE * 16 }
>> +        }
>> +    },
>> +    /* Middle element has both non-page aligned base and size. */
>> +    {
>> +        .zerocopied = true,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 3,
>> +        {
>> +            { NULL, PAGE_SIZE },
>> +            { (void *)1, 100 },
>> +            { NULL, PAGE_SIZE }
>> +        }
>> +    },
>> +    /* Middle element is unmapped. */
>> +    {
>> +        .zerocopied = false,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = ENOMEM,
>> +        .vecs_cnt = 3,
>> +        {
>> +            { NULL, PAGE_SIZE },
>> +            { MAP_FAILED, PAGE_SIZE },
>> +            { NULL, PAGE_SIZE }
>> +        }
>> +    },
>> +    /* Valid data, but SO_ZEROCOPY is off. This
>> +     * will trigger fallback to copy.
>> +     */
>> +    {
>> +        .zerocopied = false,
>> +        .so_zerocopy = false,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 1,
>> +        {
>> +            { NULL, PAGE_SIZE }
>> +        }
>> +    },
>> +    /* Valid data, but message is bigger than peer's
>> +     * buffer, so this will trigger fallback to copy.
>> +     * This test is for SOCK_STREAM only, because
>> +     * for SOCK_SEQPACKET, 'sendmsg()' returns EMSGSIZE.
>> +     */
>> +    {
>> +        .stream_only = true,
>> +        .zerocopied = false,
>> +        .so_zerocopy = true,
>> +        .sendmsg_errno = 0,
>> +        .vecs_cnt = 1,
>> +        {
>> +            { NULL, 100 * PAGE_SIZE }
>> +        }
>> +    },
>> +};
>> +
>> +#define POLL_TIMEOUT_MS        100
>> +
>> +static void test_client(const struct test_opts *opts,
>> +            const struct vsock_test_data *test_data,
>> +            bool sock_seqpacket)
>> +{
>> +    struct pollfd fds = { 0 };
>> +    struct msghdr msg = { 0 };
>> +    ssize_t sendmsg_res;
>> +    struct iovec *iovec;
>> +    int fd;
>> +
>> +    if (sock_seqpacket)
>> +        fd = vsock_seqpacket_connect(opts->peer_cid, 1234);
>> +    else
>> +        fd = vsock_stream_connect(opts->peer_cid, 1234);
>> +
>> +    if (fd < 0) {
>> +        perror("connect");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (test_data->so_zerocopy)
>> +        enable_so_zerocopy(fd);
>> +
>> +    iovec = iovec_from_test_data(test_data->vecs, test_data->vecs_cnt);
>> +
>> +    msg.msg_iov = iovec;
>> +    msg.msg_iovlen = test_data->vecs_cnt;
>> +
>> +    errno = 0;
>> +
>> +    sendmsg_res = sendmsg(fd, &msg, MSG_ZEROCOPY);
>> +    if (errno != test_data->sendmsg_errno) {
>> +        fprintf(stderr, "expected 'errno' == %i, got %i\n",
>> +            test_data->sendmsg_errno, errno);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (!errno) {
>> +        if (sendmsg_res != iovec_bytes(iovec, test_data->vecs_cnt)) {
>> +            fprintf(stderr, "expected 'sendmsg()' == %li, got %li\n",
>> +                iovec_bytes(iovec, test_data->vecs_cnt),
>> +                sendmsg_res);
>> +            exit(EXIT_FAILURE);
>> +        }
>> +    }
>> +
>> +    fds.fd = fd;
>> +    fds.events = 0;
>> +
>> +    if (poll(&fds, 1, POLL_TIMEOUT_MS) < 0) {
>> +        perror("poll");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (fds.revents & POLLERR) {
>> +        vsock_recv_completion(fd, &test_data->zerocopied);
>> +    } else if (test_data->so_zerocopy && !test_data->sendmsg_errno) {
>> +        /* If we don't have data in the error queue, but
>> +         * SO_ZEROCOPY was enabled and 'sendmsg()' was
>> +         * successful - this is an error.
>> +         */
>> +        fprintf(stderr, "POLLERR expected\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    if (!test_data->sendmsg_errno)
>> +        control_writeulong(iovec_hash_djb2(iovec, test_data->vecs_cnt));
>> +    else
>> +        control_writeulong(0);
>> +
>> +    control_writeln("DONE");
>> +    free_iovec_test_data(test_data->vecs, iovec, test_data->vecs_cnt);
>> +    close(fd);
>> +}
>> +
>> +void test_stream_msgzcopy_client(const struct test_opts *opts)
>> +{
>> +    int i;
>> +
>> +    for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
>> +        test_client(opts, &test_data_array[i], false);
>> +}
>> +
>> +void test_seqpacket_msgzcopy_client(const struct test_opts *opts)
>> +{
>> +    int i;
>> +
>> +    for (i = 0; i < ARRAY_SIZE(test_data_array); i++) {
>> +        if (test_data_array[i].stream_only)
>> +            continue;
>> +
>> +        test_client(opts, &test_data_array[i], true);
>> +    }
>> +}
>> +
>> +static void test_server(const struct test_opts *opts,
>> +            const struct vsock_test_data *test_data,
>> +            bool sock_seqpacket)
>> +{
>> +    unsigned long remote_hash;
>> +    unsigned long local_hash;
>> +    ssize_t total_bytes_rec;
>> +    unsigned char *data;
>> +    size_t data_len;
>> +    int fd;
>> +
>> +    if (sock_seqpacket)
>> +        fd = vsock_seqpacket_accept(VMADDR_CID_ANY, 1234, NULL);
>> +    else
>> +        fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
>> +
>> +    if (fd < 0) {
>> +        perror("accept");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    data_len = iovec_bytes(test_data->vecs, test_data->vecs_cnt);
>> +
>> +    data = malloc(data_len);
>> +    if (!data) {
>> +        perror("malloc");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    total_bytes_rec = 0;
>> +
>> +    while (total_bytes_rec != data_len) {
>> +        ssize_t bytes_rec;
>> +
>> +        bytes_rec = read(fd, data + total_bytes_rec,
>> +                 data_len - total_bytes_rec);
>> +        if (bytes_rec <= 0)
>> +            break;
>> +
>> +        total_bytes_rec += bytes_rec;
>> +    }
>> +
>> +    if (test_data->sendmsg_errno == 0)
>> +        local_hash = hash_djb2(data, data_len);
>> +    else
>> +        local_hash = 0;
>> +
>> +    free(data);
>> +
>> +    /* Waiting for some result. */
>> +    remote_hash = control_readulong();
>> +    if (remote_hash != local_hash) {
>> +        fprintf(stderr, "hash mismatch\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_expectln("DONE");
>> +    close(fd);
>> +}
>> +
>> +void test_stream_msgzcopy_server(const struct test_opts *opts)
>> +{
>> +    int i;
>> +
>> +    for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
>> +        test_server(opts, &test_data_array[i], false);
>> +}
>> +
>> +void test_seqpacket_msgzcopy_server(const struct test_opts *opts)
>> +{
>> +    int i;
>> +
>> +    for (i = 0; i < ARRAY_SIZE(test_data_array); i++) {
>> +        if (test_data_array[i].stream_only)
>> +            continue;
>> +
>> +        test_server(opts, &test_data_array[i], true);
>> +    }
>> +}
>> +
>> +void test_stream_msgzcopy_empty_errq_client(const struct test_opts *opts)
>> +{
>> +    struct msghdr msg = { 0 };
>> +    char cmsg_data[128];
>> +    ssize_t res;
>> +    int fd;
>> +
>> +    fd = vsock_stream_connect(opts->peer_cid, 1234);
>> +    if (fd < 0) {
>> +        perror("connect");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    msg.msg_control = cmsg_data;
>> +    msg.msg_controllen = sizeof(cmsg_data);
>> +
>> +    res = recvmsg(fd, &msg, MSG_ERRQUEUE);
>> +    if (res != -1) {
>> +        fprintf(stderr, "expected 'recvmsg(2)' failure, got %zi\n",
>> +            res);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_writeln("DONE");
>> +    close(fd);
>> +}
>> +
>> +void test_stream_msgzcopy_empty_errq_server(const struct test_opts *opts)
>> +{
>> +    int fd;
>> +
>> +    fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
>> +    if (fd < 0) {
>> +        perror("accept");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_expectln("DONE");
>> +    close(fd);
>> +}
>> diff --git a/tools/testing/vsock/vsock_test_zerocopy.h b/tools/testing/vsock/vsock_test_zerocopy.h
>> new file mode 100644
>> index 000000000000..3ef2579e024d
>> --- /dev/null
>> +++ b/tools/testing/vsock/vsock_test_zerocopy.h
>> @@ -0,0 +1,15 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +#ifndef VSOCK_TEST_ZEROCOPY_H
>> +#define VSOCK_TEST_ZEROCOPY_H
>> +#include "util.h"
>> +
>> +void test_stream_msgzcopy_client(const struct test_opts *opts);
>> +void test_stream_msgzcopy_server(const struct test_opts *opts);
>> +
>> +void test_seqpacket_msgzcopy_client(const struct test_opts *opts);
>> +void test_seqpacket_msgzcopy_server(const struct test_opts *opts);
>> +
>> +void test_stream_msgzcopy_empty_errq_client(const struct test_opts *opts);
>> +void test_stream_msgzcopy_empty_errq_server(const struct test_opts *opts);
>> +
>> +#endif /* VSOCK_TEST_ZEROCOPY_H */
>> -- 
>> 2.25.1
>>
>