Introduce vhost-user-blk-test-server

This is a test vhost-user blk server that uses libvhost combined with
libaio basically acting as a proxy between a virtual disk and an actual
file on disk or a block device.

It has near native bare-metal performance when measured using
fio+io_uring in a linux guest on QEMU vs bare-metal fio on a physical
nvme namespace.

Signed-off-by: Daniil Tatianin <[email protected]>

meson.build

@@ -59,3 +59,5 @@ libvhost = static_library(
     include_directories: libvhost_includes,
     c_args: libvhost_args + libvhost_optional_args + libvhost_defines,
 )
+
+subdir('tests')

tests/meson.build

@@ -0,0 +1,17 @@
+libaio = cc.find_library('aio', required: true)
+libpthread = cc.find_library('pthread', required: true)
+
+vhost_user_blk_test_server_includes = include_directories(
+    '../'
+)
+
+vhost_user_blk_test_server = executable(
+    'vhost-user-blk-test-server',
+    'vhost_user_blk_test_server.c',
+    link_with: libvhost,
+    dependencies: [libaio, libpthread],
+    include_directories: [
+        vhost_user_blk_test_server_includes,
+        libvhost_includes
+    ]
+)

tests/test_utils.h

@@ -0,0 +1,37 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include <time.h>
+#include "vhost/server.h"
+
+/* Normally we pass LOG_VERBOSITY from make */
+#ifndef LOG_VERBOSITY
+#   define LOG_VERBOSITY LOG_INFO
+#endif
+
+/* Log function for tests */
+static const char *log_level_str[] = {
+    "ERROR",
+    "WARNING",
+    "INFO",
+    "DEBUG"
+};
+
+__attribute__((format(printf, 2, 3)))
+static inline void vhd_log_stderr(enum LogLevel level, const char *fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    if (level <= LOG_VERBOSITY) {
+        char timestr[64];
+        struct timeval tv;
+
+        gettimeofday(&tv, NULL);
+        strftime(timestr, sizeof(timestr), "%F %T", localtime(&tv.tv_sec));
+        fprintf(stderr, "%s.%03ld [%8s] ", timestr, tv.tv_usec / 1000,
+                log_level_str[level]);
+        vfprintf(stderr, fmt, args);
+        fprintf(stderr, "\n");
+    }
+    va_end(args);
+}