qemu: add vhost-user helpers

Add qemuVhostUserFetchConfigs() to discover vhost-user helpers.

qemuVhostUserFillDomainGPU() will find the first matching GPU helper
with the required capabilities and set the associated
vhost_user_binary.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NCole Robinson <crobinso@redhat.com>

src/conf/domain_conf.c

@@ -2844,6 +2844,8 @@ virDomainVideoDefClear(virDomainVideoDefPtr def)
         VIR_FREE(def->accel->rendernode);
     VIR_FREE(def->accel);
     VIR_FREE(def->virtio);
+    if (def->driver)
+        VIR_FREE(def->driver->vhost_user_binary);
     VIR_FREE(def->driver);
 
     memset(def, 0, sizeof(*def));

src/conf/domain_conf.h

@@ -1423,6 +1423,7 @@ struct _virDomainVideoAccelDef {
 
 struct _virDomainVideoDriverDef {
    virDomainVideoVGAConf vgaconf;
+    char *vhost_user_binary;
 };
 
 struct _virDomainVideoDef {

src/qemu/Makefile.inc.am

@@ -64,6 +64,8 @@ QEMU_DRIVER_SOURCES = \
 	qemu/qemu_slirp.h \
 	qemu/qemu_tpm.c \
 	qemu/qemu_tpm.h \
+	qemu/qemu_vhost_user.c \
+	qemu/qemu_vhost_user.h \
 	$(NULL)
 
 

src/qemu/qemu_vhost_user.c

+/*
+ * qemu_vhost_user.c: QEMU vhost-user
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include "qemu_vhost_user.h"
+#include "qemu_interop_config.h"
+#include "virjson.h"
+#include "virlog.h"
+#include "virstring.h"
+#include "viralloc.h"
+#include "virenum.h"
+
+#define VIR_FROM_THIS VIR_FROM_QEMU
+
+VIR_LOG_INIT("qemu.qemu_vhost_user");
+
+typedef enum {
+    QEMU_VHOST_USER_TYPE_NONE = 0,
+    QEMU_VHOST_USER_TYPE_9P,
+    QEMU_VHOST_USER_TYPE_BALLOON,
+    QEMU_VHOST_USER_TYPE_BLOCK,
+    QEMU_VHOST_USER_TYPE_CAIF,
+    QEMU_VHOST_USER_TYPE_CONSOLE,
+    QEMU_VHOST_USER_TYPE_CRYPTO,
+    QEMU_VHOST_USER_TYPE_GPU,
+    QEMU_VHOST_USER_TYPE_INPUT,
+    QEMU_VHOST_USER_TYPE_NET,
+    QEMU_VHOST_USER_TYPE_RNG,
+    QEMU_VHOST_USER_TYPE_RPMSG,
+    QEMU_VHOST_USER_TYPE_RPROC_SERIAL,
+    QEMU_VHOST_USER_TYPE_SCSI,
+    QEMU_VHOST_USER_TYPE_VSOCK,
+    QEMU_VHOST_USER_TYPE_FS,
+
+    QEMU_VHOST_USER_TYPE_LAST
+} qemuVhostUserType;
+
+VIR_ENUM_DECL(qemuVhostUserType);
+VIR_ENUM_IMPL(qemuVhostUserType,
+              QEMU_VHOST_USER_TYPE_LAST,
+              "",
+              "9p",
+              "balloon",
+              "block",
+              "caif",
+              "console",
+              "crypto",
+              "gpu",
+              "input",
+              "net",
+              "rng",
+              "rpmsg",
+              "rproc-serial",
+              "scsi",
+              "vsock",
+              "fs",
+);
+
+typedef enum {
+    QEMU_VHOST_USER_GPU_FEATURE_NONE = 0,
+    QEMU_VHOST_USER_GPU_FEATURE_VIRGL,
+    QEMU_VHOST_USER_GPU_FEATURE_RENDER_NODE,
+
+    QEMU_VHOST_USER_GPU_FEATURE_LAST
+} qemuVhostUserGPUFeature;
+
+VIR_ENUM_DECL(qemuVhostUserGPUFeature);
+VIR_ENUM_IMPL(qemuVhostUserGPUFeature,
+              QEMU_VHOST_USER_GPU_FEATURE_LAST,
+              "",
+              "virgl",
+              "render-node",
+);
+
+typedef struct _qemuVhostUserGPU qemuVhostUserGPU;
+typedef qemuVhostUserGPU *qemuVhostUserGPUPtr;
+struct _qemuVhostUserGPU {
+    size_t nfeatures;
+    qemuVhostUserGPUFeature *features;
+};
+
+struct _qemuVhostUser {
+    /* Description intentionally not parsed. */
+    qemuVhostUserType type;
+    char *binary;
+    /* Tags intentionally not parsed. */
+
+    union {
+        qemuVhostUserGPU gpu;
+    } capabilities;
+};
+
+
+static void
+qemuVhostUserGPUFeatureFree(qemuVhostUserGPUFeature *features)
+{
+    VIR_FREE(features);
+}
+
+
+VIR_DEFINE_AUTOPTR_FUNC(qemuVhostUserGPUFeature, qemuVhostUserGPUFeatureFree);
+
+
+void
+qemuVhostUserFree(qemuVhostUserPtr vu)
+{
+    if (!vu)
+        return;
+
+    if (vu->type == QEMU_VHOST_USER_TYPE_GPU)
+        VIR_FREE(vu->capabilities.gpu.features);
+
+    VIR_FREE(vu->binary);
+
+    VIR_FREE(vu);
+}
+
+
+/* 1MiB should be enough for everybody (TM) */
+#define DOCUMENT_SIZE (1024 * 1024)
+
+
+static int
+qemuVhostUserTypeParse(const char *path,
+                       virJSONValuePtr doc,
+                       qemuVhostUserPtr vu)
+{
+    const char *type = virJSONValueObjectGetString(doc, "type");
+    int tmp;
+
+    VIR_DEBUG("vhost-user description path '%s' type : %s",
+              path, type);
+
+    if ((tmp = qemuVhostUserTypeTypeFromString(type)) <= 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("unknown vhost-user type: '%s'"),
+                       type);
+        return -1;
+    }
+
+    vu->type = tmp;
+
+    return 0;
+}
+
+
+static int
+qemuVhostUserBinaryParse(const char *path,
+                         virJSONValuePtr doc,
+                         qemuVhostUserPtr vu)
+{
+    const char *binary = virJSONValueObjectGetString(doc, "binary");
+
+    VIR_DEBUG("vhost-user description path '%s' binary : %s",
+              path, binary);
+
+    if (VIR_STRDUP(vu->binary, binary) < 0)
+        return -1;
+
+    return 0;
+}
+
+
+qemuVhostUserPtr
+qemuVhostUserParse(const char *path)
+{
+    VIR_AUTOFREE(char *) cont = NULL;
+    VIR_AUTOPTR(virJSONValue) doc = NULL;
+    VIR_AUTOPTR(qemuVhostUser) vu = NULL;
+    qemuVhostUserPtr ret = NULL;
+
+    if (virFileReadAll(path, DOCUMENT_SIZE, &cont) < 0)
+        return NULL;
+
+    if (!(doc = virJSONValueFromString(cont))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("unable to parse json file '%s'"),
+                       path);
+        return NULL;
+    }
+
+    if (VIR_ALLOC(vu) < 0)
+        return NULL;
+
+    if (qemuVhostUserTypeParse(path, doc, vu) < 0)
+        return NULL;
+
+    if (qemuVhostUserBinaryParse(path, doc, vu) < 0)
+        return NULL;
+
+    VIR_STEAL_PTR(ret, vu);
+    return ret;
+}
+
+
+char *
+qemuVhostUserFormat(qemuVhostUserPtr vu)
+{
+    VIR_AUTOPTR(virJSONValue) doc = NULL;
+
+    if (!vu)
+        return NULL;
+
+    if (!(doc = virJSONValueNewObject()))
+        return NULL;
+
+    if (virJSONValueObjectAppendString(doc, "type",
+                                       qemuVhostUserTypeTypeToString(vu->type)) < 0)
+        return NULL;
+
+    if (virJSONValueObjectAppendString(doc, "binary", vu->binary) < 0)
+        return NULL;
+
+    return virJSONValueToString(doc, true);
+}
+
+
+int
+qemuVhostUserFetchConfigs(char ***configs,
+                          bool privileged)
+{
+    return qemuInteropFetchConfigs("vhost-user", configs, privileged);
+}
+
+
+static ssize_t
+qemuVhostUserFetchParsedConfigs(bool privileged,
+                                qemuVhostUserPtr **vhostuserRet,
+                                char ***pathsRet)
+{
+    VIR_AUTOSTRINGLIST paths = NULL;
+    size_t npaths;
+    qemuVhostUserPtr *vus = NULL;
+    size_t i;
+
+    if (qemuVhostUserFetchConfigs(&paths, privileged) < 0)
+        return -1;
+
+    npaths = virStringListLength((const char **)paths);
+
+    if (VIR_ALLOC_N(vus, npaths) < 0)
+        return -1;
+
+    for (i = 0; i < npaths; i++) {
+        if (!(vus[i] = qemuVhostUserParse(paths[i])))
+            goto error;
+    }
+
+    VIR_STEAL_PTR(*vhostuserRet, vus);
+    if (pathsRet)
+        VIR_STEAL_PTR(*pathsRet, paths);
+    return npaths;
+
+ error:
+    while (i > 0)
+        qemuVhostUserFree(vus[--i]);
+    VIR_FREE(vus);
+    return -1;
+}
+
+
+static int
+qemuVhostUserGPUFillCapabilities(qemuVhostUserPtr vu,
+                                 virJSONValuePtr doc)
+{
+    qemuVhostUserGPUPtr gpu = &vu->capabilities.gpu;
+    virJSONValuePtr featuresJSON;
+    size_t nfeatures;
+    size_t i;
+    VIR_AUTOPTR(qemuVhostUserGPUFeature) features = NULL;
+
+    if (!(featuresJSON = virJSONValueObjectGetArray(doc, "features"))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("failed to get features from '%s'"),
+                       vu->binary);
+        return -1;
+    }
+
+    nfeatures = virJSONValueArraySize(featuresJSON);
+    if (VIR_ALLOC_N(features, nfeatures) < 0)
+        return -1;
+
+    for (i = 0; i < nfeatures; i++) {
+        virJSONValuePtr item = virJSONValueArrayGet(featuresJSON, i);
+        const char *tmpStr = virJSONValueGetString(item);
+        int tmp;
+
+        if ((tmp = qemuVhostUserGPUFeatureTypeFromString(tmpStr)) <= 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("unknown feature %s"),
+                           tmpStr);
+            continue;
+        }
+
+        features[i] = tmp;
+    }
+
+    VIR_STEAL_PTR(gpu->features, features);
+    gpu->nfeatures = nfeatures;
+
+    return 0;
+}
+
+
+static bool
+qemuVhostUserGPUHasFeature(qemuVhostUserGPUPtr gpu,
+                           qemuVhostUserGPUFeature feature)
+{
+    size_t i;
+
+    for (i = 0; i < gpu->nfeatures; i++) {
+        if (gpu->features[i] == feature)
+            return true;
+    }
+
+    return false;
+}
+
+
+int
+qemuVhostUserFillDomainGPU(virQEMUDriverPtr driver,
+                           virDomainVideoDefPtr video)
+{
+    qemuVhostUserPtr *vus = NULL;
+    qemuVhostUserPtr vu = NULL;
+    ssize_t nvus = 0;
+    ssize_t i;
+    int ret = -1;
+
+    if ((nvus = qemuVhostUserFetchParsedConfigs(driver->privileged,
+                                                &vus, NULL)) < 0)
+        goto end;
+
+    for (i = 0; i < nvus; i++) {
+        VIR_AUTOPTR(virJSONValue) doc = NULL;
+        VIR_AUTOFREE(char *) output = NULL;
+        VIR_AUTOPTR(virCommand) cmd = NULL;
+
+        vu = vus[i];
+        if (vu->type != QEMU_VHOST_USER_TYPE_GPU)
+            continue;
+
+        cmd = virCommandNewArgList(vu->binary, "--print-capabilities", NULL);
+        virCommandSetOutputBuffer(cmd, &output);
+        if (virCommandRun(cmd, NULL) < 0)
+            continue;
+
+        if (!(doc = virJSONValueFromString(output))) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("unable to parse json capabilities '%s'"),
+                           vu->binary);
+            continue;
+        }
+
+        if (qemuVhostUserGPUFillCapabilities(vu, doc) < 0)
+            continue;
+
+        if (video->accel) {
+            if (video->accel->accel3d &&
+                !qemuVhostUserGPUHasFeature(&vu->capabilities.gpu,
+                                            QEMU_VHOST_USER_GPU_FEATURE_VIRGL))
+                continue;
+
+            if (video->accel->rendernode &&
+                !qemuVhostUserGPUHasFeature(&vu->capabilities.gpu,
+                                            QEMU_VHOST_USER_GPU_FEATURE_RENDER_NODE))
+                continue;
+        }
+
+        if (!video->driver && VIR_ALLOC(video->driver) < 0)
+            goto end;
+
+        VIR_FREE(video->driver->vhost_user_binary);
+        if (VIR_STRDUP(video->driver->vhost_user_binary, vu->binary) < 0)
+            goto end;
+
+        break;
+    }
+
+    if (i == nvus) {
+        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+                       _("Unable to find a satisfying vhost-user-gpu"));
+        goto end;
+    }
+
+    if (!video->accel && VIR_ALLOC(video->accel) < 0)
+        goto end;
+
+    if (!video->accel->rendernode &&
+        qemuVhostUserGPUHasFeature(&vu->capabilities.gpu,
+                                   QEMU_VHOST_USER_GPU_FEATURE_RENDER_NODE)) {
+        video->accel->rendernode = virHostGetDRMRenderNode();
+        if (!video->accel->rendernode)
+            goto end;
+    }
+
+    ret = 0;
+
+ end:
+    for (i = 0; i < nvus; i++)
+        qemuVhostUserFree(vus[i]);
+    VIR_FREE(vus);
+    return ret;
+}

src/qemu/qemu_vhost_user.h

+/*
+ * qemu_vhost_user.h: QEMU vhost-user
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "domain_conf.h"
+#include "qemu_conf.h"
+#include "virautoclean.h"
+#include "virarch.h"
+
+typedef struct _qemuVhostUser qemuVhostUser;
+typedef qemuVhostUser *qemuVhostUserPtr;
+
+void
+qemuVhostUserFree(qemuVhostUserPtr fw);
+
+VIR_DEFINE_AUTOPTR_FUNC(qemuVhostUser, qemuVhostUserFree);
+
+qemuVhostUserPtr
+qemuVhostUserParse(const char *path);
+
+char *
+qemuVhostUserFormat(qemuVhostUserPtr fw);
+
+int
+qemuVhostUserFetchConfigs(char ***configs,
+                         bool privileged);
+
+int
+qemuVhostUserFillDomainGPU(virQEMUDriverPtr driver,
+                           virDomainVideoDefPtr video);

tests/Makefile.am

@@ -127,6 +127,7 @@ EXTRA_DIST = \
 	qemustatusxml2xmldata \
 	qemumemlockdata \
 	qemufirmwaredata \
+	qemuvhostuserdata \
 	secretxml2xmlin \
 	securityselinuxhelperdata \
 	securityselinuxlabeldata \
@@ -290,6 +291,7 @@ test_programs += qemuxml2argvtest qemuxml2xmltest \
 	qemumigparamstest \
 	qemusecuritytest \
 	qemufirmwaretest \
+	qemuvhostusertest \
 	$(NULL)
 test_helpers += qemucapsprobe
 test_libraries += libqemumonitortestutils.la \
@@ -692,6 +694,13 @@ qemufirmwaretest_SOURCES = \
 	$(NULL)
 qemufirmwaretest_LDADD = $(qemu_LDADDS)
 
+qemuvhostusertest_SOURCES = \
+	qemuvhostusertest.c \
+	testutils.h testutils.c \
+	virfilewrapper.c virfilewrapper.h \
+	$(NULL)
+qemuvhostusertest_LDADD = $(qemu_LDADDS)
+
 else ! WITH_QEMU
 EXTRA_DIST += qemuxml2argvtest.c qemuxml2xmltest.c \
 	qemudomaincheckpointxml2xmltest.c qemudomainsnapshotxml2xmltest.c \
@@ -706,6 +715,7 @@ EXTRA_DIST += qemuxml2argvtest.c qemuxml2xmltest.c \
 	qemusecuritytest.c qemusecuritytest.h \
 	qemusecuritymock.c \
 	qemufirmwaretest.c \
+	qemuvhostusertest.c \
 	$(QEMUMONITORTESTUTILS_SOURCES)
 endif ! WITH_QEMU
 

tests/qemuvhostuserdata/etc/qemu/vhost-user/40-gpu.json

+../../../usr/share/qemu/vhost-user/50-gpu.json
\ No newline at end of file

tests/qemuvhostuserdata/usr/libexec/qemu/vhost-user/test-vhost-user-gpu

+#!/bin/sh
+
+cat <<EOF
+{
+  "type": "gpu",
+  "features": [
+    "render-node",
+    "virgl"
+  ]
+}
+EOF

tests/qemuvhostuserdata/usr/share/qemu/vhost-user/30-gpu.json

+50-gpu.json
\ No newline at end of file

tests/qemuvhostuserdata/usr/share/qemu/vhost-user/50-gpu.json

+{
+  "description": "QEMU vhost-user-gpu",
+  "type": "gpu",
+  "binary": "/usr/libexec/qemu/vhost-user/test-vhost-user-gpu",
+  "tags": [
+    "CONFIG_OPENGL_DMABUF=y"
+  ]
+}

tests/qemuvhostuserdata/usr/share/qemu/vhost-user/60-gpu.json

+50-gpu.json
\ No newline at end of file

tests/qemuvhostusertest.c

+#include <config.h>
+
+#include <inttypes.h>
+
+#include "testutils.h"
+#include "virfilewrapper.h"
+#include "qemu/qemu_vhost_user.h"
+#include "configmake.h"
+
+#define VIR_FROM_THIS VIR_FROM_QEMU
+
+/* A very basic test. Parse given JSON vhostuser description into
+ * an internal structure, format it back and compare with the
+ * contents of the file (minus some keys that are not parsed).
+ */
+static int
+testParseFormatVU(const void *opaque)
+{
+    const char *filename = opaque;
+    VIR_AUTOFREE(char *) path = NULL;
+    VIR_AUTOPTR(qemuVhostUser) vu = NULL;
+    VIR_AUTOFREE(char *) buf = NULL;
+    VIR_AUTOPTR(virJSONValue) json = NULL;
+    VIR_AUTOFREE(char *) expected = NULL;
+    VIR_AUTOFREE(char *) actual = NULL;
+
+    if (virAsprintf(&path, "%s/qemuvhostuserdata/%s",
+                    abs_srcdir, filename) < 0)
+        return -1;
+
+    if (!(vu = qemuVhostUserParse(path)))
+        return -1;
+
+    if (virFileReadAll(path,
+                       1024 * 1024, /* 1MiB */
+                       &buf) < 0)
+        return -1;
+
+    if (!(json = virJSONValueFromString(buf)))
+        return -1;
+
+    /* Description and tags are not parsed. */
+    if (virJSONValueObjectRemoveKey(json, "description", NULL) < 0 ||
+        virJSONValueObjectRemoveKey(json, "tags", NULL) < 0)
+        return -1;
+
+    if (!(expected = virJSONValueToString(json, true)))
+        return -1;
+
+    if (!(actual = qemuVhostUserFormat(vu)))
+        return -1;
+
+    return virTestCompareToString(expected, actual);
+}
+
+
+static int
+testVUPrecedence(const void *opaque ATTRIBUTE_UNUSED)
+{
+    VIR_AUTOFREE(char *) fakehome = NULL;
+    VIR_AUTOSTRINGLIST vuList = NULL;
+    size_t nvuList;
+    size_t i;
+    const char *expected[] = {
+        PREFIX "/share/qemu/vhost-user/30-gpu.json",
+        SYSCONFDIR "/qemu/vhost-user/40-gpu.json",
+        PREFIX "/share/qemu/vhost-user/60-gpu.json",
+    };
+    const size_t nexpected = ARRAY_CARDINALITY(expected);
+
+    if (VIR_STRDUP(fakehome, abs_srcdir "/qemuvhostuserdata/home/user/.config") < 0)
+        return -1;
+
+    setenv("XDG_CONFIG_HOME", fakehome, 1);
+
+    if (qemuVhostUserFetchConfigs(&vuList, false) < 0)
+        return -1;
+
+    if (!vuList) {
+        fprintf(stderr, "Expected a non-NULL result, but got a NULL result\n");
+        return -1;
+    }
+
+    nvuList = virStringListLength((const char **)vuList);
+
+    for (i = 0; i < MAX(nvuList, nexpected); i++) {
+        const char *e = i < nexpected ? expected[i] : NULL;
+        const char *f = i < nvuList ? vuList[i] : NULL;
+
+        if (STRNEQ_NULLABLE(e, f)) {
+            fprintf(stderr,
+                    "Unexpected path (i=%zu). Expected %s got %s \n",
+                    i, NULLSTR(e), NULLSTR(f));
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+
+static int
+mymain(void)
+{
+    int ret = 0;
+
+    virFileWrapperAddPrefix(SYSCONFDIR "/qemu/vhost-user",
+                            abs_srcdir "/qemuvhostuserdata/etc/qemu/vhost-user");
+    virFileWrapperAddPrefix(PREFIX "/share/qemu/vhost-user",
+                            abs_srcdir "/qemuvhostuserdata/usr/share/qemu/vhost-user");
+    virFileWrapperAddPrefix("/home/user/.config/qemu/vhost-user",
+                            abs_srcdir "/qemuvhostuserdata/home/user/.config/qemu/vhost-user");
+
+#define DO_PARSE_TEST(filename) \
+    do { \
+        if (virTestRun("QEMU vhost-user " filename, \
+                       testParseFormatVU, filename) < 0) \
+            ret = -1; \
+    } while (0)
+
+    DO_PARSE_TEST("usr/share/qemu/vhost-user/50-gpu.json");
+
+    if (virTestRun("QEMU vhost-user precedence test", testVUPrecedence, NULL) < 0)
+        ret = -1;
+
+    virFileWrapperClearPrefixes();
+
+    return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+
+VIR_TEST_MAIN(mymain)