Re: [libvirt] [RFC v2 10/16] qemu: add vhost-user-gpu helper unit

From: Marc-André Lureau <marcandre.lureau(a)redhat.com&gt; Similar to the qemu_tpm.c, add a unit with a few functions to start/stop and setup the cgroup of the external vhost-user-gpu process. See function documentation. Signed-off-by: Marc-André Lureau <marcandre.lureau(a)redhat.com&gt; --- src/conf/device_conf.h | 1 + src/qemu/Makefile.inc.am | 2 + src/qemu/qemu_vhost_user_gpu.c | 318 +++++++++++++++++++++++++++++++++ src/qemu/qemu_vhost_user_gpu.h | 48 +++++ 4 files changed, 369 insertions(+) create mode 100644 src/qemu/qemu_vhost_user_gpu.c create mode 100644 src/qemu/qemu_vhost_user_gpu.h diff --git a/src/conf/device_conf.h b/src/conf/device_conf.h index ff7d6c9d5f..79a7ea9fe2 100644 --- a/src/conf/device_conf.h +++ b/src/conf/device_conf.h @@ -175,6 +175,7 @@ struct _virDomainDeviceInfo { * cases we might want to prevent that from happening by * locking the isolation group */ bool isolationGroupLocked; + int vhost_user_fd; }; int virDomainDeviceInfoCopy(virDomainDeviceInfoPtr dst, diff --git a/src/qemu/Makefile.inc.am b/src/qemu/Makefile.inc.am index 2afa67f195..28daf9d426 100644 --- a/src/qemu/Makefile.inc.am +++ b/src/qemu/Makefile.inc.am @@ -56,6 +56,8 @@ QEMU_DRIVER_SOURCES = \ qemu/qemu_qapi.h \ qemu/qemu_tpm.c \ qemu/qemu_tpm.h \ + qemu/qemu_vhost_user_gpu.c \ + qemu/qemu_vhost_user_gpu.h \ $(NULL) diff --git a/src/qemu/qemu_vhost_user_gpu.c b/src/qemu/qemu_vhost_user_gpu.c new file mode 100644 index 0000000000..9007614020 --- /dev/null +++ b/src/qemu/qemu_vhost_user_gpu.c @@ -0,0 +1,318 @@ +/* + * qemu_vhost_user_gpu.c: QEMU vhost-user GPU support + * + * Copyright (C) 2018 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/>;. + * + * Author: Marc-André Lureau <marcandre.lureau(a)redhat.com&gt; + */ + +#include <config.h> + +#include "qemu_extdevice.h" +#include "qemu_domain.h" +#include "qemu_security.h" + +#include "conf/domain_conf.h" +#include "vircommand.h" +#include "viralloc.h" +#include "virlog.h" +#include "virutil.h" +#include "virfile.h" +#include "virstring.h" +#include "virtime.h" +#include "virpidfile.h" +#include "qemu_vhost_user_gpu.h" + +#define VIR_FROM_THIS VIR_FROM_NONE + +VIR_LOG_INIT("qemu.vhost-user-gpu") + +/* + * Look up the vhost-user-gpu executable; to be found on the host + */ +static char *vhost_user_gpu_path; + +static int +qemuVhostUserGPUInit(void) +{ + if (!vhost_user_gpu_path) { + vhost_user_gpu_path = virFindFileInPath("vhost-user-gpu"); + if (!vhost_user_gpu_path) { + virReportSystemError(ENOENT, "%s", + _("Unable to find 'vhost-user-gpu' binary in $PATH")); + return -1; + } + if (!virFileIsExecutable(vhost_user_gpu_path)) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("vhost-user-gpu %s is not an executable"), + vhost_user_gpu_path); + VIR_FREE(vhost_user_gpu_path); + return -1; + } + } + + return 0; +} + + +static char * +qemuVhostUserGPUCreatePidFilename(const char *stateDir, + const char *shortName, + const char *alias) +{ + char *pidfile = NULL; + char *devicename = NULL; + + if (virAsprintf(&devicename, "%s-%s-vhost-user-gpu", shortName, alias) < 0) + return NULL; + + pidfile = virPidFileBuildPath(stateDir, devicename); + + VIR_FREE(devicename); + + return pidfile; +} + + +/* + * qemuVhostUserGPUGetPid + * + * @stateDir: the directory where vhost-user-gpu writes the pidfile into + * @shortName: short name of the domain + * @alias: video device alias + * @pid: pointer to pid + * + * Return -errno upon error, or zero on successful reading of the pidfile. + * If the PID was not still alive, zero will be returned, and @pid will be + * set to -1; + */ +static int +qemuVhostUserGPUGetPid(const char *stateDir, + const char *shortName, + const char *alias, + pid_t *pid) +{ + int ret; + char *pidfile = qemuVhostUserGPUCreatePidFilename(stateDir, shortName, alias); + if (!pidfile) + return -ENOMEM; + + ret = virPidFileReadPathIfAlive(pidfile, pid, vhost_user_gpu_path); + + VIR_FREE(pidfile); + + return ret; +} + + +/* + * qemuExtVhostUserGPUStart: + * + * @driver: QEMU driver + * @def: domain definition + * @video: the video device + * @logCtxt: log context + * + * Start the external vhost-user-gpu process: + * - open a socketpair for vhost-user communication + * - have the command line built + * - start the external process and sync with it before QEMU start + */ +int qemuExtVhostUserGPUStart(virQEMUDriverPtr driver, + virDomainDefPtr def, + virDomainVideoDefPtr video, + qemuDomainLogContextPtr logCtxt) +{ + int ret = -1; + virCommandPtr cmd = NULL; + int exitstatus = 0; + char *errbuf = NULL; + virQEMUDriverConfigPtr cfg; + char *pidfile, *shortName = virDomainDefGetShortName(def); + virTimeBackOffVar timebackoff; + const unsigned long long timeout = 500000; /* ms */

+ int cmdret = 0, rc; + int pair[2] = { -1, -1 }; + + pid_t pid; + + if (!shortName) + return -1; + + cfg = virQEMUDriverGetConfig(driver); + + /* stop any left-over for this VM */ + qemuExtVhostUserGPUStop(driver, def, video); + + if (!(pidfile = qemuVhostUserGPUCreatePidFilename( + cfg->stateDir, shortName, video->info.alias))) + goto error; + + if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) { + virReportSystemError(errno, "%s", _("failed to create socket")); + goto error; + }