diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | contrib/systemd/qemu-vmsr-helper.service | 15 | ||||
| -rw-r--r-- | contrib/systemd/qemu-vmsr-helper.socket | 9 | ||||
| -rw-r--r-- | docs/tools/index.rst | 1 | ||||
| -rw-r--r-- | docs/tools/qemu-vmsr-helper.rst | 89 | ||||
| -rw-r--r-- | meson.build | 7 | ||||
| -rw-r--r-- | tools/i386/qemu-vmsr-helper.c | 530 | ||||
| -rw-r--r-- | tools/i386/rapl-msr-index.h | 28 |
8 files changed, 680 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 7d9811458c..f8df6940fa 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -140,6 +140,7 @@ F: docs/system/target-i386* F: target/i386/*.[ch] F: target/i386/Kconfig F: target/i386/meson.build +F: tools/i386/ Guest CPU cores (TCG) --------------------- diff --git a/contrib/systemd/qemu-vmsr-helper.service b/contrib/systemd/qemu-vmsr-helper.service new file mode 100644 index 0000000000..8fd397bf79 --- /dev/null +++ b/contrib/systemd/qemu-vmsr-helper.service @@ -0,0 +1,15 @@ +[Unit] +Description=Virtual RAPL MSR Daemon for QEMU + +[Service] +WorkingDirectory=/tmp +Type=simple +ExecStart=/usr/bin/qemu-vmsr-helper +PrivateTmp=yes +ProtectSystem=strict +ReadWritePaths=/var/run +RestrictAddressFamilies=AF_UNIX +Restart=always +RestartSec=0 + +[Install] diff --git a/contrib/systemd/qemu-vmsr-helper.socket b/contrib/systemd/qemu-vmsr-helper.socket new file mode 100644 index 0000000000..183e8304d6 --- /dev/null +++ b/contrib/systemd/qemu-vmsr-helper.socket @@ -0,0 +1,9 @@ +[Unit] +Description=Virtual RAPL MSR helper for QEMU + +[Socket] +ListenStream=/run/qemu-vmsr-helper.sock +SocketMode=0600 + +[Install] +WantedBy=multi-user.target diff --git a/docs/tools/index.rst b/docs/tools/index.rst index 8e65ce0dfc..33ad438e86 100644 --- a/docs/tools/index.rst +++ b/docs/tools/index.rst @@ -16,3 +16,4 @@ command line utilities and other standalone programs. qemu-pr-helper qemu-trace-stap virtfs-proxy-helper + qemu-vmsr-helper diff --git a/docs/tools/qemu-vmsr-helper.rst b/docs/tools/qemu-vmsr-helper.rst new file mode 100644 index 0000000000..6ec87b49d9 --- /dev/null +++ b/docs/tools/qemu-vmsr-helper.rst @@ -0,0 +1,89 @@ +================================== +QEMU virtual RAPL MSR helper +================================== + +Synopsis +-------- + +**qemu-vmsr-helper** [*OPTION*] + +Description +----------- + +Implements the virtual RAPL MSR helper for QEMU. + +Accessing the RAPL (Running Average Power Limit) MSR enables the RAPL powercap +driver to advertise and monitor the power consumption or accumulated energy +consumption of different power domains, such as CPU packages, DRAM, and other +components when available. + +However those register are accesible under priviliged access (CAP_SYS_RAWIO). +QEMU can use an external helper to access those priviliged register. + +:program:`qemu-vmsr-helper` is that external helper; it creates a listener +socket which will accept incoming connections for communication with QEMU. + +If you want to run VMs in a setup like this, this helper should be started as a +system service, and you should read the QEMU manual section on "RAPL MSR +support" to find out how to configure QEMU to connect to the socket created by +:program:`qemu-vmsr-helper`. + +After connecting to the socket, :program:`qemu-vmsr-helper` can +optionally drop root privileges, except for those capabilities that +are needed for its operation. + +:program:`qemu-vmsr-helper` can also use the systemd socket activation +protocol. In this case, the systemd socket unit should specify a +Unix stream socket, like this:: + + [Socket] + ListenStream=/var/run/qemu-vmsr-helper.sock + +Options +------- + +.. program:: qemu-vmsr-helper + +.. option:: -d, --daemon + + run in the background (and create a PID file) + +.. option:: -q, --quiet + + decrease verbosity + +.. option:: -v, --verbose + + increase verbosity + +.. option:: -f, --pidfile=PATH + + PID file when running as a daemon. By default the PID file + is created in the system runtime state directory, for example + :file:`/var/run/qemu-vmsr-helper.pid`. + +.. option:: -k, --socket=PATH + + path to the socket. By default the socket is created in + the system runtime state directory, for example + :file:`/var/run/qemu-vmsr-helper.sock`. + +.. option:: -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE] + + .. include:: ../qemu-option-trace.rst.inc + +.. option:: -u, --user=USER + + user to drop privileges to + +.. option:: -g, --group=GROUP + + group to drop privileges to + +.. option:: -h, --help + + Display a help message and exit. + +.. option:: -V, --version + + Display version information and exit. diff --git a/meson.build b/meson.build index a1e51277b0..9d3e2d2ddb 100644 --- a/meson.build +++ b/meson.build @@ -4073,6 +4073,13 @@ if have_tools dependencies: [authz, crypto, io, qom, qemuutil, libcap_ng, mpathpersist], install: true) + + if cpu in ['x86', 'x86_64'] + executable('qemu-vmsr-helper', files('tools/i386/qemu-vmsr-helper.c'), + dependencies: [authz, crypto, io, qom, qemuutil, + libcap_ng, mpathpersist], + install: true) + endif endif if have_ivshmem diff --git a/tools/i386/qemu-vmsr-helper.c b/tools/i386/qemu-vmsr-helper.c new file mode 100644 index 0000000000..ebf562c3ff --- /dev/null +++ b/tools/i386/qemu-vmsr-helper.c @@ -0,0 +1,530 @@ +/* + * Privileged RAPL MSR helper commands for QEMU + * + * Copyright (C) 2024 Red Hat, Inc. <aharivel@redhat.com> + * + * Author: Anthony Harivel <aharivel@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; under version 2 of the License. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "qemu/osdep.h" +#include <getopt.h> +#include <stdbool.h> +#include <sys/ioctl.h> +#ifdef CONFIG_LIBCAP_NG +#include <cap-ng.h> +#endif +#include <pwd.h> +#include <grp.h> + +#include "qemu/help-texts.h" +#include "qapi/error.h" +#include "qemu/cutils.h" +#include "qemu/main-loop.h" +#include "qemu/module.h" +#include "qemu/error-report.h" +#include "qemu/config-file.h" +#include "qemu-version.h" +#include "qapi/error.h" +#include "qemu/error-report.h" +#include "qemu/log.h" +#include "qemu/systemd.h" +#include "io/channel.h" +#include "io/channel-socket.h" +#include "trace/control.h" +#include "qemu-version.h" +#include "rapl-msr-index.h" + +#define MSR_PATH_TEMPLATE "/dev/cpu/%u/msr" + +static char *socket_path; +static char *pidfile; +static enum { RUNNING, TERMINATE, TERMINATING } state; +static QIOChannelSocket *server_ioc; +static int server_watch; +static int num_active_sockets = 1; + +#ifdef CONFIG_LIBCAP_NG +static int uid = -1; +static int gid = -1; +#endif + +static void compute_default_paths(void) +{ + g_autofree char *state = qemu_get_local_state_dir(); + + socket_path = g_build_filename(state, "run", "qemu-vmsr-helper.sock", NULL); + pidfile = g_build_filename(state, "run", "qemu-vmsr-helper.pid", NULL); +} + +static int is_intel_processor(void) +{ + int result; + int ebx, ecx, edx; + + /* Execute CPUID instruction with eax=0 (basic identification) */ + asm volatile ( + "cpuid" + : "=b" (ebx), "=c" (ecx), "=d" (edx) + : "a" (0) + ); + + /* + * Check if processor is "GenuineIntel" + * 0x756e6547 = "Genu" + * 0x49656e69 = "ineI" + * 0x6c65746e = "ntel" + */ + result = (ebx == 0x756e6547) && (edx == 0x49656e69) && (ecx == 0x6c65746e); + + return result; +} + +static int is_rapl_enabled(void) +{ + const char *path = "/sys/class/powercap/intel-rapl/enabled"; + FILE *file = fopen(path, "r"); + int value = 0; + + if (file != NULL) { + if (fscanf(file, "%d", &value) != 1) { + error_report("INTEL RAPL not enabled"); + } + fclose(file); + } else { + error_report("Error opening %s", path); + } + + return value; +} + +/* + * Check if the TID that request the MSR read + * belongs to the peer. It be should a TID of a vCPU. + */ +static bool is_tid_present(pid_t pid, pid_t tid) +{ + g_autofree char *tidPath = g_strdup_printf("/proc/%d/task/%d", pid, tid); + + /* Check if the TID directory exists within the PID directory */ + if (access(tidPath, F_OK) == 0) { + return true; + } + + error_report("Failed to open /proc at %s", tidPath); + return false; +} + +/* + * Only the RAPL MSR in target/i386/cpu.h are allowed + */ +static bool is_msr_allowed(uint32_t reg) +{ + switch (reg) { + case MSR_RAPL_POWER_UNIT: + case MSR_PKG_POWER_LIMIT: + case MSR_PKG_ENERGY_STATUS: + case MSR_PKG_POWER_INFO: + return true; + default: + return false; + } +} + +static uint64_t vmsr_read_msr(uint32_t msr_register, unsigned int cpu_id) +{ + int fd; + uint64_t result = 0; + + g_autofree char *path = g_strdup_printf(MSR_PATH_TEMPLATE, cpu_id); + + fd = open(path, O_RDONLY); + if (fd < 0) { + error_report("Failed to open MSR file at %s", path); + return result; + } + + if (pread(fd, &result, sizeof(result), msr_register) != sizeof(result)) { + error_report("Failed to read MSR"); + result = 0; + } + + close(fd); + return result; +} + +static void usage(const char *name) +{ + (printf) ( +"Usage: %s [OPTIONS] FILE\n" +"Virtual RAPL MSR helper program for QEMU\n" +"\n" +" -h, --help display this help and exit\n" +" -V, --version output version information and exit\n" +"\n" +" -d, --daemon run in the background\n" +" -f, --pidfile=PATH PID file when running as a daemon\n" +" (default '%s')\n" +" -k, --socket=PATH path to the unix socket\n" +" (default '%s')\n" +" -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" +" specify tracing options\n" +#ifdef CONFIG_LIBCAP_NG +" -u, --user=USER user to drop privileges to\n" +" -g, --group=GROUP group to drop privileges to\n" +#endif +"\n" +QEMU_HELP_BOTTOM "\n" + , name, pidfile, socket_path); +} + +static void version(const char *name) +{ + printf( +"%s " QEMU_FULL_VERSION "\n" +"Written by Anthony Harivel.\n" +"\n" +QEMU_COPYRIGHT "\n" +"This is free software; see the source for copying conditions. There is NO\n" +"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" + , name); +} + +typedef struct VMSRHelperClient { + QIOChannelSocket *ioc; + Coroutine *co; +} VMSRHelperClient; + +static void coroutine_fn vh_co_entry(void *opaque) +{ + VMSRHelperClient *client = opaque; + Error *local_err = NULL; + unsigned int peer_pid; + uint32_t request[3]; + uint64_t vmsr; + int r; + + qio_channel_set_blocking(QIO_CHANNEL(client->ioc), + false, NULL); + + qio_channel_set_follow_coroutine_ctx(QIO_CHANNEL(client->ioc), true); + + /* + * Check peer credentials + */ + r = qio_channel_get_peerpid(QIO_CHANNEL(client->ioc), + &peer_pid, + &local_err); + if (r < 0) { + error_report_err(local_err); + goto out; + } + + while (r < 0) { + /* + * Read the requested MSR + * Only RAPL MSR in rapl-msr-index.h is allowed + */ + r = qio_channel_read_all(QIO_CHANNEL(client->ioc), + (char *) &request, sizeof(request), &local_err); + if (r < 0) { + error_report_err(local_err); + break; + } + + if (!is_msr_allowed(request[0])) { + error_report("Requested unallowed msr: %d", request[0]); + break; + } + + vmsr = vmsr_read_msr(request[0], request[1]); + + if (!is_tid_present(peer_pid, request[2])) { + error_report("Requested TID not in peer PID: %d %d", + peer_pid, request[2]); + vmsr = 0; + } + + r = qio_channel_write_all(QIO_CHANNEL(client->ioc), + (char *) &vmsr, + sizeof(vmsr), + &local_err); + if (r < 0) { + error_report_err(local_err); + break; + } + } +out: + object_unref(OBJECT(client->ioc)); + g_free(client); +} + +static gboolean accept_client(QIOChannel *ioc, + GIOCondition cond, + gpointer opaque) +{ + QIOChannelSocket *cioc; + VMSRHelperClient *vmsrh; + + cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc), + NULL); + if (!cioc) { + return TRUE; + } + + vmsrh = g_new(VMSRHelperClient, 1); + vmsrh->ioc = cioc; + vmsrh->co = qemu_coroutine_create(vh_co_entry, vmsrh); + qemu_coroutine_enter(vmsrh->co); + + return TRUE; +} + +static void termsig_handler(int signum) +{ + qatomic_cmpxchg(&state, RUNNING, TERMINATE); + qemu_notify_event(); +} + +static void close_server_socket(void) +{ + assert(server_ioc); + + g_source_remove(server_watch); + server_watch = -1; + object_unref(OBJECT(server_ioc)); + num_active_sockets--; +} + +#ifdef CONFIG_LIBCAP_NG +static int drop_privileges(void) +{ + /* clear all capabilities */ + capng_clear(CAPNG_SELECT_BOTH); + + if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED, + CAP_SYS_RAWIO) < 0) { + return -1; + } + + return 0; +} +#endif + +int main(int argc, char **argv) +{ + const char *sopt = "hVk:f:dT:u:g:vq"; + struct option lopt[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, 'V' }, + { "socket", required_argument, NULL, 'k' }, + { "pidfile", required_argument, NULL, 'f' }, + { "daemon", no_argument, NULL, 'd' }, + { "trace", required_argument, NULL, 'T' }, + { "verbose", no_argument, NULL, 'v' }, + { NULL, 0, NULL, 0 } + }; + int opt_ind = 0; + int ch; + Error *local_err = NULL; + bool daemonize = false; + bool pidfile_specified = false; + bool socket_path_specified = false; + unsigned socket_activation; + + struct sigaction sa_sigterm; + memset(&sa_sigterm, 0, sizeof(sa_sigterm)); + sa_sigterm.sa_handler = termsig_handler; + sigaction(SIGTERM, &sa_sigterm, NULL); + sigaction(SIGINT, &sa_sigterm, NULL); + sigaction(SIGHUP, &sa_sigterm, NULL); + + signal(SIGPIPE, SIG_IGN); + + error_init(argv[0]); + module_call_init(MODULE_INIT_TRACE); + module_call_init(MODULE_INIT_QOM); + qemu_add_opts(&qemu_trace_opts); + qemu_init_exec_dir(argv[0]); + + compute_default_paths(); + + /* + * Sanity check + * 1. cpu must be Intel cpu + * 2. RAPL must be enabled + */ + if (!is_intel_processor()) { + error_report("error: CPU is not INTEL cpu"); + exit(EXIT_FAILURE); + } + + if (!is_rapl_enabled()) { + error_report("error: RAPL driver not enable"); + exit(EXIT_FAILURE); + } + + while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { + switch (ch) { + case 'k': + g_free(socket_path); + socket_path = g_strdup(optarg); + socket_path_specified = true; + if (socket_path[0] != '/') { + error_report("socket path must be absolute"); + exit(EXIT_FAILURE); + } + break; + case 'f': + g_free(pidfile); + pidfile = g_strdup(optarg); + pidfile_specified = true; + break; +#ifdef CONFIG_LIBCAP_NG + case 'u': { + unsigned long res; + struct passwd *userinfo = getpwnam(optarg); + if (userinfo) { + uid = userinfo->pw_uid; + } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 && + (uid_t)res == res) { + uid = res; + } else { + error_report("invalid user '%s'", optarg); + exit(EXIT_FAILURE); + } + break; + } + case 'g': { + unsigned long res; + struct group *groupinfo = getgrnam(optarg); + if (groupinfo) { + gid = groupinfo->gr_gid; + } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 && + (gid_t)res == res) { + gid = res; + } else { + error_report("invalid group '%s'", optarg); + exit(EXIT_FAILURE); + } + break; + } +#else + case 'u': + case 'g': + error_report("-%c not supported by this %s", ch, argv[0]); + exit(1); +#endif + case 'd': + daemonize = true; + break; + case 'T': + trace_opt_parse(optarg); + break; + case 'V': + version(argv[0]); + exit(EXIT_SUCCESS); + break; + case 'h': + usage(argv[0]); + exit(EXIT_SUCCESS); + break; + case '?': + error_report("Try `%s --help' for more information.", argv[0]); + exit(EXIT_FAILURE); + } + } + + if (!trace_init_backends()) { + exit(EXIT_FAILURE); + } + trace_init_file(); + qemu_set_log(LOG_TRACE, &error_fatal); + + socket_activation = check_socket_activation(); + if (socket_activation == 0) { + SocketAddress saddr; + saddr = (SocketAddress){ + .type = SOCKET_ADDRESS_TYPE_UNIX, + .u.q_unix.path = socket_path, + }; + server_ioc = qio_channel_socket_new(); + if (qio_channel_socket_listen_sync(server_ioc, &saddr, + 1, &local_err) < 0) { + object_unref(OBJECT(server_ioc)); + error_report_err(local_err); + return 1; + } + } else { + /* Using socket activation - check user didn't use -p etc. */ + if (socket_path_specified) { + error_report("Unix socket can't be set when" + "using socket activation"); + exit(EXIT_FAILURE); + } + + /* Can only listen on a single socket. */ + if (socket_activation > 1) { + error_report("%s does not support socket activation" + "with LISTEN_FDS > 1", + argv[0]); + exit(EXIT_FAILURE); + } + server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD, + &local_err); + if (server_ioc == NULL) { + error_reportf_err(local_err, + "Failed to use socket activation: "); + exit(EXIT_FAILURE); + } + } + + qemu_init_main_loop(&error_fatal); + + server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc), + G_IO_IN, + accept_client, + NULL, NULL); + + if (daemonize) { + if (daemon(0, 0) < 0) { + error_report("Failed to daemonize: %s", strerror(errno)); + exit(EXIT_FAILURE); + } + } + + if (daemonize || pidfile_specified) { + qemu_write_pidfile(pidfile, &error_fatal); + } + +#ifdef CONFIG_LIBCAP_NG + if (drop_privileges() < 0) { + error_report("Failed to drop privileges: %s", strerror(errno)); + exit(EXIT_FAILURE); + } +#endif + + info_report("Listening on %s", socket_path); + + state = RUNNING; + do { + main_loop_wait(false); + if (state == TERMINATE) { + state = TERMINATING; + close_server_socket(); + } + } while (num_active_sockets > 0); + + exit(EXIT_SUCCESS); +} diff --git a/tools/i386/rapl-msr-index.h b/tools/i386/rapl-msr-index.h new file mode 100644 index 0000000000..9a7118639a --- /dev/null +++ b/tools/i386/rapl-msr-index.h @@ -0,0 +1,28 @@ +/* + * Allowed list of MSR for Privileged RAPL MSR helper commands for QEMU + * + * Copyright (C) 2023 Red Hat, Inc. <aharivel@redhat.com> + * + * Author: Anthony Harivel <aharivel@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; under version 2 of the License. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +/* + * Should stay in sync with the RAPL MSR + * in target/i386/cpu.h + */ +#define MSR_RAPL_POWER_UNIT 0x00000606 +#define MSR_PKG_POWER_LIMIT 0x00000610 +#define MSR_PKG_ENERGY_STATUS 0x00000611 +#define MSR_PKG_POWER_INFO 0x00000614 |