* [PULL 01/11] target/i386: do not crash if microvm guest uses SGX CPUID leaves
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 02/11] qio: add support for SO_PEERCRED for socket channel Paolo Bonzini
` (10 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-stable
sgx_epc_get_section assumes a PC platform is in use:
bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
{
PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
However, sgx_epc_get_section is called by CPUID regardless of whether
SGX state has been initialized or which platform is in use. Check
whether the machine has the right QOM class and if not behave as if
there are no EPC sections.
Fixes: 1dec2e1f19f ("i386: Update SGX CPUID info according to hardware/KVM/user input", 2021-09-30)
Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2142
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/i386/sgx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/hw/i386/sgx.c b/hw/i386/sgx.c
index a14a84bc6f6..849472a1286 100644
--- a/hw/i386/sgx.c
+++ b/hw/i386/sgx.c
@@ -268,10 +268,12 @@ void hmp_info_sgx(Monitor *mon, const QDict *qdict)
bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
{
- PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
+ PCMachineState *pcms =
+ (PCMachineState *)object_dynamic_cast(qdev_get_machine(),
+ TYPE_PC_MACHINE);
SGXEPCDevice *epc;
- if (pcms->sgx_epc.size == 0 || pcms->sgx_epc.nr_sections <= section_nr) {
+ if (!pcms || pcms->sgx_epc.size == 0 || pcms->sgx_epc.nr_sections <= section_nr) {
return true;
}
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 02/11] qio: add support for SO_PEERCRED for socket channel
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
2024-07-23 14:15 ` [PULL 01/11] target/i386: do not crash if microvm guest uses SGX CPUID leaves Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 03/11] tools: build qemu-vmsr-helper Paolo Bonzini
` (9 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel; +Cc: Anthony Harivel
From: Anthony Harivel <aharivel@redhat.com>
The function qio_channel_get_peercred() returns a pointer to the
credentials of the peer process connected to this socket.
This credentials structure is defined in <sys/socket.h> as follows:
struct ucred {
pid_t pid; /* Process ID of the sending process */
uid_t uid; /* User ID of the sending process */
gid_t gid; /* Group ID of the sending process */
};
The use of this function is possible only for connected AF_UNIX stream
sockets and for AF_UNIX stream and datagram socket pairs.
On platform other than Linux, the function return 0.
Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-2-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/io/channel.h | 21 +++++++++++++++++++++
io/channel-socket.c | 28 ++++++++++++++++++++++++++++
io/channel.c | 13 +++++++++++++
3 files changed, 62 insertions(+)
diff --git a/include/io/channel.h b/include/io/channel.h
index 7986c49c713..bdf0bca92ae 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -160,6 +160,9 @@ struct QIOChannelClass {
void *opaque);
int (*io_flush)(QIOChannel *ioc,
Error **errp);
+ int (*io_peerpid)(QIOChannel *ioc,
+ unsigned int *pid,
+ Error **errp);
};
/* General I/O handling functions */
@@ -981,4 +984,22 @@ int coroutine_mixed_fn qio_channel_writev_full_all(QIOChannel *ioc,
int qio_channel_flush(QIOChannel *ioc,
Error **errp);
+/**
+ * qio_channel_get_peercred:
+ * @ioc: the channel object
+ * @pid: pointer to pid
+ * @errp: pointer to a NULL-initialized error object
+ *
+ * Returns the pid of the peer process connected to this socket.
+ *
+ * The use of this function is possible only for connected
+ * AF_UNIX stream sockets and for AF_UNIX stream and datagram
+ * socket pairs on Linux.
+ * Return -1 on error with pid -1 for the non-Linux OS.
+ *
+ */
+int qio_channel_get_peerpid(QIOChannel *ioc,
+ unsigned int *pid,
+ Error **errp);
+
#endif /* QIO_CHANNEL_H */
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 3a899b06085..608bcf066ec 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -841,6 +841,33 @@ qio_channel_socket_set_cork(QIOChannel *ioc,
socket_set_cork(sioc->fd, v);
}
+static int
+qio_channel_socket_get_peerpid(QIOChannel *ioc,
+ unsigned int *pid,
+ Error **errp)
+{
+#ifdef CONFIG_LINUX
+ QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc);
+ Error *err = NULL;
+ socklen_t len = sizeof(struct ucred);
+
+ struct ucred cred;
+ if (getsockopt(sioc->fd,
+ SOL_SOCKET, SO_PEERCRED,
+ &cred, &len) == -1) {
+ error_setg_errno(&err, errno, "Unable to get peer credentials");
+ error_propagate(errp, err);
+ *pid = -1;
+ return -1;
+ }
+ *pid = (unsigned int)cred.pid;
+ return 0;
+#else
+ error_setg(errp, "Unsupported feature");
+ *pid = -1;
+ return -1;
+#endif
+}
static int
qio_channel_socket_close(QIOChannel *ioc,
@@ -938,6 +965,7 @@ static void qio_channel_socket_class_init(ObjectClass *klass,
#ifdef QEMU_MSG_ZEROCOPY
ioc_klass->io_flush = qio_channel_socket_flush;
#endif
+ ioc_klass->io_peerpid = qio_channel_socket_get_peerpid;
}
static const TypeInfo qio_channel_socket_info = {
diff --git a/io/channel.c b/io/channel.c
index a1f12f8e909..e3f17c24a00 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -548,6 +548,19 @@ void qio_channel_set_cork(QIOChannel *ioc,
}
}
+int qio_channel_get_peerpid(QIOChannel *ioc,
+ unsigned int *pid,
+ Error **errp)
+{
+ QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
+
+ if (!klass->io_peerpid) {
+ error_setg(errp, "Channel does not support peer pid");
+ return -1;
+ }
+ klass->io_peerpid(ioc, pid, errp);
+ return 0;
+}
off_t qio_channel_io_seek(QIOChannel *ioc,
off_t offset,
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 03/11] tools: build qemu-vmsr-helper
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
2024-07-23 14:15 ` [PULL 01/11] target/i386: do not crash if microvm guest uses SGX CPUID leaves Paolo Bonzini
2024-07-23 14:15 ` [PULL 02/11] qio: add support for SO_PEERCRED for socket channel Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-25 10:28 ` Peter Maydell
2024-07-23 14:15 ` [PULL 04/11] Add support for RAPL MSRs in KVM/Qemu Paolo Bonzini
` (8 subsequent siblings)
11 siblings, 1 reply; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel; +Cc: Anthony Harivel
From: Anthony Harivel <aharivel@redhat.com>
Introduce a privileged helper to access RAPL MSR.
The privileged helper tool, qemu-vmsr-helper, is designed to provide
virtual machines with the ability to read specific RAPL (Running Average
Power Limit) MSRs without requiring CAP_SYS_RAWIO privileges or relying
on external, out-of-tree patches.
The helper tool leverages Unix permissions and SO_PEERCRED socket
options to enforce access control, ensuring that only processes
explicitly requesting read access via readmsr() from a valid Thread ID
can access these MSRs.
The list of RAPL MSRs that are allowed to be read by the helper tool is
defined in rapl-msr-index.h. This list corresponds to the RAPL MSRs that
will be supported in the next commit titled "Add support for RAPL MSRs
in KVM/QEMU."
The tool is intentionally designed to run on the Linux x86 platform.
This initial implementation is tailored for Intel CPUs but can be
extended to support AMD CPUs in the future.
Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-3-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
MAINTAINERS | 1 +
docs/tools/index.rst | 1 +
docs/tools/qemu-vmsr-helper.rst | 89 ++++
meson.build | 7 +
tools/i386/rapl-msr-index.h | 28 ++
tools/i386/qemu-vmsr-helper.c | 530 +++++++++++++++++++++++
contrib/systemd/qemu-vmsr-helper.service | 15 +
contrib/systemd/qemu-vmsr-helper.socket | 9 +
8 files changed, 680 insertions(+)
create mode 100644 docs/tools/qemu-vmsr-helper.rst
create mode 100644 tools/i386/rapl-msr-index.h
create mode 100644 tools/i386/qemu-vmsr-helper.c
create mode 100644 contrib/systemd/qemu-vmsr-helper.service
create mode 100644 contrib/systemd/qemu-vmsr-helper.socket
diff --git a/MAINTAINERS b/MAINTAINERS
index 7d9811458cb..f8df6940fad 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/docs/tools/index.rst b/docs/tools/index.rst
index 8e65ce0dfc7..33ad438e86f 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 00000000000..6ec87b49d96
--- /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 a1e51277b09..9d3e2d2ddbe 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/rapl-msr-index.h b/tools/i386/rapl-msr-index.h
new file mode 100644
index 00000000000..9a7118639ae
--- /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
diff --git a/tools/i386/qemu-vmsr-helper.c b/tools/i386/qemu-vmsr-helper.c
new file mode 100644
index 00000000000..ebf562c3ff8
--- /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/contrib/systemd/qemu-vmsr-helper.service b/contrib/systemd/qemu-vmsr-helper.service
new file mode 100644
index 00000000000..8fd397bf79a
--- /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 00000000000..183e8304d6e
--- /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
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PULL 03/11] tools: build qemu-vmsr-helper
2024-07-23 14:15 ` [PULL 03/11] tools: build qemu-vmsr-helper Paolo Bonzini
@ 2024-07-25 10:28 ` Peter Maydell
2024-07-25 10:30 ` Paolo Bonzini
0 siblings, 1 reply; 21+ messages in thread
From: Peter Maydell @ 2024-07-25 10:28 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, Anthony Harivel
On Tue, 23 Jul 2024 at 15:16, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> From: Anthony Harivel <aharivel@redhat.com>
>
> Introduce a privileged helper to access RAPL MSR.
Hi; Coverity points out an issue with this commit
(CID 1558555):
> +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;
Here we have a check for r < 0 that forces an early exit...
> + }
> +
> + while (r < 0) {
...but then immediately we do a while (r < 0). r cannot be < 0
here because we just checked that, so this while loop will
never execute and the whole loop body is dead code.
What was the intention here ?
> + /*
> + * 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);
> +}
thanks
-- PMM
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PULL 03/11] tools: build qemu-vmsr-helper
2024-07-25 10:28 ` Peter Maydell
@ 2024-07-25 10:30 ` Paolo Bonzini
0 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-25 10:30 UTC (permalink / raw)
To: Peter Maydell; +Cc: qemu-devel, Anthony Harivel
On Thu, Jul 25, 2024 at 12:28 PM Peter Maydell <peter.maydell@linaro.org> wrote:
> > + if (r < 0) {
> > + error_report_err(local_err);
> > + goto out;
>
> Here we have a check for r < 0 that forces an early exit...
>
> > + }
> > +
> > + while (r < 0) {
>
> ...but then immediately we do a while (r < 0). r cannot be < 0
> here because we just checked that, so this while loop will
> never execute and the whole loop body is dead code.
>
> What was the intention here ?
The intention was to have "while (r >= 0)" which is effectively an
infinite loop.
Paolo
>
>
> > + /*
> > + * 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);
> > +}
>
> thanks
> -- PMM
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PULL 04/11] Add support for RAPL MSRs in KVM/Qemu
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (2 preceding siblings ...)
2024-07-23 14:15 ` [PULL 03/11] tools: build qemu-vmsr-helper Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-25 10:25 ` Peter Maydell
2024-07-23 14:15 ` [PULL 05/11] hpet: fix and cleanup persistence of interrupt status Paolo Bonzini
` (7 subsequent siblings)
11 siblings, 1 reply; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel; +Cc: Anthony Harivel
From: Anthony Harivel <aharivel@redhat.com>
Starting with the "Sandy Bridge" generation, Intel CPUs provide a RAPL
interface (Running Average Power Limit) for advertising the accumulated
energy consumption of various power domains (e.g. CPU packages, DRAM,
etc.).
The consumption is reported via MSRs (model specific registers) like
MSR_PKG_ENERGY_STATUS for the CPU package power domain. These MSRs are
64 bits registers that represent the accumulated energy consumption in
micro Joules. They are updated by microcode every ~1ms.
For now, KVM always returns 0 when the guest requests the value of
these MSRs. Use the KVM MSR filtering mechanism to allow QEMU handle
these MSRs dynamically in userspace.
To limit the amount of system calls for every MSR call, create a new
thread in QEMU that updates the "virtual" MSR values asynchronously.
Each vCPU has its own vMSR to reflect the independence of vCPUs. The
thread updates the vMSR values with the ratio of energy consumed of
the whole physical CPU package the vCPU thread runs on and the
thread's utime and stime values.
All other non-vCPU threads are also taken into account. Their energy
consumption is evenly distributed among all vCPUs threads running on
the same physical CPU package.
To overcome the problem that reading the RAPL MSR requires priviliged
access, a socket communication between QEMU and the qemu-vmsr-helper is
mandatory. You can specified the socket path in the parameter.
This feature is activated with -accel kvm,rapl=true,path=/path/sock.sock
Actual limitation:
- Works only on Intel host CPU because AMD CPUs are using different MSR
adresses.
- Only the Package Power-Plane (MSR_PKG_ENERGY_STATUS) is reported at
the moment.
Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-4-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
docs/specs/index.rst | 1 +
docs/specs/rapl-msr.rst | 155 ++++++++++++
include/sysemu/kvm_int.h | 32 +++
target/i386/cpu.h | 8 +
target/i386/kvm/vmsr_energy.h | 99 ++++++++
accel/kvm/kvm-all.c | 27 +++
target/i386/kvm/kvm.c | 431 +++++++++++++++++++++++++++++++++-
target/i386/kvm/vmsr_energy.c | 345 +++++++++++++++++++++++++++
target/i386/kvm/meson.build | 1 +
9 files changed, 1098 insertions(+), 1 deletion(-)
create mode 100644 docs/specs/rapl-msr.rst
create mode 100644 target/i386/kvm/vmsr_energy.h
create mode 100644 target/i386/kvm/vmsr_energy.c
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index 1484e3e7607..e738ea7d102 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -33,3 +33,4 @@ guest hardware that is specific to QEMU.
virt-ctlr
vmcoreinfo
vmgenid
+ rapl-msr
diff --git a/docs/specs/rapl-msr.rst b/docs/specs/rapl-msr.rst
new file mode 100644
index 00000000000..1202ee89bee
--- /dev/null
+++ b/docs/specs/rapl-msr.rst
@@ -0,0 +1,155 @@
+================
+RAPL MSR support
+================
+
+The RAPL interface (Running Average Power Limit) is advertising the accumulated
+energy consumption of various power domains (e.g. CPU packages, DRAM, etc.).
+
+The consumption is reported via MSRs (model specific registers) like
+MSR_PKG_ENERGY_STATUS for the CPU package power domain. These MSRs are 64 bits
+registers that represent the accumulated energy consumption in micro Joules.
+
+Thanks to the MSR Filtering patch [#a]_ not all MSRs are handled by KVM. Some
+of them can now be handled by the userspace (QEMU). It uses a mechanism called
+"MSR filtering" where a list of MSRs is given at init time of a VM to KVM so
+that a callback is put in place. The design of this patch uses only this
+mechanism for handling the MSRs between guest/host.
+
+At the moment the following MSRs are involved:
+
+.. code:: C
+
+ #define MSR_RAPL_POWER_UNIT 0x00000606
+ #define MSR_PKG_POWER_LIMIT 0x00000610
+ #define MSR_PKG_ENERGY_STATUS 0x00000611
+ #define MSR_PKG_POWER_INFO 0x00000614
+
+The ``*_POWER_UNIT``, ``*_POWER_LIMIT``, ``*_POWER INFO`` are part of the RAPL
+spec and specify the power limit of the package, provide range of parameter(min
+power, max power,..) and also the information of the multiplier for the energy
+counter to calculate the power. Those MSRs are populated once at the beginning
+by reading the host CPU MSRs and are given back to the guest 1:1 when
+requested.
+
+The MSR_PKG_ENERGY_STATUS is a counter; it represents the total amount of
+energy consumed since the last time the register was cleared. If you multiply
+it with the UNIT provided above you'll get the power in micro-joules. This
+counter is always increasing and it increases more or less faster depending on
+the consumption of the package. This counter is supposed to overflow at some
+point.
+
+Each core belonging to the same Package reading the MSR_PKG_ENERGY_STATUS (i.e
+"rdmsr 0x611") will retrieve the same value. The value represents the energy
+for the whole package. Whatever Core reading it will get the same value and a
+core that belongs to PKG-0 will not be able to get the value of PKG-1 and
+vice-versa.
+
+High level implementation
+-------------------------
+
+In order to update the value of the virtual MSR, a QEMU thread is created.
+The thread is basically just an infinity loop that does:
+
+1. Snapshot of the time metrics of all QEMU threads (Time spent scheduled in
+ Userspace and System)
+
+2. Snapshot of the actual MSR_PKG_ENERGY_STATUS counter of all packages where
+ the QEMU threads are running on.
+
+3. Sleep for 1 second - During this pause the vcpu and other non-vcpu threads
+ will do what they have to do and so the energy counter will increase.
+
+4. Repeat 2. and 3. and calculate the delta of every metrics representing the
+ time spent scheduled for each QEMU thread *and* the energy spent by the
+ packages during the pause.
+
+5. Filter the vcpu threads and the non-vcpu threads.
+
+6. Retrieve the topology of the Virtual Machine. This helps identify which
+ vCPU is running on which virtual package.
+
+7. The total energy spent by the non-vcpu threads is divided by the number
+ of vcpu threads so that each vcpu thread will get an equal part of the
+ energy spent by the QEMU workers.
+
+8. Calculate the ratio of energy spent per vcpu threads.
+
+9. Calculate the energy for each virtual package.
+
+10. The virtual MSRs are updated for each virtual package. Each vCPU that
+ belongs to the same package will return the same value when accessing the
+ the MSR.
+
+11. Loop back to 1.
+
+Ratio calculation
+-----------------
+
+In Linux, a process has an execution time associated with it. The scheduler is
+dividing the time in clock ticks. The number of clock ticks per second can be
+found by the sysconf system call. A typical value of clock ticks per second is
+100. So a core can run a process at the maximum of 100 ticks per second. If a
+package has 4 cores, 400 ticks maximum can be scheduled on all the cores
+of the package for a period of 1 second.
+
+The /proc/[pid]/stat [#b]_ is a sysfs file that can give the executed time of a
+process with the [pid] as the process ID. It gives the amount of ticks the
+process has been scheduled in userspace (utime) and kernel space (stime).
+
+By reading those metrics for a thread, one can calculate the ratio of time the
+package has spent executing the thread.
+
+Example:
+
+A 4 cores package can schedule a maximum of 400 ticks per second with 100 ticks
+per second per core. If a thread was scheduled for 100 ticks between a second
+on this package, that means my thread has been scheduled for 1/4 of the whole
+package. With that, the calculation of the energy spent by the thread on this
+package during this whole second is 1/4 of the total energy spent by the
+package.
+
+Usage
+-----
+
+Currently this feature is only working on an Intel CPU that has the RAPL driver
+mounted and available in the sysfs. if not, QEMU fails at start-up.
+
+This feature is activated with -accel
+kvm,rapl=true,rapl-helper-socket=/path/sock.sock
+
+It is important that the socket path is the same as the one
+:program:`qemu-vmsr-helper` is listening to.
+
+qemu-vmsr-helper
+----------------
+
+The qemu-vmsr-helper is working very much like the qemu-pr-helper. Instead of
+making persistent reservation, qemu-vmsr-helper is here to overcome the
+CVE-2020-8694 which remove user access to the rapl msr attributes.
+
+A socket communication is established between QEMU processes that has the RAPL
+MSR support activated and the qemu-vmsr-helper. A systemd service and socket
+activation is provided in contrib/systemd/qemu-vmsr-helper.(service/socket).
+
+The systemd socket uses 600, like contrib/systemd/qemu-pr-helper.socket. The
+socket can be passed via SCM_RIGHTS by libvirt, or its permissions can be
+changed (e.g. 660 and root:kvm for a Debian system for example). Libvirt could
+also start a separate helper if needed. All in all, the policy is left to the
+user.
+
+See the qemu-pr-helper documentation or manpage for further details.
+
+Current Limitations
+-------------------
+
+- Works only on Intel host CPUs because AMD CPUs are using different MSR
+ addresses.
+
+- Only the Package Power-Plane (MSR_PKG_ENERGY_STATUS) is reported at the
+ moment.
+
+References
+----------
+
+.. [#a] https://patchwork.kernel.org/project/kvm/patch/20200916202951.23760-7-graf@amazon.com/
+.. [#b] https://man7.org/linux/man-pages/man5/proc.5.html
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 3f3d13f8166..1d8fb1473bd 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -14,6 +14,9 @@
#include "qemu/accel.h"
#include "qemu/queue.h"
#include "sysemu/kvm.h"
+#include "hw/boards.h"
+#include "hw/i386/topology.h"
+#include "io/channel-socket.h"
typedef struct KVMSlot
{
@@ -50,6 +53,34 @@ typedef struct KVMMemoryListener {
#define KVM_MSI_HASHTAB_SIZE 256
+typedef struct KVMHostTopoInfo {
+ /* Number of package on the Host */
+ unsigned int maxpkgs;
+ /* Number of cpus on the Host */
+ unsigned int maxcpus;
+ /* Number of cpus on each different package */
+ unsigned int *pkg_cpu_count;
+ /* Each package can have different maxticks */
+ unsigned int *maxticks;
+} KVMHostTopoInfo;
+
+struct KVMMsrEnergy {
+ pid_t pid;
+ bool enable;
+ char *socket_path;
+ QIOChannelSocket *sioc;
+ QemuThread msr_thr;
+ unsigned int guest_vcpus;
+ unsigned int guest_vsockets;
+ X86CPUTopoInfo guest_topo_info;
+ KVMHostTopoInfo host_topo;
+ const CPUArchIdList *guest_cpu_list;
+ uint64_t *msr_value;
+ uint64_t msr_unit;
+ uint64_t msr_limit;
+ uint64_t msr_info;
+};
+
enum KVMDirtyRingReaperState {
KVM_DIRTY_RING_REAPER_NONE = 0,
/* The reaper is sleeping */
@@ -117,6 +148,7 @@ struct KVMState
bool kvm_dirty_ring_with_bitmap;
uint64_t kvm_eager_split_size; /* Eager Page Splitting chunk size */
struct KVMDirtyRingReaper reaper;
+ struct KVMMsrEnergy msr_energy;
NotifyVmexitOption notify_vmexit;
uint32_t notify_window;
uint32_t xen_version;
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 1e121acef54..c6cc035df3d 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -414,6 +414,10 @@ typedef enum X86Seg {
#define MSR_IA32_TSX_CTRL 0x122
#define MSR_IA32_TSCDEADLINE 0x6e0
#define MSR_IA32_PKRS 0x6e1
+#define MSR_RAPL_POWER_UNIT 0x00000606
+#define MSR_PKG_POWER_LIMIT 0x00000610
+#define MSR_PKG_ENERGY_STATUS 0x00000611
+#define MSR_PKG_POWER_INFO 0x00000614
#define MSR_ARCH_LBR_CTL 0x000014ce
#define MSR_ARCH_LBR_DEPTH 0x000014cf
#define MSR_ARCH_LBR_FROM_0 0x00001500
@@ -1880,6 +1884,10 @@ typedef struct CPUArchState {
uintptr_t retaddr;
+ /* RAPL MSR */
+ uint64_t msr_rapl_power_unit;
+ uint64_t msr_pkg_energy_status;
+
/* Fields up to this point are cleared by a CPU reset */
struct {} end_reset_fields;
diff --git a/target/i386/kvm/vmsr_energy.h b/target/i386/kvm/vmsr_energy.h
new file mode 100644
index 00000000000..16cc1f4814f
--- /dev/null
+++ b/target/i386/kvm/vmsr_energy.h
@@ -0,0 +1,99 @@
+/*
+ * QEMU KVM support -- x86 virtual energy-related MSR.
+ *
+ * Copyright 2024 Red Hat, Inc. 2024
+ *
+ * Author:
+ * Anthony Harivel <aharivel@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef VMSR_ENERGY_H
+#define VMSR_ENERGY_H
+
+#include <stdint.h>
+#include "qemu/osdep.h"
+#include "io/channel-socket.h"
+#include "hw/i386/topology.h"
+
+/*
+ * Define the interval time in micro seconds between 2 samples of
+ * energy related MSRs
+ */
+#define MSR_ENERGY_THREAD_SLEEP_US 1000000.0
+
+/*
+ * Thread statistic
+ * @ thread_id: TID (thread ID)
+ * @ is_vcpu: true if TID is vCPU thread
+ * @ cpu_id: CPU number last executed on
+ * @ pkg_id: package number of the CPU
+ * @ vcpu_id: vCPU ID
+ * @ vpkg: virtual package number
+ * @ acpi_id: APIC id of the vCPU
+ * @ utime: amount of clock ticks the thread
+ * has been scheduled in User mode
+ * @ stime: amount of clock ticks the thread
+ * has been scheduled in System mode
+ * @ delta_ticks: delta of utime+stime between
+ * the two samples (before/after sleep)
+ */
+struct vmsr_thread_stat {
+ unsigned int thread_id;
+ bool is_vcpu;
+ unsigned int cpu_id;
+ unsigned int pkg_id;
+ unsigned int vpkg_id;
+ unsigned int vcpu_id;
+ unsigned long acpi_id;
+ unsigned long long *utime;
+ unsigned long long *stime;
+ unsigned long long delta_ticks;
+};
+
+/*
+ * Package statistic
+ * @ e_start: package energy counter before the sleep
+ * @ e_end: package energy counter after the sleep
+ * @ e_delta: delta of package energy counter
+ * @ e_ratio: store the energy ratio of non-vCPU thread
+ * @ nb_vcpu: number of vCPU running on this package
+ */
+struct vmsr_package_energy_stat {
+ uint64_t e_start;
+ uint64_t e_end;
+ uint64_t e_delta;
+ uint64_t e_ratio;
+ unsigned int nb_vcpu;
+};
+
+typedef struct vmsr_thread_stat vmsr_thread_stat;
+typedef struct vmsr_package_energy_stat vmsr_package_energy_stat;
+
+char *vmsr_compute_default_paths(void);
+void vmsr_read_thread_stat(pid_t pid,
+ unsigned int thread_id,
+ unsigned long long *utime,
+ unsigned long long *stime,
+ unsigned int *cpu_id);
+
+QIOChannelSocket *vmsr_open_socket(const char *path);
+uint64_t vmsr_read_msr(uint32_t reg, uint32_t cpu_id,
+ uint32_t tid, QIOChannelSocket *sioc);
+void vmsr_delta_ticks(vmsr_thread_stat *thd_stat, int i);
+unsigned int vmsr_get_maxcpus(void);
+unsigned int vmsr_get_max_physical_package(unsigned int max_cpus);
+unsigned int vmsr_count_cpus_per_package(unsigned int *package_count,
+ unsigned int max_pkgs);
+int vmsr_get_physical_package_id(int cpu_id);
+pid_t *vmsr_get_thread_ids(pid_t pid, unsigned int *num_threads);
+double vmsr_get_ratio(uint64_t e_delta,
+ unsigned long long delta_ticks,
+ unsigned int maxticks);
+void vmsr_init_topo_info(X86CPUTopoInfo *topo_info, const MachineState *ms);
+bool is_host_cpu_intel(void);
+int is_rapl_enabled(void);
+#endif /* VMSR_ENERGY_H */
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 64bf47a0330..480c7119d1c 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -3745,6 +3745,21 @@ static void kvm_set_device(Object *obj,
s->device = g_strdup(value);
}
+static void kvm_set_kvm_rapl(Object *obj, bool value, Error **errp)
+{
+ KVMState *s = KVM_STATE(obj);
+ s->msr_energy.enable = value;
+}
+
+static void kvm_set_kvm_rapl_socket_path(Object *obj,
+ const char *str,
+ Error **errp)
+{
+ KVMState *s = KVM_STATE(obj);
+ g_free(s->msr_energy.socket_path);
+ s->msr_energy.socket_path = g_strdup(str);
+}
+
static void kvm_accel_instance_init(Object *obj)
{
KVMState *s = KVM_STATE(obj);
@@ -3764,6 +3779,7 @@ static void kvm_accel_instance_init(Object *obj)
s->xen_gnttab_max_frames = 64;
s->xen_evtchn_max_pirq = 256;
s->device = NULL;
+ s->msr_energy.enable = false;
}
/**
@@ -3808,6 +3824,17 @@ static void kvm_accel_class_init(ObjectClass *oc, void *data)
object_class_property_set_description(oc, "device",
"Path to the device node to use (default: /dev/kvm)");
+ object_class_property_add_bool(oc, "rapl",
+ NULL,
+ kvm_set_kvm_rapl);
+ object_class_property_set_description(oc, "rapl",
+ "Allow energy related MSRs for RAPL interface in Guest");
+
+ object_class_property_add_str(oc, "rapl-helper-socket", NULL,
+ kvm_set_kvm_rapl_socket_path);
+ object_class_property_set_description(oc, "rapl-helper-socket",
+ "Socket Path for comminucating with the Virtual MSR helper daemon");
+
kvm_arch_accel_class_init(oc);
}
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index becca2efa5b..b4aab9a410b 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -16,9 +16,12 @@
#include "qapi/qapi-events-run-state.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
+#include <math.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <sys/syscall.h>
+#include <sys/resource.h>
+#include <sys/time.h>
#include <linux/kvm.h>
#include <linux/kvm_para.h>
@@ -27,6 +30,7 @@
#include "cpu.h"
#include "host-cpu.h"
+#include "vmsr_energy.h"
#include "sysemu/sysemu.h"
#include "sysemu/hw_accel.h"
#include "sysemu/kvm_int.h"
@@ -2559,7 +2563,8 @@ static int kvm_get_supported_msrs(KVMState *s)
return ret;
}
-static bool kvm_rdmsr_core_thread_count(X86CPU *cpu, uint32_t msr,
+static bool kvm_rdmsr_core_thread_count(X86CPU *cpu,
+ uint32_t msr,
uint64_t *val)
{
CPUState *cs = CPU(cpu);
@@ -2570,6 +2575,53 @@ static bool kvm_rdmsr_core_thread_count(X86CPU *cpu, uint32_t msr,
return true;
}
+static bool kvm_rdmsr_rapl_power_unit(X86CPU *cpu,
+ uint32_t msr,
+ uint64_t *val)
+{
+
+ CPUState *cs = CPU(cpu);
+
+ *val = cs->kvm_state->msr_energy.msr_unit;
+
+ return true;
+}
+
+static bool kvm_rdmsr_pkg_power_limit(X86CPU *cpu,
+ uint32_t msr,
+ uint64_t *val)
+{
+
+ CPUState *cs = CPU(cpu);
+
+ *val = cs->kvm_state->msr_energy.msr_limit;
+
+ return true;
+}
+
+static bool kvm_rdmsr_pkg_power_info(X86CPU *cpu,
+ uint32_t msr,
+ uint64_t *val)
+{
+
+ CPUState *cs = CPU(cpu);
+
+ *val = cs->kvm_state->msr_energy.msr_info;
+
+ return true;
+}
+
+static bool kvm_rdmsr_pkg_energy_status(X86CPU *cpu,
+ uint32_t msr,
+ uint64_t *val)
+{
+
+ CPUState *cs = CPU(cpu);
+ *val = cs->kvm_state->msr_energy.msr_value[cs->cpu_index];
+
+ return true;
+}
+
static Notifier smram_machine_done;
static KVMMemoryListener smram_listener;
static AddressSpace smram_address_space;
@@ -2604,6 +2656,340 @@ static void register_smram_listener(Notifier *n, void *unused)
&smram_address_space, 1, "kvm-smram");
}
+static void *kvm_msr_energy_thread(void *data)
+{
+ KVMState *s = data;
+ struct KVMMsrEnergy *vmsr = &s->msr_energy;
+
+ g_autofree vmsr_package_energy_stat *pkg_stat = NULL;
+ g_autofree vmsr_thread_stat *thd_stat = NULL;
+ g_autofree CPUState *cpu = NULL;
+ g_autofree unsigned int *vpkgs_energy_stat = NULL;
+ unsigned int num_threads = 0;
+
+ X86CPUTopoIDs topo_ids;
+
+ rcu_register_thread();
+
+ /* Allocate memory for each package energy status */
+ pkg_stat = g_new0(vmsr_package_energy_stat, vmsr->host_topo.maxpkgs);
+
+ /* Allocate memory for thread stats */
+ thd_stat = g_new0(vmsr_thread_stat, 1);
+
+ /* Allocate memory for holding virtual package energy counter */
+ vpkgs_energy_stat = g_new0(unsigned int, vmsr->guest_vsockets);
+
+ /* Populate the max tick of each packages */
+ for (int i = 0; i < vmsr->host_topo.maxpkgs; i++) {
+ /*
+ * Max numbers of ticks per package
+ * Time in second * Number of ticks/second * Number of cores/package
+ * ex: 100 ticks/second/CPU, 12 CPUs per Package gives 1200 ticks max
+ */
+ vmsr->host_topo.maxticks[i] = (MSR_ENERGY_THREAD_SLEEP_US / 1000000)
+ * sysconf(_SC_CLK_TCK)
+ * vmsr->host_topo.pkg_cpu_count[i];
+ }
+
+ while (true) {
+ /* Get all qemu threads id */
+ g_autofree pid_t *thread_ids =
+ thread_ids = vmsr_get_thread_ids(vmsr->pid, &num_threads);
+
+ if (thread_ids == NULL) {
+ goto clean;
+ }
+
+ thd_stat = g_renew(vmsr_thread_stat, thd_stat, num_threads);
+ /* Unlike g_new0, g_renew0 function doesn't exist yet... */
+ memset(thd_stat, 0, num_threads * sizeof(vmsr_thread_stat));
+
+ /* Populate all the thread stats */
+ for (int i = 0; i < num_threads; i++) {
+ thd_stat[i].utime = g_new0(unsigned long long, 2);
+ thd_stat[i].stime = g_new0(unsigned long long, 2);
+ thd_stat[i].thread_id = thread_ids[i];
+ vmsr_read_thread_stat(vmsr->pid,
+ thd_stat[i].thread_id,
+ thd_stat[i].utime,
+ thd_stat[i].stime,
+ &thd_stat[i].cpu_id);
+ thd_stat[i].pkg_id =
+ vmsr_get_physical_package_id(thd_stat[i].cpu_id);
+ }
+
+ /* Retrieve all packages power plane energy counter */
+ for (int i = 0; i < vmsr->host_topo.maxpkgs; i++) {
+ for (int j = 0; j < num_threads; j++) {
+ /*
+ * Use the first thread we found that ran on the CPU
+ * of the package to read the packages energy counter
+ */
+ if (thd_stat[j].pkg_id == i) {
+ pkg_stat[i].e_start =
+ vmsr_read_msr(MSR_PKG_ENERGY_STATUS,
+ thd_stat[j].cpu_id,
+ thd_stat[j].thread_id,
+ s->msr_energy.sioc);
+ break;
+ }
+ }
+ }
+
+ /* Sleep a short period while the other threads are working */
+ usleep(MSR_ENERGY_THREAD_SLEEP_US);
+
+ /*
+ * Retrieve all packages power plane energy counter
+ * Calculate the delta of all packages
+ */
+ for (int i = 0; i < vmsr->host_topo.maxpkgs; i++) {
+ for (int j = 0; j < num_threads; j++) {
+ /*
+ * Use the first thread we found that ran on the CPU
+ * of the package to read the packages energy counter
+ */
+ if (thd_stat[j].pkg_id == i) {
+ pkg_stat[i].e_end =
+ vmsr_read_msr(MSR_PKG_ENERGY_STATUS,
+ thd_stat[j].cpu_id,
+ thd_stat[j].thread_id,
+ s->msr_energy.sioc);
+ /*
+ * Prevent the case we have migrate the VM
+ * during the sleep period or any other cases
+ * were energy counter might be lower after
+ * the sleep period.
+ */
+ if (pkg_stat[i].e_end > pkg_stat[i].e_start) {
+ pkg_stat[i].e_delta =
+ pkg_stat[i].e_end - pkg_stat[i].e_start;
+ } else {
+ pkg_stat[i].e_delta = 0;
+ }
+ break;
+ }
+ }
+ }
+
+ /* Delta of ticks spend by each thread between the sample */
+ for (int i = 0; i < num_threads; i++) {
+ vmsr_read_thread_stat(vmsr->pid,
+ thd_stat[i].thread_id,
+ thd_stat[i].utime,
+ thd_stat[i].stime,
+ &thd_stat[i].cpu_id);
+
+ if (vmsr->pid < 0) {
+ /*
+ * We don't count the dead thread
+ * i.e threads that existed before the sleep
+ * and not anymore
+ */
+ thd_stat[i].delta_ticks = 0;
+ } else {
+ vmsr_delta_ticks(thd_stat, i);
+ }
+ }
+
+ /*
+ * Identify the vcpu threads
+ * Calculate the number of vcpu per package
+ */
+ CPU_FOREACH(cpu) {
+ for (int i = 0; i < num_threads; i++) {
+ if (cpu->thread_id == thd_stat[i].thread_id) {
+ thd_stat[i].is_vcpu = true;
+ thd_stat[i].vcpu_id = cpu->cpu_index;
+ pkg_stat[thd_stat[i].pkg_id].nb_vcpu++;
+ thd_stat[i].acpi_id = kvm_arch_vcpu_id(cpu);
+ break;
+ }
+ }
+ }
+
+ /* Retrieve the virtual package number of each vCPU */
+ for (int i = 0; i < vmsr->guest_cpu_list->len; i++) {
+ for (int j = 0; j < num_threads; j++) {
+ if ((thd_stat[j].acpi_id ==
+ vmsr->guest_cpu_list->cpus[i].arch_id)
+ && (thd_stat[j].is_vcpu == true)) {
+ x86_topo_ids_from_apicid(thd_stat[j].acpi_id,
+ &vmsr->guest_topo_info, &topo_ids);
+ thd_stat[j].vpkg_id = topo_ids.pkg_id;
+ }
+ }
+ }
+
+ /* Calculate the total energy of all non-vCPU thread */
+ for (int i = 0; i < num_threads; i++) {
+ if ((thd_stat[i].is_vcpu != true) &&
+ (thd_stat[i].delta_ticks > 0)) {
+ double temp;
+ temp = vmsr_get_ratio(pkg_stat[thd_stat[i].pkg_id].e_delta,
+ thd_stat[i].delta_ticks,
+ vmsr->host_topo.maxticks[thd_stat[i].pkg_id]);
+ pkg_stat[thd_stat[i].pkg_id].e_ratio
+ += (uint64_t)lround(temp);
+ }
+ }
+
+ /* Calculate the ratio per non-vCPU thread of each package */
+ for (int i = 0; i < vmsr->host_topo.maxpkgs; i++) {
+ if (pkg_stat[i].nb_vcpu > 0) {
+ pkg_stat[i].e_ratio = pkg_stat[i].e_ratio / pkg_stat[i].nb_vcpu;
+ }
+ }
+
+ /*
+ * Calculate the energy for each Package:
+ * Energy Package = sum of each vCPU energy that belongs to the package
+ */
+ for (int i = 0; i < num_threads; i++) {
+ if ((thd_stat[i].is_vcpu == true) && \
+ (thd_stat[i].delta_ticks > 0)) {
+ double temp;
+ temp = vmsr_get_ratio(pkg_stat[thd_stat[i].pkg_id].e_delta,
+ thd_stat[i].delta_ticks,
+ vmsr->host_topo.maxticks[thd_stat[i].pkg_id]);
+ vpkgs_energy_stat[thd_stat[i].vpkg_id] +=
+ (uint64_t)lround(temp);
+ vpkgs_energy_stat[thd_stat[i].vpkg_id] +=
+ pkg_stat[thd_stat[i].pkg_id].e_ratio;
+ }
+ }
+
+ /*
+ * Finally populate the vmsr register of each vCPU with the total
+ * package value to emulate the real hardware where each CPU return the
+ * value of the package it belongs.
+ */
+ for (int i = 0; i < num_threads; i++) {
+ if ((thd_stat[i].is_vcpu == true) && \
+ (thd_stat[i].delta_ticks > 0)) {
+ vmsr->msr_value[thd_stat[i].vcpu_id] = \
+ vpkgs_energy_stat[thd_stat[i].vpkg_id];
+ }
+ }
+
+ /* Freeing memory before zeroing the pointer */
+ for (int i = 0; i < num_threads; i++) {
+ g_free(thd_stat[i].utime);
+ g_free(thd_stat[i].stime);
+ }
+ }
+
+clean:
+ rcu_unregister_thread();
+ return NULL;
+}
+
+static int kvm_msr_energy_thread_init(KVMState *s, MachineState *ms)
+{
+ MachineClass *mc = MACHINE_GET_CLASS(ms);
+ struct KVMMsrEnergy *r = &s->msr_energy;
+ int ret = 0;
+
+ /*
+ * Sanity check
+ * 1. Host cpu must be Intel cpu
+ * 2. RAPL must be enabled on the Host
+ */
+ if (is_host_cpu_intel()) {
+ error_report("The RAPL feature can only be enabled on hosts\
+ with Intel CPU models");
+ ret = 1;
+ goto out;
+ }
+
+ if (!is_rapl_enabled()) {
+ ret = 1;
+ goto out;
+ }
+
+ /* Retrieve the virtual topology */
+ vmsr_init_topo_info(&r->guest_topo_info, ms);
+
+ /* Retrieve the number of vcpu */
+ r->guest_vcpus = ms->smp.cpus;
+
+ /* Retrieve the number of virtual sockets */
+ r->guest_vsockets = ms->smp.sockets;
+
+ /* Allocate register memory (MSR_PKG_STATUS) for each vcpu */
+ r->msr_value = g_new0(uint64_t, r->guest_vcpus);
+
+ /* Retrieve the CPUArchIDlist */
+ r->guest_cpu_list = mc->possible_cpu_arch_ids(ms);
+
+ /* Max number of cpus on the Host */
+ r->host_topo.maxcpus = vmsr_get_maxcpus();
+ if (r->host_topo.maxcpus == 0) {
+ error_report("host max cpus = 0");
+ ret = 1;
+ goto out;
+ }
+
+ /* Max number of packages on the host */
+ r->host_topo.maxpkgs = vmsr_get_max_physical_package(r->host_topo.maxcpus);
+ if (r->host_topo.maxpkgs == 0) {
+ error_report("host max pkgs = 0");
+ ret = 1;
+ goto out;
+ }
+
+ /* Allocate memory for each package on the host */
+ r->host_topo.pkg_cpu_count = g_new0(unsigned int, r->host_topo.maxpkgs);
+ r->host_topo.maxticks = g_new0(unsigned int, r->host_topo.maxpkgs);
+
+ vmsr_count_cpus_per_package(r->host_topo.pkg_cpu_count,
+ r->host_topo.maxpkgs);
+ for (int i = 0; i < r->host_topo.maxpkgs; i++) {
+ if (r->host_topo.pkg_cpu_count[i] == 0) {
+ error_report("cpu per packages = 0 on package_%d", i);
+ ret = 1;
+ goto out;
+ }
+ }
+
+ /* Get QEMU PID*/
+ r->pid = getpid();
+
+ /* Compute the socket path if necessary */
+ if (s->msr_energy.socket_path == NULL) {
+ s->msr_energy.socket_path = vmsr_compute_default_paths();
+ }
+
+ /* Open socket with vmsr helper */
+ s->msr_energy.sioc = vmsr_open_socket(s->msr_energy.socket_path);
+
+ if (s->msr_energy.sioc == NULL) {
+ error_report("vmsr socket opening failed");
+ ret = 1;
+ goto out;
+ }
+
+ /* Those MSR values should not change */
+ r->msr_unit = vmsr_read_msr(MSR_RAPL_POWER_UNIT, 0, r->pid,
+ s->msr_energy.sioc);
+ r->msr_limit = vmsr_read_msr(MSR_PKG_POWER_LIMIT, 0, r->pid,
+ s->msr_energy.sioc);
+ r->msr_info = vmsr_read_msr(MSR_PKG_POWER_INFO, 0, r->pid,
+ s->msr_energy.sioc);
+ if (r->msr_unit == 0 || r->msr_limit == 0 || r->msr_info == 0) {
+ error_report("can't read any virtual msr");
+ ret = 1;
+ goto out;
+ }
+
+ qemu_thread_create(&r->msr_thr, "kvm-msr",
+ kvm_msr_energy_thread,
+ s, QEMU_THREAD_JOINABLE);
+out:
+ return ret;
+}
+
int kvm_arch_get_default_type(MachineState *ms)
{
return 0;
@@ -2804,6 +3190,49 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
strerror(-ret));
exit(1);
}
+
+ if (s->msr_energy.enable == true) {
+ r = kvm_filter_msr(s, MSR_RAPL_POWER_UNIT,
+ kvm_rdmsr_rapl_power_unit, NULL);
+ if (!r) {
+ error_report("Could not install MSR_RAPL_POWER_UNIT \
+ handler: %s",
+ strerror(-ret));
+ exit(1);
+ }
+
+ r = kvm_filter_msr(s, MSR_PKG_POWER_LIMIT,
+ kvm_rdmsr_pkg_power_limit, NULL);
+ if (!r) {
+ error_report("Could not install MSR_PKG_POWER_LIMIT \
+ handler: %s",
+ strerror(-ret));
+ exit(1);
+ }
+
+ r = kvm_filter_msr(s, MSR_PKG_POWER_INFO,
+ kvm_rdmsr_pkg_power_info, NULL);
+ if (!r) {
+ error_report("Could not install MSR_PKG_POWER_INFO \
+ handler: %s",
+ strerror(-ret));
+ exit(1);
+ }
+ r = kvm_filter_msr(s, MSR_PKG_ENERGY_STATUS,
+ kvm_rdmsr_pkg_energy_status, NULL);
+ if (!r) {
+ error_report("Could not install MSR_PKG_ENERGY_STATUS \
+ handler: %s",
+ strerror(-ret));
+ exit(1);
+ }
+ r = kvm_msr_energy_thread_init(s, ms);
+ if (r) {
+ error_report("kvm : error RAPL feature requirement not meet");
+ exit(1);
+ }
+
+ }
}
return 0;
diff --git a/target/i386/kvm/vmsr_energy.c b/target/i386/kvm/vmsr_energy.c
new file mode 100644
index 00000000000..a1d78f2f2ae
--- /dev/null
+++ b/target/i386/kvm/vmsr_energy.c
@@ -0,0 +1,345 @@
+/*
+ * QEMU KVM support -- x86 virtual RAPL msr
+ *
+ * Copyright 2024 Red Hat, Inc. 2024
+ *
+ * Author:
+ * Anthony Harivel <aharivel@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "vmsr_energy.h"
+#include "io/channel.h"
+#include "io/channel-socket.h"
+#include "hw/boards.h"
+#include "cpu.h"
+#include "host-cpu.h"
+
+char *vmsr_compute_default_paths(void)
+{
+ g_autofree char *state = qemu_get_local_state_dir();
+
+ return g_build_filename(state, "run", "qemu-vmsr-helper.sock", NULL);
+}
+
+bool is_host_cpu_intel(void)
+{
+ int family, model, stepping;
+ char vendor[CPUID_VENDOR_SZ + 1];
+
+ host_cpu_vendor_fms(vendor, &family, &model, &stepping);
+
+ return strcmp(vendor, CPUID_VENDOR_INTEL);
+}
+
+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;
+}
+
+QIOChannelSocket *vmsr_open_socket(const char *path)
+{
+ g_autofree char *socket_path = NULL;
+
+ socket_path = g_strdup(path);
+
+ SocketAddress saddr = {
+ .type = SOCKET_ADDRESS_TYPE_UNIX,
+ .u.q_unix.path = socket_path
+ };
+
+ QIOChannelSocket *sioc = qio_channel_socket_new();
+ Error *local_err = NULL;
+
+ qio_channel_set_name(QIO_CHANNEL(sioc), "vmsr-helper");
+ qio_channel_socket_connect_sync(sioc,
+ &saddr,
+ &local_err);
+ if (local_err) {
+ /* Close socket. */
+ qio_channel_close(QIO_CHANNEL(sioc), NULL);
+ object_unref(OBJECT(sioc));
+ sioc = NULL;
+ goto out;
+ }
+
+ qio_channel_set_delay(QIO_CHANNEL(sioc), false);
+out:
+ return sioc;
+}
+
+uint64_t vmsr_read_msr(uint32_t reg, uint32_t cpu_id, uint32_t tid,
+ QIOChannelSocket *sioc)
+{
+ uint64_t data = 0;
+ int r = 0;
+ Error *local_err = NULL;
+ uint32_t buffer[3];
+ /*
+ * Send the required arguments:
+ * 1. RAPL MSR register to read
+ * 2. On which CPU ID
+ * 3. From which vCPU (Thread ID)
+ */
+ buffer[0] = reg;
+ buffer[1] = cpu_id;
+ buffer[2] = tid;
+
+ r = qio_channel_write_all(QIO_CHANNEL(sioc),
+ (char *)buffer, sizeof(buffer),
+ &local_err);
+ if (r < 0) {
+ goto out_close;
+ }
+
+ r = qio_channel_read(QIO_CHANNEL(sioc),
+ (char *)&data, sizeof(data),
+ &local_err);
+ if (r < 0) {
+ data = 0;
+ goto out_close;
+ }
+
+out_close:
+ return data;
+}
+
+/* Retrieve the max number of physical package */
+unsigned int vmsr_get_max_physical_package(unsigned int max_cpus)
+{
+ const char *dir = "/sys/devices/system/cpu/";
+ const char *topo_path = "topology/physical_package_id";
+ g_autofree int *uniquePackages = g_new0(int, max_cpus);
+ unsigned int packageCount = 0;
+ FILE *file = NULL;
+
+ for (int i = 0; i < max_cpus; i++) {
+ g_autofree char *filePath = NULL;
+ g_autofree char *cpuid = g_strdup_printf("cpu%d", i);
+
+ filePath = g_build_filename(dir, cpuid, topo_path, NULL);
+
+ file = fopen(filePath, "r");
+
+ if (file == NULL) {
+ error_report("Error opening physical_package_id file");
+ return 0;
+ }
+
+ char packageId[10];
+ if (fgets(packageId, sizeof(packageId), file) == NULL) {
+ packageCount = 0;
+ }
+
+ fclose(file);
+
+ int currentPackageId = atoi(packageId);
+
+ bool isUnique = true;
+ for (int j = 0; j < packageCount; j++) {
+ if (uniquePackages[j] == currentPackageId) {
+ isUnique = false;
+ break;
+ }
+ }
+
+ if (isUnique) {
+ uniquePackages[packageCount] = currentPackageId;
+ packageCount++;
+
+ if (packageCount >= max_cpus) {
+ break;
+ }
+ }
+ }
+
+ return (packageCount == 0) ? 1 : packageCount;
+}
+
+/* Retrieve the max number of physical cpu on the host */
+unsigned int vmsr_get_maxcpus(void)
+{
+ GDir *dir;
+ const gchar *entry_name;
+ unsigned int cpu_count = 0;
+ const char *path = "/sys/devices/system/cpu/";
+
+ dir = g_dir_open(path, 0, NULL);
+ if (dir == NULL) {
+ error_report("Unable to open cpu directory");
+ return -1;
+ }
+
+ while ((entry_name = g_dir_read_name(dir)) != NULL) {
+ if (g_ascii_strncasecmp(entry_name, "cpu", 3) == 0 &&
+ isdigit(entry_name[3])) {
+ cpu_count++;
+ }
+ }
+
+ g_dir_close(dir);
+
+ return cpu_count;
+}
+
+/* Count the number of physical cpu on each packages */
+unsigned int vmsr_count_cpus_per_package(unsigned int *package_count,
+ unsigned int max_pkgs)
+{
+ g_autofree char *file_contents = NULL;
+ g_autofree char *path = NULL;
+ g_autofree char *path_name = NULL;
+ gsize length;
+
+ /* Iterate over cpus and count cpus in each package */
+ for (int cpu_id = 0; ; cpu_id++) {
+ path_name = g_strdup_printf("/sys/devices/system/cpu/cpu%d/"
+ "topology/physical_package_id", cpu_id);
+
+ path = g_build_filename(path_name, NULL);
+
+ if (!g_file_get_contents(path, &file_contents, &length, NULL)) {
+ break; /* No more cpus */
+ }
+
+ /* Get the physical package ID for this CPU */
+ int package_id = atoi(file_contents);
+
+ /* Check if the package ID is within the known number of packages */
+ if (package_id >= 0 && package_id < max_pkgs) {
+ /* If yes, count the cpu for this package*/
+ package_count[package_id]++;
+ }
+ }
+
+ return 0;
+}
+
+/* Get the physical package id from a given cpu id */
+int vmsr_get_physical_package_id(int cpu_id)
+{
+ g_autofree char *file_contents = NULL;
+ g_autofree char *file_path = NULL;
+ int package_id = -1;
+ gsize length;
+
+ file_path = g_strdup_printf("/sys/devices/system/cpu/cpu%d"
+ "/topology/physical_package_id", cpu_id);
+
+ if (!g_file_get_contents(file_path, &file_contents, &length, NULL)) {
+ goto out;
+ }
+
+ package_id = atoi(file_contents);
+
+out:
+ return package_id;
+}
+
+/* Read the scheduled time for a given thread of a give pid */
+void vmsr_read_thread_stat(pid_t pid,
+ unsigned int thread_id,
+ unsigned long long *utime,
+ unsigned long long *stime,
+ unsigned int *cpu_id)
+{
+ g_autofree char *path = NULL;
+ g_autofree char *path_name = NULL;
+
+ path_name = g_strdup_printf("/proc/%u/task/%d/stat", pid, thread_id);
+
+ path = g_build_filename(path_name, NULL);
+
+ FILE *file = fopen(path, "r");
+ if (file == NULL) {
+ pid = -1;
+ return;
+ }
+
+ if (fscanf(file, "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u"
+ " %llu %llu %*d %*d %*d %*d %*d %*d %*u %*u %*d %*u %*u"
+ " %*u %*u %*u %*u %*u %*u %*u %*u %*u %*d %*u %*u %u",
+ utime, stime, cpu_id) != 3)
+ {
+ pid = -1;
+ return;
+ }
+
+ fclose(file);
+ return;
+}
+
+/* Read QEMU stat task folder to retrieve all QEMU threads ID */
+pid_t *vmsr_get_thread_ids(pid_t pid, unsigned int *num_threads)
+{
+ g_autofree char *task_path = g_strdup_printf("%d/task", pid);
+ g_autofree char *path = g_build_filename("/proc", task_path, NULL);
+
+ DIR *dir = opendir(path);
+ if (dir == NULL) {
+ error_report("Error opening /proc/qemu/task");
+ return NULL;
+ }
+
+ pid_t *thread_ids = NULL;
+ unsigned int thread_count = 0;
+
+ g_autofree struct dirent *ent = NULL;
+ while ((ent = readdir(dir)) != NULL) {
+ if (ent->d_name[0] == '.') {
+ continue;
+ }
+ pid_t tid = atoi(ent->d_name);
+ if (pid != tid) {
+ thread_ids = g_renew(pid_t, thread_ids, (thread_count + 1));
+ thread_ids[thread_count] = tid;
+ thread_count++;
+ }
+ }
+
+ closedir(dir);
+
+ *num_threads = thread_count;
+ return thread_ids;
+}
+
+void vmsr_delta_ticks(vmsr_thread_stat *thd_stat, int i)
+{
+ thd_stat[i].delta_ticks = (thd_stat[i].utime[1] + thd_stat[i].stime[1])
+ - (thd_stat[i].utime[0] + thd_stat[i].stime[0]);
+}
+
+double vmsr_get_ratio(uint64_t e_delta,
+ unsigned long long delta_ticks,
+ unsigned int maxticks)
+{
+ return (e_delta / 100.0) * ((100.0 / maxticks) * delta_ticks);
+}
+
+void vmsr_init_topo_info(X86CPUTopoInfo *topo_info,
+ const MachineState *ms)
+{
+ topo_info->dies_per_pkg = ms->smp.dies;
+ topo_info->modules_per_die = ms->smp.modules;
+ topo_info->cores_per_module = ms->smp.cores;
+ topo_info->threads_per_core = ms->smp.threads;
+}
+
diff --git a/target/i386/kvm/meson.build b/target/i386/kvm/meson.build
index e7850981e62..3996cafaf29 100644
--- a/target/i386/kvm/meson.build
+++ b/target/i386/kvm/meson.build
@@ -3,6 +3,7 @@ i386_kvm_ss = ss.source_set()
i386_kvm_ss.add(files(
'kvm.c',
'kvm-cpu.c',
+ 'vmsr_energy.c',
))
i386_kvm_ss.add(when: 'CONFIG_XEN_EMU', if_true: files('xen-emu.c'))
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PULL 04/11] Add support for RAPL MSRs in KVM/Qemu
2024-07-23 14:15 ` [PULL 04/11] Add support for RAPL MSRs in KVM/Qemu Paolo Bonzini
@ 2024-07-25 10:25 ` Peter Maydell
0 siblings, 0 replies; 21+ messages in thread
From: Peter Maydell @ 2024-07-25 10:25 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, Anthony Harivel
On Tue, 23 Jul 2024 at 15:17, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> From: Anthony Harivel <aharivel@redhat.com>
>
> Starting with the "Sandy Bridge" generation, Intel CPUs provide a RAPL
> interface (Running Average Power Limit) for advertising the accumulated
> energy consumption of various power domains (e.g. CPU packages, DRAM,
> etc.).
>
> The consumption is reported via MSRs (model specific registers) like
> MSR_PKG_ENERGY_STATUS for the CPU package power domain. These MSRs are
> 64 bits registers that represent the accumulated energy consumption in
> micro Joules. They are updated by microcode every ~1ms.
Hi; Coverity points out a couple of issues with this commit
(details below).
> +static void *kvm_msr_energy_thread(void *data)
> +{
> + KVMState *s = data;
> + struct KVMMsrEnergy *vmsr = &s->msr_energy;
> +
> + g_autofree vmsr_package_energy_stat *pkg_stat = NULL;
> + g_autofree vmsr_thread_stat *thd_stat = NULL;
> + g_autofree CPUState *cpu = NULL;
> + g_autofree unsigned int *vpkgs_energy_stat = NULL;
> + unsigned int num_threads = 0;
> +
> + X86CPUTopoIDs topo_ids;
> +
> + rcu_register_thread();
> +
> + /* Allocate memory for each package energy status */
> + pkg_stat = g_new0(vmsr_package_energy_stat, vmsr->host_topo.maxpkgs);
> +
> + /* Allocate memory for thread stats */
> + thd_stat = g_new0(vmsr_thread_stat, 1);
> +
> + /* Allocate memory for holding virtual package energy counter */
> + vpkgs_energy_stat = g_new0(unsigned int, vmsr->guest_vsockets);
> +
> + /* Populate the max tick of each packages */
> + for (int i = 0; i < vmsr->host_topo.maxpkgs; i++) {
> + /*
> + * Max numbers of ticks per package
> + * Time in second * Number of ticks/second * Number of cores/package
> + * ex: 100 ticks/second/CPU, 12 CPUs per Package gives 1200 ticks max
> + */
> + vmsr->host_topo.maxticks[i] = (MSR_ENERGY_THREAD_SLEEP_US / 1000000)
> + * sysconf(_SC_CLK_TCK)
> + * vmsr->host_topo.pkg_cpu_count[i];
> + }
> +
> + while (true) {
> + /* Get all qemu threads id */
> + g_autofree pid_t *thread_ids =
> + thread_ids = vmsr_get_thread_ids(vmsr->pid, &num_threads);
Here you are assigning the same value to the thread_ids variable
twice. What was the intention here ? (CID 1558553)
> +
> + if (thread_ids == NULL) {
> + goto clean;
> + }
> +/* Read the scheduled time for a given thread of a give pid */
> +void vmsr_read_thread_stat(pid_t pid,
> + unsigned int thread_id,
> + unsigned long long *utime,
> + unsigned long long *stime,
> + unsigned int *cpu_id)
> +{
> + g_autofree char *path = NULL;
> + g_autofree char *path_name = NULL;
> +
> + path_name = g_strdup_printf("/proc/%u/task/%d/stat", pid, thread_id);
> +
> + path = g_build_filename(path_name, NULL);
> +
> + FILE *file = fopen(path, "r");
> + if (file == NULL) {
> + pid = -1;
> + return;
> + }
> +
> + if (fscanf(file, "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u"
> + " %llu %llu %*d %*d %*d %*d %*d %*d %*u %*u %*d %*u %*u"
> + " %*u %*u %*u %*u %*u %*u %*u %*u %*u %*d %*u %*u %u",
> + utime, stime, cpu_id) != 3)
> + {
> + pid = -1;
> + return;
In this error-exit path we leak 'file', because we opened it but
didn't close it. (CID 1558557)
Also, both here and in the previous error-exit check we set pid = -1,
which is pointless because it's a function-local variable and nothing
is going to see the new value.
> + }
> +
> + fclose(file);
> + return;
> +}
thanks
-- PMM
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (3 preceding siblings ...)
2024-07-23 14:15 ` [PULL 04/11] Add support for RAPL MSRs in KVM/Qemu Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2025-03-19 15:28 ` Fiona Ebner
2024-07-23 14:15 ` [PULL 06/11] hpet: ignore high bits of comparator in 32-bit mode Paolo Bonzini
` (6 subsequent siblings)
11 siblings, 1 reply; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
There are several bugs in the handling of the ISR register:
- switching level->edge was not lowering the interrupt and
clearing ISR
- switching on the enable bit was not raising a level-triggered
interrupt if the timer had fired
- the timer must be kept running even if not enabled, in
order to set the ISR flag, so writes to HPET_TN_CFG must
not call hpet_del_timer()
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 60 +++++++++++++++++++++++++++++++++----------------
1 file changed, 41 insertions(+), 19 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 4cb5393c0b5..58073df02b5 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -196,21 +196,31 @@ static void update_irq(struct HPETTimer *timer, int set)
}
s = timer->state;
mask = 1 << timer->tn;
- if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
+
+ if (set && (timer->config & HPET_TN_TYPE_LEVEL)) {
+ /*
+ * If HPET_TN_ENABLE bit is 0, "the timer will still operate and
+ * generate appropriate status bits, but will not cause an interrupt"
+ */
+ s->isr |= mask;
+ } else {
s->isr &= ~mask;
+ }
+
+ if (set && timer_enabled(timer) && hpet_enabled(s)) {
+ if (timer_fsb_route(timer)) {
+ address_space_stl_le(&address_space_memory, timer->fsb >> 32,
+ timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
+ NULL);
+ } else if (timer->config & HPET_TN_TYPE_LEVEL) {
+ qemu_irq_raise(s->irqs[route]);
+ } else {
+ qemu_irq_pulse(s->irqs[route]);
+ }
+ } else {
if (!timer_fsb_route(timer)) {
qemu_irq_lower(s->irqs[route]);
}
- } else if (timer_fsb_route(timer)) {
- address_space_stl_le(&address_space_memory, timer->fsb >> 32,
- timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
- NULL);
- } else if (timer->config & HPET_TN_TYPE_LEVEL) {
- s->isr |= mask;
- qemu_irq_raise(s->irqs[route]);
- } else {
- s->isr &= ~mask;
- qemu_irq_pulse(s->irqs[route]);
}
}
@@ -414,8 +424,13 @@ static void hpet_set_timer(HPETTimer *t)
static void hpet_del_timer(HPETTimer *t)
{
+ HPETState *s = t->state;
timer_del(t->qemu_timer);
- update_irq(t, 0);
+
+ if (s->isr & (1 << t->tn)) {
+ /* For level-triggered interrupt, this leaves ISR set but lowers irq. */
+ update_irq(t, 1);
+ }
}
static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
@@ -515,20 +530,26 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
switch ((addr - 0x100) % 0x20) {
case HPET_TN_CFG:
trace_hpet_ram_write_tn_cfg();
- if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
+ if (deactivating_bit(old_val, new_val, HPET_TN_TYPE_LEVEL)) {
+ /*
+ * Do this before changing timer->config; otherwise, if
+ * HPET_TN_FSB is set, update_irq will not lower the qemu_irq.
+ */
update_irq(timer, 0);
}
val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
timer->config = (timer->config & 0xffffffff00000000ULL) | val;
+ if (activating_bit(old_val, new_val, HPET_TN_ENABLE)
+ && (s->isr & (1 << timer_id))) {
+ update_irq(timer, 1);
+ }
+
if (new_val & HPET_TN_32BIT) {
timer->cmp = (uint32_t)timer->cmp;
timer->period = (uint32_t)timer->period;
}
- if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
- hpet_enabled(s)) {
+ if (hpet_enabled(s)) {
hpet_set_timer(timer);
- } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
- hpet_del_timer(timer);
}
break;
case HPET_TN_CFG + 4: // Interrupt capabilities
@@ -606,9 +627,10 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
s->hpet_offset =
ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
for (i = 0; i < s->num_timers; i++) {
- if ((&s->timer[i])->cmp != ~0ULL) {
- hpet_set_timer(&s->timer[i]);
+ if (timer_enabled(&s->timer[i]) && (s->isr & (1 << i))) {
+ update_irq(&s->timer[i], 1);
}
+ hpet_set_timer(&s->timer[i]);
}
} else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
/* Halt main counter and disable interrupt generation. */
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2024-07-23 14:15 ` [PULL 05/11] hpet: fix and cleanup persistence of interrupt status Paolo Bonzini
@ 2025-03-19 15:28 ` Fiona Ebner
2025-03-19 15:30 ` Paolo Bonzini
0 siblings, 1 reply; 21+ messages in thread
From: Fiona Ebner @ 2025-03-19 15:28 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel; +Cc: Michael S . Tsirkin
Hi,
Am 23.07.24 um 16:15 schrieb Paolo Bonzini:
> There are several bugs in the handling of the ISR register:
>
> - switching level->edge was not lowering the interrupt and
> clearing ISR
>
> - switching on the enable bit was not raising a level-triggered
> interrupt if the timer had fired
>
> - the timer must be kept running even if not enabled, in
> order to set the ISR flag, so writes to HPET_TN_CFG must
> not call hpet_del_timer()
we've been getting user reports about increased CPU usage for QEMU
processes on the host after they updated from QEMU 9.0 to QEMU 9.2.
Bisecting points to this change, and users confirmed that adding the
machine option hpet=off reduces the CPU usage again. Some quick
experimentation suggests that in particular the last part here, i.e.
"timer must be kept running even if not enabled" is the reason for this.
I reproduced the issue with a Debian 12.10 guest with kernel 6.1. It
enables and then immediately disables the HPET timer again during boot
(i.e. the HPET_TN_ENABLE bit).
I also installed 6.13.7 in the guest for comparison, but that just made
the issue worse, because it uses a higher frequency for the timer.
Is this something Linux should/could handle differently? I suppose there
is nothing that can be done on the QEMU side to avoid this while aiming
to keep the implementation correct?
If necessary, our management layer downstream could disable the hpet
timer by default and make users explicitly enable it if
desired/required. I just wanted to ask if the issue is known and if
there are any other suggestions? Thanks!
Best Regards,
Fiona
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2025-03-19 15:28 ` Fiona Ebner
@ 2025-03-19 15:30 ` Paolo Bonzini
2025-03-19 15:47 ` Fiona Ebner
0 siblings, 1 reply; 21+ messages in thread
From: Paolo Bonzini @ 2025-03-19 15:30 UTC (permalink / raw)
To: Fiona Ebner; +Cc: qemu-devel, Michael S . Tsirkin
On Wed, Mar 19, 2025 at 4:29 PM Fiona Ebner <f.ebner@proxmox.com> wrote:
>
> Hi,
> If necessary, our management layer downstream could disable the hpet
> timer by default and make users explicitly enable it if
> desired/required. I just wanted to ask if the issue is known and if
> there are any other suggestions? Thanks!
We can try to skip the timer if the interrupt would have no change -
similar to how the RTC works, it's more complex but very effective in
reducing CPU usage.
That said, if you can disable the HPET timer by default without
problems with e.g. live migration I strongly suggest you do. And in
the mean time you can also revert these patches, they were actually
reported as bugs but it's not clear what guest OS was affected.
Paolo
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2025-03-19 15:30 ` Paolo Bonzini
@ 2025-03-19 15:47 ` Fiona Ebner
2025-03-19 15:51 ` Paolo Bonzini
0 siblings, 1 reply; 21+ messages in thread
From: Fiona Ebner @ 2025-03-19 15:47 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, Michael S . Tsirkin
Am 19.03.25 um 16:30 schrieb Paolo Bonzini:
> On Wed, Mar 19, 2025 at 4:29 PM Fiona Ebner <f.ebner@proxmox.com> wrote:
>>
>> Hi,
>> If necessary, our management layer downstream could disable the hpet
>> timer by default and make users explicitly enable it if
>> desired/required. I just wanted to ask if the issue is known and if
>> there are any other suggestions? Thanks!
>
> We can try to skip the timer if the interrupt would have no change -
> similar to how the RTC works, it's more complex but very effective in
> reducing CPU usage.
>
> That said, if you can disable the HPET timer by default without
> problems with e.g. live migration I strongly suggest you do. And in
> the mean time you can also revert these patches, they were actually
> reported as bugs but it's not clear what guest OS was affected.
We'll only be able to disable it starting from a new (downstream)
machine version, but that is fine. For now, I'll go for the revert,
thank you for the suggestion! Is disabling it strongly suggested because
of those bug reports? Or are there issues in general?
Best Regards,
Fiona
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2025-03-19 15:47 ` Fiona Ebner
@ 2025-03-19 15:51 ` Paolo Bonzini
2025-03-19 15:56 ` Fiona Ebner
0 siblings, 1 reply; 21+ messages in thread
From: Paolo Bonzini @ 2025-03-19 15:51 UTC (permalink / raw)
To: Fiona Ebner; +Cc: qemu-devel, Michael S . Tsirkin
On Wed, Mar 19, 2025 at 4:47 PM Fiona Ebner <f.ebner@proxmox.com> wrote:
> We'll only be able to disable it starting from a new (downstream)
> machine version, but that is fine. For now, I'll go for the revert,
> thank you for the suggestion! Is disabling it strongly suggested because
> of those bug reports? Or are there issues in general?
No, the bug reports are really just for corner cases and there are no
huge issues. However, both Linux and Windows give the HPET a
relatively high priority that it probably does not deserve. :)
For Linux you should be using kvmclock already, and for Windows the
Hyper-V paravirtualized clock. If you don't have the Hyper-V pv clock,
the RTC periodic timer is more battle-tested as an emulated
clock/timer device; disabling the HPET ensures that Windows uses the
RTC.
Paolo
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PULL 05/11] hpet: fix and cleanup persistence of interrupt status
2025-03-19 15:51 ` Paolo Bonzini
@ 2025-03-19 15:56 ` Fiona Ebner
0 siblings, 0 replies; 21+ messages in thread
From: Fiona Ebner @ 2025-03-19 15:56 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, Michael S . Tsirkin
Am 19.03.25 um 16:51 schrieb Paolo Bonzini:
> On Wed, Mar 19, 2025 at 4:47 PM Fiona Ebner <f.ebner@proxmox.com> wrote:
>> We'll only be able to disable it starting from a new (downstream)
>> machine version, but that is fine. For now, I'll go for the revert,
>> thank you for the suggestion! Is disabling it strongly suggested because
>> of those bug reports? Or are there issues in general?
>
> No, the bug reports are really just for corner cases and there are no
> huge issues. However, both Linux and Windows give the HPET a
> relatively high priority that it probably does not deserve. :)
>
> For Linux you should be using kvmclock already, and for Windows the
> Hyper-V paravirtualized clock. If you don't have the Hyper-V pv clock,
> the RTC periodic timer is more battle-tested as an emulated
> clock/timer device; disabling the HPET ensures that Windows uses the
> RTC.
Good to know! Right, for Windows guests, we actually already disable HPET :)
Best Regards,
Fiona
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PULL 06/11] hpet: ignore high bits of comparator in 32-bit mode
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (4 preceding siblings ...)
2024-07-23 14:15 ` [PULL 05/11] hpet: fix and cleanup persistence of interrupt status Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 07/11] hpet: remove unnecessary variable "index" Paolo Bonzini
` (5 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 4 ++++
hw/timer/trace-events | 1 +
2 files changed, 5 insertions(+)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 58073df02b5..bbb1e5f0897 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -585,6 +585,10 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
}
break;
case HPET_TN_CMP + 4: // comparator register high order
+ if (timer->config & HPET_TN_32BIT) {
+ trace_hpet_ram_write_invalid_tn_cmp();
+ break;
+ }
trace_hpet_ram_write_tn_cmp(4);
if (!timer_is_periodic(timer)
|| (timer->config & HPET_TN_SETVAL)) {
diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index de769f4b716..a5fafbc6796 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -111,6 +111,7 @@ hpet_ram_write_timer_id(uint64_t timer_id) "hpet_ram_writel timer_id = 0x%" PRIx
hpet_ram_write_tn_cfg(void) "hpet_ram_writel HPET_TN_CFG"
hpet_ram_write_invalid_tn_cfg(uint8_t reg_off) "invalid HPET_TN_CFG + %" PRIu8 " write"
hpet_ram_write_tn_cmp(uint8_t reg_off) "hpet_ram_writel HPET_TN_CMP + %" PRIu8
+hpet_ram_write_invalid_tn_cmp(void) "invalid HPET_TN_CMP + 4 write"
hpet_ram_write_invalid(void) "invalid hpet_ram_writel"
hpet_ram_write_counter_write_while_enabled(void) "Writing counter while HPET enabled!"
hpet_ram_write_counter_written(uint8_t reg_off, uint64_t value, uint64_t counter) "HPET counter + %" PRIu8 "written. crt = 0x%" PRIx64 " -> 0x%" PRIx64
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 07/11] hpet: remove unnecessary variable "index"
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (5 preceding siblings ...)
2024-07-23 14:15 ` [PULL 06/11] hpet: ignore high bits of comparator in 32-bit mode Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 08/11] hpet: place read-only bits directly in "new_val" Paolo Bonzini
` (4 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index bbb1e5f0897..380e272fbeb 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -437,12 +437,12 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
unsigned size)
{
HPETState *s = opaque;
- uint64_t cur_tick, index;
+ uint64_t cur_tick;
trace_hpet_ram_read(addr);
- index = addr;
+
/*address range of all TN regs*/
- if (index >= 0x100 && index <= 0x3ff) {
+ if (addr >= 0x100 && addr <= 0x3ff) {
uint8_t timer_id = (addr - 0x100) / 0x20;
HPETTimer *timer = &s->timer[timer_id];
@@ -469,7 +469,7 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
break;
}
} else {
- switch (index) {
+ switch (addr) {
case HPET_ID:
return s->capability;
case HPET_PERIOD:
@@ -510,15 +510,14 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
{
int i;
HPETState *s = opaque;
- uint64_t old_val, new_val, val, index;
+ uint64_t old_val, new_val, val;
trace_hpet_ram_write(addr, value);
- index = addr;
old_val = hpet_ram_read(opaque, addr, 4);
new_val = value;
/*address range of all TN regs*/
- if (index >= 0x100 && index <= 0x3ff) {
+ if (addr >= 0x100 && addr <= 0x3ff) {
uint8_t timer_id = (addr - 0x100) / 0x20;
HPETTimer *timer = &s->timer[timer_id];
@@ -620,7 +619,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
}
return;
} else {
- switch (index) {
+ switch (addr) {
case HPET_ID:
return;
case HPET_CFG:
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 08/11] hpet: place read-only bits directly in "new_val"
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (6 preceding siblings ...)
2024-07-23 14:15 ` [PULL 07/11] hpet: remove unnecessary variable "index" Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 09/11] hpet: accept 64-bit reads and writes Paolo Bonzini
` (3 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
The variable "val" is used for two different purposes. As an intermediate
value when writing configuration registers, and to store the cleared bits
when writing ISR.
Use "new_val" for the former, and rename the variable so that it is clearer
for the latter case.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 380e272fbeb..831e5a95b09 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -510,7 +510,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
{
int i;
HPETState *s = opaque;
- uint64_t old_val, new_val, val;
+ uint64_t old_val, new_val, cleared;
trace_hpet_ram_write(addr, value);
old_val = hpet_ram_read(opaque, addr, 4);
@@ -536,13 +536,12 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
*/
update_irq(timer, 0);
}
- val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
- timer->config = (timer->config & 0xffffffff00000000ULL) | val;
+ new_val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
+ timer->config = (timer->config & 0xffffffff00000000ULL) | new_val;
if (activating_bit(old_val, new_val, HPET_TN_ENABLE)
&& (s->isr & (1 << timer_id))) {
update_irq(timer, 1);
}
-
if (new_val & HPET_TN_32BIT) {
timer->cmp = (uint32_t)timer->cmp;
timer->period = (uint32_t)timer->period;
@@ -623,8 +622,8 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
case HPET_ID:
return;
case HPET_CFG:
- val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
- s->config = (s->config & 0xffffffff00000000ULL) | val;
+ new_val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
+ s->config = (s->config & 0xffffffff00000000ULL) | new_val;
if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
/* Enable main counter and interrupt generation. */
s->hpet_offset =
@@ -658,9 +657,9 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
trace_hpet_invalid_hpet_cfg(4);
break;
case HPET_STATUS:
- val = new_val & s->isr;
+ cleared = new_val & s->isr;
for (i = 0; i < s->num_timers; i++) {
- if (val & (1 << i)) {
+ if (cleared & (1 << i)) {
update_irq(&s->timer[i], 0);
}
}
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 09/11] hpet: accept 64-bit reads and writes
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (7 preceding siblings ...)
2024-07-23 14:15 ` [PULL 08/11] hpet: place read-only bits directly in "new_val" Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 10/11] hpet: store full 64-bit target value of the counter Paolo Bonzini
` (2 subsequent siblings)
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
Declare the MemoryRegionOps so that 64-bit reads and writes to the HPET
are received directly. This makes it possible to unify the code to
process low and high parts: for 32-bit reads, extract the desired word;
for 32-bit writes, just merge the desired part into the old value and
proceed as with a 64-bit write.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 137 +++++++++++++-----------------------------
hw/timer/trace-events | 3 +-
2 files changed, 44 insertions(+), 96 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 831e5a95b09..ac55dd1ebd6 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -437,6 +437,7 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
unsigned size)
{
HPETState *s = opaque;
+ int shift = (addr & 4) * 8;
uint64_t cur_tick;
trace_hpet_ram_read(addr);
@@ -451,52 +452,33 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
return 0;
}
- switch ((addr - 0x100) % 0x20) {
- case HPET_TN_CFG:
- return timer->config;
- case HPET_TN_CFG + 4: // Interrupt capabilities
- return timer->config >> 32;
+ switch (addr & 0x18) {
+ case HPET_TN_CFG: // including interrupt capabilities
+ return timer->config >> shift;
case HPET_TN_CMP: // comparator register
- return timer->cmp;
- case HPET_TN_CMP + 4:
- return timer->cmp >> 32;
+ return timer->cmp >> shift;
case HPET_TN_ROUTE:
- return timer->fsb;
- case HPET_TN_ROUTE + 4:
- return timer->fsb >> 32;
+ return timer->fsb >> shift;
default:
trace_hpet_ram_read_invalid();
break;
}
} else {
- switch (addr) {
- case HPET_ID:
- return s->capability;
- case HPET_PERIOD:
- return s->capability >> 32;
+ switch (addr & ~4) {
+ case HPET_ID: // including HPET_PERIOD
+ return s->capability >> shift;
case HPET_CFG:
- return s->config;
- case HPET_CFG + 4:
- trace_hpet_invalid_hpet_cfg(4);
- return 0;
+ return s->config >> shift;
case HPET_COUNTER:
if (hpet_enabled(s)) {
cur_tick = hpet_get_ticks(s);
} else {
cur_tick = s->hpet_counter;
}
- trace_hpet_ram_read_reading_counter(0, cur_tick);
- return cur_tick;
- case HPET_COUNTER + 4:
- if (hpet_enabled(s)) {
- cur_tick = hpet_get_ticks(s);
- } else {
- cur_tick = s->hpet_counter;
- }
- trace_hpet_ram_read_reading_counter(4, cur_tick);
- return cur_tick >> 32;
+ trace_hpet_ram_read_reading_counter(addr & 4, cur_tick);
+ return cur_tick >> shift;
case HPET_STATUS:
- return s->isr;
+ return s->isr >> shift;
default:
trace_hpet_ram_read_invalid();
break;
@@ -510,11 +492,11 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
{
int i;
HPETState *s = opaque;
+ int shift = (addr & 4) * 8;
+ int len = MIN(size * 8, 64 - shift);
uint64_t old_val, new_val, cleared;
trace_hpet_ram_write(addr, value);
- old_val = hpet_ram_read(opaque, addr, 4);
- new_val = value;
/*address range of all TN regs*/
if (addr >= 0x100 && addr <= 0x3ff) {
@@ -526,9 +508,12 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
trace_hpet_timer_id_out_of_range(timer_id);
return;
}
- switch ((addr - 0x100) % 0x20) {
+ switch (addr & 0x18) {
case HPET_TN_CFG:
- trace_hpet_ram_write_tn_cfg();
+ trace_hpet_ram_write_tn_cfg(addr & 4);
+ old_val = timer->config;
+ new_val = deposit64(old_val, shift, len, value);
+ new_val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
if (deactivating_bit(old_val, new_val, HPET_TN_TYPE_LEVEL)) {
/*
* Do this before changing timer->config; otherwise, if
@@ -536,8 +521,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
*/
update_irq(timer, 0);
}
- new_val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
- timer->config = (timer->config & 0xffffffff00000000ULL) | new_val;
+ timer->config = new_val;
if (activating_bit(old_val, new_val, HPET_TN_ENABLE)
&& (s->isr & (1 << timer_id))) {
update_irq(timer, 1);
@@ -550,56 +534,28 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
hpet_set_timer(timer);
}
break;
- case HPET_TN_CFG + 4: // Interrupt capabilities
- trace_hpet_ram_write_invalid_tn_cfg(4);
- break;
case HPET_TN_CMP: // comparator register
- trace_hpet_ram_write_tn_cmp(0);
if (timer->config & HPET_TN_32BIT) {
- new_val = (uint32_t)new_val;
- }
- if (!timer_is_periodic(timer)
- || (timer->config & HPET_TN_SETVAL)) {
- timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
- }
- if (timer_is_periodic(timer)) {
- /*
- * FIXME: Clamp period to reasonable min value?
- * Clamp period to reasonable max value
- */
- if (timer->config & HPET_TN_32BIT) {
- new_val = MIN(new_val, ~0u >> 1);
+ /* High 32-bits are zero, leave them untouched. */
+ if (shift) {
+ trace_hpet_ram_write_invalid_tn_cmp();
+ break;
}
- timer->period =
- (timer->period & 0xffffffff00000000ULL) | new_val;
+ len = 64;
+ value = (uint32_t) value;
}
- /*
- * FIXME: on a 64-bit write, HPET_TN_SETVAL should apply to the
- * high bits part as well.
- */
- timer->config &= ~HPET_TN_SETVAL;
- if (hpet_enabled(s)) {
- hpet_set_timer(timer);
- }
- break;
- case HPET_TN_CMP + 4: // comparator register high order
- if (timer->config & HPET_TN_32BIT) {
- trace_hpet_ram_write_invalid_tn_cmp();
- break;
- }
- trace_hpet_ram_write_tn_cmp(4);
+ trace_hpet_ram_write_tn_cmp(addr & 4);
if (!timer_is_periodic(timer)
|| (timer->config & HPET_TN_SETVAL)) {
- timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
+ timer->cmp = deposit64(timer->cmp, shift, len, value);
}
if (timer_is_periodic(timer)) {
/*
* FIXME: Clamp period to reasonable min value?
* Clamp period to reasonable max value
*/
- new_val = MIN(new_val, ~0u >> 1);
- timer->period =
- (timer->period & 0xffffffffULL) | new_val << 32;
+ new_val = deposit64(timer->period, shift, len, value);
+ timer->period = MIN(new_val, (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1);
}
timer->config &= ~HPET_TN_SETVAL;
if (hpet_enabled(s)) {
@@ -607,10 +563,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
}
break;
case HPET_TN_ROUTE:
- timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
- break;
- case HPET_TN_ROUTE + 4:
- timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
+ timer->fsb = deposit64(timer->fsb, shift, len, value);
break;
default:
trace_hpet_ram_write_invalid();
@@ -618,12 +571,14 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
}
return;
} else {
- switch (addr) {
+ switch (addr & ~4) {
case HPET_ID:
return;
case HPET_CFG:
+ old_val = s->config;
+ new_val = deposit64(old_val, shift, len, value);
new_val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
- s->config = (s->config & 0xffffffff00000000ULL) | new_val;
+ s->config = new_val;
if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
/* Enable main counter and interrupt generation. */
s->hpet_offset =
@@ -653,10 +608,8 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
}
break;
- case HPET_CFG + 4:
- trace_hpet_invalid_hpet_cfg(4);
- break;
case HPET_STATUS:
+ new_val = value << shift;
cleared = new_val & s->isr;
for (i = 0; i < s->num_timers; i++) {
if (cleared & (1 << i)) {
@@ -668,15 +621,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
if (hpet_enabled(s)) {
trace_hpet_ram_write_counter_write_while_enabled();
}
- s->hpet_counter =
- (s->hpet_counter & 0xffffffff00000000ULL) | value;
- trace_hpet_ram_write_counter_written(0, value, s->hpet_counter);
- break;
- case HPET_COUNTER + 4:
- trace_hpet_ram_write_counter_write_while_enabled();
- s->hpet_counter =
- (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
- trace_hpet_ram_write_counter_written(4, value, s->hpet_counter);
+ s->hpet_counter = deposit64(s->hpet_counter, shift, len, value);
break;
default:
trace_hpet_ram_write_invalid();
@@ -690,7 +635,11 @@ static const MemoryRegionOps hpet_ram_ops = {
.write = hpet_ram_write,
.valid = {
.min_access_size = 4,
- .max_access_size = 4,
+ .max_access_size = 8,
+ },
+ .impl = {
+ .min_access_size = 4,
+ .max_access_size = 8,
},
.endianness = DEVICE_NATIVE_ENDIAN,
};
diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index a5fafbc6796..f48a712801e 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -108,8 +108,7 @@ hpet_ram_read_reading_counter(uint8_t reg_off, uint64_t cur_tick) "reading count
hpet_ram_read_invalid(void) "invalid hpet_ram_readl"
hpet_ram_write(uint64_t addr, uint64_t value) "enter hpet_ram_writel at 0x%" PRIx64 " = 0x%" PRIx64
hpet_ram_write_timer_id(uint64_t timer_id) "hpet_ram_writel timer_id = 0x%" PRIx64
-hpet_ram_write_tn_cfg(void) "hpet_ram_writel HPET_TN_CFG"
-hpet_ram_write_invalid_tn_cfg(uint8_t reg_off) "invalid HPET_TN_CFG + %" PRIu8 " write"
+hpet_ram_write_tn_cfg(uint8_t reg_off) "hpet_ram_writel HPET_TN_CFG + %" PRIu8
hpet_ram_write_tn_cmp(uint8_t reg_off) "hpet_ram_writel HPET_TN_CMP + %" PRIu8
hpet_ram_write_invalid_tn_cmp(void) "invalid HPET_TN_CMP + 4 write"
hpet_ram_write_invalid(void) "invalid hpet_ram_writel"
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 10/11] hpet: store full 64-bit target value of the counter
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (8 preceding siblings ...)
2024-07-23 14:15 ` [PULL 09/11] hpet: accept 64-bit reads and writes Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-23 14:15 ` [PULL 11/11] hpet: avoid timer storms on periodic timers Paolo Bonzini
2024-07-24 2:58 ` [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Richard Henderson
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
Store the full 64-bit value at which the timer should fire.
This makes it possible to skip the imprecise hpet_calculate_diff()
step, and to remove the clamping of the period to 31 or 63 bits.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 111 +++++++++++++++++++++---------------------------
1 file changed, 49 insertions(+), 62 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index ac55dd1ebd6..1654b7cb8b8 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -54,6 +54,7 @@ typedef struct HPETTimer { /* timers */
uint64_t cmp; /* comparator */
uint64_t fsb; /* FSB route */
/* Hidden register state */
+ uint64_t cmp64; /* comparator (extended to counter width) */
uint64_t period; /* Last value written to comparator */
uint8_t wrap_flag; /* timer pop will indicate wrap for one-shot 32-bit
* mode. Next pop will be actual timer expiration.
@@ -115,11 +116,6 @@ static uint32_t timer_enabled(HPETTimer *t)
}
static uint32_t hpet_time_after(uint64_t a, uint64_t b)
-{
- return ((int32_t)(b - a) < 0);
-}
-
-static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
{
return ((int64_t)(b - a) < 0);
}
@@ -156,29 +152,34 @@ static uint64_t hpet_get_ticks(HPETState *s)
return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
}
-/*
- * calculate diff between comparator value and current ticks
- */
-static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
+static uint64_t hpet_get_ns(HPETState *s, uint64_t tick)
{
+ return ticks_to_ns(tick) - s->hpet_offset;
+}
+/*
+ * calculate next value of the general counter that matches the
+ * target (either entirely, or the low 32-bit only depending on
+ * the timer mode).
+ */
+static uint64_t hpet_calculate_cmp64(HPETTimer *t, uint64_t cur_tick, uint64_t target)
+{
if (t->config & HPET_TN_32BIT) {
- uint32_t diff, cmp;
-
- cmp = (uint32_t)t->cmp;
- diff = cmp - (uint32_t)current;
- diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
- return (uint64_t)diff;
+ uint64_t result = deposit64(cur_tick, 0, 32, target);
+ if (result < cur_tick) {
+ result += 0x100000000ULL;
+ }
+ return result;
} else {
- uint64_t diff, cmp;
-
- cmp = t->cmp;
- diff = cmp - current;
- diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
- return diff;
+ return target;
}
}
+static uint64_t hpet_next_wrap(uint64_t cur_tick)
+{
+ return (cur_tick | 0xffffffffU) + 1;
+}
+
static void update_irq(struct HPETTimer *timer, int set)
{
uint64_t mask;
@@ -260,7 +261,12 @@ static bool hpet_validate_num_timers(void *opaque, int version_id)
static int hpet_post_load(void *opaque, int version_id)
{
HPETState *s = opaque;
+ int i;
+ for (i = 0; i < s->num_timers; i++) {
+ HPETTimer *t = &s->timer[i];
+ t->cmp64 = hpet_calculate_cmp64(t, s->hpet_counter, t->cmp);
+ }
/* Recalculate the offset between the main counter and guest time */
if (!s->hpet_offset_saved) {
s->hpet_offset = ticks_to_ns(s->hpet_counter)
@@ -356,14 +362,10 @@ static const VMStateDescription vmstate_hpet = {
}
};
-static void hpet_arm(HPETTimer *t, uint64_t ticks)
+static void hpet_arm(HPETTimer *t, uint64_t tick)
{
- if (ticks < ns_to_ticks(INT64_MAX / 2)) {
- timer_mod(t->qemu_timer,
- qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ticks_to_ns(ticks));
- } else {
- timer_del(t->qemu_timer);
- }
+ /* FIXME: Clamp period to reasonable min value? */
+ timer_mod(t->qemu_timer, hpet_get_ns(t->state, tick));
}
/*
@@ -372,54 +374,44 @@ static void hpet_arm(HPETTimer *t, uint64_t ticks)
static void hpet_timer(void *opaque)
{
HPETTimer *t = opaque;
- uint64_t diff;
-
uint64_t period = t->period;
uint64_t cur_tick = hpet_get_ticks(t->state);
if (timer_is_periodic(t) && period != 0) {
+ while (hpet_time_after(cur_tick, t->cmp64)) {
+ t->cmp64 += period;
+ }
if (t->config & HPET_TN_32BIT) {
- while (hpet_time_after(cur_tick, t->cmp)) {
- t->cmp = (uint32_t)(t->cmp + t->period);
- }
+ t->cmp = (uint32_t)t->cmp64;
} else {
- while (hpet_time_after64(cur_tick, t->cmp)) {
- t->cmp += period;
- }
- }
- diff = hpet_calculate_diff(t, cur_tick);
- hpet_arm(t, diff);
- } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
- if (t->wrap_flag) {
- diff = hpet_calculate_diff(t, cur_tick);
- hpet_arm(t, diff);
- t->wrap_flag = 0;
+ t->cmp = t->cmp64;
}
+ hpet_arm(t, t->cmp64);
+ } else if (t->wrap_flag) {
+ t->wrap_flag = 0;
+ hpet_arm(t, t->cmp64);
}
update_irq(t, 1);
}
static void hpet_set_timer(HPETTimer *t)
{
- uint64_t diff;
- uint32_t wrap_diff; /* how many ticks until we wrap? */
uint64_t cur_tick = hpet_get_ticks(t->state);
- /* whenever new timer is being set up, make sure wrap_flag is 0 */
t->wrap_flag = 0;
- diff = hpet_calculate_diff(t, cur_tick);
+ t->cmp64 = hpet_calculate_cmp64(t, cur_tick, t->cmp);
+ if (t->config & HPET_TN_32BIT) {
- /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
- * counter wraps in addition to an interrupt with comparator match.
- */
- if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
- wrap_diff = 0xffffffff - (uint32_t)cur_tick;
- if (wrap_diff < (uint32_t)diff) {
- diff = wrap_diff;
+ /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
+ * counter wraps in addition to an interrupt with comparator match.
+ */
+ if (!timer_is_periodic(t) && t->cmp64 > hpet_next_wrap(cur_tick)) {
t->wrap_flag = 1;
+ hpet_arm(t, hpet_next_wrap(cur_tick));
+ return;
}
}
- hpet_arm(t, diff);
+ hpet_arm(t, t->cmp64);
}
static void hpet_del_timer(HPETTimer *t)
@@ -550,12 +542,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
timer->cmp = deposit64(timer->cmp, shift, len, value);
}
if (timer_is_periodic(timer)) {
- /*
- * FIXME: Clamp period to reasonable min value?
- * Clamp period to reasonable max value
- */
- new_val = deposit64(timer->period, shift, len, value);
- timer->period = MIN(new_val, (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1);
+ timer->period = deposit64(timer->period, shift, len, value);
}
timer->config &= ~HPET_TN_SETVAL;
if (hpet_enabled(s)) {
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PULL 11/11] hpet: avoid timer storms on periodic timers
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (9 preceding siblings ...)
2024-07-23 14:15 ` [PULL 10/11] hpet: store full 64-bit target value of the counter Paolo Bonzini
@ 2024-07-23 14:15 ` Paolo Bonzini
2024-07-24 2:58 ` [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Richard Henderson
11 siblings, 0 replies; 21+ messages in thread
From: Paolo Bonzini @ 2024-07-23 14:15 UTC (permalink / raw)
To: qemu-devel
If the period is set to a value that is too low, there could be no
time left to run the rest of QEMU. Do not trigger interrupts faster
than 1 MHz.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/timer/hpet.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 1654b7cb8b8..471950adef1 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -59,6 +59,7 @@ typedef struct HPETTimer { /* timers */
uint8_t wrap_flag; /* timer pop will indicate wrap for one-shot 32-bit
* mode. Next pop will be actual timer expiration.
*/
+ uint64_t last; /* last value armed, to avoid timer storms */
} HPETTimer;
struct HPETState {
@@ -266,6 +267,7 @@ static int hpet_post_load(void *opaque, int version_id)
for (i = 0; i < s->num_timers; i++) {
HPETTimer *t = &s->timer[i];
t->cmp64 = hpet_calculate_cmp64(t, s->hpet_counter, t->cmp);
+ t->last = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - NANOSECONDS_PER_SECOND;
}
/* Recalculate the offset between the main counter and guest time */
if (!s->hpet_offset_saved) {
@@ -364,8 +366,15 @@ static const VMStateDescription vmstate_hpet = {
static void hpet_arm(HPETTimer *t, uint64_t tick)
{
- /* FIXME: Clamp period to reasonable min value? */
- timer_mod(t->qemu_timer, hpet_get_ns(t->state, tick));
+ uint64_t ns = hpet_get_ns(t->state, tick);
+
+ /* Clamp period to reasonable min value (1 us) */
+ if (timer_is_periodic(t) && ns - t->last < 1000) {
+ ns = t->last + 1000;
+ }
+
+ t->last = ns;
+ timer_mod(t->qemu_timer, ns);
}
/*
--
2.45.2
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze
2024-07-23 14:15 [PULL 00/11] target/i386, HPET changes for QEMU 9.1 soft freeze Paolo Bonzini
` (10 preceding siblings ...)
2024-07-23 14:15 ` [PULL 11/11] hpet: avoid timer storms on periodic timers Paolo Bonzini
@ 2024-07-24 2:58 ` Richard Henderson
11 siblings, 0 replies; 21+ messages in thread
From: Richard Henderson @ 2024-07-24 2:58 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel
On 7/24/24 00:15, Paolo Bonzini wrote:
> The following changes since commit a7ddb48bd1363c8bcdf42776d320289c42191f01:
>
> Merge tag 'pull-aspeed-20240721' ofhttps://github.com/legoater/qemu into staging (2024-07-22 07:52:05 +1000)
>
> are available in the Git repository at:
>
> https://gitlab.com/bonzini/qemu.git tags/for-upstream
>
> for you to fetch changes up to 7c912ffb59e8137091894d767433e65c3df8b0bf:
>
> hpet: avoid timer storms on periodic timers (2024-07-22 19:19:44 +0200)
>
> ----------------------------------------------------------------
> * target/i386/kvm: support for reading RAPL MSRs using a helper program
> * hpet: emulation improvements
Applied, thanks. Please update https://wiki.qemu.org/ChangeLog/9.1 as appropriate.
r~
^ permalink raw reply [flat|nested] 21+ messages in thread