diff options
| -rw-r--r-- | include/sysemu/sysemu.h | 1 | ||||
| -rw-r--r-- | qemu-options.hx | 24 | ||||
| -rw-r--r-- | target/i386/kvm.c | 23 | ||||
| -rw-r--r-- | vl.c | 32 |
4 files changed, 79 insertions, 1 deletions
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index e893f72..b921c6f 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -128,6 +128,7 @@ extern bool boot_strict; extern uint8_t *boot_splash_filedata; extern size_t boot_splash_filedata_size; extern bool enable_mlock; +extern bool enable_cpu_pm; extern uint8_t qemu_extra_params_fw[2]; extern QEMUClockType rtc_clock; extern const char *mem_path; diff --git a/qemu-options.hx b/qemu-options.hx index 3e45483..81b1e99 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3325,6 +3325,30 @@ mlocking qemu and guest memory can be enabled via @option{mlock=on} (enabled by default). ETEXI +DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, + "--overcommit [mem-lock=on|off][cpu-pm=on|off]\n" + " run qemu with overcommit hints\n" + " mem-lock=on|off controls memory lock support (default: off)\n" + " cpu-pm=on|off controls cpu power management (default: off)\n", + QEMU_ARCH_ALL) +STEXI +@item -overcommit mem-lock=on|off +@item -overcommit cpu-pm=on|off +@findex -overcommit +Run qemu with hints about host resource overcommit. The default is +to assume that host overcommits all resources. + +Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled +by default). This works when host memory is not overcommitted and reduces the +worst-case latency for guest. This is equivalent to @option{realtime}. + +Guest ability to manage power state of host cpus (increasing latency for other +processes on the same host cpu, but decreasing latency for guest) can be +enabled via @option{cpu-pm=on} (disabled by default). This works best when +host CPU is not overcommitted. When used, host estimates of CPU cycle and power +utilization will be incorrect, not taking into account guest idle time. +ETEXI + DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ "-gdb dev wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL) STEXI diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 2d174f3..dc991f6 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -1387,6 +1387,29 @@ int kvm_arch_init(MachineState *ms, KVMState *s) smram_machine_done.notify = register_smram_listener; qemu_add_machine_init_done_notifier(&smram_machine_done); } + + if (enable_cpu_pm) { + int disable_exits = kvm_check_extension(s, KVM_CAP_X86_DISABLE_EXITS); + int ret; + +/* Work around for kernel header with a typo. TODO: fix header and drop. */ +#if defined(KVM_X86_DISABLE_EXITS_HTL) && !defined(KVM_X86_DISABLE_EXITS_HLT) +#define KVM_X86_DISABLE_EXITS_HLT KVM_X86_DISABLE_EXITS_HTL +#endif + if (disable_exits) { + disable_exits &= (KVM_X86_DISABLE_EXITS_MWAIT | + KVM_X86_DISABLE_EXITS_HLT | + KVM_X86_DISABLE_EXITS_PAUSE); + } + + ret = kvm_vm_enable_cap(s, KVM_CAP_X86_DISABLE_EXITS, 0, + disable_exits); + if (ret < 0) { + error_report("kvm: guest stopping CPU not supported: %s", + strerror(-ret)); + } + } + return 0; } @@ -142,6 +142,7 @@ ram_addr_t ram_size; const char *mem_path = NULL; int mem_prealloc = 0; /* force preallocation of physical target memory */ bool enable_mlock = false; +bool enable_cpu_pm = false; int nb_nics; NICInfo nd_table[MAX_NICS]; int autostart; @@ -390,6 +391,22 @@ static QemuOptsList qemu_realtime_opts = { }, }; +static QemuOptsList qemu_overcommit_opts = { + .name = "overcommit", + .head = QTAILQ_HEAD_INITIALIZER(qemu_overcommit_opts.head), + .desc = { + { + .name = "mem-lock", + .type = QEMU_OPT_BOOL, + }, + { + .name = "cpu-pm", + .type = QEMU_OPT_BOOL, + }, + { /* end of list */ } + }, +}; + static QemuOptsList qemu_msg_opts = { .name = "msg", .head = QTAILQ_HEAD_INITIALIZER(qemu_msg_opts.head), @@ -3906,7 +3923,20 @@ int main(int argc, char **argv, char **envp) if (!opts) { exit(1); } - enable_mlock = qemu_opt_get_bool(opts, "mlock", true); + /* Don't override the -overcommit option if set */ + enable_mlock = enable_mlock || + qemu_opt_get_bool(opts, "mlock", true); + break; + case QEMU_OPTION_overcommit: + opts = qemu_opts_parse_noisily(qemu_find_opts("overcommit"), + optarg, false); + if (!opts) { + exit(1); + } + /* Don't override the -realtime option if set */ + enable_mlock = enable_mlock || + qemu_opt_get_bool(opts, "mem-lock", false); + enable_cpu_pm = qemu_opt_get_bool(opts, "cpu-pm", false); break; case QEMU_OPTION_msg: opts = qemu_opts_parse_noisily(qemu_find_opts("msg"), optarg, |