diff options
| -rw-r--r-- | cpus.c | 73 | ||||
| -rw-r--r-- | include/qom/cpu.h | 9 | ||||
| -rw-r--r-- | include/sysemu/cpus.h | 2 | ||||
| -rw-r--r-- | qemu-options.hx | 20 | ||||
| -rw-r--r-- | tcg/tcg.h | 9 | ||||
| -rw-r--r-- | vl.c | 49 |
6 files changed, 161 insertions, 1 deletions
@@ -25,6 +25,7 @@ /* Needed early for CONFIG_BSD etc. */ #include "qemu/osdep.h" #include "qemu-common.h" +#include "qemu/config-file.h" #include "cpu.h" #include "monitor/monitor.h" #include "qapi/qmp/qerror.h" @@ -45,6 +46,7 @@ #include "qemu/main-loop.h" #include "qemu/bitmap.h" #include "qemu/seqlock.h" +#include "tcg.h" #include "qapi-event.h" #include "hw/nmi.h" #include "sysemu/replay.h" @@ -150,6 +152,77 @@ typedef struct TimersState { } TimersState; static TimersState timers_state; +bool mttcg_enabled; + +/* + * We default to false if we know other options have been enabled + * which are currently incompatible with MTTCG. Otherwise when each + * guest (target) has been updated to support: + * - atomic instructions + * - memory ordering primitives (barriers) + * they can set the appropriate CONFIG flags in ${target}-softmmu.mak + * + * Once a guest architecture has been converted to the new primitives + * there are two remaining limitations to check. + * + * - The guest can't be oversized (e.g. 64 bit guest on 32 bit host) + * - The host must have a stronger memory order than the guest + * + * It may be possible in future to support strong guests on weak hosts + * but that will require tagging all load/stores in a guest with their + * implicit memory order requirements which would likely slow things + * down a lot. + */ + +static bool check_tcg_memory_orders_compatible(void) +{ +#if defined(TCG_GUEST_DEFAULT_MO) && defined(TCG_TARGET_DEFAULT_MO) + return (TCG_GUEST_DEFAULT_MO & ~TCG_TARGET_DEFAULT_MO) == 0; +#else + return false; +#endif +} + +static bool default_mttcg_enabled(void) +{ + QemuOpts *icount_opts = qemu_find_opts_singleton("icount"); + const char *rr = qemu_opt_get(icount_opts, "rr"); + + if (rr || TCG_OVERSIZED_GUEST) { + return false; + } else { +#ifdef TARGET_SUPPORTS_MTTCG + return check_tcg_memory_orders_compatible(); +#else + return false; +#endif + } +} + +void qemu_tcg_configure(QemuOpts *opts, Error **errp) +{ + const char *t = qemu_opt_get(opts, "thread"); + if (t) { + if (strcmp(t, "multi") == 0) { + if (TCG_OVERSIZED_GUEST) { + error_setg(errp, "No MTTCG when guest word size > hosts"); + } else { + if (!check_tcg_memory_orders_compatible()) { + error_report("Guest expects a stronger memory ordering " + "than the host provides"); + error_printf("This may cause strange/hard to debug errors"); + } + mttcg_enabled = true; + } + } else if (strcmp(t, "single") == 0) { + mttcg_enabled = false; + } else { + error_setg(errp, "Invalid 'thread' setting %s", t); + } + } else { + mttcg_enabled = default_mttcg_enabled(); + } +} int64_t cpu_get_icount_raw(void) { diff --git a/include/qom/cpu.h b/include/qom/cpu.h index f69b2407ea..2cf4ecf144 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -416,6 +416,15 @@ extern struct CPUTailQ cpus; extern __thread CPUState *current_cpu; /** + * qemu_tcg_mttcg_enabled: + * Check whether we are running MultiThread TCG or not. + * + * Returns: %true if we are in MTTCG mode %false otherwise. + */ +extern bool mttcg_enabled; +#define qemu_tcg_mttcg_enabled() (mttcg_enabled) + +/** * cpu_paging_enabled: * @cpu: The CPU whose state is to be inspected. * diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h index 3728a1ea7e..a73b5d4bce 100644 --- a/include/sysemu/cpus.h +++ b/include/sysemu/cpus.h @@ -36,4 +36,6 @@ extern int smp_threads; void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg); +void qemu_tcg_configure(QemuOpts *opts, Error **errp); + #endif diff --git a/qemu-options.hx b/qemu-options.hx index 9936cf38f3..bf458f83c3 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -95,6 +95,26 @@ STEXI Select CPU model (@code{-cpu help} for list and additional feature selection) ETEXI +DEF("accel", HAS_ARG, QEMU_OPTION_accel, + "-accel [accel=]accelerator[,thread=single|multi]\n" + " select accelerator ('-accel help for list')\n" + " thread=single|multi (enable multi-threaded TCG)", QEMU_ARCH_ALL) +STEXI +@item -accel @var{name}[,prop=@var{value}[,...]] +@findex -accel +This is used to enable an accelerator. Depending on the target architecture, +kvm, xen, or tcg can be available. By default, tcg is used. If there is more +than one accelerator specified, the next one is used if the previous one fails +to initialize. +@table @option +@item thread=single|multi +Controls number of TCG threads. When the TCG is multi-threaded there will be one +thread per vCPU therefor taking advantage of additional host cores. The default +is to enable multi-threading where both the back-end and front-ends support it and +no incompatible TCG features have been enabled (e.g. icount/replay). +@end table +ETEXI + DEF("smp", HAS_ARG, QEMU_OPTION_smp, "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]\n" " set the number of CPUs to 'n' [default=1]\n" @@ -80,6 +80,15 @@ typedef uint64_t tcg_target_ulong; #error unsupported #endif +/* Oversized TCG guests make things like MTTCG hard + * as we can't use atomics for cputlb updates. + */ +#if TARGET_LONG_BITS > TCG_TARGET_REG_BITS +#define TCG_OVERSIZED_GUEST 1 +#else +#define TCG_OVERSIZED_GUEST 0 +#endif + #if TCG_TARGET_NB_REGS <= 32 typedef uint32_t TCGRegSet; #elif TCG_TARGET_NB_REGS <= 64 @@ -300,6 +300,26 @@ static QemuOptsList qemu_machine_opts = { }, }; +static QemuOptsList qemu_accel_opts = { + .name = "accel", + .implied_opt_name = "accel", + .head = QTAILQ_HEAD_INITIALIZER(qemu_accel_opts.head), + .merge_lists = true, + .desc = { + { + .name = "accel", + .type = QEMU_OPT_STRING, + .help = "Select the type of accelerator", + }, + { + .name = "thread", + .type = QEMU_OPT_STRING, + .help = "Enable/disable multi-threaded TCG", + }, + { /* end of list */ } + }, +}; + static QemuOptsList qemu_boot_opts = { .name = "boot-opts", .implied_opt_name = "order", @@ -2928,7 +2948,8 @@ int main(int argc, char **argv, char **envp) const char *boot_once = NULL; DisplayState *ds; int cyls, heads, secs, translation; - QemuOpts *hda_opts = NULL, *opts, *machine_opts, *icount_opts = NULL; + QemuOpts *opts, *machine_opts; + QemuOpts *hda_opts = NULL, *icount_opts = NULL, *accel_opts = NULL; QemuOptsList *olist; int optind; const char *optarg; @@ -2983,6 +3004,7 @@ int main(int argc, char **argv, char **envp) qemu_add_opts(&qemu_trace_opts); qemu_add_opts(&qemu_option_rom_opts); qemu_add_opts(&qemu_machine_opts); + qemu_add_opts(&qemu_accel_opts); qemu_add_opts(&qemu_mem_opts); qemu_add_opts(&qemu_smp_opts); qemu_add_opts(&qemu_boot_opts); @@ -3675,6 +3697,26 @@ int main(int argc, char **argv, char **envp) qdev_prop_register_global(&kvm_pit_lost_tick_policy); break; } + case QEMU_OPTION_accel: + accel_opts = qemu_opts_parse_noisily(qemu_find_opts("accel"), + optarg, true); + optarg = qemu_opt_get(accel_opts, "accel"); + + olist = qemu_find_opts("machine"); + if (strcmp("kvm", optarg) == 0) { + qemu_opts_parse_noisily(olist, "accel=kvm", false); + } else if (strcmp("xen", optarg) == 0) { + qemu_opts_parse_noisily(olist, "accel=xen", false); + } else if (strcmp("tcg", optarg) == 0) { + qemu_opts_parse_noisily(olist, "accel=tcg", false); + } else { + if (!is_help_option(optarg)) { + error_printf("Unknown accelerator: %s", optarg); + } + error_printf("Supported accelerators: kvm, xen, tcg\n"); + exit(1); + } + break; case QEMU_OPTION_usb: olist = qemu_find_opts("machine"); qemu_opts_parse_noisily(olist, "usb=on", false); @@ -3983,6 +4025,8 @@ int main(int argc, char **argv, char **envp) replay_configure(icount_opts); + qemu_tcg_configure(accel_opts, &error_fatal); + machine_class = select_machine(); set_memory_options(&ram_slots, &maxram_size, machine_class); @@ -4349,6 +4393,9 @@ int main(int argc, char **argv, char **envp) if (!tcg_enabled()) { error_report("-icount is not allowed with hardware virtualization"); exit(1); + } else if (qemu_tcg_mttcg_enabled()) { + error_report("-icount does not currently work with MTTCG"); + exit(1); } configure_icount(icount_opts, &error_abort); qemu_opts_del(icount_opts); |