diff options
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/tcg/tcg-all.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c index c59d5b0024..6b000f0b94 100644 --- a/accel/tcg/tcg-all.c +++ b/accel/tcg/tcg-all.c @@ -30,6 +30,11 @@ #include "cpu.h" #include "sysemu/cpus.h" #include "qemu/main-loop.h" +#include "tcg/tcg.h" +#include "include/qapi/error.h" +#include "include/qemu/error-report.h" +#include "include/hw/boards.h" +#include "qemu/option.h" unsigned long tcg_tb_size; @@ -58,6 +63,53 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask) } } +/* + * 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) +{ + if (use_icount || TCG_OVERSIZED_GUEST) { + return false; + } else { +#ifdef TARGET_SUPPORTS_MTTCG + return check_tcg_memory_orders_compatible(); +#else + return false; +#endif + } +} + +static void tcg_accel_instance_init(Object *obj) +{ + mttcg_enabled = default_mttcg_enabled(); +} + static int tcg_init(MachineState *ms) { tcg_exec_init(tcg_tb_size * 1024 * 1024); @@ -65,6 +117,36 @@ static int tcg_init(MachineState *ms) return 0; } +void qemu_tcg_configure(QemuOpts *opts, Error **errp) +{ + const char *t = qemu_opt_get(opts, "thread"); + if (!t) { + return; + } + if (strcmp(t, "multi") == 0) { + if (TCG_OVERSIZED_GUEST) { + error_setg(errp, "No MTTCG when guest word size > hosts"); + } else if (use_icount) { + error_setg(errp, "No MTTCG when icount is enabled"); + } else { +#ifndef TARGET_SUPPORTS_MTTCG + warn_report("Guest not yet converted to MTTCG - " + "you may get unexpected results"); +#endif + if (!check_tcg_memory_orders_compatible()) { + warn_report("Guest expects a stronger memory ordering " + "than the host provides"); + error_printf("This may cause strange/hard to debug errors\n"); + } + mttcg_enabled = true; + } + } else if (strcmp(t, "single") == 0) { + mttcg_enabled = false; + } else { + error_setg(errp, "Invalid 'thread' setting %s", t); + } +} + static void tcg_accel_class_init(ObjectClass *oc, void *data) { AccelClass *ac = ACCEL_CLASS(oc); @@ -78,6 +160,7 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data) static const TypeInfo tcg_accel_type = { .name = TYPE_TCG_ACCEL, .parent = TYPE_ACCEL, + .instance_init = tcg_accel_instance_init, .class_init = tcg_accel_class_init, }; |