The primary motivation is to remove a dozen insns along the fast-path in tb_lookup. As a byproduct, this allows us to completely remove parallel_cpus. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
862 lines
27 KiB
C
862 lines
27 KiB
C
/*
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* emulator main execution loop
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*
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* Copyright (c) 2003-2005 Fabrice Bellard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qemu/qemu-print.h"
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#include "cpu.h"
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#include "hw/core/tcg-cpu-ops.h"
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#include "trace.h"
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#include "disas/disas.h"
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#include "exec/exec-all.h"
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#include "tcg/tcg.h"
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#include "qemu/atomic.h"
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#include "qemu/compiler.h"
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#include "sysemu/qtest.h"
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#include "qemu/timer.h"
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#include "qemu/rcu.h"
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#include "exec/tb-hash.h"
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#include "exec/tb-lookup.h"
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#include "exec/log.h"
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#include "qemu/main-loop.h"
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#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
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#include "hw/i386/apic.h"
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#endif
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#include "sysemu/cpus.h"
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#include "exec/cpu-all.h"
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#include "sysemu/cpu-timers.h"
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#include "sysemu/replay.h"
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#include "internal.h"
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/* -icount align implementation. */
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typedef struct SyncClocks {
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int64_t diff_clk;
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int64_t last_cpu_icount;
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int64_t realtime_clock;
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} SyncClocks;
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#if !defined(CONFIG_USER_ONLY)
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/* Allow the guest to have a max 3ms advance.
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* The difference between the 2 clocks could therefore
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* oscillate around 0.
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*/
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#define VM_CLOCK_ADVANCE 3000000
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#define THRESHOLD_REDUCE 1.5
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#define MAX_DELAY_PRINT_RATE 2000000000LL
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#define MAX_NB_PRINTS 100
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static int64_t max_delay;
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static int64_t max_advance;
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static void align_clocks(SyncClocks *sc, CPUState *cpu)
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{
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int64_t cpu_icount;
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if (!icount_align_option) {
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return;
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}
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cpu_icount = cpu->icount_extra + cpu_neg(cpu)->icount_decr.u16.low;
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sc->diff_clk += icount_to_ns(sc->last_cpu_icount - cpu_icount);
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sc->last_cpu_icount = cpu_icount;
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if (sc->diff_clk > VM_CLOCK_ADVANCE) {
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#ifndef _WIN32
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struct timespec sleep_delay, rem_delay;
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sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
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sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
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if (nanosleep(&sleep_delay, &rem_delay) < 0) {
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sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
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} else {
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sc->diff_clk = 0;
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}
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#else
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Sleep(sc->diff_clk / SCALE_MS);
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sc->diff_clk = 0;
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#endif
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}
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}
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static void print_delay(const SyncClocks *sc)
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{
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static float threshold_delay;
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static int64_t last_realtime_clock;
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static int nb_prints;
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if (icount_align_option &&
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sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
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nb_prints < MAX_NB_PRINTS) {
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if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
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(-sc->diff_clk / (float)1000000000LL <
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(threshold_delay - THRESHOLD_REDUCE))) {
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threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
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qemu_printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
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threshold_delay - 1,
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threshold_delay);
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nb_prints++;
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last_realtime_clock = sc->realtime_clock;
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}
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}
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}
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static void init_delay_params(SyncClocks *sc, CPUState *cpu)
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{
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if (!icount_align_option) {
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return;
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}
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sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
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sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
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sc->last_cpu_icount
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= cpu->icount_extra + cpu_neg(cpu)->icount_decr.u16.low;
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if (sc->diff_clk < max_delay) {
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max_delay = sc->diff_clk;
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}
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if (sc->diff_clk > max_advance) {
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max_advance = sc->diff_clk;
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}
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/* Print every 2s max if the guest is late. We limit the number
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of printed messages to NB_PRINT_MAX(currently 100) */
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print_delay(sc);
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}
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#else
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static void align_clocks(SyncClocks *sc, const CPUState *cpu)
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{
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}
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static void init_delay_params(SyncClocks *sc, const CPUState *cpu)
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{
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}
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#endif /* CONFIG USER ONLY */
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/* Execute a TB, and fix up the CPU state afterwards if necessary */
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/*
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* Disable CFI checks.
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* TCG creates binary blobs at runtime, with the transformed code.
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* A TB is a blob of binary code, created at runtime and called with an
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* indirect function call. Since such function did not exist at compile time,
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* the CFI runtime has no way to verify its signature and would fail.
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* TCG is not considered a security-sensitive part of QEMU so this does not
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* affect the impact of CFI in environment with high security requirements
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*/
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static inline TranslationBlock * QEMU_DISABLE_CFI
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cpu_tb_exec(CPUState *cpu, TranslationBlock *itb, int *tb_exit)
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{
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CPUArchState *env = cpu->env_ptr;
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uintptr_t ret;
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TranslationBlock *last_tb;
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const void *tb_ptr = itb->tc.ptr;
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qemu_log_mask_and_addr(CPU_LOG_EXEC, itb->pc,
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"Trace %d: %p ["
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TARGET_FMT_lx "/" TARGET_FMT_lx "/%#x] %s\n",
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cpu->cpu_index, itb->tc.ptr,
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itb->cs_base, itb->pc, itb->flags,
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lookup_symbol(itb->pc));
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#if defined(DEBUG_DISAS)
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if (qemu_loglevel_mask(CPU_LOG_TB_CPU)
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&& qemu_log_in_addr_range(itb->pc)) {
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FILE *logfile = qemu_log_lock();
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int flags = 0;
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if (qemu_loglevel_mask(CPU_LOG_TB_FPU)) {
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flags |= CPU_DUMP_FPU;
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}
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#if defined(TARGET_I386)
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flags |= CPU_DUMP_CCOP;
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#endif
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log_cpu_state(cpu, flags);
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qemu_log_unlock(logfile);
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}
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#endif /* DEBUG_DISAS */
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qemu_thread_jit_execute();
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ret = tcg_qemu_tb_exec(env, tb_ptr);
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cpu->can_do_io = 1;
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/*
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* TODO: Delay swapping back to the read-write region of the TB
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* until we actually need to modify the TB. The read-only copy,
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* coming from the rx region, shares the same host TLB entry as
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* the code that executed the exit_tb opcode that arrived here.
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* If we insist on touching both the RX and the RW pages, we
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* double the host TLB pressure.
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*/
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last_tb = tcg_splitwx_to_rw((void *)(ret & ~TB_EXIT_MASK));
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*tb_exit = ret & TB_EXIT_MASK;
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trace_exec_tb_exit(last_tb, *tb_exit);
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if (*tb_exit > TB_EXIT_IDX1) {
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/* We didn't start executing this TB (eg because the instruction
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* counter hit zero); we must restore the guest PC to the address
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* of the start of the TB.
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*/
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CPUClass *cc = CPU_GET_CLASS(cpu);
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qemu_log_mask_and_addr(CPU_LOG_EXEC, last_tb->pc,
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"Stopped execution of TB chain before %p ["
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TARGET_FMT_lx "] %s\n",
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last_tb->tc.ptr, last_tb->pc,
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lookup_symbol(last_tb->pc));
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if (cc->tcg_ops->synchronize_from_tb) {
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cc->tcg_ops->synchronize_from_tb(cpu, last_tb);
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} else {
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assert(cc->set_pc);
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cc->set_pc(cpu, last_tb->pc);
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}
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}
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return last_tb;
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}
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static void cpu_exec_enter(CPUState *cpu)
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{
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CPUClass *cc = CPU_GET_CLASS(cpu);
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if (cc->tcg_ops->cpu_exec_enter) {
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cc->tcg_ops->cpu_exec_enter(cpu);
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}
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}
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static void cpu_exec_exit(CPUState *cpu)
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{
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CPUClass *cc = CPU_GET_CLASS(cpu);
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if (cc->tcg_ops->cpu_exec_exit) {
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cc->tcg_ops->cpu_exec_exit(cpu);
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}
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}
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void cpu_exec_step_atomic(CPUState *cpu)
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{
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CPUArchState *env = (CPUArchState *)cpu->env_ptr;
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TranslationBlock *tb;
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target_ulong cs_base, pc;
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uint32_t flags;
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uint32_t cflags = (curr_cflags(cpu) & ~CF_PARALLEL) | 1;
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int tb_exit;
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if (sigsetjmp(cpu->jmp_env, 0) == 0) {
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start_exclusive();
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g_assert(cpu == current_cpu);
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g_assert(!cpu->running);
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cpu->running = true;
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cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
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tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
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if (tb == NULL) {
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mmap_lock();
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tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
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mmap_unlock();
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}
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cpu_exec_enter(cpu);
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/* execute the generated code */
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trace_exec_tb(tb, pc);
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cpu_tb_exec(cpu, tb, &tb_exit);
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cpu_exec_exit(cpu);
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} else {
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/*
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* The mmap_lock is dropped by tb_gen_code if it runs out of
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* memory.
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*/
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#ifndef CONFIG_SOFTMMU
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tcg_debug_assert(!have_mmap_lock());
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#endif
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if (qemu_mutex_iothread_locked()) {
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qemu_mutex_unlock_iothread();
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}
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assert_no_pages_locked();
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qemu_plugin_disable_mem_helpers(cpu);
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}
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/*
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* As we start the exclusive region before codegen we must still
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* be in the region if we longjump out of either the codegen or
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* the execution.
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*/
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g_assert(cpu_in_exclusive_context(cpu));
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cpu->running = false;
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end_exclusive();
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}
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struct tb_desc {
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target_ulong pc;
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target_ulong cs_base;
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CPUArchState *env;
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tb_page_addr_t phys_page1;
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uint32_t flags;
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uint32_t cflags;
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uint32_t trace_vcpu_dstate;
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};
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static bool tb_lookup_cmp(const void *p, const void *d)
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{
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const TranslationBlock *tb = p;
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const struct tb_desc *desc = d;
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if (tb->pc == desc->pc &&
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tb->page_addr[0] == desc->phys_page1 &&
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tb->cs_base == desc->cs_base &&
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tb->flags == desc->flags &&
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tb->trace_vcpu_dstate == desc->trace_vcpu_dstate &&
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tb_cflags(tb) == desc->cflags) {
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/* check next page if needed */
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if (tb->page_addr[1] == -1) {
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return true;
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} else {
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tb_page_addr_t phys_page2;
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target_ulong virt_page2;
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virt_page2 = (desc->pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
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phys_page2 = get_page_addr_code(desc->env, virt_page2);
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if (tb->page_addr[1] == phys_page2) {
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return true;
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}
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}
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}
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return false;
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}
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TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc,
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target_ulong cs_base, uint32_t flags,
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uint32_t cflags)
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{
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tb_page_addr_t phys_pc;
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struct tb_desc desc;
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uint32_t h;
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desc.env = (CPUArchState *)cpu->env_ptr;
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desc.cs_base = cs_base;
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desc.flags = flags;
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desc.cflags = cflags;
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desc.trace_vcpu_dstate = *cpu->trace_dstate;
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desc.pc = pc;
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phys_pc = get_page_addr_code(desc.env, pc);
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if (phys_pc == -1) {
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return NULL;
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}
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desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
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h = tb_hash_func(phys_pc, pc, flags, cflags, *cpu->trace_dstate);
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return qht_lookup_custom(&tb_ctx.htable, &desc, h, tb_lookup_cmp);
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}
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void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr)
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{
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if (TCG_TARGET_HAS_direct_jump) {
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uintptr_t offset = tb->jmp_target_arg[n];
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uintptr_t tc_ptr = (uintptr_t)tb->tc.ptr;
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uintptr_t jmp_rx = tc_ptr + offset;
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uintptr_t jmp_rw = jmp_rx - tcg_splitwx_diff;
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tb_target_set_jmp_target(tc_ptr, jmp_rx, jmp_rw, addr);
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} else {
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tb->jmp_target_arg[n] = addr;
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}
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}
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static inline void tb_add_jump(TranslationBlock *tb, int n,
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TranslationBlock *tb_next)
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{
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uintptr_t old;
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qemu_thread_jit_write();
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assert(n < ARRAY_SIZE(tb->jmp_list_next));
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qemu_spin_lock(&tb_next->jmp_lock);
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/* make sure the destination TB is valid */
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if (tb_next->cflags & CF_INVALID) {
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goto out_unlock_next;
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}
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/* Atomically claim the jump destination slot only if it was NULL */
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old = qatomic_cmpxchg(&tb->jmp_dest[n], (uintptr_t)NULL,
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(uintptr_t)tb_next);
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if (old) {
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goto out_unlock_next;
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}
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/* patch the native jump address */
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tb_set_jmp_target(tb, n, (uintptr_t)tb_next->tc.ptr);
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/* add in TB jmp list */
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tb->jmp_list_next[n] = tb_next->jmp_list_head;
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tb_next->jmp_list_head = (uintptr_t)tb | n;
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qemu_spin_unlock(&tb_next->jmp_lock);
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qemu_log_mask_and_addr(CPU_LOG_EXEC, tb->pc,
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"Linking TBs %p [" TARGET_FMT_lx
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"] index %d -> %p [" TARGET_FMT_lx "]\n",
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tb->tc.ptr, tb->pc, n,
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tb_next->tc.ptr, tb_next->pc);
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return;
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out_unlock_next:
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qemu_spin_unlock(&tb_next->jmp_lock);
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return;
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}
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static inline TranslationBlock *tb_find(CPUState *cpu,
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TranslationBlock *last_tb,
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int tb_exit, uint32_t cflags)
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{
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CPUArchState *env = (CPUArchState *)cpu->env_ptr;
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TranslationBlock *tb;
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target_ulong cs_base, pc;
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uint32_t flags;
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cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
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tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
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if (tb == NULL) {
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mmap_lock();
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tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
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mmap_unlock();
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/* We add the TB in the virtual pc hash table for the fast lookup */
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qatomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
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}
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#ifndef CONFIG_USER_ONLY
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/* We don't take care of direct jumps when address mapping changes in
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* system emulation. So it's not safe to make a direct jump to a TB
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* spanning two pages because the mapping for the second page can change.
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*/
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if (tb->page_addr[1] != -1) {
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last_tb = NULL;
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}
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#endif
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/* See if we can patch the calling TB. */
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if (last_tb) {
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tb_add_jump(last_tb, tb_exit, tb);
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}
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return tb;
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}
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static inline bool cpu_handle_halt(CPUState *cpu)
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{
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if (cpu->halted) {
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#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
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if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
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X86CPU *x86_cpu = X86_CPU(cpu);
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qemu_mutex_lock_iothread();
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apic_poll_irq(x86_cpu->apic_state);
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cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
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qemu_mutex_unlock_iothread();
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}
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#endif
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if (!cpu_has_work(cpu)) {
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return true;
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}
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cpu->halted = 0;
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}
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return false;
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}
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static inline void cpu_handle_debug_exception(CPUState *cpu)
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{
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CPUClass *cc = CPU_GET_CLASS(cpu);
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CPUWatchpoint *wp;
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if (!cpu->watchpoint_hit) {
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QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
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wp->flags &= ~BP_WATCHPOINT_HIT;
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}
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}
|
|
|
|
if (cc->tcg_ops->debug_excp_handler) {
|
|
cc->tcg_ops->debug_excp_handler(cpu);
|
|
}
|
|
}
|
|
|
|
static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
|
|
{
|
|
if (cpu->exception_index < 0) {
|
|
#ifndef CONFIG_USER_ONLY
|
|
if (replay_has_exception()
|
|
&& cpu_neg(cpu)->icount_decr.u16.low + cpu->icount_extra == 0) {
|
|
/* Execute just one insn to trigger exception pending in the log */
|
|
cpu->cflags_next_tb = (curr_cflags(cpu) & ~CF_USE_ICOUNT) | 1;
|
|
}
|
|
#endif
|
|
return false;
|
|
}
|
|
if (cpu->exception_index >= EXCP_INTERRUPT) {
|
|
/* exit request from the cpu execution loop */
|
|
*ret = cpu->exception_index;
|
|
if (*ret == EXCP_DEBUG) {
|
|
cpu_handle_debug_exception(cpu);
|
|
}
|
|
cpu->exception_index = -1;
|
|
return true;
|
|
} else {
|
|
#if defined(CONFIG_USER_ONLY)
|
|
/* if user mode only, we simulate a fake exception
|
|
which will be handled outside the cpu execution
|
|
loop */
|
|
#if defined(TARGET_I386)
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
cc->tcg_ops->do_interrupt(cpu);
|
|
#endif
|
|
*ret = cpu->exception_index;
|
|
cpu->exception_index = -1;
|
|
return true;
|
|
#else
|
|
if (replay_exception()) {
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
qemu_mutex_lock_iothread();
|
|
cc->tcg_ops->do_interrupt(cpu);
|
|
qemu_mutex_unlock_iothread();
|
|
cpu->exception_index = -1;
|
|
|
|
if (unlikely(cpu->singlestep_enabled)) {
|
|
/*
|
|
* After processing the exception, ensure an EXCP_DEBUG is
|
|
* raised when single-stepping so that GDB doesn't miss the
|
|
* next instruction.
|
|
*/
|
|
*ret = EXCP_DEBUG;
|
|
cpu_handle_debug_exception(cpu);
|
|
return true;
|
|
}
|
|
} else if (!replay_has_interrupt()) {
|
|
/* give a chance to iothread in replay mode */
|
|
*ret = EXCP_INTERRUPT;
|
|
return true;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* CPU_INTERRUPT_POLL is a virtual event which gets converted into a
|
|
* "real" interrupt event later. It does not need to be recorded for
|
|
* replay purposes.
|
|
*/
|
|
static inline bool need_replay_interrupt(int interrupt_request)
|
|
{
|
|
#if defined(TARGET_I386)
|
|
return !(interrupt_request & CPU_INTERRUPT_POLL);
|
|
#else
|
|
return true;
|
|
#endif
|
|
}
|
|
|
|
static inline bool cpu_handle_interrupt(CPUState *cpu,
|
|
TranslationBlock **last_tb)
|
|
{
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
|
|
/* Clear the interrupt flag now since we're processing
|
|
* cpu->interrupt_request and cpu->exit_request.
|
|
* Ensure zeroing happens before reading cpu->exit_request or
|
|
* cpu->interrupt_request (see also smp_wmb in cpu_exit())
|
|
*/
|
|
qatomic_mb_set(&cpu_neg(cpu)->icount_decr.u16.high, 0);
|
|
|
|
if (unlikely(qatomic_read(&cpu->interrupt_request))) {
|
|
int interrupt_request;
|
|
qemu_mutex_lock_iothread();
|
|
interrupt_request = cpu->interrupt_request;
|
|
if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
|
|
/* Mask out external interrupts for this step. */
|
|
interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
|
|
}
|
|
if (interrupt_request & CPU_INTERRUPT_DEBUG) {
|
|
cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
|
|
cpu->exception_index = EXCP_DEBUG;
|
|
qemu_mutex_unlock_iothread();
|
|
return true;
|
|
}
|
|
if (replay_mode == REPLAY_MODE_PLAY && !replay_has_interrupt()) {
|
|
/* Do nothing */
|
|
} else if (interrupt_request & CPU_INTERRUPT_HALT) {
|
|
replay_interrupt();
|
|
cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
|
|
cpu->halted = 1;
|
|
cpu->exception_index = EXCP_HLT;
|
|
qemu_mutex_unlock_iothread();
|
|
return true;
|
|
}
|
|
#if defined(TARGET_I386)
|
|
else if (interrupt_request & CPU_INTERRUPT_INIT) {
|
|
X86CPU *x86_cpu = X86_CPU(cpu);
|
|
CPUArchState *env = &x86_cpu->env;
|
|
replay_interrupt();
|
|
cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0, 0);
|
|
do_cpu_init(x86_cpu);
|
|
cpu->exception_index = EXCP_HALTED;
|
|
qemu_mutex_unlock_iothread();
|
|
return true;
|
|
}
|
|
#else
|
|
else if (interrupt_request & CPU_INTERRUPT_RESET) {
|
|
replay_interrupt();
|
|
cpu_reset(cpu);
|
|
qemu_mutex_unlock_iothread();
|
|
return true;
|
|
}
|
|
#endif
|
|
/* The target hook has 3 exit conditions:
|
|
False when the interrupt isn't processed,
|
|
True when it is, and we should restart on a new TB,
|
|
and via longjmp via cpu_loop_exit. */
|
|
else {
|
|
if (cc->tcg_ops->cpu_exec_interrupt &&
|
|
cc->tcg_ops->cpu_exec_interrupt(cpu, interrupt_request)) {
|
|
if (need_replay_interrupt(interrupt_request)) {
|
|
replay_interrupt();
|
|
}
|
|
/*
|
|
* After processing the interrupt, ensure an EXCP_DEBUG is
|
|
* raised when single-stepping so that GDB doesn't miss the
|
|
* next instruction.
|
|
*/
|
|
cpu->exception_index =
|
|
(cpu->singlestep_enabled ? EXCP_DEBUG : -1);
|
|
*last_tb = NULL;
|
|
}
|
|
/* The target hook may have updated the 'cpu->interrupt_request';
|
|
* reload the 'interrupt_request' value */
|
|
interrupt_request = cpu->interrupt_request;
|
|
}
|
|
if (interrupt_request & CPU_INTERRUPT_EXITTB) {
|
|
cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;
|
|
/* ensure that no TB jump will be modified as
|
|
the program flow was changed */
|
|
*last_tb = NULL;
|
|
}
|
|
|
|
/* If we exit via cpu_loop_exit/longjmp it is reset in cpu_exec */
|
|
qemu_mutex_unlock_iothread();
|
|
}
|
|
|
|
/* Finally, check if we need to exit to the main loop. */
|
|
if (unlikely(qatomic_read(&cpu->exit_request))
|
|
|| (icount_enabled()
|
|
&& (cpu->cflags_next_tb == -1 || cpu->cflags_next_tb & CF_USE_ICOUNT)
|
|
&& cpu_neg(cpu)->icount_decr.u16.low + cpu->icount_extra == 0)) {
|
|
qatomic_set(&cpu->exit_request, 0);
|
|
if (cpu->exception_index == -1) {
|
|
cpu->exception_index = EXCP_INTERRUPT;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
|
|
TranslationBlock **last_tb, int *tb_exit)
|
|
{
|
|
int32_t insns_left;
|
|
|
|
trace_exec_tb(tb, tb->pc);
|
|
tb = cpu_tb_exec(cpu, tb, tb_exit);
|
|
if (*tb_exit != TB_EXIT_REQUESTED) {
|
|
*last_tb = tb;
|
|
return;
|
|
}
|
|
|
|
*last_tb = NULL;
|
|
insns_left = qatomic_read(&cpu_neg(cpu)->icount_decr.u32);
|
|
if (insns_left < 0) {
|
|
/* Something asked us to stop executing chained TBs; just
|
|
* continue round the main loop. Whatever requested the exit
|
|
* will also have set something else (eg exit_request or
|
|
* interrupt_request) which will be handled by
|
|
* cpu_handle_interrupt. cpu_handle_interrupt will also
|
|
* clear cpu->icount_decr.u16.high.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
/* Instruction counter expired. */
|
|
assert(icount_enabled());
|
|
#ifndef CONFIG_USER_ONLY
|
|
/* Ensure global icount has gone forward */
|
|
icount_update(cpu);
|
|
/* Refill decrementer and continue execution. */
|
|
insns_left = MIN(CF_COUNT_MASK, cpu->icount_budget);
|
|
cpu_neg(cpu)->icount_decr.u16.low = insns_left;
|
|
cpu->icount_extra = cpu->icount_budget - insns_left;
|
|
|
|
/*
|
|
* If the next tb has more instructions than we have left to
|
|
* execute we need to ensure we find/generate a TB with exactly
|
|
* insns_left instructions in it.
|
|
*/
|
|
if (!cpu->icount_extra && insns_left > 0 && insns_left < tb->icount) {
|
|
cpu->cflags_next_tb = (tb->cflags & ~CF_COUNT_MASK) | insns_left;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* main execution loop */
|
|
|
|
int cpu_exec(CPUState *cpu)
|
|
{
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
int ret;
|
|
SyncClocks sc = { 0 };
|
|
|
|
/* replay_interrupt may need current_cpu */
|
|
current_cpu = cpu;
|
|
|
|
if (cpu_handle_halt(cpu)) {
|
|
return EXCP_HALTED;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
|
|
cpu_exec_enter(cpu);
|
|
|
|
/* Calculate difference between guest clock and host clock.
|
|
* This delay includes the delay of the last cycle, so
|
|
* what we have to do is sleep until it is 0. As for the
|
|
* advance/delay we gain here, we try to fix it next time.
|
|
*/
|
|
init_delay_params(&sc, cpu);
|
|
|
|
/* prepare setjmp context for exception handling */
|
|
if (sigsetjmp(cpu->jmp_env, 0) != 0) {
|
|
#if defined(__clang__)
|
|
/*
|
|
* Some compilers wrongly smash all local variables after
|
|
* siglongjmp (the spec requires that only non-volatile locals
|
|
* which are changed between the sigsetjmp and siglongjmp are
|
|
* permitted to be trashed). There were bug reports for gcc
|
|
* 4.5.0 and clang. The bug is fixed in all versions of gcc
|
|
* that we support, but is still unfixed in clang:
|
|
* https://bugs.llvm.org/show_bug.cgi?id=21183
|
|
*
|
|
* Reload essential local variables here for those compilers.
|
|
* Newer versions of gcc would complain about this code (-Wclobbered),
|
|
* so we only perform the workaround for clang.
|
|
*/
|
|
cpu = current_cpu;
|
|
cc = CPU_GET_CLASS(cpu);
|
|
#else
|
|
/*
|
|
* Non-buggy compilers preserve these locals; assert that
|
|
* they have the correct value.
|
|
*/
|
|
g_assert(cpu == current_cpu);
|
|
g_assert(cc == CPU_GET_CLASS(cpu));
|
|
#endif
|
|
|
|
#ifndef CONFIG_SOFTMMU
|
|
tcg_debug_assert(!have_mmap_lock());
|
|
#endif
|
|
if (qemu_mutex_iothread_locked()) {
|
|
qemu_mutex_unlock_iothread();
|
|
}
|
|
qemu_plugin_disable_mem_helpers(cpu);
|
|
|
|
assert_no_pages_locked();
|
|
}
|
|
|
|
/* if an exception is pending, we execute it here */
|
|
while (!cpu_handle_exception(cpu, &ret)) {
|
|
TranslationBlock *last_tb = NULL;
|
|
int tb_exit = 0;
|
|
|
|
while (!cpu_handle_interrupt(cpu, &last_tb)) {
|
|
uint32_t cflags = cpu->cflags_next_tb;
|
|
TranslationBlock *tb;
|
|
|
|
/* When requested, use an exact setting for cflags for the next
|
|
execution. This is used for icount, precise smc, and stop-
|
|
after-access watchpoints. Since this request should never
|
|
have CF_INVALID set, -1 is a convenient invalid value that
|
|
does not require tcg headers for cpu_common_reset. */
|
|
if (cflags == -1) {
|
|
cflags = curr_cflags(cpu);
|
|
} else {
|
|
cpu->cflags_next_tb = -1;
|
|
}
|
|
|
|
tb = tb_find(cpu, last_tb, tb_exit, cflags);
|
|
cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit);
|
|
/* Try to align the host and virtual clocks
|
|
if the guest is in advance */
|
|
align_clocks(&sc, cpu);
|
|
}
|
|
}
|
|
|
|
cpu_exec_exit(cpu);
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
void tcg_exec_realizefn(CPUState *cpu, Error **errp)
|
|
{
|
|
static bool tcg_target_initialized;
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
|
|
if (!tcg_target_initialized) {
|
|
cc->tcg_ops->initialize();
|
|
tcg_target_initialized = true;
|
|
}
|
|
tlb_init(cpu);
|
|
qemu_plugin_vcpu_init_hook(cpu);
|
|
|
|
#ifndef CONFIG_USER_ONLY
|
|
tcg_iommu_init_notifier_list(cpu);
|
|
#endif /* !CONFIG_USER_ONLY */
|
|
}
|
|
|
|
/* undo the initializations in reverse order */
|
|
void tcg_exec_unrealizefn(CPUState *cpu)
|
|
{
|
|
#ifndef CONFIG_USER_ONLY
|
|
tcg_iommu_free_notifier_list(cpu);
|
|
#endif /* !CONFIG_USER_ONLY */
|
|
|
|
qemu_plugin_vcpu_exit_hook(cpu);
|
|
tlb_destroy(cpu);
|
|
}
|
|
|
|
#ifndef CONFIG_USER_ONLY
|
|
|
|
void dump_drift_info(void)
|
|
{
|
|
if (!icount_enabled()) {
|
|
return;
|
|
}
|
|
|
|
qemu_printf("Host - Guest clock %"PRIi64" ms\n",
|
|
(cpu_get_clock() - icount_get()) / SCALE_MS);
|
|
if (icount_align_option) {
|
|
qemu_printf("Max guest delay %"PRIi64" ms\n",
|
|
-max_delay / SCALE_MS);
|
|
qemu_printf("Max guest advance %"PRIi64" ms\n",
|
|
max_advance / SCALE_MS);
|
|
} else {
|
|
qemu_printf("Max guest delay NA\n");
|
|
qemu_printf("Max guest advance NA\n");
|
|
}
|
|
}
|
|
|
|
#endif /* !CONFIG_USER_ONLY */
|