In icount mode, instructions that access io memory spaces in the middle of the translation block invoke TB recompilation. After recompilation, such instructions become last in the TB and are allowed to access io memory spaces. When the code includes instruction like i386 'xchg eax, 0xffffd080' which accesses APIC, QEMU goes into an infinite loop of the recompilation. This instruction includes two memory accesses - one read and one write. After the first access, APIC calls cpu_report_tpr_access, which restores the CPU state to get the current eip. But cpu_restore_state_from_tb resets the cpu->can_do_io flag which makes the second memory access invalid. Therefore the second memory access causes a recompilation of the block. Then these operations repeat again and again. This patch moves resetting cpu->can_do_io flag from cpu_restore_state_from_tb to cpu_loop_exit* functions. It also adds a parameter for cpu_restore_state which controls restoring icount. There is no need to restore icount when we only query CPU state without breaking the TB. Restoring it in such cases leads to the incorrect flow of the virtual time. In most cases new parameter is true (icount should be recalculated). But there are two cases in i386 and openrisc when the CPU state is only queried without the need to break the TB. This patch fixes both of these cases. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> Message-Id: <20180409091320.12504.35329.stgit@pasha-VirtualBox> [rth: Make can_do_io setting unconditional; move from cpu_exec; make cpu_loop_exit_{noexc,restore} call cpu_loop_exit.] Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
746 lines
23 KiB
C
746 lines
23 KiB
C
/*
|
|
* emulator main execution loop
|
|
*
|
|
* Copyright (c) 2003-2005 Fabrice Bellard
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include "qemu/osdep.h"
|
|
#include "cpu.h"
|
|
#include "trace.h"
|
|
#include "disas/disas.h"
|
|
#include "exec/exec-all.h"
|
|
#include "tcg.h"
|
|
#include "qemu/atomic.h"
|
|
#include "sysemu/qtest.h"
|
|
#include "qemu/timer.h"
|
|
#include "exec/address-spaces.h"
|
|
#include "qemu/rcu.h"
|
|
#include "exec/tb-hash.h"
|
|
#include "exec/tb-lookup.h"
|
|
#include "exec/log.h"
|
|
#include "qemu/main-loop.h"
|
|
#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
|
|
#include "hw/i386/apic.h"
|
|
#endif
|
|
#include "sysemu/cpus.h"
|
|
#include "sysemu/replay.h"
|
|
|
|
/* -icount align implementation. */
|
|
|
|
typedef struct SyncClocks {
|
|
int64_t diff_clk;
|
|
int64_t last_cpu_icount;
|
|
int64_t realtime_clock;
|
|
} SyncClocks;
|
|
|
|
#if !defined(CONFIG_USER_ONLY)
|
|
/* Allow the guest to have a max 3ms advance.
|
|
* The difference between the 2 clocks could therefore
|
|
* oscillate around 0.
|
|
*/
|
|
#define VM_CLOCK_ADVANCE 3000000
|
|
#define THRESHOLD_REDUCE 1.5
|
|
#define MAX_DELAY_PRINT_RATE 2000000000LL
|
|
#define MAX_NB_PRINTS 100
|
|
|
|
static void align_clocks(SyncClocks *sc, const CPUState *cpu)
|
|
{
|
|
int64_t cpu_icount;
|
|
|
|
if (!icount_align_option) {
|
|
return;
|
|
}
|
|
|
|
cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
|
|
sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount);
|
|
sc->last_cpu_icount = cpu_icount;
|
|
|
|
if (sc->diff_clk > VM_CLOCK_ADVANCE) {
|
|
#ifndef _WIN32
|
|
struct timespec sleep_delay, rem_delay;
|
|
sleep_delay.tv_sec = sc->diff_clk / 1000000000LL;
|
|
sleep_delay.tv_nsec = sc->diff_clk % 1000000000LL;
|
|
if (nanosleep(&sleep_delay, &rem_delay) < 0) {
|
|
sc->diff_clk = rem_delay.tv_sec * 1000000000LL + rem_delay.tv_nsec;
|
|
} else {
|
|
sc->diff_clk = 0;
|
|
}
|
|
#else
|
|
Sleep(sc->diff_clk / SCALE_MS);
|
|
sc->diff_clk = 0;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
static void print_delay(const SyncClocks *sc)
|
|
{
|
|
static float threshold_delay;
|
|
static int64_t last_realtime_clock;
|
|
static int nb_prints;
|
|
|
|
if (icount_align_option &&
|
|
sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
|
|
nb_prints < MAX_NB_PRINTS) {
|
|
if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
|
|
(-sc->diff_clk / (float)1000000000LL <
|
|
(threshold_delay - THRESHOLD_REDUCE))) {
|
|
threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
|
|
printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
|
|
threshold_delay - 1,
|
|
threshold_delay);
|
|
nb_prints++;
|
|
last_realtime_clock = sc->realtime_clock;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void init_delay_params(SyncClocks *sc,
|
|
const CPUState *cpu)
|
|
{
|
|
if (!icount_align_option) {
|
|
return;
|
|
}
|
|
sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
|
|
sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - sc->realtime_clock;
|
|
sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
|
|
if (sc->diff_clk < max_delay) {
|
|
max_delay = sc->diff_clk;
|
|
}
|
|
if (sc->diff_clk > max_advance) {
|
|
max_advance = sc->diff_clk;
|
|
}
|
|
|
|
/* Print every 2s max if the guest is late. We limit the number
|
|
of printed messages to NB_PRINT_MAX(currently 100) */
|
|
print_delay(sc);
|
|
}
|
|
#else
|
|
static void align_clocks(SyncClocks *sc, const CPUState *cpu)
|
|
{
|
|
}
|
|
|
|
static void init_delay_params(SyncClocks *sc, const CPUState *cpu)
|
|
{
|
|
}
|
|
#endif /* CONFIG USER ONLY */
|
|
|
|
/* Execute a TB, and fix up the CPU state afterwards if necessary */
|
|
static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb)
|
|
{
|
|
CPUArchState *env = cpu->env_ptr;
|
|
uintptr_t ret;
|
|
TranslationBlock *last_tb;
|
|
int tb_exit;
|
|
uint8_t *tb_ptr = itb->tc.ptr;
|
|
|
|
qemu_log_mask_and_addr(CPU_LOG_EXEC, itb->pc,
|
|
"Trace %d: %p ["
|
|
TARGET_FMT_lx "/" TARGET_FMT_lx "/%#x] %s\n",
|
|
cpu->cpu_index, itb->tc.ptr,
|
|
itb->cs_base, itb->pc, itb->flags,
|
|
lookup_symbol(itb->pc));
|
|
|
|
#if defined(DEBUG_DISAS)
|
|
if (qemu_loglevel_mask(CPU_LOG_TB_CPU)
|
|
&& qemu_log_in_addr_range(itb->pc)) {
|
|
qemu_log_lock();
|
|
#if defined(TARGET_I386)
|
|
log_cpu_state(cpu, CPU_DUMP_CCOP);
|
|
#else
|
|
log_cpu_state(cpu, 0);
|
|
#endif
|
|
qemu_log_unlock();
|
|
}
|
|
#endif /* DEBUG_DISAS */
|
|
|
|
cpu->can_do_io = !use_icount;
|
|
ret = tcg_qemu_tb_exec(env, tb_ptr);
|
|
cpu->can_do_io = 1;
|
|
last_tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
|
|
tb_exit = ret & TB_EXIT_MASK;
|
|
trace_exec_tb_exit(last_tb, tb_exit);
|
|
|
|
if (tb_exit > TB_EXIT_IDX1) {
|
|
/* We didn't start executing this TB (eg because the instruction
|
|
* counter hit zero); we must restore the guest PC to the address
|
|
* of the start of the TB.
|
|
*/
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
qemu_log_mask_and_addr(CPU_LOG_EXEC, last_tb->pc,
|
|
"Stopped execution of TB chain before %p ["
|
|
TARGET_FMT_lx "] %s\n",
|
|
last_tb->tc.ptr, last_tb->pc,
|
|
lookup_symbol(last_tb->pc));
|
|
if (cc->synchronize_from_tb) {
|
|
cc->synchronize_from_tb(cpu, last_tb);
|
|
} else {
|
|
assert(cc->set_pc);
|
|
cc->set_pc(cpu, last_tb->pc);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
#ifndef CONFIG_USER_ONLY
|
|
/* Execute the code without caching the generated code. An interpreter
|
|
could be used if available. */
|
|
static void cpu_exec_nocache(CPUState *cpu, int max_cycles,
|
|
TranslationBlock *orig_tb, bool ignore_icount)
|
|
{
|
|
TranslationBlock *tb;
|
|
uint32_t cflags = curr_cflags() | CF_NOCACHE;
|
|
|
|
if (ignore_icount) {
|
|
cflags &= ~CF_USE_ICOUNT;
|
|
}
|
|
|
|
/* Should never happen.
|
|
We only end up here when an existing TB is too long. */
|
|
cflags |= MIN(max_cycles, CF_COUNT_MASK);
|
|
|
|
tb_lock();
|
|
tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base,
|
|
orig_tb->flags, cflags);
|
|
tb->orig_tb = orig_tb;
|
|
tb_unlock();
|
|
|
|
/* execute the generated code */
|
|
trace_exec_tb_nocache(tb, tb->pc);
|
|
cpu_tb_exec(cpu, tb);
|
|
|
|
tb_lock();
|
|
tb_phys_invalidate(tb, -1);
|
|
tb_remove(tb);
|
|
tb_unlock();
|
|
}
|
|
#endif
|
|
|
|
void cpu_exec_step_atomic(CPUState *cpu)
|
|
{
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
TranslationBlock *tb;
|
|
target_ulong cs_base, pc;
|
|
uint32_t flags;
|
|
uint32_t cflags = 1;
|
|
uint32_t cf_mask = cflags & CF_HASH_MASK;
|
|
/* volatile because we modify it between setjmp and longjmp */
|
|
volatile bool in_exclusive_region = false;
|
|
|
|
if (sigsetjmp(cpu->jmp_env, 0) == 0) {
|
|
tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, cf_mask);
|
|
if (tb == NULL) {
|
|
mmap_lock();
|
|
tb_lock();
|
|
tb = tb_htable_lookup(cpu, pc, cs_base, flags, cf_mask);
|
|
if (likely(tb == NULL)) {
|
|
tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
|
|
}
|
|
tb_unlock();
|
|
mmap_unlock();
|
|
}
|
|
|
|
start_exclusive();
|
|
|
|
/* Since we got here, we know that parallel_cpus must be true. */
|
|
parallel_cpus = false;
|
|
in_exclusive_region = true;
|
|
cc->cpu_exec_enter(cpu);
|
|
/* execute the generated code */
|
|
trace_exec_tb(tb, pc);
|
|
cpu_tb_exec(cpu, tb);
|
|
cc->cpu_exec_exit(cpu);
|
|
} else {
|
|
/* We may have exited due to another problem here, so we need
|
|
* to reset any tb_locks we may have taken but didn't release.
|
|
* The mmap_lock is dropped by tb_gen_code if it runs out of
|
|
* memory.
|
|
*/
|
|
#ifndef CONFIG_SOFTMMU
|
|
tcg_debug_assert(!have_mmap_lock());
|
|
#endif
|
|
tb_lock_reset();
|
|
}
|
|
|
|
if (in_exclusive_region) {
|
|
/* We might longjump out of either the codegen or the
|
|
* execution, so must make sure we only end the exclusive
|
|
* region if we started it.
|
|
*/
|
|
parallel_cpus = true;
|
|
end_exclusive();
|
|
}
|
|
}
|
|
|
|
struct tb_desc {
|
|
target_ulong pc;
|
|
target_ulong cs_base;
|
|
CPUArchState *env;
|
|
tb_page_addr_t phys_page1;
|
|
uint32_t flags;
|
|
uint32_t cf_mask;
|
|
uint32_t trace_vcpu_dstate;
|
|
};
|
|
|
|
static bool tb_cmp(const void *p, const void *d)
|
|
{
|
|
const TranslationBlock *tb = p;
|
|
const struct tb_desc *desc = d;
|
|
|
|
if (tb->pc == desc->pc &&
|
|
tb->page_addr[0] == desc->phys_page1 &&
|
|
tb->cs_base == desc->cs_base &&
|
|
tb->flags == desc->flags &&
|
|
tb->trace_vcpu_dstate == desc->trace_vcpu_dstate &&
|
|
(tb_cflags(tb) & (CF_HASH_MASK | CF_INVALID)) == desc->cf_mask) {
|
|
/* check next page if needed */
|
|
if (tb->page_addr[1] == -1) {
|
|
return true;
|
|
} else {
|
|
tb_page_addr_t phys_page2;
|
|
target_ulong virt_page2;
|
|
|
|
virt_page2 = (desc->pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
|
|
phys_page2 = get_page_addr_code(desc->env, virt_page2);
|
|
if (tb->page_addr[1] == phys_page2) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc,
|
|
target_ulong cs_base, uint32_t flags,
|
|
uint32_t cf_mask)
|
|
{
|
|
tb_page_addr_t phys_pc;
|
|
struct tb_desc desc;
|
|
uint32_t h;
|
|
|
|
desc.env = (CPUArchState *)cpu->env_ptr;
|
|
desc.cs_base = cs_base;
|
|
desc.flags = flags;
|
|
desc.cf_mask = cf_mask;
|
|
desc.trace_vcpu_dstate = *cpu->trace_dstate;
|
|
desc.pc = pc;
|
|
phys_pc = get_page_addr_code(desc.env, pc);
|
|
desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
|
|
h = tb_hash_func(phys_pc, pc, flags, cf_mask, *cpu->trace_dstate);
|
|
return qht_lookup(&tb_ctx.htable, tb_cmp, &desc, h);
|
|
}
|
|
|
|
void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr)
|
|
{
|
|
if (TCG_TARGET_HAS_direct_jump) {
|
|
uintptr_t offset = tb->jmp_target_arg[n];
|
|
uintptr_t tc_ptr = (uintptr_t)tb->tc.ptr;
|
|
tb_target_set_jmp_target(tc_ptr, tc_ptr + offset, addr);
|
|
} else {
|
|
tb->jmp_target_arg[n] = addr;
|
|
}
|
|
}
|
|
|
|
/* Called with tb_lock held. */
|
|
static inline void tb_add_jump(TranslationBlock *tb, int n,
|
|
TranslationBlock *tb_next)
|
|
{
|
|
assert(n < ARRAY_SIZE(tb->jmp_list_next));
|
|
if (tb->jmp_list_next[n]) {
|
|
/* Another thread has already done this while we were
|
|
* outside of the lock; nothing to do in this case */
|
|
return;
|
|
}
|
|
qemu_log_mask_and_addr(CPU_LOG_EXEC, tb->pc,
|
|
"Linking TBs %p [" TARGET_FMT_lx
|
|
"] index %d -> %p [" TARGET_FMT_lx "]\n",
|
|
tb->tc.ptr, tb->pc, n,
|
|
tb_next->tc.ptr, tb_next->pc);
|
|
|
|
/* patch the native jump address */
|
|
tb_set_jmp_target(tb, n, (uintptr_t)tb_next->tc.ptr);
|
|
|
|
/* add in TB jmp circular list */
|
|
tb->jmp_list_next[n] = tb_next->jmp_list_first;
|
|
tb_next->jmp_list_first = (uintptr_t)tb | n;
|
|
}
|
|
|
|
static inline TranslationBlock *tb_find(CPUState *cpu,
|
|
TranslationBlock *last_tb,
|
|
int tb_exit, uint32_t cf_mask)
|
|
{
|
|
TranslationBlock *tb;
|
|
target_ulong cs_base, pc;
|
|
uint32_t flags;
|
|
bool acquired_tb_lock = false;
|
|
|
|
tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, cf_mask);
|
|
if (tb == NULL) {
|
|
/* mmap_lock is needed by tb_gen_code, and mmap_lock must be
|
|
* taken outside tb_lock. As system emulation is currently
|
|
* single threaded the locks are NOPs.
|
|
*/
|
|
mmap_lock();
|
|
tb_lock();
|
|
acquired_tb_lock = true;
|
|
|
|
/* There's a chance that our desired tb has been translated while
|
|
* taking the locks so we check again inside the lock.
|
|
*/
|
|
tb = tb_htable_lookup(cpu, pc, cs_base, flags, cf_mask);
|
|
if (likely(tb == NULL)) {
|
|
/* if no translated code available, then translate it now */
|
|
tb = tb_gen_code(cpu, pc, cs_base, flags, cf_mask);
|
|
}
|
|
|
|
mmap_unlock();
|
|
/* We add the TB in the virtual pc hash table for the fast lookup */
|
|
atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
|
|
}
|
|
#ifndef CONFIG_USER_ONLY
|
|
/* We don't take care of direct jumps when address mapping changes in
|
|
* system emulation. So it's not safe to make a direct jump to a TB
|
|
* spanning two pages because the mapping for the second page can change.
|
|
*/
|
|
if (tb->page_addr[1] != -1) {
|
|
last_tb = NULL;
|
|
}
|
|
#endif
|
|
/* See if we can patch the calling TB. */
|
|
if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
|
|
if (!acquired_tb_lock) {
|
|
tb_lock();
|
|
acquired_tb_lock = true;
|
|
}
|
|
if (!(tb->cflags & CF_INVALID)) {
|
|
tb_add_jump(last_tb, tb_exit, tb);
|
|
}
|
|
}
|
|
if (acquired_tb_lock) {
|
|
tb_unlock();
|
|
}
|
|
return tb;
|
|
}
|
|
|
|
static inline bool cpu_handle_halt(CPUState *cpu)
|
|
{
|
|
if (cpu->halted) {
|
|
#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
|
|
if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
|
|
&& replay_interrupt()) {
|
|
X86CPU *x86_cpu = X86_CPU(cpu);
|
|
qemu_mutex_lock_iothread();
|
|
apic_poll_irq(x86_cpu->apic_state);
|
|
cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
|
|
qemu_mutex_unlock_iothread();
|
|
}
|
|
#endif
|
|
if (!cpu_has_work(cpu)) {
|
|
return true;
|
|
}
|
|
|
|
cpu->halted = 0;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static inline void cpu_handle_debug_exception(CPUState *cpu)
|
|
{
|
|
CPUClass *cc = CPU_GET_CLASS(cpu);
|
|
CPUWatchpoint *wp;
|
|
|
|
if (!cpu->watchpoint_hit) {
|
|
QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
|
|
wp->flags &= ~BP_WATCHPOINT_HIT;
|
|
}
|
|
}
|
|
|
|
cc->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->icount_decr.u16.low + cpu->icount_extra == 0) {
|
|
/* try to cause an exception pending in the log */
|
|
cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0, curr_cflags()), true);
|
|
}
|
|
#endif
|
|
if (cpu->exception_index < 0) {
|
|
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->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->do_interrupt(cpu);
|
|
qemu_mutex_unlock_iothread();
|
|
cpu->exception_index = -1;
|
|
} else if (!replay_has_interrupt()) {
|
|
/* give a chance to iothread in replay mode */
|
|
*ret = EXCP_INTERRUPT;
|
|
return true;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
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())
|
|
*/
|
|
atomic_mb_set(&cpu->icount_decr.u16.high, 0);
|
|
|
|
if (unlikely(atomic_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->cpu_exec_interrupt(cpu, interrupt_request)) {
|
|
replay_interrupt();
|
|
cpu->exception_index = -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(atomic_read(&cpu->exit_request)
|
|
|| (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0))) {
|
|
atomic_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)
|
|
{
|
|
uintptr_t ret;
|
|
int32_t insns_left;
|
|
|
|
trace_exec_tb(tb, tb->pc);
|
|
ret = cpu_tb_exec(cpu, tb);
|
|
tb = (TranslationBlock *)(ret & ~TB_EXIT_MASK);
|
|
*tb_exit = ret & TB_EXIT_MASK;
|
|
if (*tb_exit != TB_EXIT_REQUESTED) {
|
|
*last_tb = tb;
|
|
return;
|
|
}
|
|
|
|
*last_tb = NULL;
|
|
insns_left = atomic_read(&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(use_icount);
|
|
#ifndef CONFIG_USER_ONLY
|
|
/* Ensure global icount has gone forward */
|
|
cpu_update_icount(cpu);
|
|
/* Refill decrementer and continue execution. */
|
|
insns_left = MIN(0xffff, cpu->icount_budget);
|
|
cpu->icount_decr.u16.low = insns_left;
|
|
cpu->icount_extra = cpu->icount_budget - insns_left;
|
|
if (!cpu->icount_extra) {
|
|
/* Execute any remaining instructions, then let the main loop
|
|
* handle the next event.
|
|
*/
|
|
if (insns_left > 0) {
|
|
cpu_exec_nocache(cpu, insns_left, tb, false);
|
|
}
|
|
}
|
|
#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();
|
|
|
|
cc->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__) || !QEMU_GNUC_PREREQ(4, 6)
|
|
/* Some compilers wrongly smash all local variables after
|
|
* siglongjmp. There were bug reports for gcc 4.5.0 and clang.
|
|
* Reload essential local variables here for those compilers.
|
|
* Newer versions of gcc would complain about this code (-Wclobbered). */
|
|
cpu = current_cpu;
|
|
cc = CPU_GET_CLASS(cpu);
|
|
#else /* buggy compiler */
|
|
/* Assert that the compiler does not smash local variables. */
|
|
g_assert(cpu == current_cpu);
|
|
g_assert(cc == CPU_GET_CLASS(cpu));
|
|
#endif /* buggy compiler */
|
|
tb_lock_reset();
|
|
if (qemu_mutex_iothread_locked()) {
|
|
qemu_mutex_unlock_iothread();
|
|
}
|
|
}
|
|
|
|
/* 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();
|
|
} 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);
|
|
}
|
|
}
|
|
|
|
cc->cpu_exec_exit(cpu);
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|