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qemu-patch-raspberry4/accel/tcg/cpu-exec.c
Alex Bennée aff0e204cb accel/tcg: suppress IRQ check for special TBs 
When we set cpu->cflags_next_tb it is because we want to carefully
control the execution of the next TB. Currently there is a race that
causes the second stage of watchpoint handling to get ignored if an
IRQ is processed before we finish executing the instruction that
triggers the watchpoint. Use the new CF_NOIRQ facility to avoid the
race.

We also suppress IRQs when handling precise self modifying code to
avoid unnecessary bouncing.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/245
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211129140932.4115115-3-alex.bennee@linaro.org>
2021-11-29 15:12:37 +00:00

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/*
* 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 2.1 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 "qemu-common.h"
#include "qemu/qemu-print.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-machine.h"
#include "qapi/type-helpers.h"
#include "hw/core/tcg-cpu-ops.h"
#include "trace.h"
#include "disas/disas.h"
#include "exec/exec-all.h"
#include "tcg/tcg.h"
#include "qemu/atomic.h"
#include "qemu/compiler.h"
#include "qemu/timer.h"
#include "qemu/rcu.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 "exec/cpu-all.h"
#include "sysemu/cpu-timers.h"
#include "sysemu/replay.h"
#include "sysemu/tcg.h"
#include "exec/helper-proto.h"
#include "tb-hash.h"
#include "tb-context.h"
#include "internal.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 int64_t max_delay;
static int64_t max_advance;
static void align_clocks(SyncClocks *sc, CPUState *cpu)
{
int64_t cpu_icount;
if (!icount_align_option) {
return;
}
cpu_icount = cpu->icount_extra + cpu_neg(cpu)->icount_decr.u16.low;
sc->diff_clk += 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;
qemu_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, 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_neg(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 */
uint32_t curr_cflags(CPUState *cpu)
{
uint32_t cflags = cpu->tcg_cflags;
/*
* Record gdb single-step. We should be exiting the TB by raising
* EXCP_DEBUG, but to simplify other tests, disable chaining too.
*
* For singlestep and -d nochain, suppress goto_tb so that
* we can log -d cpu,exec after every TB.
*/
if (unlikely(cpu->singlestep_enabled)) {
cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | CF_SINGLE_STEP | 1;
} else if (singlestep) {
cflags |= CF_NO_GOTO_TB | 1;
} else if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
cflags |= CF_NO_GOTO_TB;
}
return cflags;
}
/* Might cause an exception, so have a longjmp destination ready */
static inline TranslationBlock *tb_lookup(CPUState *cpu, target_ulong pc,
target_ulong cs_base,
uint32_t flags, uint32_t cflags)
{
TranslationBlock *tb;
uint32_t hash;
/* we should never be trying to look up an INVALID tb */
tcg_debug_assert(!(cflags & CF_INVALID));
hash = tb_jmp_cache_hash_func(pc);
tb = qatomic_rcu_read(&cpu->tb_jmp_cache[hash]);
if (likely(tb &&
tb->pc == pc &&
tb->cs_base == cs_base &&
tb->flags == flags &&
tb->trace_vcpu_dstate == *cpu->trace_dstate &&
tb_cflags(tb) == cflags)) {
return tb;
}
tb = tb_htable_lookup(cpu, pc, cs_base, flags, cflags);
if (tb == NULL) {
return NULL;
}
qatomic_set(&cpu->tb_jmp_cache[hash], tb);
return tb;
}
static inline void log_cpu_exec(target_ulong pc, CPUState *cpu,
const TranslationBlock *tb)
{
if (unlikely(qemu_loglevel_mask(CPU_LOG_TB_CPU | CPU_LOG_EXEC))
&& qemu_log_in_addr_range(pc)) {
qemu_log_mask(CPU_LOG_EXEC,
"Trace %d: %p [" TARGET_FMT_lx
"/" TARGET_FMT_lx "/%08x/%08x] %s\n",
cpu->cpu_index, tb->tc.ptr, tb->cs_base, pc,
tb->flags, tb->cflags, lookup_symbol(pc));
#if defined(DEBUG_DISAS)
if (qemu_loglevel_mask(CPU_LOG_TB_CPU)) {
FILE *logfile = qemu_log_lock();
int flags = 0;
if (qemu_loglevel_mask(CPU_LOG_TB_FPU)) {
flags |= CPU_DUMP_FPU;
}
#if defined(TARGET_I386)
flags |= CPU_DUMP_CCOP;
#endif
log_cpu_state(cpu, flags);
qemu_log_unlock(logfile);
}
#endif /* DEBUG_DISAS */
}
}
static bool check_for_breakpoints(CPUState *cpu, target_ulong pc,
uint32_t *cflags)
{
CPUBreakpoint *bp;
bool match_page = false;
if (likely(QTAILQ_EMPTY(&cpu->breakpoints))) {
return false;
}
/*
* Singlestep overrides breakpoints.
* This requirement is visible in the record-replay tests, where
* we would fail to make forward progress in reverse-continue.
*
* TODO: gdb singlestep should only override gdb breakpoints,
* so that one could (gdb) singlestep into the guest kernel's
* architectural breakpoint handler.
*/
if (cpu->singlestep_enabled) {
return false;
}
QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
/*
* If we have an exact pc match, trigger the breakpoint.
* Otherwise, note matches within the page.
*/
if (pc == bp->pc) {
bool match_bp = false;
if (bp->flags & BP_GDB) {
match_bp = true;
} else if (bp->flags & BP_CPU) {
#ifdef CONFIG_USER_ONLY
g_assert_not_reached();
#else
CPUClass *cc = CPU_GET_CLASS(cpu);
assert(cc->tcg_ops->debug_check_breakpoint);
match_bp = cc->tcg_ops->debug_check_breakpoint(cpu);
#endif
}
if (match_bp) {
cpu->exception_index = EXCP_DEBUG;
return true;
}
} else if (((pc ^ bp->pc) & TARGET_PAGE_MASK) == 0) {
match_page = true;
}
}
/*
* Within the same page as a breakpoint, single-step,
* returning to helper_lookup_tb_ptr after each insn looking
* for the actual breakpoint.
*
* TODO: Perhaps better to record all of the TBs associated
* with a given virtual page that contains a breakpoint, and
* then invalidate them when a new overlapping breakpoint is
* set on the page. Non-overlapping TBs would not be
* invalidated, nor would any TB need to be invalidated as
* breakpoints are removed.
*/
if (match_page) {
*cflags = (*cflags & ~CF_COUNT_MASK) | CF_NO_GOTO_TB | 1;
}
return false;
}
/**
* helper_lookup_tb_ptr: quick check for next tb
* @env: current cpu state
*
* Look for an existing TB matching the current cpu state.
* If found, return the code pointer. If not found, return
* the tcg epilogue so that we return into cpu_tb_exec.
*/
const void *HELPER(lookup_tb_ptr)(CPUArchState *env)
{
CPUState *cpu = env_cpu(env);
TranslationBlock *tb;
target_ulong cs_base, pc;
uint32_t flags, cflags;
cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
cflags = curr_cflags(cpu);
if (check_for_breakpoints(cpu, pc, &cflags)) {
cpu_loop_exit(cpu);
}
tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
if (tb == NULL) {
return tcg_code_gen_epilogue;
}
log_cpu_exec(pc, cpu, tb);
return tb->tc.ptr;
}
/* Execute a TB, and fix up the CPU state afterwards if necessary */
/*
* Disable CFI checks.
* TCG creates binary blobs at runtime, with the transformed code.
* A TB is a blob of binary code, created at runtime and called with an
* indirect function call. Since such function did not exist at compile time,
* the CFI runtime has no way to verify its signature and would fail.
* TCG is not considered a security-sensitive part of QEMU so this does not
* affect the impact of CFI in environment with high security requirements
*/
static inline TranslationBlock * QEMU_DISABLE_CFI
cpu_tb_exec(CPUState *cpu, TranslationBlock *itb, int *tb_exit)
{
CPUArchState *env = cpu->env_ptr;
uintptr_t ret;
TranslationBlock *last_tb;
const void *tb_ptr = itb->tc.ptr;
log_cpu_exec(itb->pc, cpu, itb);
qemu_thread_jit_execute();
ret = tcg_qemu_tb_exec(env, tb_ptr);
cpu->can_do_io = 1;
/*
* TODO: Delay swapping back to the read-write region of the TB
* until we actually need to modify the TB. The read-only copy,
* coming from the rx region, shares the same host TLB entry as
* the code that executed the exit_tb opcode that arrived here.
* If we insist on touching both the RX and the RW pages, we
* double the host TLB pressure.
*/
last_tb = tcg_splitwx_to_rw((void *)(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->tcg_ops->synchronize_from_tb) {
cc->tcg_ops->synchronize_from_tb(cpu, last_tb);
} else {
assert(cc->set_pc);
cc->set_pc(cpu, last_tb->pc);
}
}
/*
* If gdb single-step, and we haven't raised another exception,
* raise a debug exception. Single-step with another exception
* is handled in cpu_handle_exception.
*/
if (unlikely(cpu->singlestep_enabled) && cpu->exception_index == -1) {
cpu->exception_index = EXCP_DEBUG;
cpu_loop_exit(cpu);
}
return last_tb;
}
static void cpu_exec_enter(CPUState *cpu)
{
CPUClass *cc = CPU_GET_CLASS(cpu);
if (cc->tcg_ops->cpu_exec_enter) {
cc->tcg_ops->cpu_exec_enter(cpu);
}
}
static void cpu_exec_exit(CPUState *cpu)
{
CPUClass *cc = CPU_GET_CLASS(cpu);
if (cc->tcg_ops->cpu_exec_exit) {
cc->tcg_ops->cpu_exec_exit(cpu);
}
}
void cpu_exec_step_atomic(CPUState *cpu)
{
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb;
target_ulong cs_base, pc;
uint32_t flags, cflags;
int tb_exit;
if (sigsetjmp(cpu->jmp_env, 0) == 0) {
start_exclusive();
g_assert(cpu == current_cpu);
g_assert(!cpu->running);
cpu->running = true;
cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
cflags = curr_cflags(cpu);
/* Execute in a serial context. */
cflags &= ~CF_PARALLEL;
/* After 1 insn, return and release the exclusive lock. */
cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | 1;
/*
* No need to check_for_breakpoints here.
* We only arrive in cpu_exec_step_atomic after beginning execution
* of an insn that includes an atomic operation we can't handle.
* Any breakpoint for this insn will have been recognized earlier.
*/
tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
if (tb == NULL) {
mmap_lock();
tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
mmap_unlock();
}
cpu_exec_enter(cpu);
/* execute the generated code */
trace_exec_tb(tb, pc);
cpu_tb_exec(cpu, tb, &tb_exit);
cpu_exec_exit(cpu);
} else {
/*
* The mmap_lock is dropped by tb_gen_code if it runs out of
* memory.
*/
#ifndef CONFIG_SOFTMMU
clear_helper_retaddr();
tcg_debug_assert(!have_mmap_lock());
#endif
if (qemu_mutex_iothread_locked()) {
qemu_mutex_unlock_iothread();
}
assert_no_pages_locked();
qemu_plugin_disable_mem_helpers(cpu);
}
/*
* As we start the exclusive region before codegen we must still
* be in the region if we longjump out of either the codegen or
* the execution.
*/
g_assert(cpu_in_exclusive_context(cpu));
cpu->running = false;
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 cflags;
uint32_t trace_vcpu_dstate;
};
static bool tb_lookup_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) == desc->cflags) {
/* 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 cflags)
{
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.cflags = cflags;
desc.trace_vcpu_dstate = *cpu->trace_dstate;
desc.pc = pc;
phys_pc = get_page_addr_code(desc.env, pc);
if (phys_pc == -1) {
return NULL;
}
desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
h = tb_hash_func(phys_pc, pc, flags, cflags, *cpu->trace_dstate);
return qht_lookup_custom(&tb_ctx.htable, &desc, h, tb_lookup_cmp);
}
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;
uintptr_t jmp_rx = tc_ptr + offset;
uintptr_t jmp_rw = jmp_rx - tcg_splitwx_diff;
tb_target_set_jmp_target(tc_ptr, jmp_rx, jmp_rw, addr);
} else {
tb->jmp_target_arg[n] = addr;
}
}
static inline void tb_add_jump(TranslationBlock *tb, int n,
TranslationBlock *tb_next)
{
uintptr_t old;
qemu_thread_jit_write();
assert(n < ARRAY_SIZE(tb->jmp_list_next));
qemu_spin_lock(&tb_next->jmp_lock);
/* make sure the destination TB is valid */
if (tb_next->cflags & CF_INVALID) {
goto out_unlock_next;
}
/* Atomically claim the jump destination slot only if it was NULL */
old = qatomic_cmpxchg(&tb->jmp_dest[n], (uintptr_t)NULL,
(uintptr_t)tb_next);
if (old) {
goto out_unlock_next;
}
/* patch the native jump address */
tb_set_jmp_target(tb, n, (uintptr_t)tb_next->tc.ptr);
/* add in TB jmp list */
tb->jmp_list_next[n] = tb_next->jmp_list_head;
tb_next->jmp_list_head = (uintptr_t)tb | n;
qemu_spin_unlock(&tb_next->jmp_lock);
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);
return;
out_unlock_next:
qemu_spin_unlock(&tb_next->jmp_lock);
return;
}
static inline bool cpu_handle_halt(CPUState *cpu)
{
#ifndef CONFIG_USER_ONLY
if (cpu->halted) {
#if defined(TARGET_I386)
if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
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 /* TARGET_I386 */
if (!cpu_has_work(cpu)) {
return true;
}
cpu->halted = 0;
}
#endif /* !CONFIG_USER_ONLY */
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;
}
}
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->fake_user_interrupt(cpu);
#endif /* TARGET_I386 */
*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;
}
#ifndef CONFIG_USER_ONLY
/*
* 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
}
#endif /* !CONFIG_USER_ONLY */
static inline bool cpu_handle_interrupt(CPUState *cpu,
TranslationBlock **last_tb)
{
/*
* If we have requested custom cflags with CF_NOIRQ we should
* skip checking here. Any pending interrupts will get picked up
* by the next TB we execute under normal cflags.
*/
if (cpu->cflags_next_tb != -1 && cpu->cflags_next_tb & CF_NOIRQ) {
return false;
}
/* 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 !defined(CONFIG_USER_ONLY)
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 /* !TARGET_I386 */
/* 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 {
CPUClass *cc = CPU_GET_CLASS(cpu);
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;
}
#endif /* !CONFIG_USER_ONLY */
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(0xffff, 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 (insns_left > 0 && insns_left < tb->icount) {
assert(insns_left <= CF_COUNT_MASK);
assert(cpu->icount_extra == 0);
cpu->cflags_next_tb = (tb->cflags & ~CF_COUNT_MASK) | insns_left;
}
#endif
}
/* main execution loop */
int cpu_exec(CPUState *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 an essential local variable 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;
#else
/* Non-buggy compilers preserve this; assert the correct value. */
g_assert(cpu == current_cpu);
#endif
#ifndef CONFIG_SOFTMMU
clear_helper_retaddr();
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)) {
TranslationBlock *tb;
target_ulong cs_base, pc;
uint32_t flags, cflags;
cpu_get_tb_cpu_state(cpu->env_ptr, &pc, &cs_base, &flags);
/*
* 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.
*/
cflags = cpu->cflags_next_tb;
if (cflags == -1) {
cflags = curr_cflags(cpu);
} else {
cpu->cflags_next_tb = -1;
}
if (check_for_breakpoints(cpu, pc, &cflags)) {
break;
}
tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
if (tb == NULL) {
mmap_lock();
tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
mmap_unlock();
/*
* We add the TB in the virtual pc hash table
* for the fast lookup
*/
qatomic_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) {
tb_add_jump(last_tb, tb_exit, tb);
}
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(GString *buf)
{
if (!icount_enabled()) {
return;
}
g_string_append_printf(buf, "Host - Guest clock %"PRIi64" ms\n",
(cpu_get_clock() - icount_get()) / SCALE_MS);
if (icount_align_option) {
g_string_append_printf(buf, "Max guest delay %"PRIi64" ms\n",
-max_delay / SCALE_MS);
g_string_append_printf(buf, "Max guest advance %"PRIi64" ms\n",
max_advance / SCALE_MS);
} else {
g_string_append_printf(buf, "Max guest delay NA\n");
g_string_append_printf(buf, "Max guest advance NA\n");
}
}
HumanReadableText *qmp_x_query_jit(Error **errp)
{
g_autoptr(GString) buf = g_string_new("");
if (!tcg_enabled()) {
error_setg(errp, "JIT information is only available with accel=tcg");
return NULL;
}
dump_exec_info(buf);
dump_drift_info(buf);
return human_readable_text_from_str(buf);
}
HumanReadableText *qmp_x_query_opcount(Error **errp)
{
g_autoptr(GString) buf = g_string_new("");
if (!tcg_enabled()) {
error_setg(errp, "Opcode count information is only available with accel=tcg");
return NULL;
}
dump_opcount_info(buf);
return human_readable_text_from_str(buf);
}
#endif /* !CONFIG_USER_ONLY */
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