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mttcg/i386: Patch instruction using async_safe_* framework 

In mttcg, calling pause_all_vcpus() during execution from the
generated TBs causes a deadlock if some vCPU is waiting for exclusive
execution in start_exclusive(). Fix this by using the aync_safe_*
framework instead of pausing vcpus for patching instructions.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Message-Id: <20170712215143.19594-2-bobby.prani@gmail.com>
[Get rid completely of the TCG-specific code. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pranith Kumar 2017-07-12 17:51:43 -04:00 committed by Paolo Bonzini
parent 406bc339b0
commit cb58a6d361
1 changed files with 54 additions and 61 deletions
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115
hw/i386/kvmvapic.c
View File

@ -383,8 +383,7 @@ static void patch_byte(X86CPU *cpu, target_ulong addr, uint8_t byte)
cpu_memory_rw_debug(CPU(cpu), addr, &byte, 1, 1);
}
static void patch_call(VAPICROMState *s, X86CPU *cpu, target_ulong ip,
uint32_t target)
static void patch_call(X86CPU *cpu, target_ulong ip, uint32_t target)
{
uint32_t offset;
@ -393,16 +392,59 @@ static void patch_call(VAPICROMState *s, X86CPU *cpu, target_ulong ip,
cpu_memory_rw_debug(CPU(cpu), ip + 1, (void *)&offset, sizeof(offset), 1);
}
typedef struct PatchInfo {
VAPICHandlers *handler;
target_ulong ip;
} PatchInfo;
static void do_patch_instruction(CPUState *cs, run_on_cpu_data data)
{
X86CPU *x86_cpu = X86_CPU(cs);
PatchInfo *info = (PatchInfo *) data.host_ptr;
VAPICHandlers *handlers = info->handler;
target_ulong ip = info->ip;
uint8_t opcode[2];
uint32_t imm32 = 0;
cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0);
switch (opcode[0]) {
case 0x89: /* mov r32 to r/m32 */
patch_byte(x86_cpu, ip, 0x50 + modrm_reg(opcode[1])); /* push reg */
patch_call(x86_cpu, ip + 1, handlers->set_tpr);
break;
case 0x8b: /* mov r/m32 to r32 */
patch_byte(x86_cpu, ip, 0x90);
patch_call(x86_cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
break;
case 0xa1: /* mov abs to eax */
patch_call(x86_cpu, ip, handlers->get_tpr[0]);
break;
case 0xa3: /* mov eax to abs */
patch_call(x86_cpu, ip, handlers->set_tpr_eax);
break;
case 0xc7: /* mov imm32, r/m32 (c7/0) */
patch_byte(x86_cpu, ip, 0x68); /* push imm32 */
cpu_memory_rw_debug(cs, ip + 6, (void *)&imm32, sizeof(imm32), 0);
cpu_memory_rw_debug(cs, ip + 1, (void *)&imm32, sizeof(imm32), 1);
patch_call(x86_cpu, ip + 5, handlers->set_tpr);
break;
case 0xff: /* push r/m32 */
patch_byte(x86_cpu, ip, 0x50); /* push eax */
patch_call(x86_cpu, ip + 1, handlers->get_tpr_stack);
break;
default:
abort();
}
g_free(info);
}
static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
{
CPUState *cs = CPU(cpu);
CPUX86State *env = &cpu->env;
VAPICHandlers *handlers;
uint8_t opcode[2];
uint32_t imm32 = 0;
target_ulong current_pc = 0;
target_ulong current_cs_base = 0;
uint32_t current_flags = 0;
PatchInfo *info;
if (smp_cpus == 1) {
handlers = &s->rom_state.up;
@ -410,60 +452,11 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
handlers = &s->rom_state.mp;
}
if (tcg_enabled()) {
cpu_restore_state(cs, cs->mem_io_pc);
cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
&current_flags);
/* Account this instruction, because we will exit the tb.
This is the first instruction in the block. Therefore
there is no need in restoring CPU state. */
if (use_icount) {
--cs->icount_decr.u16.low;
}
}
info = g_new(PatchInfo, 1);
info->handler = handlers;
info->ip = ip;
pause_all_vcpus();
cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0);
switch (opcode[0]) {
case 0x89: /* mov r32 to r/m32 */
patch_byte(cpu, ip, 0x50 + modrm_reg(opcode[1])); /* push reg */
patch_call(s, cpu, ip + 1, handlers->set_tpr);
break;
case 0x8b: /* mov r/m32 to r32 */
patch_byte(cpu, ip, 0x90);
patch_call(s, cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
break;
case 0xa1: /* mov abs to eax */
patch_call(s, cpu, ip, handlers->get_tpr[0]);
break;
case 0xa3: /* mov eax to abs */
patch_call(s, cpu, ip, handlers->set_tpr_eax);
break;
case 0xc7: /* mov imm32, r/m32 (c7/0) */
patch_byte(cpu, ip, 0x68); /* push imm32 */
cpu_memory_rw_debug(cs, ip + 6, (void *)&imm32, sizeof(imm32), 0);
cpu_memory_rw_debug(cs, ip + 1, (void *)&imm32, sizeof(imm32), 1);
patch_call(s, cpu, ip + 5, handlers->set_tpr);
break;
case 0xff: /* push r/m32 */
patch_byte(cpu, ip, 0x50); /* push eax */
patch_call(s, cpu, ip + 1, handlers->get_tpr_stack);
break;
default:
abort();
}
resume_all_vcpus();
if (tcg_enabled()) {
/* Both tb_lock and iothread_mutex will be reset when
* longjmps back into the cpu_exec loop. */
tb_lock();
tb_gen_code(cs, current_pc, current_cs_base, current_flags, 1);
cpu_loop_exit_noexc(cs);
}
async_safe_run_on_cpu(cs, do_patch_instruction, RUN_ON_CPU_HOST_PTR(info));
}
void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip,