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: Richard Henderson <r...@twiddle.net>
CC: Peter Maydell <peter.mayd...@linaro.org>
CC: Alex Bennée <alex.ben...@linaro.org>
Signed-off-by: Pranith Kumar <bobby.pr...@gmail.com>
---
hw/i386/kvmvapic.c | 104 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 76 insertions(+), 28 deletions(-)
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 82a4955..15eb39d 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -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;
@@ -393,17 +392,74 @@ static void patch_call(VAPICROMState *s, X86CPU *cpu,
target_ulong ip,
cpu_memory_rw_debug(CPU(cpu), ip + 1, (void *)&offset, sizeof(offset), 1);
}
-static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
+struct PatchInfo {
+ VAPICHandlers *handler;
+ target_ulong ip;
+};
+
+static void do_patch_instruction(CPUState *cs, run_on_cpu_data data)
{
- CPUState *cs = CPU(cpu);
- CPUX86State *env = &cpu->env;
- VAPICHandlers *handlers;
+ X86CPU *x86_cpu = X86_CPU(cs);
+ CPUX86State *env = &x86_cpu->env;
+ struct PatchInfo *info = (struct PatchInfo *) data.host_ptr;
+ VAPICHandlers *handlers = info->handler;
+ target_ulong ip = info->ip;
uint8_t opcode[2];
uint32_t imm32 = 0;
target_ulong current_pc = 0;
target_ulong current_cs_base = 0;
uint32_t current_flags = 0;
+ cpu_get_tb_cpu_state(env, ¤t_pc, ¤t_cs_base,
+ ¤t_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;
+ }
+
+ 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);
+ VAPICHandlers *handlers;
+ uint8_t opcode[2];
+ uint32_t imm32 = 0;
+
if (smp_cpus == 1) {
handlers = &s->rom_state.up;
} else {
@@ -411,14 +467,14 @@ static void patch_instruction(VAPICROMState *s, X86CPU
*cpu, target_ulong ip)
}
if (!kvm_enabled()) {
- cpu_get_tb_cpu_state(env, ¤t_pc, ¤t_cs_base,
- ¤t_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;
- }
+ struct PatchInfo *info = g_new(struct PatchInfo, 1);
+ const run_on_cpu_func fn = do_patch_instruction;
+ info->handler = handlers;
+ info->ip = ip;
+
+ async_safe_run_on_cpu(cs, fn, RUN_ON_CPU_HOST_PTR(info));
+ cs->exception_index = EXCP_INTERRUPT;
+ cpu_loop_exit(cs);
}
pause_all_vcpus();
@@ -428,41 +484,33 @@ static void patch_instruction(VAPICROMState *s, X86CPU
*cpu, target_ulong ip)
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);
+ patch_call(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])]);
+ patch_call(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]);
+ patch_call(cpu, ip, handlers->get_tpr[0]);
break;
case 0xa3: /* mov eax to abs */
- patch_call(s, cpu, ip, handlers->set_tpr_eax);
+ patch_call(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);
+ patch_call(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);
+ patch_call(cpu, ip + 1, handlers->get_tpr_stack);
break;
default:
abort();
}
