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[73.207.178.95]) by smtp.gmail.com with ESMTPSA id v207sm2941830ywa.6.2017.02.23.21.42.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 23 Feb 2017 21:42:57 -0800 (PST) From: Pranith Kumar To: Date: Fri, 24 Feb 2017 00:42:29 -0500 Message-Id: <1487914949-1294-1-git-send-email-bobby.prani@gmail.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:4002:c05::241 Subject: [Qemu-devel] [PATCH v2] mttcg/i386: Patch instruction using async_safe_* framework X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , =?UTF-8?q?Alex=20Benn=C3=A9e?= , qemu-devel@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 CC: Peter Maydell CC: Alex Bennée Signed-off-by: Pranith Kumar Reviewed-by: Richard Henderson Reviewed-by: Alex Bennée --- hw/i386/kvmvapic.c | 82 ++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 52 insertions(+), 30 deletions(-) diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index 82a4955..11b0d49 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; @@ -393,23 +392,24 @@ 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; - if (smp_cpus == 1) { - handlers = &s->rom_state.up; - } else { - handlers = &s->rom_state.mp; - } - if (!kvm_enabled()) { cpu_get_tb_cpu_state(env, ¤t_pc, ¤t_cs_base, ¤t_flags); @@ -421,48 +421,70 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong 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); + 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(cpu, ip, 0x90); - patch_call(s, cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]); + 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(s, cpu, ip, handlers->get_tpr[0]); + patch_call(x86_cpu, ip, handlers->get_tpr[0]); break; case 0xa3: /* mov eax to abs */ - patch_call(s, cpu, ip, handlers->set_tpr_eax); + patch_call(x86_cpu, ip, handlers->set_tpr_eax); break; case 0xc7: /* mov imm32, r/m32 (c7/0) */ - patch_byte(cpu, ip, 0x68); /* push imm32 */ + 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(s, cpu, ip + 5, handlers->set_tpr); + patch_call(x86_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_byte(x86_cpu, ip, 0x50); /* push eax */ + patch_call(x86_cpu, ip + 1, handlers->get_tpr_stack); break; default: abort(); } - resume_all_vcpus(); + g_free(info); +} + +static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) +{ + CPUState *cs = CPU(cpu); + VAPICHandlers *handlers; + struct PatchInfo *info; + + if (smp_cpus == 1) { + handlers = &s->rom_state.up; + } else { + handlers = &s->rom_state.mp; + } + + info = g_new(struct PatchInfo, 1); + info->handler = handlers; + info->ip = ip; if (!kvm_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); + const run_on_cpu_func fn = do_patch_instruction; + + 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(); + + do_patch_instruction(cs, RUN_ON_CPU_HOST_PTR(info)); + + resume_all_vcpus(); + g_free(info); } void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip,