From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46167) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dQTc2-0003YS-Nu for qemu-devel@nongnu.org; Thu, 29 Jun 2017 03:11:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dQTbz-0002KY-2f for qemu-devel@nongnu.org; Thu, 29 Jun 2017 03:11:38 -0400 Received: from mail-yw0-x241.google.com ([2607:f8b0:4002:c05::241]:34076) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dQTby-0002KT-T5 for qemu-devel@nongnu.org; Thu, 29 Jun 2017 03:11:35 -0400 Received: by mail-yw0-x241.google.com with SMTP id g124so4570967ywg.1 for ; Thu, 29 Jun 2017 00:11:34 -0700 (PDT) From: Pranith Kumar Date: Thu, 29 Jun 2017 03:11:29 -0400 Message-Id: <20170629071129.29362-3-bobby.prani@gmail.com> In-Reply-To: <20170629071129.29362-1-bobby.prani@gmail.com> References: <20170629071129.29362-1-bobby.prani@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v3 2/2] mttcg/i386: Patch instruction using async_safe_* framework List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: alex.bennee@linaro.org Cc: qemu-devel@nongnu.org, rth@twiddle.net, pbonzini@redhat.com, ehabkost@redhat.com, Peter Maydell 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 CC: Peter Maydell Reviewed-by: Richard Henderson Reviewed-by: Alex BennĂ©e Signed-off-by: Pranith Kumar --- hw/i386/kvmvapic.c | 73 +++++++++++++++++++++++++++++++----------------------- 1 file changed, 42 insertions(+), 31 deletions(-) diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index 82a49556af..5e0c8219b0 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 +421,59 @@ 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); +} - 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); +static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) +{ + CPUState *cs = CPU(cpu); + VAPICHandlers *handlers; + struct PatchInfo *info; + const run_on_cpu_func fn = do_patch_instruction; + + 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; + + async_safe_run_on_cpu(cs, fn, RUN_ON_CPU_HOST_PTR(info)); + cpu_exit(cs); } void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip, -- 2.13.0