From patchwork Fri Jun 3 20:40:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 630024 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3rLxKP0bQnz9t7N for ; Sat, 4 Jun 2016 06:59:05 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b=gukEGbCt; dkim-atps=neutral Received: from localhost ([::1]:57723 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8wBL-0001Rm-1L for incoming@patchwork.ozlabs.org; Fri, 03 Jun 2016 16:59:03 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8vtj-0000DJ-FI for qemu-devel@nongnu.org; Fri, 03 Jun 2016 16:40:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b8vtg-0000co-4x for qemu-devel@nongnu.org; Fri, 03 Jun 2016 16:40:51 -0400 Received: from mail-wm0-x233.google.com ([2a00:1450:400c:c09::233]:35802) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8vte-0000ai-5z for qemu-devel@nongnu.org; Fri, 03 Jun 2016 16:40:48 -0400 Received: by mail-wm0-x233.google.com with SMTP id a136so12051222wme.0 for ; Fri, 03 Jun 2016 13:40:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ALddy5lZfeoavldvKpJVJE1sSTPVUH9Fut4dwWJKPoo=; b=gukEGbCtJb5/TAjGIzgnEkw6L66HQ/aAO3fsaPykiRj3OIuOZLr53P3AHBMpqy/e7t IyxMxKEbYhMlyMnNJSz0KJnRON6mjxiguY/kMlGQO4bHoffrtX9dlSM4LCac0Iuj1LbD KZtEnhH1ycUe8eCJ4J8kFcVoFCV7zF0Ar8S08= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ALddy5lZfeoavldvKpJVJE1sSTPVUH9Fut4dwWJKPoo=; b=VjO4LMbqWGsp1RVUZn9EnLwiDU/aidYH15UKf9v6ptZtER/HKCZTCFpj9Ob9hGFSSq FqJGB4z9RfbmZ6h7Z7cpzMbUCNcXZtriQU82+/3QXwObDycGXOnzHJuqdiqw6G/qPGaG MQ292tD11a6TM9srq4M1PPhTFFNv1XyM3IUADES8Vq3ADXkL4G/LDGonj/7Xrjb/3AOc kCYuB/SrSbokul4lGcgfXNKhXYmEHHwwv38tYBHnkj4pZW9BI5JXZr0IFoDgLYcP5baP BxaEL/BkfnHj3Uo3N+v9KrdUJdAcXN2PTH9ORJyqyf/jXppUVXjsRjm2+vuKMpuQ/QmN fBAA== X-Gm-Message-State: ALyK8tIlsyoke0mvW8tIKVrS5XaDiZt/o4w7Lj4peV7DtCrTAHFr22Ehbogq2MQOltfnWx4p X-Received: by 10.194.89.33 with SMTP id bl1mr5031104wjb.43.1464986445336; Fri, 03 Jun 2016 13:40:45 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id b201sm1240486wmb.9.2016.06.03.13.40.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Jun 2016 13:40:37 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 69AAD3E305A; Fri, 3 Jun 2016 21:40:40 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: mttcg@listserver.greensocs.com, qemu-devel@nongnu.org, fred.konrad@greensocs.com, a.rigo@virtualopensystems.com, serge.fdrv@gmail.com, cota@braap.org, bobby.prani@gmail.com Date: Fri, 3 Jun 2016 21:40:24 +0100 Message-Id: <1464986428-6739-16-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1464986428-6739-1-git-send-email-alex.bennee@linaro.org> References: <1464986428-6739-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2a00:1450:400c:c09::233 Subject: [Qemu-devel] [RFC v3 15/19] tcg: drop global lock during TCG code execution 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@linaro.org, Eduardo Habkost , Peter Crosthwaite , claudio.fontana@huawei.com, "Michael S. Tsirkin" , mark.burton@greensocs.com, jan.kiszka@siemens.com, pbonzini@redhat.com, =?UTF-8?q?Alex=20Benn=C3=A9e?= , rth@twiddle.net Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This finally allows TCG to benefit from the iothread introduction: Drop the global mutex while running pure TCG CPU code. Reacquire the lock when entering MMIO or PIO emulation, or when leaving the TCG loop. We have to revert a few optimization for the current TCG threading model, namely kicking the TCG thread in qemu_mutex_lock_iothread and not kicking it in qemu_cpu_kick. We also need to disable RAM block reordering until we have a more efficient locking mechanism at hand. Still, a Linux x86 UP guest and my Musicpal ARM model boot fine here. These numbers demonstrate where we gain something: 20338 jan 20 0 331m 75m 6904 R 99 0.9 0:50.95 qemu-system-arm 20337 jan 20 0 331m 75m 6904 S 20 0.9 0:26.50 qemu-system-arm The guest CPU was fully loaded, but the iothread could still run mostly independent on a second core. Without the patch we don't get beyond 32206 jan 20 0 330m 73m 7036 R 82 0.9 1:06.00 qemu-system-arm 32204 jan 20 0 330m 73m 7036 S 21 0.9 0:17.03 qemu-system-arm We don't benefit significantly, though, when the guest is not fully loading a host CPU. Signed-off-by: Jan Kiszka Message-Id: <1439220437-23957-10-git-send-email-fred.konrad@greensocs.com> [FK: Rebase, fix qemu_devices_reset deadlock, rm address_space_* mutex] Signed-off-by: KONRAD Frederic [EGC: fixed iothread lock for cpu-exec IRQ handling] Signed-off-by: Emilio G. Cota [AJB: -smp single-threaded fix, rm old info from commit msg] Signed-off-by: Alex BennĂ©e --- v3 (ajb, base-patches): - stale iothread_unlocks removed (cpu_exit/resume_from_signal deals with it in the longjmp). - fix re-base conflicts v2 (ajb): - merge with tcg: grab iothread lock in cpu-exec interrupt handling - use existing fns for tracking lock state - lock iothread for mem_region - add assert on mem region modification - ensure smm_helper holds iothread - Add JK s-o-b - Fix-up FK s-o-b annotation v1 (ajb, base-patches): - SMP failure now fixed by previous commit Changes from Fred Konrad (mttcg-v7 via paolo): * Rebase on the current HEAD. * Fixes a deadlock in qemu_devices_reset(). * Remove the mutex in address_space_* --- cpu-exec.c | 11 +++++++++++ cpus.c | 26 +++----------------------- cputlb.c | 1 + exec.c | 12 +++++++++--- hw/i386/kvmvapic.c | 4 ++-- memory.c | 2 ++ softmmu_template.h | 17 +++++++++++++++++ target-i386/smm_helper.c | 7 +++++++ translate-all.c | 9 +++++++-- 9 files changed, 59 insertions(+), 30 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index 1613c63..e1fb9ca 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -29,6 +29,7 @@ #include "qemu/rcu.h" #include "exec/tb-hash.h" #include "exec/log.h" +#include "qemu/main-loop.h" #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) #include "hw/i386/apic.h" #endif @@ -460,6 +461,8 @@ static inline void cpu_handle_interrupt(CPUState *cpu, int interrupt_request = cpu->interrupt_request; if (unlikely(interrupt_request)) { + qemu_mutex_lock_iothread(); + if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) { /* Mask out external interrupts for this step. */ interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK; @@ -514,6 +517,10 @@ static inline void cpu_handle_interrupt(CPUState *cpu, 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(); + } if (unlikely(cpu->exit_request || replay_has_interrupt())) { cpu->exit_request = 0; @@ -642,8 +649,12 @@ int cpu_exec(CPUState *cpu) g_assert(cpu == current_cpu); g_assert(cc == CPU_GET_CLASS(cpu)); #endif /* buggy compiler */ + cpu->can_do_io = 1; tb_lock_reset(); + if (qemu_mutex_iothread_locked()) { + qemu_mutex_unlock_iothread(); + } } } /* for(;;) */ diff --git a/cpus.c b/cpus.c index a84f02c..35374fd 100644 --- a/cpus.c +++ b/cpus.c @@ -915,8 +915,6 @@ static void qemu_kvm_init_cpu_signals(CPUState *cpu) #endif /* _WIN32 */ static QemuMutex qemu_global_mutex; -static QemuCond qemu_io_proceeded_cond; -static unsigned iothread_requesting_mutex; static QemuThread io_thread; @@ -932,7 +930,6 @@ void qemu_init_cpu_loop(void) qemu_cond_init(&qemu_cpu_cond); qemu_cond_init(&qemu_pause_cond); qemu_cond_init(&qemu_work_cond); - qemu_cond_init(&qemu_io_proceeded_cond); qemu_mutex_init(&qemu_global_mutex); qemu_thread_get_self(&io_thread); @@ -1045,10 +1042,6 @@ static void qemu_tcg_wait_io_event(CPUState *cpu) qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); } - while (iothread_requesting_mutex) { - qemu_cond_wait(&qemu_io_proceeded_cond, &qemu_global_mutex); - } - CPU_FOREACH(cpu) { qemu_wait_io_event_common(cpu); } @@ -1205,7 +1198,9 @@ static int tcg_cpu_exec(CPUState *cpu) cpu->icount_decr.u16.low = decr; cpu->icount_extra = count; } + qemu_mutex_unlock_iothread(); ret = cpu_exec(cpu); + qemu_mutex_lock_iothread(); #ifdef CONFIG_PROFILER tcg_time += profile_getclock() - ti; #endif @@ -1392,22 +1387,7 @@ bool qemu_mutex_iothread_locked(void) void qemu_mutex_lock_iothread(void) { - atomic_inc(&iothread_requesting_mutex); - /* In the simple case there is no need to bump the VCPU thread out of - * TCG code execution. - */ - if (!tcg_enabled() || qemu_in_vcpu_thread() || - !first_cpu || !first_cpu->created) { - qemu_mutex_lock(&qemu_global_mutex); - atomic_dec(&iothread_requesting_mutex); - } else { - if (qemu_mutex_trylock(&qemu_global_mutex)) { - qemu_cpu_kick_rr_cpu(); - qemu_mutex_lock(&qemu_global_mutex); - } - atomic_dec(&iothread_requesting_mutex); - qemu_cond_broadcast(&qemu_io_proceeded_cond); - } + qemu_mutex_lock(&qemu_global_mutex); iothread_locked = true; } diff --git a/cputlb.c b/cputlb.c index 1ff6354..78e9879 100644 --- a/cputlb.c +++ b/cputlb.c @@ -18,6 +18,7 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" #include "cpu.h" #include "exec/exec-all.h" #include "exec/memory.h" diff --git a/exec.c b/exec.c index e23039c..b7744b9 100644 --- a/exec.c +++ b/exec.c @@ -2149,9 +2149,9 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) } cpu->watchpoint_hit = wp; - /* The tb_lock will be reset when cpu_loop_exit or - * cpu_resume_from_signal longjmp back into the cpu_exec - * main loop. + /* Both tb_lock and iothread_mutex will be reset when + * cpu_loop_exit or cpu_resume_from_signal longjmp + * back into the cpu_exec main loop. */ tb_lock(); tb_check_watchpoint(cpu); @@ -2387,8 +2387,14 @@ static void io_mem_init(void) memory_region_init_io(&io_mem_rom, NULL, &unassigned_mem_ops, NULL, NULL, UINT64_MAX); memory_region_init_io(&io_mem_unassigned, NULL, &unassigned_mem_ops, NULL, NULL, UINT64_MAX); + + /* io_mem_notdirty calls tb_invalidate_phys_page_fast, + * which must be called without the iothread mutex. + */ memory_region_init_io(&io_mem_notdirty, NULL, ¬dirty_mem_ops, NULL, NULL, UINT64_MAX); + memory_region_clear_global_locking(&io_mem_notdirty); + memory_region_init_io(&io_mem_watch, NULL, &watch_mem_ops, NULL, NULL, UINT64_MAX); } diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index d98fe2a..12ed58e 100644 --- a/hw/i386/kvmvapic.c +++ b/hw/i386/kvmvapic.c @@ -450,8 +450,8 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) resume_all_vcpus(); if (!kvm_enabled()) { - /* tb_lock will be reset when cpu_resume_from_signal longjmps - * back into the cpu_exec loop. */ + /* Both tb_lock and iothread_mutex will be reset when + * cpu_resume_from_signal longjmps back into the cpu_exec loop. */ tb_lock(); tb_gen_code(cs, current_pc, current_cs_base, current_flags, 1); cpu_resume_from_signal(cs, NULL); diff --git a/memory.c b/memory.c index 4e3cda8..2a318d7 100644 --- a/memory.c +++ b/memory.c @@ -914,6 +914,8 @@ void memory_region_transaction_commit(void) AddressSpace *as; assert(memory_region_transaction_depth); + assert(qemu_mutex_iothread_locked()); + --memory_region_transaction_depth; if (!memory_region_transaction_depth) { if (memory_region_update_pending) { diff --git a/softmmu_template.h b/softmmu_template.h index 208f808..0b6c609 100644 --- a/softmmu_template.h +++ b/softmmu_template.h @@ -151,6 +151,7 @@ static inline DATA_TYPE glue(io_read, SUFFIX)(CPUArchState *env, CPUState *cpu = ENV_GET_CPU(env); hwaddr physaddr = iotlbentry->addr; MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs); + bool locked = false; physaddr = (physaddr & TARGET_PAGE_MASK) + addr; cpu->mem_io_pc = retaddr; @@ -159,8 +160,15 @@ static inline DATA_TYPE glue(io_read, SUFFIX)(CPUArchState *env, } cpu->mem_io_vaddr = addr; + if (mr->global_locking) { + qemu_mutex_lock_iothread(); + locked = true; + } memory_region_dispatch_read(mr, physaddr, &val, 1 << SHIFT, iotlbentry->attrs); + if (locked) { + qemu_mutex_unlock_iothread(); + } return val; } #endif @@ -358,6 +366,7 @@ static inline void glue(io_write, SUFFIX)(CPUArchState *env, CPUState *cpu = ENV_GET_CPU(env); hwaddr physaddr = iotlbentry->addr; MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs); + bool locked = false; physaddr = (physaddr & TARGET_PAGE_MASK) + addr; if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) { @@ -366,8 +375,16 @@ static inline void glue(io_write, SUFFIX)(CPUArchState *env, cpu->mem_io_vaddr = addr; cpu->mem_io_pc = retaddr; + + if (mr->global_locking) { + qemu_mutex_lock_iothread(); + locked = true; + } memory_region_dispatch_write(mr, physaddr, val, 1 << SHIFT, iotlbentry->attrs); + if (locked) { + qemu_mutex_unlock_iothread(); + } } void helper_le_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val, diff --git a/target-i386/smm_helper.c b/target-i386/smm_helper.c index 4dd6a2c..6a5489b 100644 --- a/target-i386/smm_helper.c +++ b/target-i386/smm_helper.c @@ -18,6 +18,7 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" #include "cpu.h" #include "exec/helper-proto.h" #include "exec/log.h" @@ -42,11 +43,14 @@ void helper_rsm(CPUX86State *env) #define SMM_REVISION_ID 0x00020000 #endif +/* Called we iothread lock taken */ void cpu_smm_update(X86CPU *cpu) { CPUX86State *env = &cpu->env; bool smm_enabled = (env->hflags & HF_SMM_MASK); + g_assert(qemu_mutex_iothread_locked()); + if (cpu->smram) { memory_region_set_enabled(cpu->smram, smm_enabled); } @@ -333,7 +337,10 @@ void helper_rsm(CPUX86State *env) } env->hflags2 &= ~HF2_SMM_INSIDE_NMI_MASK; env->hflags &= ~HF_SMM_MASK; + + qemu_mutex_lock_iothread(); cpu_smm_update(cpu); + qemu_mutex_unlock_iothread(); qemu_log_mask(CPU_LOG_INT, "SMM: after RSM\n"); log_cpu_state_mask(CPU_LOG_INT, CPU(cpu), CPU_DUMP_CCOP); diff --git a/translate-all.c b/translate-all.c index f54ab3e..818520e 100644 --- a/translate-all.c +++ b/translate-all.c @@ -1476,7 +1476,9 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end, } #ifdef CONFIG_SOFTMMU -/* len must be <= 8 and start must be a multiple of len */ +/* len must be <= 8 and start must be a multiple of len. + * Called via softmmu_template.h, with iothread mutex not held. + */ void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len) { PageDesc *p; @@ -1670,7 +1672,10 @@ void tb_check_watchpoint(CPUState *cpu) #ifndef CONFIG_USER_ONLY /* in deterministic execution mode, instructions doing device I/Os - must be at the end of the TB */ + * must be at the end of the TB. + * + * Called by softmmu_template.h, with iothread mutex not held. + */ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr) { #if defined(TARGET_MIPS) || defined(TARGET_SH4)