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Re: [Qemu-devel] [PULL 08/24] tcg: drop global lock during TCG code exec
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From: |
Aaron Lindsay |
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Subject: |
Re: [Qemu-devel] [PULL 08/24] tcg: drop global lock during TCG code execution |
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Date: |
Fri, 3 Mar 2017 15:59:05 -0500 |
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User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Feb 27 14:39, Alex Bennée wrote:
>
> Laurent Desnogues <address@hidden> writes:
>
> > Hello,
> >
> > On Fri, Feb 24, 2017 at 12:20 PM, Alex Bennée <address@hidden> wrote:
> >> From: Jan Kiszka <address@hidden>
> >>
> >> 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.
> >
> > I tried this patch (8d04fb55 in the repository) with the following image:
> >
> > http://wiki.qemu.org/download/arm-test-0.2.tar.gz
> >
> > Running the image with no option works fine. But specifying '-icount
> > 1' results in a (guest) deadlock. Enabling some heavy logging (-d
> > in_asm,exec) sometimes results in a 'Bad ram offset'.
> >
> > Is it expected that this patch breaks -icount?
>
> Not really. Using icount will disable MTTCG and run single threaded as
> before. Paolo reported another icount failure so they may be related. I
> shall have a look at it.
>
> Thanks for the report.
I have not experienced a guest deadlock, but for me this patch makes
booting a simple Linux distribution take about an order of magnitude
longer when using '-icount 0' (from about 1.6 seconds to 17.9). It was
slow enough to get to the printk the first time after recompiling that I
killed it thinking it *had* deadlocked.
`perf report` from before this patch (snipped to >1%):
23.81% qemu-system-aar perf-9267.map [.] 0x0000000041a5cc9e
7.15% qemu-system-aar [kernel.kallsyms] [k] 0xffffffff8172bc82
6.29% qemu-system-aar qemu-system-aarch64 [.] cpu_exec
4.99% qemu-system-aar qemu-system-aarch64 [.] tcg_gen_code
4.71% qemu-system-aar qemu-system-aarch64 [.] cpu_get_tb_cpu_state
4.39% qemu-system-aar qemu-system-aarch64 [.] tcg_optimize
3.28% qemu-system-aar qemu-system-aarch64 [.] helper_dc_zva
2.66% qemu-system-aar qemu-system-aarch64 [.] liveness_pass_1
1.98% qemu-system-aar qemu-system-aarch64 [.] qht_lookup
1.93% qemu-system-aar qemu-system-aarch64 [.] tcg_out_opc
1.81% qemu-system-aar qemu-system-aarch64 [.] get_phys_addr_lpae
1.71% qemu-system-aar qemu-system-aarch64 [.]
object_class_dynamic_cast_assert
1.38% qemu-system-aar qemu-system-aarch64 [.] arm_regime_tbi1
1.10% qemu-system-aar qemu-system-aarch64 [.] arm_regime_tbi0
and after this patch:
20.10% qemu-system-aar perf-3285.map [.] 0x0000000040a3b690
*18.08% qemu-system-aar [kernel.kallsyms] [k] 0xffffffff81371865
7.87% qemu-system-aar qemu-system-aarch64 [.] cpu_exec
4.70% qemu-system-aar qemu-system-aarch64 [.] cpu_get_tb_cpu_state
* 2.64% qemu-system-aar qemu-system-aarch64 [.] g_mutex_get_impl
2.39% qemu-system-aar qemu-system-aarch64 [.] gic_update
* 1.89% qemu-system-aar qemu-system-aarch64 [.] pthread_mutex_unlock
1.61% qemu-system-aar qemu-system-aarch64 [.]
object_class_dynamic_cast_assert
* 1.55% qemu-system-aar qemu-system-aarch64 [.] pthread_mutex_lock
1.31% qemu-system-aar qemu-system-aarch64 [.] get_phys_addr_lpae
1.21% qemu-system-aar qemu-system-aarch64 [.] arm_regime_tbi0
1.13% qemu-system-aar qemu-system-aarch64 [.] arm_regime_tbi1
I've put asterisks by a few suspicious mutex-related functions, though I wonder
if the slowdowns are also partially inlined into some of the other functions.
The kernel also jumps up, presumably from handling more mutexes?
I confess I'm not familiar enough with this code to suggest optimizations, but
I'll be glad to test any.
-Aaron
>
> >
> > Thanks,
> >
> > Laurent
> >
> > PS - To clarify 791158d9 works.
> >
> >> Signed-off-by: Jan Kiszka <address@hidden>
> >> Message-Id: <address@hidden>
> >> [FK: Rebase, fix qemu_devices_reset deadlock, rm address_space_* mutex]
> >> Signed-off-by: KONRAD Frederic <address@hidden>
> >> [EGC: fixed iothread lock for cpu-exec IRQ handling]
> >> Signed-off-by: Emilio G. Cota <address@hidden>
> >> [AJB: -smp single-threaded fix, clean commit msg, BQL fixes]
> >> Signed-off-by: Alex Bennée <address@hidden>
> >> Reviewed-by: Richard Henderson <address@hidden>
> >> Reviewed-by: Pranith Kumar <address@hidden>
> >> [PM: target-arm changes]
> >> Acked-by: Peter Maydell <address@hidden>
> >> ---
> >> cpu-exec.c | 23 +++++++++++++++++++++--
> >> cpus.c | 28 +++++-----------------------
> >> cputlb.c | 21 ++++++++++++++++++++-
> >> exec.c | 12 +++++++++---
> >> hw/core/irq.c | 1 +
> >> hw/i386/kvmvapic.c | 4 ++--
> >> hw/intc/arm_gicv3_cpuif.c | 3 +++
> >> hw/ppc/ppc.c | 16 +++++++++++++++-
> >> hw/ppc/spapr.c | 3 +++
> >> include/qom/cpu.h | 1 +
> >> memory.c | 2 ++
> >> qom/cpu.c | 10 ++++++++++
> >> target/arm/helper.c | 6 ++++++
> >> target/arm/op_helper.c | 43
> >> +++++++++++++++++++++++++++++++++++++++----
> >> target/i386/smm_helper.c | 7 +++++++
> >> target/s390x/misc_helper.c | 5 ++++-
> >> translate-all.c | 9 +++++++--
> >> translate-common.c | 21 +++++++++++----------
> >> 18 files changed, 166 insertions(+), 49 deletions(-)
> >>
> >> diff --git a/cpu-exec.c b/cpu-exec.c
> >> index 06a6b25564..1bd3d72002 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
> >> @@ -388,8 +389,10 @@ static inline bool cpu_handle_halt(CPUState *cpu)
> >> if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
> >> && replay_interrupt()) {
> >> X86CPU *x86_cpu = X86_CPU(cpu);
> >> + qemu_mutex_lock_iothread();
> >> apic_poll_irq(x86_cpu->apic_state);
> >> cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
> >> + qemu_mutex_unlock_iothread();
> >> }
> >> #endif
> >> if (!cpu_has_work(cpu)) {
> >> @@ -443,7 +446,9 @@ static inline bool cpu_handle_exception(CPUState *cpu,
> >> int *ret)
> >> #else
> >> if (replay_exception()) {
> >> CPUClass *cc = CPU_GET_CLASS(cpu);
> >> + qemu_mutex_lock_iothread();
> >> cc->do_interrupt(cpu);
> >> + qemu_mutex_unlock_iothread();
> >> cpu->exception_index = -1;
> >> } else if (!replay_has_interrupt()) {
> >> /* give a chance to iothread in replay mode */
> >> @@ -469,9 +474,11 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
> >> TranslationBlock **last_tb)
> >> {
> >> CPUClass *cc = CPU_GET_CLASS(cpu);
> >> - int interrupt_request = cpu->interrupt_request;
> >>
> >> - if (unlikely(interrupt_request)) {
> >> + if (unlikely(atomic_read(&cpu->interrupt_request))) {
> >> + int interrupt_request;
> >> + qemu_mutex_lock_iothread();
> >> + interrupt_request = cpu->interrupt_request;
> >> if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
> >> /* Mask out external interrupts for this step. */
> >> interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
> >> @@ -479,6 +486,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
> >> if (interrupt_request & CPU_INTERRUPT_DEBUG) {
> >> cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
> >> cpu->exception_index = EXCP_DEBUG;
> >> + qemu_mutex_unlock_iothread();
> >> return true;
> >> }
> >> if (replay_mode == REPLAY_MODE_PLAY && !replay_has_interrupt()) {
> >> @@ -488,6 +496,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
> >> cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
> >> cpu->halted = 1;
> >> cpu->exception_index = EXCP_HLT;
> >> + qemu_mutex_unlock_iothread();
> >> return true;
> >> }
> >> #if defined(TARGET_I386)
> >> @@ -498,12 +507,14 @@ static inline bool cpu_handle_interrupt(CPUState
> >> *cpu,
> >> cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0, 0);
> >> do_cpu_init(x86_cpu);
> >> cpu->exception_index = EXCP_HALTED;
> >> + qemu_mutex_unlock_iothread();
> >> return true;
> >> }
> >> #else
> >> else if (interrupt_request & CPU_INTERRUPT_RESET) {
> >> replay_interrupt();
> >> cpu_reset(cpu);
> >> + qemu_mutex_unlock_iothread();
> >> return true;
> >> }
> >> #endif
> >> @@ -526,7 +537,12 @@ static inline bool 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(atomic_read(&cpu->exit_request) ||
> >> replay_has_interrupt())) {
> >> atomic_set(&cpu->exit_request, 0);
> >> cpu->exception_index = EXCP_INTERRUPT;
> >> @@ -643,6 +659,9 @@ int cpu_exec(CPUState *cpu)
> >> #endif /* buggy compiler */
> >> cpu->can_do_io = 1;
> >> tb_lock_reset();
> >> + if (qemu_mutex_iothread_locked()) {
> >> + qemu_mutex_unlock_iothread();
> >> + }
> >> }
> >>
> >> /* if an exception is pending, we execute it here */
> >> diff --git a/cpus.c b/cpus.c
> >> index 860034a794..0ae8f69be5 100644
> >> --- a/cpus.c
> >> +++ b/cpus.c
> >> @@ -1027,8 +1027,6 @@ 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;
> >>
> >> @@ -1042,7 +1040,6 @@ void qemu_init_cpu_loop(void)
> >> qemu_init_sigbus();
> >> qemu_cond_init(&qemu_cpu_cond);
> >> qemu_cond_init(&qemu_pause_cond);
> >> - qemu_cond_init(&qemu_io_proceeded_cond);
> >> qemu_mutex_init(&qemu_global_mutex);
> >>
> >> qemu_thread_get_self(&io_thread);
> >> @@ -1085,10 +1082,6 @@ static void qemu_tcg_wait_io_event(CPUState *cpu)
> >>
> >> start_tcg_kick_timer();
> >>
> >> - while (iothread_requesting_mutex) {
> >> - qemu_cond_wait(&qemu_io_proceeded_cond, &qemu_global_mutex);
> >> - }
> >> -
> >> CPU_FOREACH(cpu) {
> >> qemu_wait_io_event_common(cpu);
> >> }
> >> @@ -1249,9 +1242,11 @@ static int tcg_cpu_exec(CPUState *cpu)
> >> cpu->icount_decr.u16.low = decr;
> >> cpu->icount_extra = count;
> >> }
> >> + qemu_mutex_unlock_iothread();
> >> cpu_exec_start(cpu);
> >> ret = cpu_exec(cpu);
> >> cpu_exec_end(cpu);
> >> + qemu_mutex_lock_iothread();
> >> #ifdef CONFIG_PROFILER
> >> tcg_time += profile_getclock() - ti;
> >> #endif
> >> @@ -1479,27 +1474,14 @@ 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);
> >> - }
> >> + g_assert(!qemu_mutex_iothread_locked());
> >> + qemu_mutex_lock(&qemu_global_mutex);
> >> iothread_locked = true;
> >> }
> >>
> >> void qemu_mutex_unlock_iothread(void)
> >> {
> >> + g_assert(qemu_mutex_iothread_locked());
> >> iothread_locked = false;
> >> qemu_mutex_unlock(&qemu_global_mutex);
> >> }
> >> diff --git a/cputlb.c b/cputlb.c
> >> index 6c39927455..1cc9d9da51 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"
> >> @@ -495,6 +496,7 @@ static uint64_t io_readx(CPUArchState *env,
> >> CPUIOTLBEntry *iotlbentry,
> >> hwaddr physaddr = iotlbentry->addr;
> >> MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs);
> >> uint64_t val;
> >> + bool locked = false;
> >>
> >> physaddr = (physaddr & TARGET_PAGE_MASK) + addr;
> >> cpu->mem_io_pc = retaddr;
> >> @@ -503,7 +505,16 @@ static uint64_t io_readx(CPUArchState *env,
> >> CPUIOTLBEntry *iotlbentry,
> >> }
> >>
> >> cpu->mem_io_vaddr = addr;
> >> +
> >> + if (mr->global_locking) {
> >> + qemu_mutex_lock_iothread();
> >> + locked = true;
> >> + }
> >> memory_region_dispatch_read(mr, physaddr, &val, size,
> >> iotlbentry->attrs);
> >> + if (locked) {
> >> + qemu_mutex_unlock_iothread();
> >> + }
> >> +
> >> return val;
> >> }
> >>
> >> @@ -514,15 +525,23 @@ static void io_writex(CPUArchState *env,
> >> CPUIOTLBEntry *iotlbentry,
> >> 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) {
> >> cpu_io_recompile(cpu, retaddr);
> >> }
> >> -
> >> 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, size,
> >> iotlbentry->attrs);
> >> + if (locked) {
> >> + qemu_mutex_unlock_iothread();
> >> + }
> >> }
> >>
> >> /* Return true if ADDR is present in the victim tlb, and has been copied
> >> diff --git a/exec.c b/exec.c
> >> index 865a1e8295..3adf2b1861 100644
> >> --- a/exec.c
> >> +++ b/exec.c
> >> @@ -2134,9 +2134,9 @@ 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_loop_exit_noexc longjmp back into the cpu_exec
> >> - * main loop.
> >> + /* Both tb_lock and iothread_mutex will be reset when
> >> + * cpu_loop_exit or cpu_loop_exit_noexc longjmp
> >> + * back into the cpu_exec main loop.
> >> */
> >> tb_lock();
> >> tb_check_watchpoint(cpu);
> >> @@ -2371,8 +2371,14 @@ 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 can 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/core/irq.c b/hw/core/irq.c
> >> index 49ff2e64fe..b98d1d69f5 100644
> >> --- a/hw/core/irq.c
> >> +++ b/hw/core/irq.c
> >> @@ -22,6 +22,7 @@
> >> * THE SOFTWARE.
> >> */
> >> #include "qemu/osdep.h"
> >> +#include "qemu/main-loop.h"
> >> #include "qemu-common.h"
> >> #include "hw/irq.h"
> >> #include "qom/object.h"
> >> diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
> >> index 7135633863..82a49556af 100644
> >> --- a/hw/i386/kvmvapic.c
> >> +++ b/hw/i386/kvmvapic.c
> >> @@ -457,8 +457,8 @@ static void patch_instruction(VAPICROMState *s, X86CPU
> >> *cpu, target_ulong ip)
> >> resume_all_vcpus();
> >>
> >> if (!kvm_enabled()) {
> >> - /* tb_lock will be reset when cpu_loop_exit_noexc longjmps
> >> - * back into the cpu_exec loop. */
> >> + /* 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);
> >> diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
> >> index c25ee03556..f775aba507 100644
> >> --- a/hw/intc/arm_gicv3_cpuif.c
> >> +++ b/hw/intc/arm_gicv3_cpuif.c
> >> @@ -14,6 +14,7 @@
> >>
> >> #include "qemu/osdep.h"
> >> #include "qemu/bitops.h"
> >> +#include "qemu/main-loop.h"
> >> #include "trace.h"
> >> #include "gicv3_internal.h"
> >> #include "cpu.h"
> >> @@ -733,6 +734,8 @@ void gicv3_cpuif_update(GICv3CPUState *cs)
> >> ARMCPU *cpu = ARM_CPU(cs->cpu);
> >> CPUARMState *env = &cpu->env;
> >>
> >> + g_assert(qemu_mutex_iothread_locked());
> >> +
> >> trace_gicv3_cpuif_update(gicv3_redist_affid(cs), cs->hppi.irq,
> >> cs->hppi.grp, cs->hppi.prio);
> >>
> >> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> >> index d171e60b5c..5f93083d4a 100644
> >> --- a/hw/ppc/ppc.c
> >> +++ b/hw/ppc/ppc.c
> >> @@ -62,7 +62,16 @@ void ppc_set_irq(PowerPCCPU *cpu, int n_IRQ, int level)
> >> {
> >> CPUState *cs = CPU(cpu);
> >> CPUPPCState *env = &cpu->env;
> >> - unsigned int old_pending = env->pending_interrupts;
> >> + unsigned int old_pending;
> >> + bool locked = false;
> >> +
> >> + /* We may already have the BQL if coming from the reset path */
> >> + if (!qemu_mutex_iothread_locked()) {
> >> + locked = true;
> >> + qemu_mutex_lock_iothread();
> >> + }
> >> +
> >> + old_pending = env->pending_interrupts;
> >>
> >> if (level) {
> >> env->pending_interrupts |= 1 << n_IRQ;
> >> @@ -80,9 +89,14 @@ void ppc_set_irq(PowerPCCPU *cpu, int n_IRQ, int level)
> >> #endif
> >> }
> >>
> >> +
> >> LOG_IRQ("%s: %p n_IRQ %d level %d => pending %08" PRIx32
> >> "req %08x\n", __func__, env, n_IRQ, level,
> >> env->pending_interrupts, CPU(cpu)->interrupt_request);
> >> +
> >> + if (locked) {
> >> + qemu_mutex_unlock_iothread();
> >> + }
> >> }
> >>
> >> /* PowerPC 6xx / 7xx internal IRQ controller */
> >> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> >> index e465d7ac98..b1e374f3f9 100644
> >> --- a/hw/ppc/spapr.c
> >> +++ b/hw/ppc/spapr.c
> >> @@ -1010,6 +1010,9 @@ static void
> >> emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
> >> {
> >> CPUPPCState *env = &cpu->env;
> >>
> >> + /* The TCG path should also be holding the BQL at this point */
> >> + g_assert(qemu_mutex_iothread_locked());
> >> +
> >> if (msr_pr) {
> >> hcall_dprintf("Hypercall made with MSR[PR]=1\n");
> >> env->gpr[3] = H_PRIVILEGE;
> >> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> >> index 2cf4ecf144..10db89b16a 100644
> >> --- a/include/qom/cpu.h
> >> +++ b/include/qom/cpu.h
> >> @@ -329,6 +329,7 @@ struct CPUState {
> >> bool unplug;
> >> bool crash_occurred;
> >> bool exit_request;
> >> + /* updates protected by BQL */
> >> uint32_t interrupt_request;
> >> int singlestep_enabled;
> >> int64_t icount_extra;
> >> diff --git a/memory.c b/memory.c
> >> index ed8b5aa83e..d61caee867 100644
> >> --- a/memory.c
> >> +++ b/memory.c
> >> @@ -917,6 +917,8 @@ 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/qom/cpu.c b/qom/cpu.c
> >> index ed87c50cea..58784bcbea 100644
> >> --- a/qom/cpu.c
> >> +++ b/qom/cpu.c
> >> @@ -113,9 +113,19 @@ static void cpu_common_get_memory_mapping(CPUState
> >> *cpu,
> >> error_setg(errp, "Obtaining memory mappings is unsupported on this
> >> CPU.");
> >> }
> >>
> >> +/* Resetting the IRQ comes from across the code base so we take the
> >> + * BQL here if we need to. cpu_interrupt assumes it is held.*/
> >> void cpu_reset_interrupt(CPUState *cpu, int mask)
> >> {
> >> + bool need_lock = !qemu_mutex_iothread_locked();
> >> +
> >> + if (need_lock) {
> >> + qemu_mutex_lock_iothread();
> >> + }
> >> cpu->interrupt_request &= ~mask;
> >> + if (need_lock) {
> >> + qemu_mutex_unlock_iothread();
> >> + }
> >> }
> >>
> >> void cpu_exit(CPUState *cpu)
> >> diff --git a/target/arm/helper.c b/target/arm/helper.c
> >> index 47250bcf16..753a69d40d 100644
> >> --- a/target/arm/helper.c
> >> +++ b/target/arm/helper.c
> >> @@ -6769,6 +6769,12 @@ void arm_cpu_do_interrupt(CPUState *cs)
> >> arm_cpu_do_interrupt_aarch32(cs);
> >> }
> >>
> >> + /* Hooks may change global state so BQL should be held, also the
> >> + * BQL needs to be held for any modification of
> >> + * cs->interrupt_request.
> >> + */
> >> + g_assert(qemu_mutex_iothread_locked());
> >> +
> >> arm_call_el_change_hook(cpu);
> >>
> >> if (!kvm_enabled()) {
> >> diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
> >> index fb366fdc35..5f3e3bdae2 100644
> >> --- a/target/arm/op_helper.c
> >> +++ b/target/arm/op_helper.c
> >> @@ -18,6 +18,7 @@
> >> */
> >> #include "qemu/osdep.h"
> >> #include "qemu/log.h"
> >> +#include "qemu/main-loop.h"
> >> #include "cpu.h"
> >> #include "exec/helper-proto.h"
> >> #include "internals.h"
> >> @@ -487,7 +488,9 @@ void HELPER(cpsr_write_eret)(CPUARMState *env,
> >> uint32_t val)
> >> */
> >> env->regs[15] &= (env->thumb ? ~1 : ~3);
> >>
> >> + qemu_mutex_lock_iothread();
> >> arm_call_el_change_hook(arm_env_get_cpu(env));
> >> + qemu_mutex_unlock_iothread();
> >> }
> >>
> >> /* Access to user mode registers from privileged modes. */
> >> @@ -735,28 +738,58 @@ void HELPER(set_cp_reg)(CPUARMState *env, void *rip,
> >> uint32_t value)
> >> {
> >> const ARMCPRegInfo *ri = rip;
> >>
> >> - ri->writefn(env, ri, value);
> >> + if (ri->type & ARM_CP_IO) {
> >> + qemu_mutex_lock_iothread();
> >> + ri->writefn(env, ri, value);
> >> + qemu_mutex_unlock_iothread();
> >> + } else {
> >> + ri->writefn(env, ri, value);
> >> + }
> >> }
> >>
> >> uint32_t HELPER(get_cp_reg)(CPUARMState *env, void *rip)
> >> {
> >> const ARMCPRegInfo *ri = rip;
> >> + uint32_t res;
> >>
> >> - return ri->readfn(env, ri);
> >> + if (ri->type & ARM_CP_IO) {
> >> + qemu_mutex_lock_iothread();
> >> + res = ri->readfn(env, ri);
> >> + qemu_mutex_unlock_iothread();
> >> + } else {
> >> + res = ri->readfn(env, ri);
> >> + }
> >> +
> >> + return res;
> >> }
> >>
> >> void HELPER(set_cp_reg64)(CPUARMState *env, void *rip, uint64_t value)
> >> {
> >> const ARMCPRegInfo *ri = rip;
> >>
> >> - ri->writefn(env, ri, value);
> >> + if (ri->type & ARM_CP_IO) {
> >> + qemu_mutex_lock_iothread();
> >> + ri->writefn(env, ri, value);
> >> + qemu_mutex_unlock_iothread();
> >> + } else {
> >> + ri->writefn(env, ri, value);
> >> + }
> >> }
> >>
> >> uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void *rip)
> >> {
> >> const ARMCPRegInfo *ri = rip;
> >> + uint64_t res;
> >> +
> >> + if (ri->type & ARM_CP_IO) {
> >> + qemu_mutex_lock_iothread();
> >> + res = ri->readfn(env, ri);
> >> + qemu_mutex_unlock_iothread();
> >> + } else {
> >> + res = ri->readfn(env, ri);
> >> + }
> >>
> >> - return ri->readfn(env, ri);
> >> + return res;
> >> }
> >>
> >> void HELPER(msr_i_pstate)(CPUARMState *env, uint32_t op, uint32_t imm)
> >> @@ -989,7 +1022,9 @@ void HELPER(exception_return)(CPUARMState *env)
> >> cur_el, new_el, env->pc);
> >> }
> >>
> >> + qemu_mutex_lock_iothread();
> >> arm_call_el_change_hook(arm_env_get_cpu(env));
> >> + qemu_mutex_unlock_iothread();
> >>
> >> return;
> >>
> >> diff --git a/target/i386/smm_helper.c b/target/i386/smm_helper.c
> >> index 4dd6a2c544..f051a77c4a 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 with 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/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
> >> index c9604ea9c7..3cb942e8bb 100644
> >> --- a/target/s390x/misc_helper.c
> >> +++ b/target/s390x/misc_helper.c
> >> @@ -25,6 +25,7 @@
> >> #include "exec/helper-proto.h"
> >> #include "sysemu/kvm.h"
> >> #include "qemu/timer.h"
> >> +#include "qemu/main-loop.h"
> >> #include "exec/address-spaces.h"
> >> #ifdef CONFIG_KVM
> >> #include <linux/kvm.h>
> >> @@ -109,11 +110,13 @@ void program_interrupt(CPUS390XState *env, uint32_t
> >> code, int ilen)
> >> /* SCLP service call */
> >> uint32_t HELPER(servc)(CPUS390XState *env, uint64_t r1, uint64_t r2)
> >> {
> >> + qemu_mutex_lock_iothread();
> >> int r = sclp_service_call(env, r1, r2);
> >> if (r < 0) {
> >> program_interrupt(env, -r, 4);
> >> - return 0;
> >> + r = 0;
> >> }
> >> + qemu_mutex_unlock_iothread();
> >> return r;
> >> }
> >>
> >> diff --git a/translate-all.c b/translate-all.c
> >> index 8a861cb583..f810259c41 100644
> >> --- a/translate-all.c
> >> +++ b/translate-all.c
> >> @@ -55,6 +55,7 @@
> >> #include "translate-all.h"
> >> #include "qemu/bitmap.h"
> >> #include "qemu/timer.h"
> >> +#include "qemu/main-loop.h"
> >> #include "exec/log.h"
> >>
> >> /* #define DEBUG_TB_INVALIDATE */
> >> @@ -1523,7 +1524,7 @@ 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.
> >> * Called via softmmu_template.h when code areas are written to with
> >> - * tb_lock held.
> >> + * iothread mutex not held.
> >> */
> >> void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len)
> >> {
> >> @@ -1725,7 +1726,10 @@ 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)
> >> @@ -1937,6 +1941,7 @@ void dump_opcount_info(FILE *f, fprintf_function
> >> cpu_fprintf)
> >>
> >> void cpu_interrupt(CPUState *cpu, int mask)
> >> {
> >> + g_assert(qemu_mutex_iothread_locked());
> >> cpu->interrupt_request |= mask;
> >> cpu->tcg_exit_req = 1;
> >> }
> >> diff --git a/translate-common.c b/translate-common.c
> >> index 5e989cdf70..d504dd0d33 100644
> >> --- a/translate-common.c
> >> +++ b/translate-common.c
> >> @@ -21,6 +21,7 @@
> >> #include "qemu-common.h"
> >> #include "qom/cpu.h"
> >> #include "sysemu/cpus.h"
> >> +#include "qemu/main-loop.h"
> >>
> >> uintptr_t qemu_real_host_page_size;
> >> intptr_t qemu_real_host_page_mask;
> >> @@ -30,6 +31,7 @@ intptr_t qemu_real_host_page_mask;
> >> static void tcg_handle_interrupt(CPUState *cpu, int mask)
> >> {
> >> int old_mask;
> >> + g_assert(qemu_mutex_iothread_locked());
> >>
> >> old_mask = cpu->interrupt_request;
> >> cpu->interrupt_request |= mask;
> >> @@ -40,17 +42,16 @@ static void tcg_handle_interrupt(CPUState *cpu, int
> >> mask)
> >> */
> >> if (!qemu_cpu_is_self(cpu)) {
> >> qemu_cpu_kick(cpu);
> >> - return;
> >> - }
> >> -
> >> - if (use_icount) {
> >> - cpu->icount_decr.u16.high = 0xffff;
> >> - if (!cpu->can_do_io
> >> - && (mask & ~old_mask) != 0) {
> >> - cpu_abort(cpu, "Raised interrupt while not in I/O function");
> >> - }
> >> } else {
> >> - cpu->tcg_exit_req = 1;
> >> + if (use_icount) {
> >> + cpu->icount_decr.u16.high = 0xffff;
> >> + if (!cpu->can_do_io
> >> + && (mask & ~old_mask) != 0) {
> >> + cpu_abort(cpu, "Raised interrupt while not in I/O
> >> function");
> >> + }
> >> + } else {
> >> + cpu->tcg_exit_req = 1;
> >> + }
> >> }
> >> }
> >>
> >> --
> >> 2.11.0
> >>
> >>
>
>
> --
> Alex Bennée
>
--
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
- Re: [Qemu-devel] [PULL 08/24] tcg: drop global lock during TCG code execution,
Aaron Lindsay <=