diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index bde494654bcc..6a79314bc1df 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -148,6 +148,7 @@ struct kvm_vm_stat { }; struct kvm_vcpu_stat { + u32 halt_successful_poll; u32 halt_wakeup; }; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2c49aa4ac818..8efde89613f2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -165,6 +165,7 @@ struct kvm_vm_stat { }; struct kvm_vcpu_stat { + u32 halt_successful_poll; u32 halt_wakeup; }; diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index f2c249796ea8..ac4fc716062b 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -120,6 +120,7 @@ struct kvm_vcpu_stat { u32 resvd_inst_exits; u32 break_inst_exits; u32 flush_dcache_exits; + u32 halt_successful_poll; u32 halt_wakeup; }; diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index e97b90784031..c9eccf5df912 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -49,6 +49,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "resvd_inst", VCPU_STAT(resvd_inst_exits), KVM_STAT_VCPU }, { "break_inst", VCPU_STAT(break_inst_exits), KVM_STAT_VCPU }, { "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU }, + { "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU }, { "halt_wakeup", VCPU_STAT(halt_wakeup), KVM_STAT_VCPU }, {NULL} }; diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 7efd666a3fa7..8ef05121d3cd 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -107,6 +107,7 @@ struct kvm_vcpu_stat { u32 emulated_inst_exits; u32 dec_exits; u32 ext_intr_exits; + u32 halt_successful_poll; u32 halt_wakeup; u32 dbell_exits; u32 gdbell_exits; diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 888bf466d8c6..cfbcdc654201 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -52,6 +52,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "dec", VCPU_STAT(dec_exits) }, { "ext_intr", VCPU_STAT(ext_intr_exits) }, { "queue_intr", VCPU_STAT(queue_intr) }, + { "halt_successful_poll", VCPU_STAT(halt_successful_poll), }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "pf_storage", VCPU_STAT(pf_storage) }, { "sp_storage", VCPU_STAT(sp_storage) }, diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index 9b55dec2d6cc..6c1316a15a27 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -62,6 +62,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "inst_emu", VCPU_STAT(emulated_inst_exits) }, { "dec", VCPU_STAT(dec_exits) }, { "ext_intr", VCPU_STAT(ext_intr_exits) }, + { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "doorbell", VCPU_STAT(dbell_exits) }, { "guest doorbell", VCPU_STAT(gdbell_exits) }, diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index d1ecc7fd0579..f79058e3fd98 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -196,6 +196,7 @@ struct kvm_vcpu_stat { u32 exit_stop_request; u32 exit_validity; u32 exit_instruction; + u32 halt_successful_poll; u32 halt_wakeup; u32 instruction_lctl; u32 instruction_lctlg; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index b2371c0fd1f8..1dbab2340a66 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -51,6 +51,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "exit_instruction", VCPU_STAT(exit_instruction) }, { "exit_program_interruption", VCPU_STAT(exit_program_interruption) }, { "exit_instr_and_program_int", VCPU_STAT(exit_instr_and_program) }, + { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "instruction_lctlg", VCPU_STAT(instruction_lctlg) }, { "instruction_lctl", VCPU_STAT(instruction_lctl) }, diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 848947ac6ade..a236e39cc385 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -655,6 +655,7 @@ struct kvm_vcpu_stat { u32 irq_window_exits; u32 nmi_window_exits; u32 halt_exits; + u32 halt_successful_poll; u32 halt_wakeup; u32 request_irq_exits; u32 irq_exits; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1373e04e1f19..bd7a70be41b3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -145,6 +145,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "irq_window", VCPU_STAT(irq_window_exits) }, { "nmi_window", VCPU_STAT(nmi_window_exits) }, { "halt_exits", VCPU_STAT(halt_exits) }, + { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "hypercalls", VCPU_STAT(hypercalls) }, { "request_irq", VCPU_STAT(request_irq_exits) }, diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index 6edf1f2028cd..6bfe7eec1c2c 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -37,6 +37,25 @@ TRACE_EVENT(kvm_userspace_exit, __entry->errno < 0 ? -__entry->errno : __entry->reason) ); +TRACE_EVENT(kvm_vcpu_wakeup, + TP_PROTO(__u64 ns, bool waited), + TP_ARGS(ns, waited), + + TP_STRUCT__entry( + __field( __u64, ns ) + __field( bool, waited ) + ), + + TP_fast_assign( + __entry->ns = ns; + __entry->waited = waited; + ), + + TP_printk("%s time %lld ns", + __entry->waited ? "wait" : "poll", + __entry->ns) +); + #if defined(CONFIG_HAVE_KVM_IRQFD) TRACE_EVENT(kvm_set_irq, TP_PROTO(unsigned int gsi, int level, int irq_source_id), diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0c281760a1c5..32449e0e9aa8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -66,6 +66,9 @@ MODULE_AUTHOR("Qumranet"); MODULE_LICENSE("GPL"); +unsigned int halt_poll_ns = 0; +module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR); + /* * Ordering of locks: * @@ -1813,29 +1816,60 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(mark_page_dirty); +static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) +{ + if (kvm_arch_vcpu_runnable(vcpu)) { + kvm_make_request(KVM_REQ_UNHALT, vcpu); + return -EINTR; + } + if (kvm_cpu_has_pending_timer(vcpu)) + return -EINTR; + if (signal_pending(current)) + return -EINTR; + + return 0; +} + /* * The vCPU has executed a HLT instruction with in-kernel mode enabled. */ void kvm_vcpu_block(struct kvm_vcpu *vcpu) { + ktime_t start, cur; DEFINE_WAIT(wait); + bool waited = false; + + start = cur = ktime_get(); + if (halt_poll_ns) { + ktime_t stop = ktime_add_ns(ktime_get(), halt_poll_ns); + do { + /* + * This sets KVM_REQ_UNHALT if an interrupt + * arrives. + */ + if (kvm_vcpu_check_block(vcpu) < 0) { + ++vcpu->stat.halt_successful_poll; + goto out; + } + cur = ktime_get(); + } while (single_task_running() && ktime_before(cur, stop)); + } for (;;) { prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE); - if (kvm_arch_vcpu_runnable(vcpu)) { - kvm_make_request(KVM_REQ_UNHALT, vcpu); - break; - } - if (kvm_cpu_has_pending_timer(vcpu)) - break; - if (signal_pending(current)) + if (kvm_vcpu_check_block(vcpu) < 0) break; + waited = true; schedule(); } finish_wait(&vcpu->wq, &wait); + cur = ktime_get(); + +out: + trace_kvm_vcpu_wakeup(ktime_to_ns(cur) - ktime_to_ns(start), waited); } EXPORT_SYMBOL_GPL(kvm_vcpu_block);