This patch updates the Posted-Interrupts Descriptor when vCPU is blocked. pre-block: - Add the vCPU to the blocked per-CPU list - Clear 'SN' - Set 'NV' to POSTED_INTR_WAKEUP_VECTOR
post-block: - Remove the vCPU from the per-CPU list Signed-off-by: Feng Wu <[email protected]> --- arch/x86/include/asm/kvm_host.h | 2 + arch/x86/kvm/vmx.c | 96 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 22 +++++++--- include/linux/kvm_host.h | 4 ++ virt/kvm/kvm_main.c | 6 +++ 5 files changed, 123 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 13e3e40..32c110a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -101,6 +101,8 @@ static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level) #define ASYNC_PF_PER_VCPU 64 +extern void (*wakeup_handler_callback)(void); + enum kvm_reg { VCPU_REGS_RAX = 0, VCPU_REGS_RCX = 1, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index bf2e6cd..a1c83a2 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -832,6 +832,13 @@ static DEFINE_PER_CPU(struct vmcs *, current_vmcs); static DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu); static DEFINE_PER_CPU(struct desc_ptr, host_gdt); +/* + * We maintian a per-CPU linked-list of vCPU, so in wakeup_handler() we + * can find which vCPU should be waken up. + */ +static DEFINE_PER_CPU(struct list_head, blocked_vcpu_on_cpu); +static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock); + static unsigned long *vmx_io_bitmap_a; static unsigned long *vmx_io_bitmap_b; static unsigned long *vmx_msr_bitmap_legacy; @@ -1921,6 +1928,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); struct pi_desc old, new; unsigned int dest; + unsigned long flags; memset(&old, 0, sizeof(old)); memset(&new, 0, sizeof(new)); @@ -1942,6 +1950,20 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) new.nv = POSTED_INTR_VECTOR; } while (cmpxchg(&pi_desc->control, old.control, new.control) != old.control); + + /* + * Delete the vCPU from the related wakeup queue + * if we are resuming from blocked state + */ + if (vcpu->blocked) { + vcpu->blocked = false; + spin_lock_irqsave(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->wakeup_cpu), flags); + list_del(&vcpu->blocked_vcpu_list); + spin_unlock_irqrestore(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->wakeup_cpu), flags); + vcpu->wakeup_cpu = -1; + } } } @@ -1950,6 +1972,9 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu) if (irq_remapping_cap(IRQ_POSTING_CAP)) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); struct pi_desc old, new; + unsigned long flags; + int cpu; + struct cpumask cpu_others_mask; memset(&old, 0, sizeof(old)); memset(&new, 0, sizeof(new)); @@ -1961,6 +1986,54 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu) pi_set_sn(&new); } while (cmpxchg(&pi_desc->control, old.control, new.control) != old.control); + } else if (vcpu->blocked) { + /* + * The vcpu is blocked on the wait queue. + * Store the blocked vCPU on the list of the + * vcpu->wakeup_cpu, which is the destination + * of the wake-up notification event. + */ + vcpu->wakeup_cpu = vcpu->cpu; + spin_lock_irqsave(&per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->wakeup_cpu), flags); + list_add_tail(&vcpu->blocked_vcpu_list, + &per_cpu(blocked_vcpu_on_cpu, + vcpu->wakeup_cpu)); + spin_unlock_irqrestore( + &per_cpu(blocked_vcpu_on_cpu_lock, + vcpu->wakeup_cpu), flags); + + do { + old.control = new.control = pi_desc->control; + + /* + * We should not block the vCPU if + * an interrupt is posted for it. + */ + if (pi_test_on(pi_desc) == 1) { + /* + * We need schedule the wakeup worker + * on a different cpu other than + * vcpu->cpu, because in some case, + * schedule_work() will call + * try_to_wake_up() which needs acquire + * the rq lock. This can cause deadlock. + */ + cpumask_copy(&cpu_others_mask, + cpu_online_mask); + cpu_clear(vcpu->cpu, cpu_others_mask); + cpu = any_online_cpu(cpu_others_mask); + + schedule_work_on(cpu, + &vcpu->wakeup_worker); + } + + pi_clear_sn(&new); + + /* set 'NV' to 'wakeup vector' */ + new.nv = POSTED_INTR_WAKEUP_VECTOR; + } while (cmpxchg(&pi_desc->control, old.control, + new.control) != old.control); } } @@ -2842,6 +2915,8 @@ static int hardware_enable(void) return -EBUSY; INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); + INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu)); + spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); /* * Now we can enable the vmclear operation in kdump @@ -9315,6 +9390,25 @@ static struct kvm_x86_ops vmx_x86_ops = { .pi_set_sn = vmx_pi_set_sn, }; +/* + * Handler for POSTED_INTERRUPT_WAKEUP_VECTOR. + */ +void wakeup_handler(void) +{ + struct kvm_vcpu *vcpu; + int cpu = smp_processor_id(); + + spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + list_for_each_entry(vcpu, &per_cpu(blocked_vcpu_on_cpu, cpu), + blocked_vcpu_list) { + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); + + if (pi_test_on(pi_desc) == 1) + kvm_vcpu_kick(vcpu); + } + spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); +} + static int __init vmx_init(void) { int r, i, msr; @@ -9429,6 +9523,8 @@ static int __init vmx_init(void) update_ple_window_actual_max(); + wakeup_handler_callback = wakeup_handler; + return 0; out7: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0033df3..1551a46 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6152,6 +6152,21 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_vcpu_reload_apic_access_page(vcpu); } + /* + * Since posted-interrupts can be set by VT-d HW now, in this + * case, KVM_REQ_EVENT is not set. We move the following + * operations out of the if statement. + */ + if (kvm_lapic_enabled(vcpu)) { + /* + * Update architecture specific hints for APIC + * virtual interrupt delivery. + */ + if (kvm_x86_ops->hwapic_irr_update) + kvm_x86_ops->hwapic_irr_update(vcpu, + kvm_lapic_find_highest_irr(vcpu)); + } + if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { kvm_apic_accept_events(vcpu); if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { @@ -6168,13 +6183,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_x86_ops->enable_irq_window(vcpu); if (kvm_lapic_enabled(vcpu)) { - /* - * Update architecture specific hints for APIC - * virtual interrupt delivery. - */ - if (kvm_x86_ops->hwapic_irr_update) - kvm_x86_ops->hwapic_irr_update(vcpu, - kvm_lapic_find_highest_irr(vcpu)); update_cr8_intercept(vcpu); kvm_lapic_sync_to_vapic(vcpu); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3d7242c..d981d16 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -239,6 +239,9 @@ struct kvm_vcpu { unsigned long requests; unsigned long guest_debug; + int wakeup_cpu; + struct list_head blocked_vcpu_list; + struct mutex mutex; struct kvm_run *run; @@ -282,6 +285,7 @@ struct kvm_vcpu { } spin_loop; #endif bool preempted; + bool blocked; struct kvm_vcpu_arch arch; }; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ba53fd6..6deb994 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -233,6 +233,9 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) INIT_WORK(&vcpu->wakeup_worker, wakeup_thread); + vcpu->wakeup_cpu = -1; + INIT_LIST_HEAD(&vcpu->blocked_vcpu_list); + page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) { r = -ENOMEM; @@ -243,6 +246,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) kvm_vcpu_set_in_spin_loop(vcpu, false); kvm_vcpu_set_dy_eligible(vcpu, false); vcpu->preempted = false; + vcpu->blocked = false; r = kvm_arch_vcpu_init(vcpu); if (r < 0) @@ -1752,6 +1756,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) DEFINE_WAIT(wait); for (;;) { + vcpu->blocked = true; prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE); if (kvm_arch_vcpu_runnable(vcpu)) { @@ -1767,6 +1772,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) } finish_wait(&vcpu->wq, &wait); + vcpu->blocked = false; } EXPORT_SYMBOL_GPL(kvm_vcpu_block); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
