diff options
Diffstat (limited to 'arch/x86/kvm/vmx/posted_intr.c')
| -rw-r--r-- | arch/x86/kvm/vmx/posted_intr.c | 93 |
1 files changed, 56 insertions, 37 deletions
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index ec08fa3caf43..99d1d599ff8c 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -11,6 +11,7 @@ #include "posted_intr.h" #include "trace.h" #include "vmx.h" +#include "tdx.h" /* * Maintain a per-CPU list of vCPUs that need to be awakened by wakeup_handler() @@ -31,9 +32,11 @@ static DEFINE_PER_CPU(struct list_head, wakeup_vcpus_on_cpu); */ static DEFINE_PER_CPU(raw_spinlock_t, wakeup_vcpus_on_cpu_lock); -static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu) +#define PI_LOCK_SCHED_OUT SINGLE_DEPTH_NESTING + +struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu) { - return &(to_vmx(vcpu)->pi_desc); + return &(to_vt(vcpu)->pi_desc); } static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new) @@ -53,7 +56,7 @@ static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new) void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); - struct vcpu_vmx *vmx = to_vmx(vcpu); + struct vcpu_vt *vt = to_vt(vcpu); struct pi_desc old, new; unsigned long flags; unsigned int dest; @@ -89,9 +92,20 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) * current pCPU if the task was migrated. */ if (pi_desc->nv == POSTED_INTR_WAKEUP_VECTOR) { - raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); - list_del(&vmx->pi_wakeup_list); - raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); + raw_spinlock_t *spinlock = &per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu); + + /* + * In addition to taking the wakeup lock for the regular/IRQ + * context, tell lockdep it is being taken for the "sched out" + * context as well. vCPU loads happens in task context, and + * this is taking the lock of the *previous* CPU, i.e. can race + * with both the scheduler and the wakeup handler. + */ + raw_spin_lock(spinlock); + spin_acquire(&spinlock->dep_map, PI_LOCK_SCHED_OUT, 0, _RET_IP_); + list_del(&vt->pi_wakeup_list); + spin_release(&spinlock->dep_map, _RET_IP_); + raw_spin_unlock(spinlock); } dest = cpu_physical_id(cpu); @@ -146,14 +160,26 @@ static bool vmx_can_use_vtd_pi(struct kvm *kvm) static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); - struct vcpu_vmx *vmx = to_vmx(vcpu); + struct vcpu_vt *vt = to_vt(vcpu); struct pi_desc old, new; - unsigned long flags; - local_irq_save(flags); + lockdep_assert_irqs_disabled(); - raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); - list_add_tail(&vmx->pi_wakeup_list, + /* + * Acquire the wakeup lock using the "sched out" context to workaround + * a lockdep false positive. When this is called, schedule() holds + * various per-CPU scheduler locks. When the wakeup handler runs, it + * holds this CPU's wakeup lock while calling try_to_wake_up(), which + * can eventually take the aforementioned scheduler locks, which causes + * lockdep to assume there is deadlock. + * + * Deadlock can't actually occur because IRQs are disabled for the + * entirety of the sched_out critical section, i.e. the wakeup handler + * can't run while the scheduler locks are held. + */ + raw_spin_lock_nested(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu), + PI_LOCK_SCHED_OUT); + list_add_tail(&vt->pi_wakeup_list, &per_cpu(wakeup_vcpus_on_cpu, vcpu->cpu)); raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu)); @@ -176,8 +202,6 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) */ if (pi_test_on(&new)) __apic_send_IPI_self(POSTED_INTR_WAKEUP_VECTOR); - - local_irq_restore(flags); } static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu) @@ -190,7 +214,8 @@ static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu) * notification vector is switched to the one that calls * back to the pi_wakeup_handler() function. */ - return vmx_can_use_ipiv(vcpu) || vmx_can_use_vtd_pi(vcpu->kvm); + return (vmx_can_use_ipiv(vcpu) && !is_td_vcpu(vcpu)) || + vmx_can_use_vtd_pi(vcpu->kvm); } void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) @@ -200,7 +225,9 @@ void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) if (!vmx_needs_pi_wakeup(vcpu)) return; - if (kvm_vcpu_is_blocking(vcpu) && !vmx_interrupt_blocked(vcpu)) + if (kvm_vcpu_is_blocking(vcpu) && + ((is_td_vcpu(vcpu) && tdx_interrupt_allowed(vcpu)) || + (!is_td_vcpu(vcpu) && !vmx_interrupt_blocked(vcpu)))) pi_enable_wakeup_handler(vcpu); /* @@ -220,13 +247,13 @@ void pi_wakeup_handler(void) int cpu = smp_processor_id(); struct list_head *wakeup_list = &per_cpu(wakeup_vcpus_on_cpu, cpu); raw_spinlock_t *spinlock = &per_cpu(wakeup_vcpus_on_cpu_lock, cpu); - struct vcpu_vmx *vmx; + struct vcpu_vt *vt; raw_spin_lock(spinlock); - list_for_each_entry(vmx, wakeup_list, pi_wakeup_list) { + list_for_each_entry(vt, wakeup_list, pi_wakeup_list) { - if (pi_test_on(&vmx->pi_desc)) - kvm_vcpu_wake_up(&vmx->vcpu); + if (pi_test_on(&vt->pi_desc)) + kvm_vcpu_wake_up(vt_to_vcpu(vt)); } raw_spin_unlock(spinlock); } @@ -274,6 +301,7 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, { struct kvm_kernel_irq_routing_entry *e; struct kvm_irq_routing_table *irq_rt; + bool enable_remapped_mode = true; struct kvm_lapic_irq irq; struct kvm_vcpu *vcpu; struct vcpu_data vcpu_info; @@ -312,21 +340,8 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, kvm_set_msi_irq(kvm, e, &irq); if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu) || - !kvm_irq_is_postable(&irq)) { - /* - * Make sure the IRTE is in remapped mode if - * we don't handle it in posted mode. - */ - ret = irq_set_vcpu_affinity(host_irq, NULL); - if (ret < 0) { - printk(KERN_INFO - "failed to back to remapped mode, irq: %u\n", - host_irq); - goto out; - } - + !kvm_irq_is_postable(&irq)) continue; - } vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)); vcpu_info.vector = irq.vector; @@ -334,11 +349,12 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id, e->gsi, vcpu_info.vector, vcpu_info.pi_desc_addr, set); - if (set) - ret = irq_set_vcpu_affinity(host_irq, &vcpu_info); - else - ret = irq_set_vcpu_affinity(host_irq, NULL); + if (!set) + continue; + + enable_remapped_mode = false; + ret = irq_set_vcpu_affinity(host_irq, &vcpu_info); if (ret < 0) { printk(KERN_INFO "%s: failed to update PI IRTE\n", __func__); @@ -346,6 +362,9 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, } } + if (enable_remapped_mode) + ret = irq_set_vcpu_affinity(host_irq, NULL); + ret = 0; out: srcu_read_unlock(&kvm->irq_srcu, idx); |