diff options
Diffstat (limited to 'arch/x86/kvm/vmx/posted_intr.c')
| -rw-r--r-- | arch/x86/kvm/vmx/posted_intr.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 07e5fcf5a5aa..1b56c5e5c9fb 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -34,7 +34,7 @@ static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu) return &(to_vmx(vcpu)->pi_desc); } -static int pi_try_set_control(struct pi_desc *pi_desc, u64 old, u64 new) +static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new) { /* * PID.ON can be set at any time by a different vCPU or by hardware, @@ -42,7 +42,7 @@ static int pi_try_set_control(struct pi_desc *pi_desc, u64 old, u64 new) * update must be retried with a fresh snapshot an ON change causes * the cmpxchg to fail. */ - if (cmpxchg64(&pi_desc->control, old, new) != old) + if (!try_cmpxchg64(&pi_desc->control, pold, new)) return -EBUSY; return 0; @@ -96,8 +96,9 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) if (!x2apic_mode) dest = (dest << 8) & 0xFF00; + old.control = READ_ONCE(pi_desc->control); do { - old.control = new.control = READ_ONCE(pi_desc->control); + new.control = old.control; /* * Clear SN (as above) and refresh the destination APIC ID to @@ -111,7 +112,7 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) * descriptor was modified on "put" to use the wakeup vector. */ new.nv = POSTED_INTR_VECTOR; - } while (pi_try_set_control(pi_desc, old.control, new.control)); + } while (pi_try_set_control(pi_desc, &old.control, new.control)); local_irq_restore(flags); @@ -156,12 +157,12 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) WARN(pi_desc->sn, "PI descriptor SN field set before blocking"); + old.control = READ_ONCE(pi_desc->control); do { - old.control = new.control = READ_ONCE(pi_desc->control); - /* set 'NV' to 'wakeup vector' */ + new.control = old.control; new.nv = POSTED_INTR_WAKEUP_VECTOR; - } while (pi_try_set_control(pi_desc, old.control, new.control)); + } while (pi_try_set_control(pi_desc, &old.control, new.control)); /* * Send a wakeup IPI to this CPU if an interrupt may have been posted @@ -177,11 +178,24 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu) local_irq_restore(flags); } +static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu) +{ + /* + * The default posted interrupt vector does nothing when + * invoked outside guest mode. Return whether a blocked vCPU + * can be the target of posted interrupts, as is the case when + * using either IPI virtualization or VT-d PI, so that the + * 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); +} + void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); - if (!vmx_can_use_vtd_pi(vcpu->kvm)) + if (!vmx_needs_pi_wakeup(vcpu)) return; if (kvm_vcpu_is_blocking(vcpu) && !vmx_interrupt_blocked(vcpu)) |