From 01f218803757c9ec1152ac2fd39d03c27c452634 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 17 Oct 2012 18:06:02 +0200 Subject: [PATCH] kvm: add kvm_set_irq_inatomic Add an API to inject IRQ from atomic context. Return EWOULDBLOCK if impossible (e.g. for multicast). Only MSI is supported ATM. Signed-off-by: Michael S. Tsirkin Signed-off-by: Gleb Natapov --- include/linux/kvm_host.h | 1 + virt/kvm/irq_comm.c | 83 ++++++++++++++++++++++++++++++++++------ 2 files changed, 72 insertions(+), 12 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 8e5c7b651655..36c3704bfa7c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -693,6 +693,7 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic, unsigned long *deliver_bitmask); #endif int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level); +int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level); int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm, int irq_source_id, int level); void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin); diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c index 2eb58af7ee99..656fa455e154 100644 --- a/virt/kvm/irq_comm.c +++ b/virt/kvm/irq_comm.c @@ -102,6 +102,23 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, return r; } +static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e, + struct kvm_lapic_irq *irq) +{ + trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data); + + irq->dest_id = (e->msi.address_lo & + MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT; + irq->vector = (e->msi.data & + MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT; + irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo; + irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data; + irq->delivery_mode = e->msi.data & 0x700; + irq->level = 1; + irq->shorthand = 0; + /* TODO Deal with RH bit of MSI message address */ +} + int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, int irq_source_id, int level) { @@ -110,22 +127,26 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, if (!level) return -1; - trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data); + kvm_set_msi_irq(e, &irq); - irq.dest_id = (e->msi.address_lo & - MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT; - irq.vector = (e->msi.data & - MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT; - irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo; - irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data; - irq.delivery_mode = e->msi.data & 0x700; - irq.level = 1; - irq.shorthand = 0; - - /* TODO Deal with RH bit of MSI message address */ return kvm_irq_delivery_to_apic(kvm, NULL, &irq); } + +static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e, + struct kvm *kvm) +{ + struct kvm_lapic_irq irq; + int r; + + kvm_set_msi_irq(e, &irq); + + if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r)) + return r; + else + return -EWOULDBLOCK; +} + int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi) { struct kvm_kernel_irq_routing_entry route; @@ -178,6 +199,44 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level) return ret; } +/* + * Deliver an IRQ in an atomic context if we can, or return a failure, + * user can retry in a process context. + * Return value: + * -EWOULDBLOCK - Can't deliver in atomic context: retry in a process context. + * Other values - No need to retry. + */ +int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level) +{ + struct kvm_kernel_irq_routing_entry *e; + int ret = -EINVAL; + struct kvm_irq_routing_table *irq_rt; + struct hlist_node *n; + + trace_kvm_set_irq(irq, level, irq_source_id); + + /* + * Injection into either PIC or IOAPIC might need to scan all CPUs, + * which would need to be retried from thread context; when same GSI + * is connected to both PIC and IOAPIC, we'd have to report a + * partial failure here. + * Since there's no easy way to do this, we only support injecting MSI + * which is limited to 1:1 GSI mapping. + */ + rcu_read_lock(); + irq_rt = rcu_dereference(kvm->irq_routing); + if (irq < irq_rt->nr_rt_entries) + hlist_for_each_entry(e, n, &irq_rt->map[irq], link) { + if (likely(e->type == KVM_IRQ_ROUTING_MSI)) + ret = kvm_set_msi_inatomic(e, kvm); + else + ret = -EWOULDBLOCK; + break; + } + rcu_read_unlock(); + return ret; +} + void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) { struct kvm_irq_ack_notifier *kian; -- GitLab