diff options
| -rw-r--r-- | accel/kvm/kvm-all.c | 79 | ||||
| -rw-r--r-- | accel/kvm/trace-events | 1 | ||||
| -rw-r--r-- | hw/intc/ioapic.c | 19 | ||||
| -rw-r--r-- | include/sysemu/kvm.h | 4 |
4 files changed, 101 insertions, 2 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index b048c10af9..f24d7da783 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -160,9 +160,59 @@ static const KVMCapabilityInfo kvm_required_capabilites[] = { static NotifierList kvm_irqchip_change_notifiers = NOTIFIER_LIST_INITIALIZER(kvm_irqchip_change_notifiers); +struct KVMResampleFd { + int gsi; + EventNotifier *resample_event; + QLIST_ENTRY(KVMResampleFd) node; +}; +typedef struct KVMResampleFd KVMResampleFd; + +/* + * Only used with split irqchip where we need to do the resample fd + * kick for the kernel from userspace. + */ +static QLIST_HEAD(, KVMResampleFd) kvm_resample_fd_list = + QLIST_HEAD_INITIALIZER(kvm_resample_fd_list); + #define kvm_slots_lock(kml) qemu_mutex_lock(&(kml)->slots_lock) #define kvm_slots_unlock(kml) qemu_mutex_unlock(&(kml)->slots_lock) +static inline void kvm_resample_fd_remove(int gsi) +{ + KVMResampleFd *rfd; + + QLIST_FOREACH(rfd, &kvm_resample_fd_list, node) { + if (rfd->gsi == gsi) { + QLIST_REMOVE(rfd, node); + g_free(rfd); + break; + } + } +} + +static inline void kvm_resample_fd_insert(int gsi, EventNotifier *event) +{ + KVMResampleFd *rfd = g_new0(KVMResampleFd, 1); + + rfd->gsi = gsi; + rfd->resample_event = event; + + QLIST_INSERT_HEAD(&kvm_resample_fd_list, rfd, node); +} + +void kvm_resample_fd_notify(int gsi) +{ + KVMResampleFd *rfd; + + QLIST_FOREACH(rfd, &kvm_resample_fd_list, node) { + if (rfd->gsi == gsi) { + event_notifier_set(rfd->resample_event); + trace_kvm_resample_fd_notify(gsi); + return; + } + } +} + int kvm_get_max_memslots(void) { KVMState *s = KVM_STATE(current_accel()); @@ -1676,8 +1726,33 @@ static int kvm_irqchip_assign_irqfd(KVMState *s, EventNotifier *event, }; if (rfd != -1) { - irqfd.flags |= KVM_IRQFD_FLAG_RESAMPLE; - irqfd.resamplefd = rfd; + assert(assign); + if (kvm_irqchip_is_split()) { + /* + * When the slow irqchip (e.g. IOAPIC) is in the + * userspace, KVM kernel resamplefd will not work because + * the EOI of the interrupt will be delivered to userspace + * instead, so the KVM kernel resamplefd kick will be + * skipped. The userspace here mimics what the kernel + * provides with resamplefd, remember the resamplefd and + * kick it when we receive EOI of this IRQ. + * + * This is hackery because IOAPIC is mostly bypassed + * (except EOI broadcasts) when irqfd is used. However + * this can bring much performance back for split irqchip + * with INTx IRQs (for VFIO, this gives 93% perf of the + * full fast path, which is 46% perf boost comparing to + * the INTx slow path). + */ + kvm_resample_fd_insert(virq, resample); + } else { + irqfd.flags |= KVM_IRQFD_FLAG_RESAMPLE; + irqfd.resamplefd = rfd; + } + } else if (!assign) { + if (kvm_irqchip_is_split()) { + kvm_resample_fd_remove(virq); + } } if (!kvm_irqfds_enabled()) { diff --git a/accel/kvm/trace-events b/accel/kvm/trace-events index 4fb6e59d19..a68eb66534 100644 --- a/accel/kvm/trace-events +++ b/accel/kvm/trace-events @@ -16,4 +16,5 @@ kvm_set_ioeventfd_mmio(int fd, uint64_t addr, uint32_t val, bool assign, uint32_ kvm_set_ioeventfd_pio(int fd, uint16_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%x val=0x%x assign: %d size: %d match: %d" kvm_set_user_memory(uint32_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, int ret) "Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " ret=%d" kvm_clear_dirty_log(uint32_t slot, uint64_t start, uint32_t size) "slot#%"PRId32" start 0x%"PRIx64" size 0x%"PRIx32 +kvm_resample_fd_notify(int gsi) "gsi %d" diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c index ffe30dc457..bca71b5934 100644 --- a/hw/intc/ioapic.c +++ b/hw/intc/ioapic.c @@ -241,6 +241,25 @@ void ioapic_eoi_broadcast(int vector) continue; } +#ifdef CONFIG_KVM + /* + * When IOAPIC is in the userspace while APIC is still in + * the kernel (i.e., split irqchip), we have a trick to + * kick the resamplefd logic for registered irqfds from + * userspace to deactivate the IRQ. When that happens, it + * means the irq bypassed userspace IOAPIC (so the irr and + * remote-irr of the table entry should be bypassed too + * even if interrupt come). Still kick the resamplefds if + * they're bound to the IRQ, to make sure to EOI the + * interrupt for the hardware correctly. + * + * Note: We still need to go through the irr & remote-irr + * operations below because we don't know whether there're + * emulated devices that are using/sharing the same IRQ. + */ + kvm_resample_fd_notify(n); +#endif + if (!(entry & IOAPIC_LVT_REMOTE_IRR)) { continue; } diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 3b2250471c..b4174d941c 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -554,4 +554,8 @@ int kvm_set_one_reg(CPUState *cs, uint64_t id, void *source); int kvm_get_one_reg(CPUState *cs, uint64_t id, void *target); struct ppc_radix_page_info *kvm_get_radix_page_info(void); int kvm_get_max_memslots(void); + +/* Notify resamplefd for EOI of specific interrupts. */ +void kvm_resample_fd_notify(int gsi); + #endif |