From d7c5cb0105ddeff56694f4c6222ee7221824bad3 Mon Sep 17 00:00:00 2001 From: Michael Mueller Date: Mon, 12 Jun 2017 14:15:19 +0200 Subject: [PATCH] KVM: s390: exploit GISA and AIV for emulated interrupts The adapter interruption virtualization (AIV) facility is an optional facility that comes with functionality expected to increase the performance of adapter interrupt handling for both emulated and passed-through adapter interrupts. With AIV, adapter interrupts can be delivered to the guest without exiting SIE. This patch provides some preparations for using AIV for emulated adapter interrupts (including virtio) if it's available. When using AIV, the interrupts are delivered at the so called GISA by setting the bit corresponding to its Interruption Subclass (ISC) in the Interruption Pending Mask (IPM) instead of inserting a node into the floating interrupt list. To keep the change reasonably small, the handling of this new state is deferred in get_all_floating_irqs and handle_tpi. This patch concentrates on the code handling enqueuement of emulated adapter interrupts, and their delivery to the guest. Note that care is still required for adapter interrupts using AIV, because there is no guarantee that AIV is going to deliver the adapter interrupts pending at the GISA (consider all vcpus idle). When delivering GISA adapter interrupts by the host (usual mechanism) special attention is required to honor interrupt priorities. Empirical results show that the time window between making an interrupt pending at the GISA and doing kvm_s390_deliver_pending_interrupts is sufficient for a guest with at least moderate cpu activity to get adapter interrupts delivered within the SIE, and potentially save some SIE exits (if not other deliverable interrupts). The code will be activated with a follow-up patch. Signed-off-by: Michael Mueller Acked-by: Christian Borntraeger Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/interrupt.c | 93 +++++++++++++++++++++++++------- arch/s390/kvm/kvm-s390.c | 8 +++ arch/s390/kvm/kvm-s390.h | 3 ++ 4 files changed, 87 insertions(+), 18 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 4f89b2783512..76d6f0ef3dbd 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -785,6 +785,7 @@ struct kvm_arch{ struct kvm_s390_migration_state *migration_state; /* subset of available cpu features enabled by user space */ DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); + struct kvm_s390_gisa *gisa; }; #define KVM_HVA_ERR_BAD (-1UL) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 8985ce51f687..f293c956e6db 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -234,7 +234,8 @@ static inline int kvm_s390_gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gis static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu) { return vcpu->kvm->arch.float_int.pending_irqs | - vcpu->arch.local_int.pending_irqs; + vcpu->arch.local_int.pending_irqs | + kvm_s390_gisa_get_ipm(vcpu->kvm->arch.gisa) << IRQ_PEND_IO_ISC_7; } static inline int isc_to_irq_type(unsigned long isc) @@ -919,18 +920,38 @@ static int __must_check __deliver_virtio(struct kvm_vcpu *vcpu) return rc ? -EFAULT : 0; } +static int __do_deliver_io(struct kvm_vcpu *vcpu, struct kvm_s390_io_info *io) +{ + int rc; + + rc = put_guest_lc(vcpu, io->subchannel_id, (u16 *)__LC_SUBCHANNEL_ID); + rc |= put_guest_lc(vcpu, io->subchannel_nr, (u16 *)__LC_SUBCHANNEL_NR); + rc |= put_guest_lc(vcpu, io->io_int_parm, (u32 *)__LC_IO_INT_PARM); + rc |= put_guest_lc(vcpu, io->io_int_word, (u32 *)__LC_IO_INT_WORD); + rc |= write_guest_lc(vcpu, __LC_IO_OLD_PSW, + &vcpu->arch.sie_block->gpsw, + sizeof(psw_t)); + rc |= read_guest_lc(vcpu, __LC_IO_NEW_PSW, + &vcpu->arch.sie_block->gpsw, + sizeof(psw_t)); + return rc ? -EFAULT : 0; +} + static int __must_check __deliver_io(struct kvm_vcpu *vcpu, unsigned long irq_type) { struct list_head *isc_list; struct kvm_s390_float_interrupt *fi; struct kvm_s390_interrupt_info *inti = NULL; + struct kvm_s390_io_info io; + u32 isc; int rc = 0; fi = &vcpu->kvm->arch.float_int; spin_lock(&fi->lock); - isc_list = &fi->lists[irq_type_to_isc(irq_type)]; + isc = irq_type_to_isc(irq_type); + isc_list = &fi->lists[isc]; inti = list_first_entry_or_null(isc_list, struct kvm_s390_interrupt_info, list); @@ -958,24 +979,31 @@ static int __must_check __deliver_io(struct kvm_vcpu *vcpu, spin_unlock(&fi->lock); if (inti) { - rc = put_guest_lc(vcpu, inti->io.subchannel_id, - (u16 *)__LC_SUBCHANNEL_ID); - rc |= put_guest_lc(vcpu, inti->io.subchannel_nr, - (u16 *)__LC_SUBCHANNEL_NR); - rc |= put_guest_lc(vcpu, inti->io.io_int_parm, - (u32 *)__LC_IO_INT_PARM); - rc |= put_guest_lc(vcpu, inti->io.io_int_word, - (u32 *)__LC_IO_INT_WORD); - rc |= write_guest_lc(vcpu, __LC_IO_OLD_PSW, - &vcpu->arch.sie_block->gpsw, - sizeof(psw_t)); - rc |= read_guest_lc(vcpu, __LC_IO_NEW_PSW, - &vcpu->arch.sie_block->gpsw, - sizeof(psw_t)); + rc = __do_deliver_io(vcpu, &(inti->io)); kfree(inti); + goto out; } - return rc ? -EFAULT : 0; + if (vcpu->kvm->arch.gisa && + kvm_s390_gisa_tac_ipm_gisc(vcpu->kvm->arch.gisa, isc)) { + /* + * in case an adapter interrupt was not delivered + * in SIE context KVM will handle the delivery + */ + VCPU_EVENT(vcpu, 4, "%s isc %u", "deliver: I/O (AI/gisa)", isc); + memset(&io, 0, sizeof(io)); + io.io_int_word = (isc << 27) | 0x80000000; + vcpu->stat.deliver_io_int++; + trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, + KVM_S390_INT_IO(1, 0, 0, 0), + ((__u32)io.subchannel_id << 16) | + io.subchannel_nr, + ((__u64)io.io_int_parm << 32) | + io.io_int_word); + rc = __do_deliver_io(vcpu, &io); + } +out: + return rc; } typedef int (*deliver_irq_t)(struct kvm_vcpu *vcpu); @@ -1539,6 +1567,15 @@ static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti) struct list_head *list; int isc; + isc = int_word_to_isc(inti->io.io_int_word); + + if (kvm->arch.gisa && inti->type & KVM_S390_INT_IO_AI_MASK) { + VM_EVENT(kvm, 4, "%s isc %1u", "inject: I/O (AI/gisa)", isc); + kvm_s390_gisa_set_ipm_gisc(kvm->arch.gisa, isc); + kfree(inti); + return 0; + } + fi = &kvm->arch.float_int; spin_lock(&fi->lock); if (fi->counters[FIRQ_CNTR_IO] >= KVM_S390_MAX_FLOAT_IRQS) { @@ -1554,7 +1591,6 @@ static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti) inti->io.subchannel_id >> 8, inti->io.subchannel_id >> 1 & 0x3, inti->io.subchannel_nr); - isc = int_word_to_isc(inti->io.io_int_word); list = &fi->lists[FIRQ_LIST_IO_ISC_0 + isc]; list_add_tail(&inti->list, list); set_bit(isc_to_irq_type(isc), &fi->pending_irqs); @@ -2705,3 +2741,24 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len) return n; } + +void kvm_s390_gisa_clear(struct kvm *kvm) +{ + if (kvm->arch.gisa) { + memset(kvm->arch.gisa, 0, sizeof(struct kvm_s390_gisa)); + kvm->arch.gisa->next_alert = (u32)(u64)kvm->arch.gisa; + VM_EVENT(kvm, 3, "gisa 0x%pK cleared", kvm->arch.gisa); + } +} + +void kvm_s390_gisa_init(struct kvm *kvm) +{ + /* not implemented yet */ +} + +void kvm_s390_gisa_destroy(struct kvm *kvm) +{ + if (!kvm->arch.gisa) + return; + kvm->arch.gisa = NULL; +} diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2fbdb1601089..2c5e25b39435 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1999,6 +1999,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) spin_lock_init(&kvm->arch.start_stop_lock); kvm_s390_vsie_init(kvm); + kvm_s390_gisa_init(kvm); KVM_EVENT(3, "vm 0x%pK created by pid %u", kvm, current->pid); return 0; @@ -2061,6 +2062,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm) kvm_free_vcpus(kvm); sca_dispose(kvm); debug_unregister(kvm->arch.dbf); + kvm_s390_gisa_destroy(kvm); free_page((unsigned long)kvm->arch.sie_page2); if (!kvm_is_ucontrol(kvm)) gmap_remove(kvm->arch.gmap); @@ -2471,6 +2473,11 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) if (test_kvm_facility(vcpu->kvm, 139)) vcpu->arch.sie_block->ecd |= ECD_MEF; + if (vcpu->arch.sie_block->gd) { + vcpu->arch.sie_block->eca |= ECA_AIV; + VCPU_EVENT(vcpu, 3, "AIV gisa format-%u enabled for cpu %03u", + vcpu->arch.sie_block->gd & 0x3, vcpu->vcpu_id); + } vcpu->arch.sie_block->sdnxo = ((unsigned long) &vcpu->run->s.regs.sdnx) | SDNXC; vcpu->arch.sie_block->riccbd = (unsigned long) &vcpu->run->s.regs.riccb; @@ -2523,6 +2530,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, vcpu->arch.sie_block->icpua = id; spin_lock_init(&vcpu->arch.local_int.lock); + vcpu->arch.sie_block->gd = (u32)(u64)kvm->arch.gisa; seqcount_init(&vcpu->arch.cputm_seqcount); rc = kvm_vcpu_init(vcpu, kvm, id); diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index f110fa96807e..bd31b37b0e6f 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -382,6 +382,9 @@ int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu, void __user *buf, int len); int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len); +void kvm_s390_gisa_init(struct kvm *kvm); +void kvm_s390_gisa_clear(struct kvm *kvm); +void kvm_s390_gisa_destroy(struct kvm *kvm); /* implemented in guestdbg.c */ void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu); -- 2.30.2