From 9f30f62163786a0b80e0886046b5c66e714e7e71 Mon Sep 17 00:00:00 2001 From: Michael Mueller Date: Thu, 31 Jan 2019 09:52:44 +0100 Subject: KVM: s390: add gib_alert_irq_handler() The patch implements a handler for GIB alert interruptions on the host. Its task is to alert guests that interrupts are pending for them. A GIB alert interrupt statistic counter is added as well: $ cat /proc/interrupts CPU0 CPU1 ... GAL: 23 37 [I/O] GIB Alert ... Signed-off-by: Michael Mueller Acked-by: Halil Pasic Reviewed-by: Pierre Morel Message-Id: <20190131085247.13826-14-mimu@linux.ibm.com> Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/irq.h | 1 + arch/s390/include/asm/isc.h | 1 + arch/s390/include/asm/kvm_host.h | 3 + arch/s390/kernel/irq.c | 1 + arch/s390/kvm/interrupt.c | 169 ++++++++++++++++++++++++++++++++++++++- arch/s390/kvm/kvm-s390.c | 2 + 6 files changed, 175 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h index 2f7f27e5493f..afaf5e3c57fd 100644 --- a/arch/s390/include/asm/irq.h +++ b/arch/s390/include/asm/irq.h @@ -62,6 +62,7 @@ enum interruption_class { IRQIO_MSI, IRQIO_VIR, IRQIO_VAI, + IRQIO_GAL, NMI_NMI, CPU_RST, NR_ARCH_IRQS diff --git a/arch/s390/include/asm/isc.h b/arch/s390/include/asm/isc.h index 6cb9e2ed05b6..b2cc1ec78d06 100644 --- a/arch/s390/include/asm/isc.h +++ b/arch/s390/include/asm/isc.h @@ -21,6 +21,7 @@ /* Adapter interrupts. */ #define QDIO_AIRQ_ISC IO_SCH_ISC /* I/O subchannel in qdio mode */ #define PCI_ISC 2 /* PCI I/O subchannels */ +#define GAL_ISC 5 /* GIB alert */ #define AP_ISC 6 /* adjunct processor (crypto) devices */ /* Functions for registration of I/O interruption subclasses */ diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 2cfff617cb21..c5f51566ecd6 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -825,6 +825,9 @@ struct kvm_s390_gisa_iam { struct kvm_s390_gisa_interrupt { struct kvm_s390_gisa *origin; struct kvm_s390_gisa_iam alert; + struct hrtimer timer; + u64 expires; + DECLARE_BITMAP(kicked_mask, KVM_MAX_VCPUS); }; struct kvm_arch{ diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c index 0e8d68bac82c..0cd5a5f96729 100644 --- a/arch/s390/kernel/irq.c +++ b/arch/s390/kernel/irq.c @@ -88,6 +88,7 @@ static const struct irq_class irqclass_sub_desc[] = { {.irq = IRQIO_MSI, .name = "MSI", .desc = "[I/O] MSI Interrupt" }, {.irq = IRQIO_VIR, .name = "VIR", .desc = "[I/O] Virtual I/O Devices"}, {.irq = IRQIO_VAI, .name = "VAI", .desc = "[I/O] Virtual I/O Devices AI"}, + {.irq = IRQIO_GAL, .name = "GAL", .desc = "[I/O] GIB Alert"}, {.irq = NMI_NMI, .name = "NMI", .desc = "[NMI] Machine Check"}, {.irq = CPU_RST, .name = "RST", .desc = "[CPU] CPU Restart"}, }; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 9faaa8f96fc3..dc446203e5a4 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -26,6 +26,7 @@ #include #include #include +#include #include "kvm-s390.h" #include "gaccess.h" #include "trace-s390.h" @@ -268,6 +269,38 @@ static inline void gisa_clear_ipm(struct kvm_s390_gisa *gisa) } while (cmpxchg(&gisa->u64.word[0], word, _word) != word); } +/** + * gisa_get_ipm_or_restore_iam - return IPM or restore GISA IAM + * + * @gi: gisa interrupt struct to work on + * + * Atomically restores the interruption alert mask if none of the + * relevant ISCs are pending and return the IPM. + * + * Returns: the relevant pending ISCs + */ +static inline u8 gisa_get_ipm_or_restore_iam(struct kvm_s390_gisa_interrupt *gi) +{ + u8 pending_mask, alert_mask; + u64 word, _word; + + do { + word = READ_ONCE(gi->origin->u64.word[0]); + alert_mask = READ_ONCE(gi->alert.mask); + pending_mask = (u8)(word >> 24) & alert_mask; + if (pending_mask) + return pending_mask; + _word = (word & ~0xffUL) | alert_mask; + } while (cmpxchg(&gi->origin->u64.word[0], word, _word) != word); + + return 0; +} + +static inline int gisa_in_alert_list(struct kvm_s390_gisa *gisa) +{ + return READ_ONCE(gisa->next_alert) != (u32)(u64)gisa; +} + static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) { set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); @@ -1141,6 +1174,7 @@ static u64 __calculate_sltime(struct kvm_vcpu *vcpu) int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) { + struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int; u64 sltime; vcpu->stat.exit_wait_state++; @@ -1154,6 +1188,11 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) return -EOPNOTSUPP; /* disabled wait */ } + if (gi->origin && + (gisa_get_ipm_or_restore_iam(gi) & + vcpu->arch.sie_block->gcr[6] >> 24)) + return 0; + if (!ckc_interrupts_enabled(vcpu) && !cpu_timer_interrupts_enabled(vcpu)) { VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer"); @@ -2939,6 +2978,93 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len) return n; } +static void __airqs_kick_single_vcpu(struct kvm *kvm, u8 deliverable_mask) +{ + int vcpu_id, online_vcpus = atomic_read(&kvm->online_vcpus); + struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; + struct kvm_vcpu *vcpu; + + for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { + vcpu = kvm_get_vcpu(kvm, vcpu_id); + if (psw_ioint_disabled(vcpu)) + continue; + deliverable_mask &= (u8)(vcpu->arch.sie_block->gcr[6] >> 24); + if (deliverable_mask) { + /* lately kicked but not yet running */ + if (test_and_set_bit(vcpu_id, gi->kicked_mask)) + return; + kvm_s390_vcpu_wakeup(vcpu); + return; + } + } +} + +static enum hrtimer_restart gisa_vcpu_kicker(struct hrtimer *timer) +{ + struct kvm_s390_gisa_interrupt *gi = + container_of(timer, struct kvm_s390_gisa_interrupt, timer); + struct kvm *kvm = + container_of(gi->origin, struct sie_page2, gisa)->kvm; + u8 pending_mask; + + pending_mask = gisa_get_ipm_or_restore_iam(gi); + if (pending_mask) { + __airqs_kick_single_vcpu(kvm, pending_mask); + hrtimer_forward_now(timer, ns_to_ktime(gi->expires)); + return HRTIMER_RESTART; + }; + + return HRTIMER_NORESTART; +} + +#define NULL_GISA_ADDR 0x00000000UL +#define NONE_GISA_ADDR 0x00000001UL +#define GISA_ADDR_MASK 0xfffff000UL + +static void process_gib_alert_list(void) +{ + struct kvm_s390_gisa_interrupt *gi; + struct kvm_s390_gisa *gisa; + struct kvm *kvm; + u32 final, origin = 0UL; + + do { + /* + * If the NONE_GISA_ADDR is still stored in the alert list + * origin, we will leave the outer loop. No further GISA has + * been added to the alert list by millicode while processing + * the current alert list. + */ + final = (origin & NONE_GISA_ADDR); + /* + * Cut off the alert list and store the NONE_GISA_ADDR in the + * alert list origin to avoid further GAL interruptions. + * A new alert list can be build up by millicode in parallel + * for guests not in the yet cut-off alert list. When in the + * final loop, store the NULL_GISA_ADDR instead. This will re- + * enable GAL interruptions on the host again. + */ + origin = xchg(&gib->alert_list_origin, + (!final) ? NONE_GISA_ADDR : NULL_GISA_ADDR); + /* + * Loop through the just cut-off alert list and start the + * gisa timers to kick idle vcpus to consume the pending + * interruptions asap. + */ + while (origin & GISA_ADDR_MASK) { + gisa = (struct kvm_s390_gisa *)(u64)origin; + origin = gisa->next_alert; + gisa->next_alert = (u32)(u64)gisa; + kvm = container_of(gisa, struct sie_page2, gisa)->kvm; + gi = &kvm->arch.gisa_int; + if (hrtimer_active(&gi->timer)) + hrtimer_cancel(&gi->timer); + hrtimer_start(&gi->timer, 0, HRTIMER_MODE_REL); + } + } while (!final); + +} + void kvm_s390_gisa_clear(struct kvm *kvm) { struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; @@ -2958,6 +3084,9 @@ void kvm_s390_gisa_init(struct kvm *kvm) gi->origin = &kvm->arch.sie_page2->gisa; gi->alert.mask = 0; spin_lock_init(&gi->alert.ref_lock); + gi->expires = 50 * 1000; /* 50 usec */ + hrtimer_init(&gi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + gi->timer.function = gisa_vcpu_kicker; memset(gi->origin, 0, sizeof(struct kvm_s390_gisa)); gi->origin->next_alert = (u32)(u64)gi->origin; VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin); @@ -2965,7 +3094,17 @@ void kvm_s390_gisa_init(struct kvm *kvm) void kvm_s390_gisa_destroy(struct kvm *kvm) { - kvm->arch.gisa_int.origin = NULL; + struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; + + if (!gi->origin) + return; + if (gi->alert.mask) + KVM_EVENT(3, "vm 0x%pK has unexpected iam 0x%02x", + kvm, gi->alert.mask); + while (gisa_in_alert_list(gi->origin)) + cpu_relax(); + hrtimer_cancel(&gi->timer); + gi->origin = NULL; } /** @@ -3051,11 +3190,23 @@ out: } EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister); +static void gib_alert_irq_handler(struct airq_struct *airq) +{ + inc_irq_stat(IRQIO_GAL); + process_gib_alert_list(); +} + +static struct airq_struct gib_alert_irq = { + .handler = gib_alert_irq_handler, + .lsi_ptr = &gib_alert_irq.lsi_mask, +}; + void kvm_s390_gib_destroy(void) { if (!gib) return; chsc_sgib(0); + unregister_adapter_interrupt(&gib_alert_irq); free_page((unsigned long)gib); gib = NULL; } @@ -3075,16 +3226,30 @@ int kvm_s390_gib_init(u8 nisc) goto out; } + gib_alert_irq.isc = nisc; + if (register_adapter_interrupt(&gib_alert_irq)) { + pr_err("Registering the GIB alert interruption handler failed\n"); + rc = -EIO; + goto out_free_gib; + } + gib->nisc = nisc; if (chsc_sgib((u32)(u64)gib)) { pr_err("Associating the GIB with the AIV facility failed\n"); free_page((unsigned long)gib); gib = NULL; rc = -EIO; - goto out; + goto out_unreg_gal; } KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc); + goto out; + +out_unreg_gal: + unregister_adapter_interrupt(&gib_alert_irq); +out_free_gib: + free_page((unsigned long)gib); + gib = NULL; out: return rc; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 0de062e989e2..0099fbda2e98 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3460,6 +3460,8 @@ static int vcpu_pre_run(struct kvm_vcpu *vcpu) kvm_s390_patch_guest_per_regs(vcpu); } + clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.gisa_int.kicked_mask); + vcpu->arch.sie_block->icptcode = 0; cpuflags = atomic_read(&vcpu->arch.sie_block->cpuflags); VCPU_EVENT(vcpu, 6, "entering sie flags %x", cpuflags); -- cgit v1.2.3