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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 <mimu@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Message-Id: <20190131085247.13826-14-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Michael Mueller 2019-01-31 09:52:44 +01:00 committed by Christian Borntraeger
parent 174dd4f888
commit 9f30f62163
6 changed files with 175 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/s390/include/asm/irq.h
View File

@ -62,6 +62,7 @@ enum interruption_class {
IRQIO_MSI,
IRQIO_VIR,
IRQIO_VAI,
IRQIO_GAL,
NMI_NMI,
CPU_RST,
NR_ARCH_IRQS

1
arch/s390/include/asm/isc.h
View File

@ -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 */

3
arch/s390/include/asm/kvm_host.h
View File

@ -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{

1
arch/s390/kernel/irq.c
View File

@ -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"},
};

169
arch/s390/kvm/interrupt.c
View File

@ -26,6 +26,7 @@
#include <asm/gmap.h>
#include <asm/switch_to.h>
#include <asm/nmi.h>
#include <asm/airq.h>
#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;
}

2
arch/s390/kvm/kvm-s390.c
View File

@ -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);