The patch implements a handler for GIB alert interruptions
on the host. Its task is to alert storage backed guests that
interrupts are pending for them.
A GIB alert interrupt statistic counter is added as well:
$ cat /proc/interrupts
CPU0 CPU1
...
GAL: 0 0 [I/O] GIB Alert
...
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
---
arch/s390/include/asm/irq.h | 1 +
arch/s390/include/asm/isc.h | 1 +
arch/s390/kernel/irq.c | 1 +
arch/s390/kvm/interrupt.c | 57 +++++++++++++++++++++++++++++++++++++--------
arch/s390/kvm/kvm-s390.c | 6 +++++
arch/s390/kvm/kvm-s390.h | 5 ++++
6 files changed, 61 insertions(+), 10 deletions(-)
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/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 40878efbd5cd..240b58b67f18 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -23,6 +23,7 @@
#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"
@@ -2890,7 +2891,7 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len)
return n;
}
-static struct kvm_s390_gisa __maybe_unused *unlink_gib_alert_list(void)
+static struct kvm_s390_gisa *unlink_gib_alert_list(void)
{
u32 gisa;
@@ -2919,7 +2920,7 @@ static void nullify_gisa(struct kvm_s390_gisa *gisa)
* belongs to. Thus, the pending guest interruption will be processed
* in SIE context.
*/
-static void __maybe_unused process_gib_alert_list(void)
+static void process_gib_alert_list(void)
{
struct kvm_s390_gisa *gisa = unlink_gib_alert_list();
struct kvm_s390_gisa *next_alert;
@@ -2941,6 +2942,9 @@ static void __maybe_unused process_gib_alert_list(void)
void kvm_s390_gisa_clear(struct kvm *kvm)
{
if (kvm->arch.gisa) {
+ kvm->arch.gisa->iam = 0;
+ while (in_alert_list(kvm->arch.gisa))
+ process_gib_alert_list();
nullify_gisa(kvm->arch.gisa);
VM_EVENT(kvm, 3, "gisa 0x%pK cleared", kvm->arch.gisa);
}
@@ -2952,9 +2956,9 @@ void kvm_s390_gisa_init(struct kvm *kvm)
kvm->arch.gisa = &kvm->arch.sie_page2->gisa;
kvm->arch.iam = 0;
spin_lock_init(&kvm->arch.iam_ref_lock);
- VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa);
- kvm_s390_gisa_clear(kvm);
+ nullify_gisa(kvm->arch.gisa);
kvm->arch.gib_in_use = !!gib;
+ VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa);
}
}
@@ -2962,6 +2966,10 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
{
if (!kvm->arch.gisa)
return;
+
+ kvm->arch.gisa->iam = 0;
+ while (in_alert_list(kvm->arch.gisa))
+ process_gib_alert_list();
kvm->arch.gisa = NULL;
kvm->arch.iam = 0;
}
@@ -3007,36 +3015,65 @@ int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc)
}
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;
}
int kvm_s390_gib_init(u8 nisc)
{
+ int rc = 0;
+
if (!css_general_characteristics.aiv) {
KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
- return 0;
+ goto out;
}
gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!gib) {
KVM_EVENT(3, "gib 0x%pK memory allocation failed", gib);
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ gib_alert_irq.isc = nisc;
+ if (register_adapter_interrupt(&gib_alert_irq)) {
+ KVM_EVENT(3, "gib 0x%pK GAI registration failed", gib);
+ rc = -EIO;
+ goto out_free;
}
gib->nisc = nisc;
if (chsc_sgib((u32)(u64)gib)) {
KVM_EVENT(3, "gib 0x%pK AIV association failed", gib);
- free_page((unsigned long)gib);
- gib = NULL;
- return -EIO;
+ rc = -EIO;
+ goto out_unreg;
}
KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
- return 0;
+ return rc;
+
+out_unreg:
+ unregister_adapter_interrupt(&gib_alert_irq);
+out_free:
+ 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 d55de44df135..386f98029a3f 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)
}
atomic_inc(&vcpu->kvm->arch.vcpus_in_sie);
+ if (vcpu->kvm->arch.gib_in_use)
+ vcpu->kvm->arch.gisa->iam = 0;
vcpu->arch.sie_block->icptcode = 0;
cpuflags = atomic_read(&vcpu->arch.sie_block->cpuflags);
@@ -3521,6 +3523,10 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
vcpu->run->s.regs.gprs[15] = vcpu->arch.sie_block->gg15;
atomic_dec(&vcpu->kvm->arch.vcpus_in_sie);
+ if (vcpu->kvm->arch.gib_in_use &&
+ !in_alert_list(vcpu->kvm->arch.gisa) &&
+ !atomic_fetch_andnot(0, &vcpu->kvm->arch.vcpus_in_sie))
+ vcpu->kvm->arch.gisa->iam = vcpu->kvm->arch.iam;
if (exit_reason == -EINTR) {
VCPU_EVENT(vcpu, 3, "%s", "machine check");
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 1a79105b0e9f..1c93ceaeb9e4 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -196,6 +196,11 @@ static inline int kvm_s390_user_cpu_state_ctrl(struct kvm *kvm)
return kvm->arch.user_cpu_state_ctrl != 0;
}
+static inline bool in_alert_list(struct kvm_s390_gisa *gisa)
+{
+ return (u32)(u64)gisa != gisa->next_alert;
+}
+
/* implemented in interrupt.c */
int kvm_s390_handle_wait(struct kvm_vcpu *vcpu);
void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu);
--
2.13.4
