KVM: s390: pci: enable host forwarding of Adapter Event Notifications

In cases where interrupts are not forwarded to the guest via firmware,
KVM is responsible for ensuring delivery.  When an interrupt presents
with the forwarding bit, we must process the forwarding tables until
all interrupts are delivered.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-14-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 766028d54a3efef4d88c89bbc0cbbeff7cf11aa9..c1518a505060011a920194d76a9e849c84013baa 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -759,6 +759,7 @@ struct kvm_vm_stat {
        u64 inject_pfault_done;
        u64 inject_service_signal;
        u64 inject_virtio;
+       u64 aen_forward;
 };
 
 struct kvm_arch_memory_slot {

diff --git a/arch/s390/include/asm/tpi.h b/arch/s390/include/asm/tpi.h
index 1ac538b8cbf5529333f671d55b6f7f30c7f526a0..f76e5fdff23a2309fc0fa9817c4c63dc418bd761 100644 (file)
--- a/arch/s390/include/asm/tpi.h
+++ b/arch/s390/include/asm/tpi.h
@@ -19,6 +19,19 @@ struct tpi_info {
        u32 :12;
 } __packed __aligned(4);
 
+/* I/O-Interruption Code as stored by TPI for an Adapter I/O */
+struct tpi_adapter_info {
+       u32 aism:8;
+       u32 :22;
+       u32 error:1;
+       u32 forward:1;
+       u32 reserved;
+       u32 adapter_IO:1;
+       u32 directed_irq:1;
+       u32 isc:3;
+       u32 :27;
+} __packed __aligned(4);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_S390_TPI_H */

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 37ff4358121a67350c3b4d550157ccf524ad79f6..d8e1fce78b7c23039309a9e26da4bbe5bb606228 100644 (file)
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -3313,11 +3313,87 @@ out:
 }
 EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister);
 
+static void aen_host_forward(unsigned long si)
+{
+       struct kvm_s390_gisa_interrupt *gi;
+       struct zpci_gaite *gaite;
+       struct kvm *kvm;
+
+       gaite = (struct zpci_gaite *)aift->gait +
+               (si * sizeof(struct zpci_gaite));
+       if (gaite->count == 0)
+               return;
+       if (gaite->aisb != 0)
+               set_bit_inv(gaite->aisbo, (unsigned long *)gaite->aisb);
+
+       kvm = kvm_s390_pci_si_to_kvm(aift, si);
+       if (!kvm)
+               return;
+       gi = &kvm->arch.gisa_int;
+
+       if (!(gi->origin->g1.simm & AIS_MODE_MASK(gaite->gisc)) ||
+           !(gi->origin->g1.nimm & AIS_MODE_MASK(gaite->gisc))) {
+               gisa_set_ipm_gisc(gi->origin, gaite->gisc);
+               if (hrtimer_active(&gi->timer))
+                       hrtimer_cancel(&gi->timer);
+               hrtimer_start(&gi->timer, 0, HRTIMER_MODE_REL);
+               kvm->stat.aen_forward++;
+       }
+}
+
+static void aen_process_gait(u8 isc)
+{
+       bool found = false, first = true;
+       union zpci_sic_iib iib = {{0}};
+       unsigned long si, flags;
+
+       spin_lock_irqsave(&aift->gait_lock, flags);
+
+       if (!aift->gait) {
+               spin_unlock_irqrestore(&aift->gait_lock, flags);
+               return;
+       }
+
+       for (si = 0;;) {
+               /* Scan adapter summary indicator bit vector */
+               si = airq_iv_scan(aift->sbv, si, airq_iv_end(aift->sbv));
+               if (si == -1UL) {
+                       if (first || found) {
+                               /* Re-enable interrupts. */
+                               zpci_set_irq_ctrl(SIC_IRQ_MODE_SINGLE, isc,
+                                                 &iib);
+                               first = found = false;
+                       } else {
+                               /* Interrupts on and all bits processed */
+                               break;
+                       }
+                       found = false;
+                       si = 0;
+                       /* Scan again after re-enabling interrupts */
+                       continue;
+               }
+               found = true;
+               aen_host_forward(si);
+       }
+
+       spin_unlock_irqrestore(&aift->gait_lock, flags);
+}
+
 static void gib_alert_irq_handler(struct airq_struct *airq,
                                  struct tpi_info *tpi_info)
 {
+       struct tpi_adapter_info *info = (struct tpi_adapter_info *)tpi_info;
+
        inc_irq_stat(IRQIO_GAL);
-       process_gib_alert_list();
+
+       if ((info->forward || info->error) &&
+           IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)) {
+               aen_process_gait(info->isc);
+               if (info->aism != 0)
+                       process_gib_alert_list();
+       } else {
+               process_gib_alert_list();
+       }
 }
 
 static struct airq_struct gib_alert_irq = {

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 251eaaff9c67685da6072be9400fa356294751ac..d96c9be0480bf88f47f61665b5de236def35d4c1 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -64,7 +64,8 @@ const struct _kvm_stats_desc kvm_vm_stats_desc[] = {
        STATS_DESC_COUNTER(VM, inject_float_mchk),
        STATS_DESC_COUNTER(VM, inject_pfault_done),
        STATS_DESC_COUNTER(VM, inject_service_signal),
-       STATS_DESC_COUNTER(VM, inject_virtio)
+       STATS_DESC_COUNTER(VM, inject_virtio),
+       STATS_DESC_COUNTER(VM, aen_forward)
 };
 
 const struct kvm_stats_header kvm_vm_stats_header = {

diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index c357d900f8b046d1fbfaf0b9b2a594cf293bd1fa..9f7828d97605759442121811e45240b7d4132421 100644 (file)
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -13,6 +13,7 @@
 #include <linux/kvm_host.h>
 #include <linux/pci.h>
 #include <linux/mutex.h>
+#include <linux/kvm_host.h>
 #include <asm/airq.h>
 #include <asm/cpu.h>
 
@@ -40,6 +41,15 @@ struct zpci_aift {
 
 extern struct zpci_aift *aift;
 
+static inline struct kvm *kvm_s390_pci_si_to_kvm(struct zpci_aift *aift,
+                                                unsigned long si)
+{
+       if (!IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM) || aift->kzdev == 0 ||
+           aift->kzdev[si] == 0)
+               return 0;
+       return aift->kzdev[si]->kvm;
+};
+
 int kvm_s390_pci_aen_init(u8 nisc);
 void kvm_s390_pci_aen_exit(void);