KVM: s390: Support for I/O interrupts.

Add support for handling I/O interrupts (standard, subchannel-related
ones and rudimentary adapter interrupts).

The subchannel-identifying parameters are encoded into the interrupt
type.

I/O interrupts are floating, so they can't be injected on a specific
vcpu.

Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

4 files changed, 116 insertions, 2 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index a4df5535996b..83bd92b52936 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2069,6 +2069,10 @@ KVM_S390_INT_VIRTIO (vm) - virtio external interrupt; external interrupt
 KVM_S390_INT_SERVICE (vm) - sclp external interrupt; sclp parameter in parm
 KVM_S390_INT_EMERGENCY (vcpu) - sigp emergency; source cpu in parm
 KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm
+KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) - compound value to indicate an
+    I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel);
+    I/O interruption parameters in parm (subchannel) and parm64 (intparm,
+    interruption subclass)
 
 Note that the vcpu ioctl is asynchronous to vcpu execution.
 
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 711c5ab391cf..a8e35c43df78 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -74,6 +74,7 @@ struct kvm_s390_sie_block {
         __u64   epoch;                  /* 0x0038 */
         __u8    reserved40[4];          /* 0x0040 */
 #define LCTL_CR0        0x8000
+#define LCTL_CR6        0x0200
         __u16   lctl;                   /* 0x0044 */
         __s16   icpua;                  /* 0x0046 */
         __u32   ictl;                   /* 0x0048 */
@@ -125,6 +126,7 @@ struct kvm_vcpu_stat {
         u32 deliver_prefix_signal;
         u32 deliver_restart_signal;
         u32 deliver_program_int;
+        u32 deliver_io_int;
         u32 exit_wait_state;
         u32 instruction_stidp;
         u32 instruction_spx;
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index c30615e605ac..52cdf20906ab 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -21,11 +21,26 @@
 #include "gaccess.h"
 #include "trace-s390.h"
 
+#define IOINT_SCHID_MASK 0x0000ffff
+#define IOINT_SSID_MASK 0x00030000
+#define IOINT_CSSID_MASK 0x03fc0000
+#define IOINT_AI_MASK 0x04000000
+
+static int is_ioint(u64 type)
+{
+        return ((type & 0xfffe0000u) != 0xfffe0000u);
+}
+
 static int psw_extint_disabled(struct kvm_vcpu *vcpu)
 {
         return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT);
 }
 
+static int psw_ioint_disabled(struct kvm_vcpu *vcpu)
+{
+        return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO);
+}
+
 static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
 {
         if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
@@ -67,7 +82,15 @@ static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
         case KVM_S390_SIGP_SET_PREFIX:
         case KVM_S390_RESTART:
                 return 1;
+        case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+                if (psw_ioint_disabled(vcpu))
+                        return 0;
+                if (vcpu->arch.sie_block->gcr[6] & inti->io.io_int_word)
+                        return 1;
+                return 0;
         default:
+                printk(KERN_WARNING "illegal interrupt type %llx\n",
+                       inti->type);
                 BUG();
         }
         return 0;
@@ -116,6 +139,12 @@ static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
         case KVM_S390_SIGP_STOP:
                 __set_cpuflag(vcpu, CPUSTAT_STOP_INT);
                 break;
+        case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+                if (psw_ioint_disabled(vcpu))
+                        __set_cpuflag(vcpu, CPUSTAT_IO_INT);
+                else
+                        vcpu->arch.sie_block->lctl |= LCTL_CR6;
+                break;
         default:
                 BUG();
         }
@@ -297,6 +326,47 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
                         exception = 1;
                 break;
 
+        case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+        {
+                __u32 param0 = ((__u32)inti->io.subchannel_id << 16) |
+                        inti->io.subchannel_nr;
+                __u64 param1 = ((__u64)inti->io.io_int_parm << 32) |
+                        inti->io.io_int_word;
+                VCPU_EVENT(vcpu, 4, "interrupt: I/O %llx", inti->type);
+                vcpu->stat.deliver_io_int++;
+                trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
+                                                 param0, param1);
+                rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_ID,
+                                   inti->io.subchannel_id);
+                if (rc == -EFAULT)
+                        exception = 1;
+
+                rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_NR,
+                                   inti->io.subchannel_nr);
+                if (rc == -EFAULT)
+                        exception = 1;
+
+                rc = put_guest_u32(vcpu, __LC_IO_INT_PARM,
+                                   inti->io.io_int_parm);
+                if (rc == -EFAULT)
+                        exception = 1;
+
+                rc = put_guest_u32(vcpu, __LC_IO_INT_WORD,
+                                   inti->io.io_int_word);
+                if (rc == -EFAULT)
+                        exception = 1;
+
+                rc = copy_to_guest(vcpu, __LC_IO_OLD_PSW,
+                                   &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+                if (rc == -EFAULT)
+                        exception = 1;
+
+                rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
+                                     __LC_IO_NEW_PSW, sizeof(psw_t));
+                if (rc == -EFAULT)
+                        exception = 1;
+                break;
+        }
         default:
                 BUG();
         }
@@ -545,7 +615,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
 {
         struct kvm_s390_local_interrupt *li;
         struct kvm_s390_float_interrupt *fi;
-        struct kvm_s390_interrupt_info *inti;
+        struct kvm_s390_interrupt_info *inti, *iter;
         int sigcpu;
 
         inti = kzalloc(sizeof(*inti), GFP_KERNEL);
@@ -569,6 +639,22 @@ int kvm_s390_inject_vm(struct kvm *kvm,
         case KVM_S390_SIGP_STOP:
         case KVM_S390_INT_EXTERNAL_CALL:
         case KVM_S390_INT_EMERGENCY:
+                kfree(inti);
+                return -EINVAL;
+        case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+                if (s390int->type & IOINT_AI_MASK)
+                        VM_EVENT(kvm, 5, "%s", "inject: I/O (AI)");
+                else
+                        VM_EVENT(kvm, 5, "inject: I/O css %x ss %x schid %04x",
+                                 s390int->type & IOINT_CSSID_MASK,
+                                 s390int->type & IOINT_SSID_MASK,
+                                 s390int->type & IOINT_SCHID_MASK);
+                inti->type = s390int->type;
+                inti->io.subchannel_id = s390int->parm >> 16;
+                inti->io.subchannel_nr = s390int->parm & 0x0000ffffu