Merge tag 'kvm-s390-20140506' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next

1. Fixes an error return code for the breakpoint setup

2. External interrupt fixes
2.1. Some interrupt conditions like cpu timer or clock comparator
stay pending even after the interrupt is injected. If the external
new PSW is enabled for interrupts this will result in an endless
loop. Usually this indicates a programming error in the guest OS.
Lets detect such situations and go to userspace. We will provide
a QEMU patch that sets the guest in panicked/crashed state to avoid
wasting CPU cycles.
2.2 Resend external interrupts back to the guest if the HW could
not do it.
-

6 files changed, 88 insertions, 7 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2014ff12b492..0581f6c40f2b 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2211,6 +2211,8 @@ KVM_S390_SIGP_STOP (vcpu) - sigp restart
 KVM_S390_PROGRAM_INT (vcpu) - program check; code in parm
 KVM_S390_SIGP_SET_PREFIX (vcpu) - sigp set prefix; prefix address in parm
 KVM_S390_RESTART (vcpu) - restart
+KVM_S390_INT_CLOCK_COMP (vcpu) - clock comparator interrupt
+KVM_S390_INT_CPU_TIMER (vcpu) - CPU timer interrupt
 KVM_S390_INT_VIRTIO (vm) - virtio external interrupt; external interrupt
                            parameters in parm and parm64
 KVM_S390_INT_SERVICE (vm) - sclp external interrupt; sclp parameter in parm
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index f0a1dc5e5d1f..96b8a67ddaf8 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -132,7 +132,10 @@ struct kvm_s390_sie_block {
         psw_t   gpsw;                   /* 0x0090 */
         __u64   gg14;                   /* 0x00a0 */
         __u64   gg15;                   /* 0x00a8 */
-        __u8    reservedb0[28];         /* 0x00b0 */
+        __u8    reservedb0[20];         /* 0x00b0 */
+        __u16   extcpuaddr;             /* 0x00c4 */
+        __u16   eic;                    /* 0x00c6 */
+        __u32   reservedc8;             /* 0x00c8 */
         __u16   pgmilc;                 /* 0x00cc */
         __u16   iprcc;                  /* 0x00ce */
         __u32   dxc;                    /* 0x00d0 */
diff --git a/arch/s390/kvm/guestdbg.c b/arch/s390/kvm/guestdbg.c
index 757ccef62fd5..3e8d4092ce30 100644
--- a/arch/s390/kvm/guestdbg.c
+++ b/arch/s390/kvm/guestdbg.c
@@ -223,9 +223,10 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu,
                 goto error;
         }
 
-        ret = copy_from_user(bp_data, dbg->arch.hw_bp, size);
-        if (ret)
+        if (copy_from_user(bp_data, dbg->arch.hw_bp, size)) {
+                ret = -EFAULT;
                 goto error;
+        }
 
         for (i = 0; i < dbg->arch.nr_hw_bp; i++) {
                 switch (bp_data[i].type) {
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 99e4b76e3487..bd607cf01a5d 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -17,6 +17,7 @@
 
 #include <asm/kvm_host.h>
 #include <asm/asm-offsets.h>
+#include <asm/irq.h>
 
 #include "kvm-s390.h"
 #include "gaccess.h"
@@ -46,9 +47,6 @@ static int handle_noop(struct kvm_vcpu *vcpu)
         case 0x10:
                 vcpu->stat.exit_external_request++;
                 break;
-        case 0x14:
-                vcpu->stat.exit_external_interrupt++;
-                break;
         default:
                 break; /* nothing */
         }
@@ -234,6 +232,49 @@ static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
 }
 
 /**
+ * handle_external_interrupt - used for external interruption interceptions
+ *
+ * This interception only occurs if the CPUSTAT_EXT_INT bit was set, or if
+ * the new PSW does not have external interrupts disabled. In the first case,
+ * we've got to deliver the interrupt manually, and in the second case, we
+ * drop to userspace to handle the situation there.
+ */
+static int handle_external_interrupt(struct kvm_vcpu *vcpu)
+{
+        u16 eic = vcpu->arch.sie_block->eic;
+        struct kvm_s390_interrupt irq;
+        psw_t newpsw;
+        int rc;
+
+        vcpu->stat.exit_external_interrupt++;
+
+        rc = read_guest_lc(vcpu, __LC_EXT_NEW_PSW, &newpsw, sizeof(psw_t));
+        if (rc)
+                return rc;
+        /* We can not handle clock comparator or timer interrupt with bad PSW */
+        if ((eic == EXT_IRQ_CLK_COMP || eic == EXT_IRQ_CPU_TIMER) &&
+            (newpsw.mask & PSW_MASK_EXT))
+                return -EOPNOTSUPP;
+
+        switch (eic) {
+        case EXT_IRQ_CLK_COMP:
+                irq.type = KVM_S390_INT_CLOCK_COMP;
+                break;
+        case EXT_IRQ_CPU_TIMER:
+                irq.type = KVM_S390_INT_CPU_TIMER;
+                break;
+        case EXT_IRQ_EXTERNAL_CALL:
+                irq.type = KVM_S390_INT_EXTERNAL_CALL;
+                irq.parm = vcpu->arch.sie_block->extcpuaddr;
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        return kvm_s390_inject_vcpu(vcpu, &irq);
+}
+
+/**
  * Handle MOVE PAGE partial execution interception.
  *
  * This interception can only happen for guests with DAT disabled and
@@ -291,7 +332,7 @@ static const intercept_handler_t intercept_funcs[] = {
         [0x08 >> 2] = handle_prog,
         [0x0C >> 2] = handle_instruction_and_prog,
         [0x10 >> 2] = handle_noop,
-        [0x14 >> 2] = handle_noop,
+        [0x14 >> 2] = handle_external_interrupt,
         [0x18 >> 2] = handle_noop,
         [0x1C >> 2] = kvm_s390_handle_wait,
         [0x20 >> 2] = handle_validity,
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index d9526bb29194..75cd3217cd5a 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -27,6 +27,8 @@
 #define IOINT_CSSID_MASK 0x03fc0000
 #define IOINT_AI_MASK 0x04000000
 
+static void deliver_ckc_interrupt(struct kvm_vcpu *vcpu);
+
 static int is_ioint(u64 type)
 {
         return ((type & 0xfffe0000u) != 0xfffe0000u);
@@ -89,6 +91,14 @@ static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
                 if (vcpu->arch.sie_block->gcr[0] & 0x4000ul)
                         return 1;
                 return 0;
+        case KVM_S390_INT_CLOCK_COMP:
+                return ckc_interrupts_enabled(vcpu);
+        case KVM_S390_INT_CPU_TIMER:
+                if (psw_extint_disabled(vcpu))
+                        return 0;
+                if (vcpu->arch.sie_block->gcr[0] & 0x400ul)
+                        return 1;
+                return 0;
         case KVM_S390_INT_SERVICE:
         case KVM_S390_INT_PFAULT_INIT:
         case KVM_S390_INT_PFAULT_DONE:
@@ -166,6 +176,8 @@ static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
         case KVM_S390_INT_PFAULT_INIT:
         case KVM_S390_INT_PFAULT_DONE:
         case KVM_S390_INT_VIRTIO:
+        case KVM_S390_INT_CLOCK_COMP:
+        case KVM_S390_INT_CPU_TIMER:
                 if (psw_extint_disabled(vcpu))
                         __set_cpuflag(vcpu, CPUSTAT_EXT_INT);
                 else
@@ -326,6 +338,24 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
                                     &vcpu->arch.sie_block->gpsw,
                                     sizeof(psw_t));
                 break;
+        case KVM_S390_INT_CLOCK_COMP:
+                trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
+                                                 inti->ext.ext_params, 0);
+                deliver_ckc_interrupt(vcpu);
+                break;
+        case KVM_S390_INT_CPU_TIMER:
+                trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
+                                                 inti->ext.ext_params, 0);
+                rc  = put_guest_lc(vcpu, EXT_IRQ_CPU_TIMER,
+                                   (u16 *)__LC_EXT_INT_CODE);
+                rc |= write_guest_lc(vcpu, __LC_EXT_OLD_PSW,
+                                     &vcpu->arch.sie_block->gpsw,
+                                     sizeof(psw_t));
+                rc |= read_guest_lc(vcpu, __LC_EXT_NEW_PSW,
+                                    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
+                rc |= put_guest_lc(vcpu, inti->ext.ext_params,
+                                   (u32 *)__LC_EXT_PARAMS);
+                break;
         case KVM_S390_INT_SERVICE:
                 VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",
                            inti->ext.ext_params);
@@ -984,6 +1014,8 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
                 break;
         case KVM_S390_SIGP_STOP:
         case KVM_S390_RESTART:
+        case KVM_S390_INT_CLOCK_COMP:
+        case KVM_S390_INT_CPU_TIMER:
                 VCPU_EVENT(vcpu, 3, "inject: type %x", s390int->type);
                 inti->type = s390int->type;
                 break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 836e15b7abc8..2b83cf35437a 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -416,6 +416,8 @@ struct kvm_s390_psw {
 #define KVM_S390_INT_PFAULT_INIT        0xfffe0004u
 #define KVM_S390_INT_PFAULT_DONE        0xfffe0005u
 #define KVM_S390_MCHK                   0xfffe1000u
+#define KVM_S390_INT_CLOCK_COMP         0xffff1004u
+#define KVM_S390_INT_CPU_TIMER          0xffff1005u
 #define KVM_S390_INT_VIRTIO             0xffff2603u
 #define KVM_S390_INT_SERVICE            0xffff2401u
 #define KVM_S390_INT_EMERGENCY          0xffff1201u