From: Carsten Otte <[EMAIL PROTECTED]>
From: Christian Borntraeger <[EMAIL PROTECTED]>

This patch introduces in-kernel handling of _some_ sigp interprocessor
signals (similar to ipi).
kvm_s390_handle_sigp() decodes the sigp instruction and calls individual
handlers depending on the operation requested:
- sigp sense tries to retrieve information such as existence or running state
  of the remote cpu
- sigp emergency sends an external interrupt to the remove cpu
- sigp stop stops a remove cpu
- sigp stop store status stops a remote cpu, and stores its entire internal
  state to the cpus lowcore
- sigp set arch sets the architecture mode of the remote cpu. setting to
  ESAME (s390x 64bit) is accepted, setting to ESA/S390 (s390, 31 or 24 bit) is
  denied, all others are passed to userland
- sigp set prefix sets the prefix register of a remote cpu

For implementation of this, the stop intercept indication starts to get reused
on purpose: a set of action bits defines what to do once a cpu gets stopped:
ACTION_STOP_ON_STOP  really stops the cpu when a stop intercept is recognized
ACTION_STORE_ON_STOP stores the cpu status to lowcore when a stop intercept is
                     recognized

Acked-by: Martin Schwidefsky <[EMAIL PROTECTED]>
Signed-off-by: Christian Borntraeger <[EMAIL PROTECTED]>
Signed-off-by: Carsten Otte <[EMAIL PROTECTED]>
---
 arch/s390/kvm/Makefile      |    2 
 arch/s390/kvm/intercept.c   |   22 +++
 arch/s390/kvm/kvm-s390.c    |    7 +
 arch/s390/kvm/kvm-s390.h    |    7 +
 arch/s390/kvm/sigp.c        |  289 ++++++++++++++++++++++++++++++++++++++++++++
 include/asm-s390/kvm_host.h |   12 +
 6 files changed, 336 insertions(+), 3 deletions(-)

Index: kvm/arch/s390/kvm/Makefile
===================================================================
--- kvm.orig/arch/s390/kvm/Makefile
+++ kvm/arch/s390/kvm/Makefile
@@ -10,5 +10,5 @@ common-objs = $(addprefix ../../../virt/
 
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/s390/kvm
 
-kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o
+kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o 
sigp.o
 obj-$(CONFIG_KVM) += kvm.o
Index: kvm/arch/s390/kvm/intercept.c
===================================================================
--- kvm.orig/arch/s390/kvm/intercept.c
+++ kvm/arch/s390/kvm/intercept.c
@@ -100,6 +100,7 @@ static int handle_lctl(struct kvm_vcpu *
 }
 
 static intercept_handler_t instruction_handlers[256] = {
+       [0xae] = kvm_s390_handle_sigp,
        [0xb2] = kvm_s390_handle_priv,
        [0xb7] = handle_lctl,
        [0xeb] = handle_lctg,
@@ -122,10 +123,27 @@ static int handle_noop(struct kvm_vcpu *
 
 static int handle_stop(struct kvm_vcpu *vcpu)
 {
+       int rc;
+
        vcpu->stat.exit_stop_request++;
-       VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
        atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
-       return -ENOTSUPP;
+       spin_lock_bh(&vcpu->arch.local_int.lock);
+       if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
+               vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
+               rc = __kvm_s390_vcpu_store_status(vcpu,
+                                                 KVM_S390_STORE_STATUS_NOADDR);
+               if (rc >= 0)
+                       rc = -ENOTSUPP;
+       }
+
+       if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
+               vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
+               VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
+               rc = -ENOTSUPP;
+       } else
+               rc = 0;
+       spin_unlock_bh(&vcpu->arch.local_int.lock);
+       return rc;
 }
 
 static int handle_validity(struct kvm_vcpu *vcpu)
Index: kvm/arch/s390/kvm/kvm-s390.c
===================================================================
--- kvm.orig/arch/s390/kvm/kvm-s390.c
+++ kvm/arch/s390/kvm/kvm-s390.c
@@ -57,6 +57,12 @@ struct kvm_stats_debugfs_item debugfs_en
        { "instruction_chsc", VCPU_STAT(instruction_chsc) },
        { "instruction_stsi", VCPU_STAT(instruction_stsi) },
        { "instruction_stfl", VCPU_STAT(instruction_stfl) },
+       { "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) },
+       { "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) },
+       { "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) },
+       { "instruction_sigp_set_arch", VCPU_STAT(instruction_sigp_arch) },
+       { "instruction_sigp_set_prefix", VCPU_STAT(instruction_sigp_prefix) },
+       { "instruction_sigp_restart", VCPU_STAT(instruction_sigp_restart) },
        { NULL }
 };
 
@@ -290,6 +296,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(st
        spin_lock_bh(&kvm->arch.float_int.lock);
        kvm->arch.float_int.local_int[id] = &vcpu->arch.local_int;
        init_waitqueue_head(&vcpu->arch.local_int.wq);
+       vcpu->arch.local_int.cpuflags = &vcpu->arch.sie_block->cpuflags;
        spin_unlock_bh(&kvm->arch.float_int.lock);
 
        rc = kvm_vcpu_init(vcpu, kvm, id);
Index: kvm/arch/s390/kvm/kvm-s390.h
===================================================================
--- kvm.orig/arch/s390/kvm/kvm-s390.h
+++ kvm/arch/s390/kvm/kvm-s390.h
@@ -50,4 +50,11 @@ int kvm_s390_inject_program_int(struct k
 
 /* implemented in priv.c */
 int kvm_s390_handle_priv(struct kvm_vcpu *vcpu);
+
+/* implemented in sigp.c */
+int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu);
+
+/* implemented in kvm-s390.c */
+int __kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu,
+                                unsigned long addr);
 #endif
Index: kvm/arch/s390/kvm/sigp.c
===================================================================
--- /dev/null
+++ kvm/arch/s390/kvm/sigp.c
@@ -0,0 +1,289 @@
+/*
+ * sigp.c - handlinge interprocessor communication
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Carsten Otte <[EMAIL PROTECTED]>
+ *               Christian Borntraeger <[EMAIL PROTECTED]>
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include "gaccess.h"
+#include "kvm-s390.h"
+
+/* sigp order codes */
+#define SIGP_SENSE             0x01
+#define SIGP_EXTERNAL_CALL     0x02
+#define SIGP_EMERGENCY         0x03
+#define SIGP_START             0x04
+#define SIGP_STOP              0x05
+#define SIGP_RESTART           0x06
+#define SIGP_STOP_STORE_STATUS 0x09
+#define SIGP_INITIAL_CPU_RESET 0x0b
+#define SIGP_CPU_RESET         0x0c
+#define SIGP_SET_PREFIX        0x0d
+#define SIGP_STORE_STATUS_ADDR 0x0e
+#define SIGP_SET_ARCH          0x12
+
+/* cpu status bits */
+#define SIGP_STAT_EQUIPMENT_CHECK   0x80000000UL
+#define SIGP_STAT_INCORRECT_STATE   0x00000200UL
+#define SIGP_STAT_INVALID_PARAMETER 0x00000100UL
+#define SIGP_STAT_EXT_CALL_PENDING  0x00000080UL
+#define SIGP_STAT_STOPPED           0x00000040UL
+#define SIGP_STAT_OPERATOR_INTERV   0x00000020UL
+#define SIGP_STAT_CHECK_STOP        0x00000010UL
+#define SIGP_STAT_INOPERATIVE       0x00000004UL
+#define SIGP_STAT_INVALID_ORDER     0x00000002UL
+#define SIGP_STAT_RECEIVER_CHECK    0x00000001UL
+
+
+static int __sigp_sense(struct kvm_vcpu *vcpu, u16 cpu_addr, u64 *reg)
+{
+       struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
+       int rc;
+
+       if (cpu_addr >= KVM_MAX_VCPUS)
+               return 3; /* not operational */
+
+       spin_lock_bh(&fi->lock);
+       if (fi->local_int[cpu_addr] == NULL)
+               rc = 3; /* not operational */
+       else if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
+                & CPUSTAT_RUNNING) {
+               *reg &= 0xffffffff00000000UL;
+               rc = 1; /* status stored */
+       } else {
+               *reg &= 0xffffffff00000000UL;
+               *reg |= SIGP_STAT_STOPPED;
+               rc = 1; /* status stored */
+       }
+       spin_unlock_bh(&fi->lock);
+
+       VCPU_EVENT(vcpu, 4, "sensed status of cpu %x rc %x", cpu_addr, rc);
+       return rc;
+}
+
+static int __sigp_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr)
+{
+       struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
+       struct local_interrupt *li;
+       struct interrupt_info *inti;
+       int rc;
+
+       if (cpu_addr >= KVM_MAX_VCPUS)
+               return 3; /* not operational */
+
+       inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+       if (!inti)
+               return -ENOMEM;
+
+       inti->type = KVM_S390_INT_EMERGENCY;
+
+       spin_lock_bh(&fi->lock);
+       li = fi->local_int[cpu_addr];
+       if (li == NULL) {
+               rc = 3; /* not operational */
+               kfree(inti);
+               goto unlock;
+       }
+       spin_lock_bh(&li->lock);
+       list_add_tail(&inti->list, &li->list);
+       atomic_set(&li->active, 1);
+       atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
+       if (waitqueue_active(&li->wq))
+               wake_up_interruptible(&li->wq);
+       spin_unlock_bh(&li->lock);
+       rc = 0; /* order accepted */
+unlock:
+       spin_unlock_bh(&fi->lock);
+       VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
+       return rc;
+}
+
+static int __sigp_stop(struct kvm_vcpu *vcpu, u16 cpu_addr, int store)
+{
+       struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
+       struct local_interrupt *li;
+       struct interrupt_info *inti;
+       int rc;
+
+       if (cpu_addr >= KVM_MAX_VCPUS)
+               return 3; /* not operational */
+
+       inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+       if (!inti)
+               return -ENOMEM;
+
+       inti->type = KVM_S390_SIGP_STOP;
+
+       spin_lock_bh(&fi->lock);
+       li = fi->local_int[cpu_addr];
+       if (li == NULL) {
+               rc = 3; /* not operational */
+               kfree(inti);
+               goto unlock;
+       }
+       spin_lock_bh(&li->lock);
+       list_add_tail(&inti->list, &li->list);
+       atomic_set(&li->active, 1);
+       atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
+       if (store)
+               li->action_bits |= ACTION_STORE_ON_STOP;
+       li->action_bits |= ACTION_STOP_ON_STOP;
+       if (waitqueue_active(&li->wq))
+               wake_up_interruptible(&li->wq);
+       spin_unlock_bh(&li->lock);
+       rc = 0; /* order accepted */
+unlock:
+       spin_unlock_bh(&fi->lock);
+       VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x", cpu_addr);
+       return rc;
+}
+
+static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
+{
+       int rc;
+       parameter = parameter & 0xff;
+
+       switch (parameter) {
+       case 0:
+               printk(KERN_WARNING "kvm: request to switch to ESA/390 mode"
+                                                       " not supported");
+               rc = 3; /* not operational */
+               break;
+       case 1:
+       case 2:
+               rc = 0; /* order accepted */
+               break;
+       default:
+               rc = -ENOTSUPP;
+       }
+       return rc;
+}
+
+static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
+                            u64 *reg)
+{
+       struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
+       struct local_interrupt *li;
+       struct interrupt_info *inti;
+       int rc;
+       u8 tmp;
+
+       /* make sure that the new value is valid memory */
+       address = address & 0x7fffe000u;
+       if ((copy_from_guest(vcpu, &tmp,
+               (u64) (address + vcpu->kvm->arch.guest_origin) , 1)) ||
+          (copy_from_guest(vcpu, &tmp, (u64) (address +
+                       vcpu->kvm->arch.guest_origin + PAGE_SIZE), 1))) {
+               *reg |= SIGP_STAT_INVALID_PARAMETER;
+               return 1; /* invalid parameter */
+       }
+
+       inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+       if (!inti)
+               return 2; /* busy */
+
+       spin_lock_bh(&fi->lock);
+       li = fi->local_int[cpu_addr];
+
+       if ((cpu_addr >= KVM_MAX_VCPUS) || (li == NULL)) {
+               rc = 1; /* incorrect state */
+               *reg &= SIGP_STAT_INCORRECT_STATE;
+               kfree(inti);
+               goto out_fi;
+       }
+
+       spin_lock_bh(&li->lock);
+       /* cpu must be in stopped state */
+       if (atomic_read(li->cpuflags) & CPUSTAT_RUNNING) {
+               rc = 1; /* incorrect state */
+               *reg &= SIGP_STAT_INCORRECT_STATE;
+               kfree(inti);
+               goto out_li;
+       }
+
+       inti->type = KVM_S390_SIGP_SET_PREFIX;
+       inti->prefix.address = address;
+
+       list_add_tail(&inti->list, &li->list);
+       atomic_set(&li->active, 1);
+       if (waitqueue_active(&li->wq))
+               wake_up_interruptible(&li->wq);
+       rc = 0; /* order accepted */
+
+       VCPU_EVENT(vcpu, 4, "set prefix of cpu %02x to %x", cpu_addr, address);
+out_li:
+       spin_unlock_bh(&li->lock);
+out_fi:
+       spin_unlock_bh(&fi->lock);
+       return rc;
+}
+
+int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
+{
+       int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
+       int r3 = vcpu->arch.sie_block->ipa & 0x000f;
+       int base2 = vcpu->arch.sie_block->ipb >> 28;
+       int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+       u32 parameter;
+       u16 cpu_addr = vcpu->arch.guest_gprs[r3];
+       u8 order_code;
+       int rc;
+
+       order_code = disp2;
+       if (base2)
+               order_code += vcpu->arch.guest_gprs[base2];
+
+       if (r1 % 2)
+               parameter = vcpu->arch.guest_gprs[r1];
+       else
+               parameter = vcpu->arch.guest_gprs[r1 + 1];
+
+       switch (order_code) {
+       case SIGP_SENSE:
+               vcpu->stat.instruction_sigp_sense++;
+               rc = __sigp_sense(vcpu, cpu_addr,
+                                 &vcpu->arch.guest_gprs[r1]);
+               break;
+       case SIGP_EMERGENCY:
+               vcpu->stat.instruction_sigp_emergency++;
+               rc = __sigp_emergency(vcpu, cpu_addr);
+               break;
+       case SIGP_STOP:
+               vcpu->stat.instruction_sigp_stop++;
+               rc = __sigp_stop(vcpu, cpu_addr, 0);
+               break;
+       case SIGP_STOP_STORE_STATUS:
+               vcpu->stat.instruction_sigp_stop++;
+               rc = __sigp_stop(vcpu, cpu_addr, 1);
+               break;
+       case SIGP_SET_ARCH:
+               vcpu->stat.instruction_sigp_arch++;
+               rc = __sigp_set_arch(vcpu, parameter);
+               break;
+       case SIGP_SET_PREFIX:
+               vcpu->stat.instruction_sigp_prefix++;
+               rc = __sigp_set_prefix(vcpu, cpu_addr, parameter,
+                                      &vcpu->arch.guest_gprs[r1]);
+               break;
+       case SIGP_RESTART:
+               vcpu->stat.instruction_sigp_restart++;
+               /* user space must know about restart */
+       default:
+               return -ENOTSUPP;
+       }
+
+       if (rc < 0)
+               return rc;
+
+       vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+       vcpu->arch.sie_block->gpsw.mask |= (rc & 3ul) << 44;
+       return 0;
+}
Index: kvm/include/asm-s390/kvm_host.h
===================================================================
--- kvm.orig/include/asm-s390/kvm_host.h
+++ kvm/include/asm-s390/kvm_host.h
@@ -120,6 +120,12 @@ struct kvm_vcpu_stat {
        u32 instruction_chsc;
        u32 instruction_stsi;
        u32 instruction_stfl;
+       u32 instruction_sigp_sense;
+       u32 instruction_sigp_emergency;
+       u32 instruction_sigp_stop;
+       u32 instruction_sigp_arch;
+       u32 instruction_sigp_prefix;
+       u32 instruction_sigp_restart;
 };
 
 struct io_info {
@@ -161,6 +167,10 @@ struct interrupt_info {
        };
 };
 
+/* for local_interrupt.action_flags */
+#define ACTION_STORE_ON_STOP 1
+#define ACTION_STOP_ON_STOP  2
+
 struct local_interrupt {
        spinlock_t lock;
        struct list_head list;
@@ -168,6 +178,8 @@ struct local_interrupt {
        struct float_interrupt *float_int;
        int timer_due; /* event indicator for waitqueue below */
        wait_queue_head_t wq;
+       atomic_t *cpuflags;
+       unsigned int action_bits;
 };
 
 struct float_interrupt {



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