s390x/kvm: implement handling of new SIGP orders

This patch adds handling code for the following SIGP orders:
- SIGP SET ARCHITECTURE
- SIGP SET PREFIX
- SIGP STOP
- SIGP STOP AND STORE STATUS
- SIGP STORE STATUS AT ADDRESS

SIGP STOP (AND STORE STATUS) are the only orders that can stay pending forever
(and may only be interrupted by resets), so special care has to be taken about
them. Their status also has to be tracked within QEMU. This patch takes
care of migrating this status (e.g. if migration happens during a SIGP STOP).

Due to the BQL, only one VCPU is currently able to execute SIGP handlers at a
time. According to the PoP, BUSY should be returned if another SIGP order is
currently being executed on a VCPU. This can only be implemented when the BQL
does not protect all handlers. For now, all SIGP orders on all VCPUs will be
serialized, which will be okay for the first shot.

Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <1424783731-43426-7-git-send-email-jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 201 insertions, 3 deletions

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index c4c867c00f..127a3b8024 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -38,6 +38,7 @@
 #include "qapi/qmp/qjson.h"
 #include "monitor/monitor.h"
 #include "exec/gdbstub.h"
+#include "exec/address-spaces.h"
 #include "trace.h"
 #include "qapi-event.h"
 #include "hw/s390x/s390-pci-inst.h"
@@ -1133,6 +1134,114 @@ static void sigp_start(void *arg)
     si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
 }
 
+static void sigp_stop(void *arg)
+{
+    SigpInfo *si = arg;
+    struct kvm_s390_irq irq = {
+        .type = KVM_S390_SIGP_STOP,
+    };
+
+    if (s390_cpu_get_state(si->cpu) != CPU_STATE_OPERATING) {
+        si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
+        return;
+    }
+
+    /* disabled wait - sleeping in user space */
+    if (CPU(si->cpu)->halted) {
+        s390_cpu_set_state(CPU_STATE_STOPPED, si->cpu);
+    } else {
+        /* execute the stop function */
+        si->cpu->env.sigp_order = SIGP_STOP;
+        kvm_s390_vcpu_interrupt(si->cpu, &irq);
+    }
+    si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
+}
+
+#define KVM_S390_STORE_STATUS_DEF_ADDR offsetof(LowCore, floating_pt_save_area)
+#define SAVE_AREA_SIZE 512
+static int kvm_s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch)
+{
+    static const uint8_t ar_id = 1;
+    uint64_t ckc = cpu->env.ckc >> 8;
+    void *mem;
+    hwaddr len = SAVE_AREA_SIZE;
+
+    mem = cpu_physical_memory_map(addr, &len, 1);
+    if (!mem) {
+        return -EFAULT;
+    }
+    if (len != SAVE_AREA_SIZE) {
+        cpu_physical_memory_unmap(mem, len, 1, 0);
+        return -EFAULT;
+    }
+
+    if (store_arch) {
+        cpu_physical_memory_write(offsetof(LowCore, ar_access_id), &ar_id, 1);
+    }
+    memcpy(mem, &cpu->env.fregs, 128);
+    memcpy(mem + 128, &cpu->env.regs, 128);
+    memcpy(mem + 256, &cpu->env.psw, 16);
+    memcpy(mem + 280, &cpu->env.psa, 4);
+    memcpy(mem + 284, &cpu->env.fpc, 4);
+    memcpy(mem + 292, &cpu->env.todpr, 4);
+    memcpy(mem + 296, &cpu->env.cputm, 8);
+    memcpy(mem + 304, &ckc, 8);
+    memcpy(mem + 320, &cpu->env.aregs, 64);
+    memcpy(mem + 384, &cpu->env.cregs, 128);
+
+    cpu_physical_memory_unmap(mem, len, 1, len);
+
+    return 0;
+}
+
+static void sigp_stop_and_store_status(void *arg)
+{
+    SigpInfo *si = arg;
+    struct kvm_s390_irq irq = {
+        .type = KVM_S390_SIGP_STOP,
+    };
+
+    /* disabled wait - sleeping in user space */
+    if (s390_cpu_get_state(si->cpu) == CPU_STATE_OPERATING &&
+        CPU(si->cpu)->halted) {
+        s390_cpu_set_state(CPU_STATE_STOPPED, si->cpu);
+    }
+
+    switch (s390_cpu_get_state(si->cpu)) {
+    case CPU_STATE_OPERATING:
+        si->cpu->env.sigp_order = SIGP_STOP_STORE_STATUS;
+        kvm_s390_vcpu_interrupt(si->cpu, &irq);
+        /* store will be performed when handling the stop intercept */
+        break;
+    case CPU_STATE_STOPPED:
+        /* already stopped, just store the status */
+        cpu_synchronize_state(CPU(si->cpu));
+        kvm_s390_store_status(si->cpu, KVM_S390_STORE_STATUS_DEF_ADDR, true);
+        break;
+    }
+    si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
+}
+
+static void sigp_store_status_at_address(void *arg)
+{
+    SigpInfo *si = arg;
+    uint32_t address = si->param & 0x7ffffe00u;
+
+    /* cpu has to be stopped */
+    if (s390_cpu_get_state(si->cpu) != CPU_STATE_STOPPED) {
+        set_sigp_status(si, SIGP_STAT_INCORRECT_STATE);
+        return;
+    }
+
+    cpu_synchronize_state(CPU(si->cpu));
+
+    if (kvm_s390_store_status(si->cpu, address, false)) {
+        set_sigp_status(si, SIGP_STAT_INVALID_PARAMETER);
+        return;
+    }
+    si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
+}
+
 static void sigp_restart(void *arg)
 {
     SigpInfo *si = arg;
@@ -1180,6 +1289,30 @@ static void sigp_cpu_reset(void *arg)
     si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
 }
 
+static void sigp_set_prefix(void *arg)
+{
+    SigpInfo *si = arg;
+    uint32_t addr = si->param & 0x7fffe000u;
+
+    cpu_synchronize_state(CPU(si->cpu));
+
+    if (!address_space_access_valid(&address_space_memory, addr,
+                                    sizeof(struct LowCore), false)) {
+        set_sigp_status(si, SIGP_STAT_INVALID_PARAMETER);
+        return;
+    }
+
+    /* cpu has to be stopped */
+    if (s390_cpu_get_state(si->cpu) != CPU_STATE_STOPPED) {
+        set_sigp_status(si, SIGP_STAT_INCORRECT_STATE);
+        return;
+    }
+
+    si->cpu->env.psa = addr;
+    cpu_synchronize_post_init(CPU(si->cpu));
+    si->cc = SIGP_CC_ORDER_CODE_ACCEPTED;
+}
+
 static int handle_sigp_single_dst(S390CPU *dst_cpu, uint8_t order,
                                   uint64_t param, uint64_t *status_reg)
 {
@@ -1194,12 +1327,32 @@ static int handle_sigp_single_dst(S390CPU *dst_cpu, uint8_t order,
         return SIGP_CC_NOT_OPERATIONAL;
     }
 
+    /* only resets can break pending orders */
+    if (dst_cpu->env.sigp_order != 0 &&
+        order != SIGP_CPU_RESET &&
+        order != SIGP_INITIAL_CPU_RESET) {
+        return SIGP_CC_BUSY;
+    }
+
     switch (order) {
     case SIGP_START:
         run_on_cpu(CPU(dst_cpu), sigp_start, &si);
         break;
+    case SIGP_STOP:
+        run_on_cpu(CPU(dst_cpu), sigp_stop, &si);
+        break;
     case SIGP_RESTART:
         run_on_cpu(CPU(dst_cpu), sigp_restart, &si);
+        break;
+    case SIGP_STOP_STORE_STATUS:
+        run_on_cpu(CPU(dst_cpu), sigp_stop_and_store_status, &si);
+        break;
+    case SIGP_STORE_STATUS_ADDR:
+        run_on_cpu(CPU(dst_cpu), sigp_store_status_at_address, &si);
+        break;
+    case SIGP_SET_PREFIX:
+        run_on_cpu(CPU(dst_cpu), sigp_set_prefix, &si);
+        break;
     case SIGP_INITIAL_CPU_RESET:
         run_on_cpu(CPU(dst_cpu), sigp_initial_cpu_reset, &si);
         break;
@@ -1214,6 +1367,48 @@ static int handle_sigp_single_dst(S390CPU *dst_cpu, uint8_t order,
     return si.cc;
 }
 
+static int sigp_set_architecture(S390CPU *cpu, uint32_t param,
+                                 uint64_t *status_reg)
+{
+    CPUState *cur_cs;
+    S390CPU *cur_cpu;
+
+    /* due to the BQL, we are the only active cpu */
+    CPU_FOREACH(cur_cs) {
+        cur_cpu = S390_CPU(cur_cs);
+        if (cur_cpu->env.sigp_order != 0) {
+            return SIGP_CC_BUSY;
+        }
+        cpu_synchronize_state(cur_cs);
+        /* all but the current one have to be stopped */
+        if (cur_cpu != cpu &&
+            s390_cpu_get_state(cur_cpu) != CPU_STATE_STOPPED) {
+            *status_reg &= 0xffffffff00000000ULL;
+            *status_reg |= SIGP_STAT_INCORRECT_STATE;
+            return SIGP_CC_STATUS_STORED;
+        }
+    }
+
+    switch (param & 0xff) {
+    case SIGP_MODE_ESA_S390:
+        /* not supported */
+        return SIGP_CC_NOT_OPERATIONAL;
+    case SIGP_MODE_Z_ARCH_TRANS_ALL_PSW:
+    case SIGP_MODE_Z_ARCH_TRANS_CUR_PSW:
+        CPU_FOREACH(cur_cs) {
+            cur_cpu = S390_CPU(cur_cs);
+            cur_cpu->env.pfault_token = -1UL;
+        }
+        break;
+    default:
+        *status_reg &= 0xffffffff00000000ULL;
+        *status_reg |= SIGP_STAT_INVALID_PARAMETER;
+        return SIGP_CC_STATUS_STORED;
+    }
+
+    return SIGP_CC_ORDER_CODE_ACCEPTED;
+}
+
 #define SIGP_ORDER_MASK 0x000000ff
 
 static int handle_sigp(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
@@ -1236,9 +1431,7 @@ static int handle_sigp(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
 
     switch (order) {
     case SIGP_SET_ARCH:
-        *status_reg &= 0xffffffff00000000ULL;
-        *status_reg |= SIGP_STAT_INVALID_PARAMETER;
-        ret = SIGP_CC_STATUS_STORED;
+        ret = sigp_set_architecture(cpu, param, status_reg);
         break;
     default:
         /* all other sigp orders target a single vcpu */
@@ -1357,6 +1550,11 @@ static int handle_intercept(S390CPU *cpu)
             if (s390_cpu_set_state(CPU_STATE_STOPPED, cpu) == 0) {
                 qemu_system_shutdown_request();
             }
+            if (cpu->env.sigp_order == SIGP_STOP_STORE_STATUS) {
+                kvm_s390_store_status(cpu, KVM_S390_STORE_STATUS_DEF_ADDR,
+                                      true);
+            }
+            cpu->env.sigp_order = 0;
             r = EXCP_HALTED;
             break;
         case ICPT_SOFT_INTERCEPT: