s390x/tcg: STSI overhaul

Current STSI implementation is a mess, so let's rewrite it.

Problems fixed by this patch:
1) The order of exceptions/when recognized is wrong.
2) We have to store to virtual address space, not absolute.
3) Alignment check of the block is missing.
3) The SMP information is not indicated.

While at it:
a) Make the code look nicer
    - get rid of nesting levels
    - use struct initialization instead of initializing to zero
    - rename a misspelled field and rename function code defines
    - use a union and have only one write statement
    - use cpu_to_beX()
b) Indicate the VM name/extended name + UUID just like KVM does
c) Indicate that all LPAR CPUs we fake are dedicated
d) Add a comment why we fake being a KVM guest
e) Give our guest as default the name "TCGguest"
f) Fake the same CPU information we have in our Guest for all layers

While at it, get rid of "potential_page_fault()" by forwarding the
retaddr properly.

The result is best verified by looking at "/proc/sysinfo" in the guest
when specifying on the qemu command line
    -uuid "74738ff5-5367-5958-9aee-98fffdcd1876" \
    -name "extra long guest name"

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180129125623.21729-14-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 115 insertions, 97 deletions

diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
index 466231de0b..c1ff152571 100644
--- a/target/s390x/misc_helper.c
+++ b/target/s390x/misc_helper.c
@@ -37,6 +37,8 @@
 #include "hw/s390x/s390-virtio-hcall.h"
 #include "hw/s390x/sclp.h"
 #include "hw/s390x/s390_flic.h"
+#include "hw/s390x/ioinst.h"
+#include "hw/boards.h"
 #endif
 
 /* #define DEBUG_HELPER */
@@ -195,132 +197,148 @@ void HELPER(spt)(CPUS390XState *env, uint64_t time)
 }
 
 /* Store System Information */
-uint32_t HELPER(stsi)(CPUS390XState *env, uint64_t a0,
-                      uint64_t r0, uint64_t r1)
+uint32_t HELPER(stsi)(CPUS390XState *env, uint64_t a0, uint64_t r0, uint64_t r1)
 {
+    const uintptr_t ra = GETPC();
+    const uint32_t sel1 = r0 & STSI_R0_SEL1_MASK;
+    const uint32_t sel2 = r1 & STSI_R1_SEL2_MASK;
+    const MachineState *ms = MACHINE(qdev_get_machine());
+    uint16_t total_cpus = 0, conf_cpus = 0, reserved_cpus = 0;
     S390CPU *cpu = s390_env_get_cpu(env);
-    int cc = 0;
-    int sel1, sel2;
+    SysIB sysib = { 0 };
+    int i, cc = 0;
+
+    if ((r0 & STSI_R0_FC_MASK) > STSI_R0_FC_LEVEL_3) {
+        /* invalid function code: no other checks are performed */
+        return 3;
+    }
 
-    if ((r0 & STSI_LEVEL_MASK) <= STSI_LEVEL_3 &&
-        ((r0 & STSI_R0_RESERVED_MASK) || (r1 & STSI_R1_RESERVED_MASK))) {
-        /* valid function code, invalid reserved bits */
-        s390_program_interrupt(env, PGM_SPECIFICATION, 4, GETPC());
+    if ((r0 & STSI_R0_RESERVED_MASK) || (r1 & STSI_R1_RESERVED_MASK)) {
+        s390_program_interrupt(env, PGM_SPECIFICATION, 4, ra);
     }
 
-    sel1 = r0 & STSI_R0_SEL1_MASK;
-    sel2 = r1 & STSI_R1_SEL2_MASK;
+    if ((r0 & STSI_R0_FC_MASK) == STSI_R0_FC_CURRENT) {
+        /* query the current level: no further checks are performed */
+        env->regs[0] = STSI_R0_FC_LEVEL_3;
+        return 0;
+    }
 
-    /* XXX: spec exception if sysib is not 4k-aligned */
+    if (a0 & ~TARGET_PAGE_MASK) {
+        s390_program_interrupt(env, PGM_SPECIFICATION, 4, ra);
+    }
 
-    switch (r0 & STSI_LEVEL_MASK) {
-    case STSI_LEVEL_1:
+    /* count the cpus and split them into configured and reserved ones */
+    for (i = 0; i < ms->possible_cpus->len; i++) {
+        total_cpus++;
+        if (ms->possible_cpus->cpus[i].cpu) {
+            conf_cpus++;
+        } else {
+            reserved_cpus++;
+        }
+    }
+
+    /*
+     * In theory, we could report Level 1 / Level 2 as current. However,
+     * the Linux kernel will detect this as running under LPAR and assume
+     * that we have a sclp linemode console (which is always present on
+     * LPAR, but not the default for QEMU), therefore not displaying boot
+     * messages and making booting a Linux kernel under TCG harder.
+     *
+     * For now we fake the same SMP configuration on all levels.
+     *
+     * TODO: We could later make the level configurable via the machine
+     *       and change defaults (linemode console) based on machine type
+     *       and accelerator.
+     */
+    switch (r0 & STSI_R0_FC_MASK) {
+    case STSI_R0_FC_LEVEL_1:
         if ((sel1 == 1) && (sel2 == 1)) {
             /* Basic Machine Configuration */
-            SysIB_111 sysib;
             char type[5] = {};
 
-            memset(&sysib, 0, sizeof(sysib));
-            ebcdic_put(sysib.manuf, "QEMU            ", 16);
+            ebcdic_put(sysib.sysib_111.manuf, "QEMU            ", 16);
             /* same as machine type number in STORE CPU ID, but in EBCDIC */
             snprintf(type, ARRAY_SIZE(type), "%X", cpu->model->def->type);
-            ebcdic_put(sysib.type, type, 4);
+            ebcdic_put(sysib.sysib_111.type, type, 4);
             /* model number (not stored in STORE CPU ID for z/Architecure) */
-            ebcdic_put(sysib.model, "QEMU            ", 16);
-            ebcdic_put(sysib.sequence, "QEMU            ", 16);
-            ebcdic_put(sysib.plant, "QEMU", 4);
-            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
+            ebcdic_put(sysib.sysib_111.model, "QEMU            ", 16);
+            ebcdic_put(sysib.sysib_111.sequence, "QEMU            ", 16);
+            ebcdic_put(sysib.sysib_111.plant, "QEMU", 4);
         } else if ((sel1 == 2) && (sel2 == 1)) {
             /* Basic Machine CPU */
-            SysIB_121 sysib;
-
-            memset(&sysib, 0, sizeof(sysib));
-            /* XXX make different for different CPUs? */
-            ebcdic_put(sysib.sequence, "QEMUQEMUQEMUQEMU", 16);
-            ebcdic_put(sysib.plant, "QEMU", 4);
-            stw_p(&sysib.cpu_addr, env->core_id);
-            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
+            ebcdic_put(sysib.sysib_121.sequence, "QEMUQEMUQEMUQEMU", 16);
+            ebcdic_put(sysib.sysib_121.plant, "QEMU", 4);
+            sysib.sysib_121.cpu_addr = cpu_to_be16(env->core_id);
         } else if ((sel1 == 2) && (sel2 == 2)) {
             /* Basic Machine CPUs */
-            SysIB_122 sysib;
-
-            memset(&sysib, 0, sizeof(sysib));
-            stl_p(&sysib.capability, 0x443afc29);
-            /* XXX change when SMP comes */
-            stw_p(&sysib.total_cpus, 1);
-            stw_p(&sysib.active_cpus, 1);
-            stw_p(&sysib.standby_cpus, 0);
-            stw_p(&sysib.reserved_cpus, 0);
-            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
+            sysib.sysib_122.capability = cpu_to_be32(0x443afc29);
+            sysib.sysib_122.total_cpus = cpu_to_be16(total_cpus);
+            sysib.sysib_122.conf_cpus = cpu_to_be16(conf_cpus);
+            sysib.sysib_122.reserved_cpus = cpu_to_be16(reserved_cpus);
         } else {
             cc = 3;
         }
         break;
-    case STSI_LEVEL_2:
-        {
-            if ((sel1 == 2) && (sel2 == 1)) {
-                /* LPAR CPU */
-                SysIB_221 sysib;
-
-                memset(&sysib, 0, sizeof(sysib));
-                /* XXX make different for different CPUs? */
-                ebcdic_put(sysib.sequence, "QEMUQEMUQEMUQEMU", 16);
-                ebcdic_put(sysib.plant, "QEMU", 4);
-                stw_p(&sysib.cpu_addr, env->core_id);
-                stw_p(&sysib.cpu_id, 0);
-                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
-            } else if ((sel1 == 2) && (sel2 == 2)) {
-                /* LPAR CPUs */
-                SysIB_222 sysib;
-
-                memset(&sysib, 0, sizeof(sysib));
-                stw_p(&sysib.lpar_num, 0);
-                sysib.lcpuc = 0;
-                /* XXX change when SMP comes */
-                stw_p(&sysib.total_cpus, 1);
-                stw_p(&sysib.conf_cpus, 1);
-                stw_p(&sysib.standby_cpus, 0);
-                stw_p(&sysib.reserved_cpus, 0);
-                ebcdic_put(sysib.name, "QEMU    ", 8);
-                stl_p(&sysib.caf, 1000);
-                stw_p(&sysib.dedicated_cpus, 0);
-                stw_p(&sysib.shared_cpus, 0);
-                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
-            } else {
-                cc = 3;
-            }
-            break;
+    case STSI_R0_FC_LEVEL_2:
+        if ((sel1 == 2) && (sel2 == 1)) {
+            /* LPAR CPU */
+            ebcdic_put(sysib.sysib_221.sequence, "QEMUQEMUQEMUQEMU", 16);
+            ebcdic_put(sysib.sysib_221.plant, "QEMU", 4);
+            sysib.sysib_221.cpu_addr = cpu_to_be16(env->core_id);
+        } else if ((sel1 == 2) && (sel2 == 2)) {
+            /* LPAR CPUs */
+            sysib.sysib_222.lcpuc = 0x80; /* dedicated */
+            sysib.sysib_222.total_cpus = cpu_to_be16(total_cpus);
+            sysib.sysib_222.conf_cpus = cpu_to_be16(conf_cpus);
+            sysib.sysib_222.reserved_cpus = cpu_to_be16(reserved_cpus);
+            ebcdic_put(sysib.sysib_222.name, "QEMU    ", 8);
+            sysib.sysib_222.caf = cpu_to_be32(1000);
+            sysib.sysib_222.dedicated_cpus = cpu_to_be16(conf_cpus);
+        } else {
+            cc = 3;
         }
-    case STSI_LEVEL_3:
-        {
-            if ((sel1 == 2) && (sel2 == 2)) {
-                /* VM CPUs */
-                SysIB_322 sysib;
-
-                memset(&sysib, 0, sizeof(sysib));
-                sysib.count = 1;
-                /* XXX change when SMP comes */
-                stw_p(&sysib.vm[0].total_cpus, 1);
-                stw_p(&sysib.vm[0].conf_cpus, 1);
-                stw_p(&sysib.vm[0].standby_cpus, 0);
-                stw_p(&sysib.vm[0].reserved_cpus, 0);
-                ebcdic_put(sysib.vm[0].name, "KVMguest", 8);
-                stl_p(&sysib.vm[0].caf, 1000);
-                ebcdic_put(sysib.vm[0].cpi, "KVM/Linux       ", 16);
-                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
+        break;
+    case STSI_R0_FC_LEVEL_3:
+        if ((sel1 == 2) && (sel2 == 2)) {
+            /* VM CPUs */
+            sysib.sysib_322.count = 1;
+            sysib.sysib_322.vm[0].total_cpus = cpu_to_be16(total_cpus);
+            sysib.sysib_322.vm[0].conf_cpus = cpu_to_be16(conf_cpus);
+            sysib.sysib_322.vm[0].reserved_cpus = cpu_to_be16(reserved_cpus);
+            sysib.sysib_322.vm[0].caf = cpu_to_be32(1000);
+            /* Linux kernel uses this to distinguish us from z/VM */
+            ebcdic_put(sysib.sysib_322.vm[0].cpi, "KVM/Linux       ", 16);
+            sysib.sysib_322.vm[0].ext_name_encoding = 2; /* UTF-8 */
+
+            /* If our VM has a name, use the real name */
+            if (qemu_name) {
+                memset(sysib.sysib_322.vm[0].name, 0x40,
+                       sizeof(sysib.sysib_322.vm[0].name));
+                ebcdic_put(sysib.sysib_322.vm[0].name, qemu_name,
+                           MIN(sizeof(sysib.sysib_322.vm[0].name),
+                               strlen(qemu_name)));
+                strncpy((char *)sysib.sysib_322.ext_names[0], qemu_name,
+                        sizeof(sysib.sysib_322.ext_names[0]));
             } else {
-                cc = 3;
+                ebcdic_put(sysib.sysib_322.vm[0].name, "TCGguest", 8);
+                strcpy((char *)sysib.sysib_322.ext_names[0], "TCGguest");
             }
-            break;
+
+            /* add the uuid */
+            memcpy(sysib.sysib_322.vm[0].uuid, &qemu_uuid,
+                   sizeof(sysib.sysib_322.vm[0].uuid));
+        } else {
+            cc = 3;
         }
-    case STSI_LEVEL_CURRENT:
-        env->regs[0] = STSI_LEVEL_3;
-        break;
-    default:
-        cc = 3;
         break;
     }
 
+    if (cc == 0) {
+        if (s390_cpu_virt_mem_write(cpu, a0, 0, &sysib, sizeof(sysib))) {
+            s390_cpu_virt_mem_handle_exc(cpu, ra);
+        }
+    }
+
     return cc;
 }