Some improvements for s390.

Two patches deal with address translation, one fixes a problem in the
 channel subsystem code.
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Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20140507' into staging

Some improvements for s390.

Two patches deal with address translation, one fixes a problem in the
channel subsystem code.

# gpg: Signature made Wed 07 May 2014 09:29:30 BST using RSA key ID C6F02FAF
# gpg: Can't check signature: public key not found

* remotes/cohuck/tags/s390x-20140507:
  s390x/css: Don't save orb in subchannel.
  s390x/helper: Added format control bit to MMU translation
  s390x/helper: Fixed real-to-absolute address translation

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/s390x/css.c

@@ -140,7 +140,6 @@ static void sch_handle_clear_func(SubchDev *sch)
     s->flags &= ~SCSW_FLAGS_MASK_PNO;
 
     /* We always 'attempt to issue the clear signal', and we always succeed. */
-    sch->orb = NULL;
     sch->channel_prog = 0x0;
     sch->last_cmd_valid = false;
     s->ctrl &= ~SCSW_ACTL_CLEAR_PEND;
@@ -163,7 +162,6 @@ static void sch_handle_halt_func(SubchDev *sch)
     path = 0x80;
 
     /* We always 'attempt to issue the halt signal', and we always succeed. */
-    sch->orb = NULL;
     sch->channel_prog = 0x0;
     sch->last_cmd_valid = false;
     s->ctrl &= ~SCSW_ACTL_HALT_PEND;
@@ -317,12 +315,11 @@ static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr)
     return ret;
 }
 
-static void sch_handle_start_func(SubchDev *sch)
+static void sch_handle_start_func(SubchDev *sch, ORB *orb)
 {
 
     PMCW *p = &sch->curr_status.pmcw;
     SCSW *s = &sch->curr_status.scsw;
-    ORB *orb = sch->orb;
     int path;
     int ret;
 
@@ -331,6 +328,7 @@ static void sch_handle_start_func(SubchDev *sch)
 
     if (!(s->ctrl & SCSW_ACTL_SUSP)) {
         /* Look at the orb and try to execute the channel program. */
+        assert(orb != NULL); /* resume does not pass an orb */
         p->intparm = orb->intparm;
         if (!(orb->lpm & path)) {
             /* Generate a deferred cc 3 condition. */
@@ -406,7 +404,7 @@ static void sch_handle_start_func(SubchDev *sch)
  * read/writes) asynchronous later on if we start supporting more than
  * our current very simple devices.
  */
-static void do_subchannel_work(SubchDev *sch)
+static void do_subchannel_work(SubchDev *sch, ORB *orb)
 {
 
     SCSW *s = &sch->curr_status.scsw;
@@ -416,7 +414,7 @@ static void do_subchannel_work(SubchDev *sch)
     } else if (s->ctrl & SCSW_FCTL_HALT_FUNC) {
         sch_handle_halt_func(sch);
     } else if (s->ctrl & SCSW_FCTL_START_FUNC) {
-        sch_handle_start_func(sch);
+        sch_handle_start_func(sch, orb);
     } else {
         /* Cannot happen. */
         return;
@@ -594,7 +592,6 @@ int css_do_xsch(SubchDev *sch)
                  SCSW_ACTL_SUSP);
     sch->channel_prog = 0x0;
     sch->last_cmd_valid = false;
-    sch->orb = NULL;
     s->dstat = 0;
     s->cstat = 0;
     ret = 0;
@@ -618,7 +615,7 @@ int css_do_csch(SubchDev *sch)
     s->ctrl &= ~(SCSW_CTRL_MASK_FCTL | SCSW_CTRL_MASK_ACTL);
     s->ctrl |= SCSW_FCTL_CLEAR_FUNC | SCSW_FCTL_CLEAR_FUNC;
 
-    do_subchannel_work(sch);
+    do_subchannel_work(sch, NULL);
     ret = 0;
 
 out:
@@ -659,7 +656,7 @@ int css_do_hsch(SubchDev *sch)
     }
     s->ctrl |= SCSW_ACTL_HALT_PEND;
 
-    do_subchannel_work(sch);
+    do_subchannel_work(sch, NULL);
     ret = 0;
 
 out:
@@ -721,13 +718,12 @@ int css_do_ssch(SubchDev *sch, ORB *orb)
     if (channel_subsys->chnmon_active) {
         css_update_chnmon(sch);
     }
-    sch->orb = orb;
     sch->channel_prog = orb->cpa;
     /* Trigger the start function. */
     s->ctrl |= (SCSW_FCTL_START_FUNC | SCSW_ACTL_START_PEND);
     s->flags &= ~SCSW_FLAGS_MASK_PNO;
 
-    do_subchannel_work(sch);
+    do_subchannel_work(sch, orb);
     ret = 0;
 
 out:
@@ -957,7 +953,7 @@ int css_do_rsch(SubchDev *sch)
     }
 
     s->ctrl |= SCSW_ACTL_RESUME_PEND;
-    do_subchannel_work(sch);
+    do_subchannel_work(sch, NULL);
     ret = 0;
 
 out:
@@ -1267,7 +1263,6 @@ void css_reset_sch(SubchDev *sch)
 
     sch->channel_prog = 0x0;
     sch->last_cmd_valid = false;
-    sch->orb = NULL;
     sch->thinint_active = false;
 }
 

hw/s390x/css.h

@@ -76,7 +76,6 @@ struct SubchDev {
     hwaddr channel_prog;
     CCW1 last_cmd;
     bool last_cmd_valid;
-    ORB *orb;
     bool thinint_active;
     /* transport-provided data: */
     int (*ccw_cb) (SubchDev *, CCW1);

hw/s390x/virtio-ccw.c

@@ -559,7 +559,6 @@ static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
     /* Initialize subchannel structure. */
     sch->channel_prog = 0x0;
     sch->last_cmd_valid = false;
-    sch->orb = NULL;
     sch->thinint_active = false;
     /*
      * Use a device number if provided. Otherwise, fall back to subchannel

target-s390x/cpu.h

@@ -270,6 +270,9 @@ typedef struct CPUS390XState {
 #define FLAG_MASK_64            (PSW_MASK_64     >> 32)
 #define FLAG_MASK_32            0x00001000
 
+/* Control register 0 bits */
+#define CR0_EDAT                0x0000000000800000ULL
+
 static inline int cpu_mmu_index (CPUS390XState *env)
 {
     if (env->psw.mask & PSW_MASK_PSTATE) {
@@ -927,6 +930,7 @@ struct sysib_322 {
 #define _REGION_ENTRY_LENGTH    0x03      /* region third length              */
 
 #define _SEGMENT_ENTRY_ORIGIN   ~0x7ffULL /* segment table origin             */
+#define _SEGMENT_ENTRY_FC       0x400     /* format control                   */
 #define _SEGMENT_ENTRY_RO       0x200     /* page protection bit              */
 #define _SEGMENT_ENTRY_INV      0x20      /* invalid segment table entry      */
 

target-s390x/helper.c

@@ -170,6 +170,64 @@ static void trigger_page_fault(CPUS390XState *env, target_ulong vaddr,
     trigger_pgm_exception(env, type, ilen);
 }
 
+/**
+ * Translate real address to absolute (= physical)
+ * address by taking care of the prefix mapping.
+ */
+static target_ulong mmu_real2abs(CPUS390XState *env, target_ulong raddr)
+{
+    if (raddr < 0x2000) {
+        return raddr + env->psa;    /* Map the lowcore. */
+    } else if (raddr >= env->psa && raddr < env->psa + 0x2000) {
+        return raddr - env->psa;    /* Map the 0 page. */
+    }
+    return raddr;
+}
+
+/* Decode page table entry (normal 4KB page) */
+static int mmu_translate_pte(CPUS390XState *env, target_ulong vaddr,
+                             uint64_t asc, uint64_t asce,
+                             target_ulong *raddr, int *flags, int rw)
+{
+    if (asce & _PAGE_INVALID) {
+        DPRINTF("%s: PTE=0x%" PRIx64 " invalid\n", __func__, asce);
+        trigger_page_fault(env, vaddr, PGM_PAGE_TRANS, asc, rw);
+        return -1;
+    }
+
+    if (asce & _PAGE_RO) {
+        *flags &= ~PAGE_WRITE;
+    }
+
+    *raddr = asce & _ASCE_ORIGIN;
+
+    PTE_DPRINTF("%s: PTE=0x%" PRIx64 "\n", __func__, asce);
+
+    return 0;
+}
+
+/* Decode EDAT1 segment frame absolute address (1MB page) */
+static int mmu_translate_sfaa(CPUS390XState *env, target_ulong vaddr,
+                              uint64_t asc, uint64_t asce, target_ulong *raddr,
+                              int *flags, int rw)
+{
+    if (asce & _SEGMENT_ENTRY_INV) {
+        DPRINTF("%s: SEG=0x%" PRIx64 " invalid\n", __func__, asce);
+        trigger_page_fault(env, vaddr, PGM_SEGMENT_TRANS, asc, rw);
+        return -1;
+    }
+
+    if (asce & _SEGMENT_ENTRY_RO) {
+        *flags &= ~PAGE_WRITE;
+    }
+
+    *raddr = (asce & 0xfffffffffff00000ULL) | (vaddr & 0xfffff);
+
+    PTE_DPRINTF("%s: SEG=0x%" PRIx64 "\n", __func__, asce);
+
+    return 0;
+}
+
 static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
                               uint64_t asc, uint64_t asce, int level,
                               target_ulong *raddr, int *flags, int rw)
@@ -229,28 +287,18 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
     PTE_DPRINTF("%s: 0x%" PRIx64 " + 0x%" PRIx64 " => 0x%016" PRIx64 "\n",
                 __func__, origin, offs, new_asce);
 
-    if (level != _ASCE_TYPE_SEGMENT) {
+    if (level == _ASCE_TYPE_SEGMENT) {
+        /* 4KB page */
+        return mmu_translate_pte(env, vaddr, asc, new_asce, raddr, flags, rw);
+    } else if (level - 4 == _ASCE_TYPE_SEGMENT &&
+               (new_asce & _SEGMENT_ENTRY_FC) && (env->cregs[0] & CR0_EDAT)) {
+        /* 1MB page */
+        return mmu_translate_sfaa(env, vaddr, asc, new_asce, raddr, flags, rw);
+    } else {
         /* yet another region */
         return mmu_translate_asce(env, vaddr, asc, new_asce, level - 4, raddr,
                                   flags, rw);
     }
-
-    /* PTE */
-    if (new_asce & _PAGE_INVALID) {
-        DPRINTF("%s: PTE=0x%" PRIx64 " invalid\n", __func__, new_asce);
-        trigger_page_fault(env, vaddr, PGM_PAGE_TRANS, asc, rw);
-        return -1;
-    }
-
-    if (new_asce & _PAGE_RO) {
-        *flags &= ~PAGE_WRITE;
-    }
-
-    *raddr = new_asce & _ASCE_ORIGIN;
-
-    PTE_DPRINTF("%s: PTE=0x%" PRIx64 "\n", __func__, new_asce);
-
-    return 0;
 }
 
 static int mmu_translate_asc(CPUS390XState *env, target_ulong vaddr,
@@ -363,9 +411,7 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
 
  out:
     /* Convert real address -> absolute address */
-    if (*raddr < 0x2000) {
+    *raddr = mmu_real2abs(env, *raddr);
-        *raddr = *raddr + env->psa;
-    }
 
     if (*raddr <= ram_size) {
         sk = &env->storage_keys[*raddr / TARGET_PAGE_SIZE];