[PATCH] target/s390x: Implement the MVPG condition-code-option bit

[Thomas Huth <thuth@redhat.com>]

If the CCO bit is set, MVPG should not generate an exception
but report page translation faults via a CC code, so we have
to check the translation in this case before calling the
access_prepare() function.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 This patch is required to get Claudio's new kvm-unit-tests patches
 working with TCG: https://www.spinics.net/lists/kvm/msg236784.html

 target/s390x/cpu.h         | 14 ++++++++++++++
 target/s390x/excp_helper.c | 14 --------------
 target/s390x/mem_helper.c  | 23 ++++++++++++++++++++++-
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 60d434d5ed..731e2c6452 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -366,6 +366,20 @@ static inline int cpu_mmu_index(CPUS390XState *env, bool ifetch)
 #endif
 }
 
+static inline uint64_t cpu_mmu_idx_to_asc(int mmu_idx)
+{
+    switch (mmu_idx) {
+    case MMU_PRIMARY_IDX:
+        return PSW_ASC_PRIMARY;
+    case MMU_SECONDARY_IDX:
+        return PSW_ASC_SECONDARY;
+    case MMU_HOME_IDX:
+        return PSW_ASC_HOME;
+    default:
+        abort();
+    }
+}
+
 static inline void cpu_get_tb_cpu_state(CPUS390XState* env, target_ulong *pc,
                                         target_ulong *cs_base, uint32_t *flags)
 {
diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
index ce16af394b..44bff27f8f 100644
--- a/target/s390x/excp_helper.c
+++ b/target/s390x/excp_helper.c
@@ -105,20 +105,6 @@ bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 
 #else /* !CONFIG_USER_ONLY */
 
-static inline uint64_t cpu_mmu_idx_to_asc(int mmu_idx)
-{
-    switch (mmu_idx) {
-    case MMU_PRIMARY_IDX:
-        return PSW_ASC_PRIMARY;
-    case MMU_SECONDARY_IDX:
-        return PSW_ASC_SECONDARY;
-    case MMU_HOME_IDX:
-        return PSW_ASC_HOME;
-    default:
-        abort();
-    }
-}
-
 bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                        MMUAccessType access_type, int mmu_idx,
                        bool probe, uintptr_t retaddr)
diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index 25cfede806..c7037adf2c 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -855,10 +855,31 @@ uint32_t HELPER(mvpg)(CPUS390XState *env, uint64_t r0, uint64_t r1, uint64_t r2)
     r1 = wrap_address(env, r1 & TARGET_PAGE_MASK);
     r2 = wrap_address(env, r2 & TARGET_PAGE_MASK);
 
+    /*
+     * If the condition-code-option (CCO) bit is set and DAT is enabled,
+     * we have to check for page table translation faults first:
+     */
+#ifndef CONFIG_USER_ONLY
+    if (extract64(r0, 8, 1) && mmu_idx != MMU_REAL_IDX) {
+        uint64_t asc = cpu_mmu_idx_to_asc(mmu_idx);
+        uint64_t raddr, tec;
+        int flags, exc;
+
+        exc = mmu_translate(env, r2, MMU_DATA_LOAD, asc, &raddr, &flags, &tec);
+        if (exc) {
+            return 2;
+        }
+
+        exc = mmu_translate(env, r1, MMU_DATA_STORE, asc, &raddr, &flags, &tec);
+        if (exc && exc != PGM_PROTECTION) {
+            return 1;
+        }
+    }
+#endif
+
     /*
      * TODO:
      * - Access key handling
-     * - CC-option with surpression of page-translation exceptions
      * - Store r1/r2 register identifiers at real location 162
      */
     srca = access_prepare(env, r2, TARGET_PAGE_SIZE, MMU_DATA_LOAD, mmu_idx,
-- 
2.27.0