target-ppc: Update ppc_hash64_store_hpte to support updating in-kernel htab

This support updating htab managed by the hypervisor. Currently we don't have
any user for this feature. This actually bring the store_hpte interface
in-line with the load_hpte one. We may want to use this when we want to
emulate henter hcall in qemu for HV kvm.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ folded fix for the "warn_unused_result" build break in
  kvmppc_hash64_write_pte(), Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

target-ppc/kvm.c

@@ -1992,3 +1992,39 @@ void kvmppc_hash64_free_pteg(uint64_t token)
     g_free(htab_buf);
     return;
 }
+
+void kvmppc_hash64_write_pte(CPUPPCState *env, target_ulong pte_index,
+                             target_ulong pte0, target_ulong pte1)
+{
+    int htab_fd;
+    struct kvm_get_htab_fd ghf;
+    struct kvm_get_htab_buf hpte_buf;
+
+    ghf.flags = 0;
+    ghf.start_index = 0;     /* Ignored */
+    htab_fd = kvm_vm_ioctl(kvm_state, KVM_PPC_GET_HTAB_FD, &ghf);
+    if (htab_fd < 0) {
+        goto error_out;
+    }
+
+    hpte_buf.header.n_valid = 1;
+    hpte_buf.header.n_invalid = 0;
+    hpte_buf.header.index = pte_index;
+    hpte_buf.hpte[0] = pte0;
+    hpte_buf.hpte[1] = pte1;
+    /*
+     * Write the hpte entry.
+     * CAUTION: write() has the warn_unused_result attribute. Hence we
+     * need to check the return value, even though we do nothing.
+     */
+    if (write(htab_fd, &hpte_buf, sizeof(hpte_buf)) < 0) {
+        goto out_close;
+    }
+
+out_close:
+    close(htab_fd);
+    return;
+
+error_out:
+    return;
+}

target-ppc/kvm_ppc.h

@@ -47,6 +47,9 @@ int kvmppc_load_htab_chunk(QEMUFile *f, int fd, uint32_t index,
 uint64_t kvmppc_hash64_read_pteg(PowerPCCPU *cpu, target_ulong pte_index);
 void kvmppc_hash64_free_pteg(uint64_t token);
 
+void kvmppc_hash64_write_pte(CPUPPCState *env, target_ulong pte_index,
+                             target_ulong pte0, target_ulong pte1);
+
 #else
 
 static inline uint32_t kvmppc_get_tbfreq(void)
@@ -207,6 +210,13 @@ static inline void kvmppc_hash64_free_pteg(uint64_t token)
     abort();
 }
 
+static inline void kvmppc_hash64_write_pte(CPUPPCState *env,
+                                           target_ulong pte_index,
+                                           target_ulong pte0, target_ulong pte1)
+{
+    abort();
+}
+
 #endif
 
 #ifndef CONFIG_KVM

target-ppc/mmu-hash64.c

@@ -603,3 +603,23 @@ hwaddr ppc_hash64_get_phys_page_debug(CPUPPCState *env, target_ulong addr)
 
     return ppc_hash64_pte_raddr(slb, pte, addr) & TARGET_PAGE_MASK;
 }
+
+void ppc_hash64_store_hpte(CPUPPCState *env,
+                           target_ulong pte_index,
+                           target_ulong pte0, target_ulong pte1)
+{
+    CPUState *cs = ENV_GET_CPU(env);
+
+    if (kvmppc_kern_htab) {
+        return kvmppc_hash64_write_pte(env, pte_index, pte0, pte1);
+    }
+
+    pte_index *= HASH_PTE_SIZE_64;
+    if (env->external_htab) {
+        stq_p(env->external_htab + pte_index, pte0);
+        stq_p(env->external_htab + pte_index + HASH_PTE_SIZE_64/2, pte1);
+    } else {
+        stq_phys(cs->as, env->htab_base + pte_index, pte0);
+        stq_phys(cs->as, env->htab_base + pte_index + HASH_PTE_SIZE_64/2, pte1);
+    }
+}

target-ppc/mmu-hash64.h

@@ -9,6 +9,8 @@ int ppc_store_slb (CPUPPCState *env, target_ulong rb, target_ulong rs);
 hwaddr ppc_hash64_get_phys_page_debug(CPUPPCState *env, target_ulong addr);
 int ppc_hash64_handle_mmu_fault(CPUPPCState *env, target_ulong address, int rw,
                                 int mmu_idx);
+void ppc_hash64_store_hpte(CPUPPCState *env, target_ulong index,
+                           target_ulong pte0, target_ulong pte1);
 #endif
 
 /*
@@ -106,21 +108,6 @@ static inline target_ulong ppc_hash64_load_hpte1(CPUPPCState *env,
     }
 }
 
-static inline void ppc_hash64_store_hpte(CPUPPCState *env,
-                                         target_ulong pte_index,
-                                         target_ulong pte0, target_ulong pte1)
-{
-    CPUState *cs = ENV_GET_CPU(env);
-    pte_index *= HASH_PTE_SIZE_64;
-    if (env->external_htab) {
-        stq_p(env->external_htab + pte_index, pte0);
-        stq_p(env->external_htab + pte_index + HASH_PTE_SIZE_64/2, pte1);
-    } else {
-        stq_phys(cs->as, env->htab_base + pte_index, pte0);
-        stq_phys(cs->as, env->htab_base + pte_index + HASH_PTE_SIZE_64/2, pte1);
-    }
-}
-
 typedef struct {
     uint64_t pte0, pte1;
 } ppc_hash_pte64_t;