target-ppc: Add hooks for handling tcg and kvm limitations

On target-ppc, our table of CPU types and features encodes the features as
found on the hardware, regardless of whether these features are actually
usable under TCG or KVM.  We already have cases where the information from
the cpu table must be fixed up to account for limitations in the emulation
method we're using.  e.g. TCG does not support the DFP and VSX instructions
and KVM needs different numbering of the CPUs in order to tell it the
correct thread to core mappings.

This patch cleans up these hacks to handle emulation limitations by
consolidating them into a pair of functions specifically for the purpose.

Signed-off-by: David Gibson <[email protected]>
[AF: Style and typo fixes, rename new functions and drop ppc_def_t arg]
Signed-off-by: Andreas Färber <[email protected]>

diff --git a/target-ppc/helper.c b/target-ppc/helper.c
index f61b8b261ecda77e2d2ad9eacb4a6210d7990359..b34dcbeb0fecd96bbb8e22fc370878d4125c39ef 100644 (file)
--- a/target-ppc/helper.c
+++ b/target-ppc/helper.c
@@ -3198,15 +3198,6 @@ CPUPPCState *cpu_ppc_init (const char *cpu_model)
     if (tcg_enabled()) {
         ppc_translate_init();
     }
-    /* Adjust cpu index for SMT */
-#if !defined(CONFIG_USER_ONLY)
-    if (kvm_enabled()) {
-        int smt = kvmppc_smt_threads();
-
-        env->cpu_index = (env->cpu_index / smp_threads)*smt
-            + (env->cpu_index % smp_threads);
-    }
-#endif /* !CONFIG_USER_ONLY */
     env->cpu_model_str = cpu_model;
     cpu_ppc_register_internal(env, def);
 

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index d929213a04f5091768e005345251a34a970e9671..c09cc39c78a7962b032b5a01c1d1d6a6132d065f 100644 (file)
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -27,6 +27,7 @@
 #include "kvm.h"
 #include "kvm_ppc.h"
 #include "cpu.h"
+#include "cpus.h"
 #include "device_tree.h"
 #include "hw/sysbus.h"
 #include "hw/spapr.h"
@@ -938,6 +939,19 @@ const ppc_def_t *kvmppc_host_cpu_def(void)
     return spec;
 }
 
+int kvmppc_fixup_cpu(CPUPPCState *env)
+{
+    int smt;
+
+    /* Adjust cpu index for SMT */
+    smt = kvmppc_smt_threads();
+    env->cpu_index = (env->cpu_index / smp_threads) * smt
+        + (env->cpu_index % smp_threads);
+
+    return 0;
+}
+
+
 bool kvm_arch_stop_on_emulation_error(CPUPPCState *env)
 {
     return true;

diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index 8f1267c6cc9a75fec89ed9bd79665a369425fd63..34ecad3e263c0b50a585c50fa4eaba2b57983672 100644 (file)
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -29,6 +29,7 @@ void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd);
 int kvmppc_remove_spapr_tce(void *table, int pfd, uint32_t window_size);
 #endif /* !CONFIG_USER_ONLY */
 const ppc_def_t *kvmppc_host_cpu_def(void);
+int kvmppc_fixup_cpu(CPUPPCState *env);
 
 #else
 
@@ -95,6 +96,10 @@ static inline const ppc_def_t *kvmppc_host_cpu_def(void)
     return NULL;
 }
 
+static inline int kvmppc_fixup_cpu(CPUPPCState *env)
+{
+    return -1;
+}
 #endif
 
 #ifndef CONFIG_KVM

diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index b1f87854a0a8df9f7dcb1237fa860332a71966c7..067e07ea548ca14a19c91d8a5e02ca31a925a371 100644 (file)
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -9889,6 +9889,28 @@ static int gdb_set_spe_reg(CPUPPCState *env, uint8_t *mem_buf, int n)
     return 0;
 }
 
+static int ppc_fixup_cpu(CPUPPCState *env)
+{
+    /* TCG doesn't (yet) emulate some groups of instructions that
+     * are implemented on some otherwise supported CPUs (e.g. VSX
+     * and decimal floating point instructions on POWER7).  We
+     * remove unsupported instruction groups from the cpu state's
+     * instruction masks and hope the guest can cope.  For at
+     * least the pseries machine, the unavailability of these
+     * instructions can be advertised to the guest via the device
+     * tree. */
+    if ((env->insns_flags & ~PPC_TCG_INSNS)
+        || (env->insns_flags2 & ~PPC_TCG_INSNS2)) {
+        fprintf(stderr, "Warning: Disabling some instructions which are not "
+                "emulated by TCG (0x%" PRIx64 ", 0x%" PRIx64 ")\n",
+                env->insns_flags & ~PPC_TCG_INSNS,
+                env->insns_flags2 & ~PPC_TCG_INSNS2);
+    }
+    env->insns_flags &= PPC_TCG_INSNS;
+    env->insns_flags2 &= PPC_TCG_INSNS2;
+    return 0;
+}
+
 int cpu_ppc_register_internal (CPUPPCState *env, const ppc_def_t *def)
 {
     env->msr_mask = def->msr_mask;
@@ -9897,25 +9919,22 @@ int cpu_ppc_register_internal (CPUPPCState *env, const ppc_def_t *def)
     env->bus_model = def->bus_model;
     env->insns_flags = def->insns_flags;
     env->insns_flags2 = def->insns_flags2;
-    if (!kvm_enabled()) {
-        /* TCG doesn't (yet) emulate some groups of instructions that
-         * are implemented on some otherwise supported CPUs (e.g. VSX
-         * and decimal floating point instructions on POWER7).  We
-         * remove unsupported instruction groups from the cpu state's
-         * instruction masks and hope the guest can cope.  For at
-         * least the pseries machine, the unavailability of these
-         * instructions can be advertise to the guest via the device
-         * tree.
-         *
-         * FIXME: we should have a similar masking for CPU features
-         * not accessible under KVM, but so far, there aren't any of
-         * those. */
-        env->insns_flags &= PPC_TCG_INSNS;
-        env->insns_flags2 &= PPC_TCG_INSNS2;
-    }
     env->flags = def->flags;
     env->bfd_mach = def->bfd_mach;
     env->check_pow = def->check_pow;
+
+    if (kvm_enabled()) {
+        if (kvmppc_fixup_cpu(env) != 0) {
+            fprintf(stderr, "Unable to virtualize selected CPU with KVM\n");
+            exit(1);
+        }
+    } else {
+        if (ppc_fixup_cpu(env) != 0) {
+            fprintf(stderr, "Unable to emulate selected CPU with TCG\n");
+            exit(1);
+        }
+    }
+
     if (create_ppc_opcodes(env, def) < 0)
         return -1;
     init_ppc_proc(env, def);