pseries: Move CPU compatibility property to machine

Server class POWER CPUs have a "compat" property, which is used to set the
backwards compatibility mode for the processor.  However, this only makes
sense for machine types which don't give the guest access to hypervisor
privilege - otherwise the compatibility level is under the guest's control.

To reflect this, this removes the CPU 'compat' property and instead
creates a 'max-cpu-compat' property on the pseries machine.  Strictly
speaking this breaks compatibility, but AFAIK the 'compat' option was
never (directly) used with -device or device_add.

The option was used with -cpu.  So, to maintain compatibility, this
patch adds a hack to the cpu option parsing to strip out any compat
options supplied with -cpu and set them on the machine property
instead of the now deprecated cpu property.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Tested-by: Andrea Bolognani <abologna@redhat.com>

3 files changed, 62 insertions, 7 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index ea44358..67d4c13 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2131,7 +2131,7 @@ static void ppc_spapr_init(MachineState *machine)
         machine->cpu_model = kvm_enabled() ? "host" : smc->tcg_default_cpu;
     }
 
-    ppc_cpu_parse_features(machine->cpu_model);
+    spapr_cpu_parse_features(spapr);
 
     spapr_init_cpus(spapr);
 
@@ -2503,6 +2503,10 @@ static void spapr_machine_initfn(Object *obj)
                                     " place of standard EPOW events when possible"
                                     " (required for memory hot-unplug support)",
                                     NULL);
+
+    ppc_compat_add_property(obj, "max-cpu-compat", &spapr->max_compat_pvr,
+                            "Maximum permitted CPU compatibility mode",
+                            &error_fatal);
 }
 
 static void spapr_machine_finalizefn(Object *obj)
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 9fb896b..97472fd 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -20,6 +20,57 @@
 #include "sysemu/numa.h"
 #include "qemu/error-report.h"
 
+void spapr_cpu_parse_features(sPAPRMachineState *spapr)
+{
+    /*
+     * Backwards compatibility hack:
+     *
+     *   CPUs had a "compat=" property which didn't make sense for
+     *   anything except pseries.  It was replaced by "max-cpu-compat"
+     *   machine option.  This supports old command lines like
+     *       -cpu POWER8,compat=power7
+     *   By stripping the compat option and applying it to the machine
+     *   before passing it on to the cpu level parser.
+     */
+    gchar **inpieces;
+    int i, j;
+    gchar *compat_str = NULL;
+
+    inpieces = g_strsplit(MACHINE(spapr)->cpu_model, ",", 0);
+
+    /* inpieces[0] is the actual model string */
+    i = 1;
+    j = 1;
+    while (inpieces[i]) {
+        if (g_str_has_prefix(inpieces[i], "compat=")) {
+            /* in case of multiple compat= options */
+            g_free(compat_str);
+            compat_str = inpieces[i];
+        } else {
+            j++;
+        }
+
+        i++;
+        /* Excise compat options from list */
+        inpieces[j] = inpieces[i];
+    }
+
+    if (compat_str) {
+        char *val = compat_str + strlen("compat=");
+        gchar *newprops = g_strjoinv(",", inpieces);
+
+        object_property_set_str(OBJECT(spapr), val, "max-cpu-compat",
+                                &error_fatal);
+
+        ppc_cpu_parse_features(newprops);
+        g_free(newprops);
+    } else {
+        ppc_cpu_parse_features(MACHINE(spapr)->cpu_model);
+    }
+
+    g_strfreev(inpieces);
+}
+
 static void spapr_cpu_reset(void *opaque)
 {
     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
@@ -67,10 +118,10 @@ static void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu,
     /* Enable PAPR mode in TCG or KVM */
     cpu_ppc_set_papr(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
 
-    if (cpu->max_compat) {
+    if (spapr->max_compat_pvr) {
         Error *local_err = NULL;
 
-        ppc_set_compat(cpu, cpu->max_compat, &local_err);
+        ppc_set_compat(cpu, spapr->max_compat_pvr, &local_err);
         if (local_err) {
             error_propagate(errp, local_err);
             return;
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index aa1ffea..8624ce8 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1045,11 +1045,11 @@ static target_ulong h_signal_sys_reset(PowerPCCPU *cpu,
     }
 }
 
-static uint32_t cas_check_pvr(PowerPCCPU *cpu, target_ulong *addr,
-                              Error **errp)
+static uint32_t cas_check_pvr(sPAPRMachineState *spapr, PowerPCCPU *cpu,
+                              target_ulong *addr, Error **errp)
 {
     bool explicit_match = false; /* Matched the CPU's real PVR */
-    uint32_t max_compat = cpu->max_compat;
+    uint32_t max_compat = spapr->max_compat_pvr;
     uint32_t best_compat = 0;
     int i;
 
@@ -1105,7 +1105,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
     bool guest_radix;
     Error *local_err = NULL;
 
-    cas_pvr = cas_check_pvr(cpu, &addr, &local_err);
+    cas_pvr = cas_check_pvr(spapr, cpu, &addr, &local_err);
     if (local_err) {
         error_report_err(local_err);
         return H_HARDWARE;