[Qemu-ppc] [PATCH RFC 4/4] PPC: KVM: Expose possible VSMT modes via QMP and HMP

[Sam Bobroff]

Use a new PPC KVM capability, KVM_PPC_CAP_SMT_POSSIBLE, to expose the
valid VSMT modes to users via a new info subcommand ("info vsmt") and
QMP clients.

Signed-off-by: Sam Bobroff <address@hidden>
---
 accel/kvm/kvm-all.c       |  2 ++
 hmp-commands-info.hx      | 14 ++++++++++++++
 hmp.c                     | 16 ++++++++++++++++
 hmp.h                     |  1 +
 hw/ppc/spapr.c            |  1 +
 include/sysemu/kvm.h      |  1 +
 linux-headers/linux/kvm.h |  1 +
 qapi-schema.json          | 28 ++++++++++++++++++++++++++++
 qmp.c                     | 20 ++++++++++++++++++++
 9 files changed, 84 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 75feffa504..fc44d3ae28 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -123,6 +123,7 @@ bool kvm_direct_msi_allowed;
 bool kvm_ioeventfd_any_length_allowed;
 bool kvm_msi_use_devid;
 static bool kvm_immediate_exit;
+uint64_t kvmppc_smt_possible;
 
 static const KVMCapabilityInfo kvm_required_capabilites[] = {
     KVM_CAP_INFO(USER_MEMORY),
@@ -1721,6 +1722,7 @@ static int kvm_init(MachineState *ms)
 #ifdef KVM_CAP_IRQ_ROUTING
     kvm_direct_msi_allowed = (kvm_check_extension(s, KVM_CAP_SIGNAL_MSI) > 0);
 #endif
+    kvmppc_smt_possible = kvm_check_extension(s, KVM_CAP_PPC_SMT_POSSIBLE);
 
     s->intx_set_mask = kvm_check_extension(s, KVM_CAP_PCI_2_3);
 
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index ae169011b1..eb0ca52395 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -304,6 +304,20 @@ Show KVM information.
 ETEXI
 
     {
+        .name       = "vsmt",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show VSMT information",
+        .cmd        = hmp_info_vsmt,
+    },
+
+STEXI
address@hidden info vsmt
address@hidden vsmt
+Show VSMT information.
+ETEXI
+
+    {
         .name       = "numa",
         .args_type  = "",
         .params     = "",
diff --git a/hmp.c b/hmp.c
index 8c72c58b20..207668c112 100644
--- a/hmp.c
+++ b/hmp.c
@@ -95,6 +95,22 @@ void hmp_info_kvm(Monitor *mon, const QDict *qdict)
     qapi_free_KvmInfo(info);
 }
 
+void hmp_info_vsmt(Monitor *mon, const QDict *qdict)
+{
+    VsmtInfo *info;
+    intList *entry;
+
+    info = qmp_query_vsmt(NULL);
+    monitor_printf(mon, "Host KVM supports these VSMT modes:");
+    entry = info->possible;
+    while (entry) {
+        monitor_printf(mon, " %ld", entry->value);
+        entry = entry->next;
+    }
+    qapi_free_VsmtInfo(info);
+    monitor_printf(mon, "\n");
+}
+
 void hmp_info_status(Monitor *mon, const QDict *qdict)
 {
     StatusInfo *info;
diff --git a/hmp.h b/hmp.h
index d8b94ce9dc..dfda944231 100644
--- a/hmp.h
+++ b/hmp.h
@@ -22,6 +22,7 @@
 void hmp_info_name(Monitor *mon, const QDict *qdict);
 void hmp_info_version(Monitor *mon, const QDict *qdict);
 void hmp_info_kvm(Monitor *mon, const QDict *qdict);
+void hmp_info_vsmt(Monitor *mon, const QDict *qdict);
 void hmp_info_status(Monitor *mon, const QDict *qdict);
 void hmp_info_uuid(Monitor *mon, const QDict *qdict);
 void hmp_info_chardev(Monitor *mon, const QDict *qdict);
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index c9ec1e87a1..d2536e2943 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2086,6 +2086,7 @@ static void ppc_set_vsmt_mode(sPAPRMachineState *spapr)
     /* else TCG: nothing to do currently */
     return;
 error:
+    error_report("Note: \"info vsmt\" shows supported VSMT modes (if any).");
     exit(1);
 
 }
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 1e91613ca9..dcde6cdd2d 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -54,6 +54,7 @@ extern bool kvm_readonly_mem_allowed;
 extern bool kvm_direct_msi_allowed;
 extern bool kvm_ioeventfd_any_length_allowed;
 extern bool kvm_msi_use_devid;
+extern uint64_t kvmppc_smt_possible;
 
 #if defined CONFIG_KVM || !defined NEED_CPU_H
 #define kvm_enabled()           (kvm_allowed)
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index d2892da172..be708cbf77 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -895,6 +895,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_SPAPR_TCE_VFIO 142
 #define KVM_CAP_X86_GUEST_MWAIT 143
 #define KVM_CAP_ARM_USER_IRQ 144
+#define KVM_CAP_PPC_SMT_POSSIBLE 146 /* NEEDS HEADER UPDATE */
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/qapi-schema.json b/qapi-schema.json
index 4b50b652d3..120721e658 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -230,6 +230,34 @@
 { 'command': 'query-kvm', 'returns': 'KvmInfo' }
 
 ##
+# @VsmtInfo:
+#
+# Information about VSMT modes
+#
+# @possible: list of available modes
+#
+# Since: 2.10
+##
+{ 'struct': 'VsmtInfo', 'data': {'possible': ['int'] } }
+
+##
+# @query-vsmt:
+#
+# Returns information about VSMT modes
+#
+# Returns: @VsmtInfo
+#
+# Since: 2.10
+#
+# Example:
+#
+# -> { "execute": "query-vsmt" }
+# <- { "return": { "possible": [8] } }
+#
+##
+{ 'command': 'query-vsmt', 'returns': 'VsmtInfo' }
+
+##
 # @RunState:
 #
 # An enumeration of VM run states.
diff --git a/qmp.c b/qmp.c
index 7ee9bcfdcf..7960e400e1 100644
--- a/qmp.c
+++ b/qmp.c
@@ -73,6 +73,26 @@ KvmInfo *qmp_query_kvm(Error **errp)
     return info;
 }
 
+VsmtInfo *qmp_query_vsmt(Error **errp)
+{
+    VsmtInfo *info = g_malloc0(sizeof(*info));
+    intList *list = NULL, *entry;
+    int i;
+
+    for (i = 63; i <= 0; i++) {
+        if ((1 << i) & kvmppc_smt_possible) {
+            entry = g_malloc0(sizeof(*entry));
+            entry->value = (1UL << i);
+            entry->next = list;
+            list = entry;
+        }
+    }
+
+    info->possible = list;
+
+    return info;
+}
+
 UuidInfo *qmp_query_uuid(Error **errp)
 {
     UuidInfo *info = g_malloc0(sizeof(*info));
-- 
2.12.1.382.gc0f9c7058