PowerPC : Add support for launching VM in 'compat' mode.

PowerISA allows processors to run VMs in binary compatibility ("compat")
mode supporting an older version of ISA. QEMU has recently added support to
explicitly denote a VM running in compatibility mode through commit 6d9412ea
& 8dfa3a5e85. Now, a "compat" mode VM can be run by invoking this qemu
commandline on a POWER8 host:  -cpu host,compat=power7.

This patch allows libvirt to exploit cpu mode 'host-model' to describe this
new mode for PowerKVM guests. For example, when a user wants to request a
power7 vm to run in compatibility mode on a Power8 host, this can be
described in XML as follows :

  <cpu mode='host-model'>
    <model>power7</model>
  </cpu>

Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Signed-off-by: Pradipta Kr. Banerjee <bpradip@in.ibm.com>
Acked-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c
index 5475c073d305139c39ada40a5304eeb17d7ba2cd..1c74c666a1f3bc7ef0d971b2a8c234e005d37220 100644 (file)
--- a/src/conf/cpu_conf.c
+++ b/src/conf/cpu_conf.c
@@ -619,6 +619,7 @@ virCPUDefFormatBuf(virBufferPtr buf,
         return 0;
 
     formatModel = (def->mode == VIR_CPU_MODE_CUSTOM ||
+                   def->mode == VIR_CPU_MODE_HOST_MODEL ||
                    (flags & VIR_DOMAIN_XML_UPDATE_CPU));
     formatFallback = (def->type == VIR_CPU_TYPE_GUEST &&
                       (def->mode == VIR_CPU_MODE_HOST_MODEL ||

diff --git a/src/cpu/cpu_powerpc.c b/src/cpu/cpu_powerpc.c
index d591c184ab8d4e8bf45a27bb46dc163601c85a86..4ea1835d52640bca0930536c3610f7584f6eec33 100644 (file)
--- a/src/cpu/cpu_powerpc.c
+++ b/src/cpu/cpu_powerpc.c
@@ -562,8 +562,8 @@ ppcUpdate(virCPUDefPtr guest,
 static virCPUDefPtr
 ppcBaseline(virCPUDefPtr *cpus,
             unsigned int ncpus,
-            const char **models,
-            unsigned int nmodels,
+            const char **models ATTRIBUTE_UNUSED,
+            unsigned int nmodels ATTRIBUTE_UNUSED,
             unsigned int flags)
 {
     struct ppc_map *map = NULL;
@@ -583,13 +583,6 @@ ppcBaseline(virCPUDefPtr *cpus,
         goto error;
     }
 
-    if (!cpuModelIsAllowed(model->name, models, nmodels)) {
-        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                        _("CPU model %s is not supported by hypervisor"),
-                        model->name);
-        goto error;
-    }
-
     for (i = 0; i < ncpus; i++) {
         const struct ppc_vendor *vnd;
 

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index bd56b05c9d394577b82f7dc93a0c26f13f4e7c41..e031dca0b792c6cbee7cc45f4aede9ca0ba94a67 100644 (file)
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6226,7 +6226,9 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver,
         *hasHwVirt = hasSVM > 0 ? true : false;
     }
 
-    if (cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH) {
+    if ((cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH) ||
+        ((cpu->mode == VIR_CPU_MODE_HOST_MODEL) &&
+          ARCH_IS_PPC64(def->os.arch))) {
         const char *mode = virCPUModeTypeToString(cpu->mode);
         if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_CPU_HOST)) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@@ -6241,6 +6243,12 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver,
             goto cleanup;
         }
         virBufferAddLit(buf, "host");
+
+        if (ARCH_IS_PPC64(def->os.arch) &&
+            cpu->mode == VIR_CPU_MODE_HOST_MODEL) {
+            virBufferAsprintf(buf, ",compat=%s", def->cpu->model);
+        }
+
     } else {
         if (VIR_ALLOC(guest) < 0)
             goto cleanup;