[RFC,3/4] NOT FOR MERGE target/i386: use x86-64-abi1 CPU model as default on x86_64

Commit Message

Daniel P. Berrangé Feb. 1, 2021, 3:36 p.m. UTC

The only differences between x86-64-abi1 and qemu64 is that the former
does not have the 'vme' or 'svm' flags.

In practice I don't think we should make this change, because it doesn't
especially add any value as-is. The only possible case is around 'svm'
because KVM already masks that feature, but TCG allows it. Thus using
x86-64-abi1 would mean that KVM and TCG expose a more consistent feature
set.

Also note that while libvirt can cope with default CPUs changing now,
it can't with the default CPU being a model name that it does not
already know about.

Signed-off-by: Daniel P. Berrangé <[e-mail]>
---
 hw/i386/pc_piix.c | 3 +++
 hw/i386/pc_q35.c  | 3 +++
 target/i386/cpu.h | 2 +-
 3 files changed, 7 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 6188c3e97e..c4c003599f 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -445,6 +445,9 @@  static void pc_i440fx_5_2_machine_options(MachineClass *m)
     m->is_default = false;
     compat_props_add(m->compat_props, hw_compat_5_2, hw_compat_5_2_len);
     compat_props_add(m->compat_props, pc_compat_5_2, pc_compat_5_2_len);
+#ifdef TARGET_X86_64
+    m->default_cpu_type = X86_CPU_TYPE_NAME("qemu64");
+#endif
 }
 
 DEFINE_I440FX_MACHINE(v5_2, "pc-i440fx-5.2", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 0a212443aa..606ac4f1f4 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -361,6 +361,9 @@  static void pc_q35_5_2_machine_options(MachineClass *m)
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_5_2, hw_compat_5_2_len);
     compat_props_add(m->compat_props, pc_compat_5_2, pc_compat_5_2_len);
+#ifdef TARGET_X86_64
+    m->default_cpu_type = X86_CPU_TYPE_NAME("qemu64");
+#endif
 }
 
 DEFINE_Q35_MACHINE(v5_2, "pc-q35-5.2", NULL,
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index d23a5b340a..0a436b575f 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1956,7 +1956,7 @@  uint64_t cpu_get_tsc(CPUX86State *env);
 #define CPU_RESOLVING_TYPE TYPE_X86_CPU
 
 #ifdef TARGET_X86_64
-#define TARGET_DEFAULT_CPU_TYPE X86_CPU_TYPE_NAME("qemu64")
+#define TARGET_DEFAULT_CPU_TYPE X86_CPU_TYPE_NAME("x86-64-abi1")
 #else
 #define TARGET_DEFAULT_CPU_TYPE X86_CPU_TYPE_NAME("qemu32")
 #endif