pc: Create pc_compat_2_1() functions

We will need new compat code for the 2.1 machine-types.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Rename KVM auto-feature-enable compat function

The x86_cpu_compat_disable_kvm_features() name was a bit confusing, as
it won't forcibly disable the feature for all CPU models (i.e. add it to
kvm_default_unset_features), but it will instead turn off the KVM
auto-enabling of the feature (i.e. remove it from kvm_default_features),
meaning the feature may still be enabled by default in some CPU models).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Disable CPUID_ACPI by default in KVM mode

KVM never supported the CPUID_ACPI flag, so it doesn't make sense to
have it enabled by default when KVM is enabled.

The motivation here is exactly the same we had for the MONITOR flag
(disabled by commit 136a7e9a85d7047461f8153f7d12c514a3d68f69).

And like in the MONITOR flag case, we don't need machine-type compat code
because it is currently impossible to run a KVM VM with the ACPI flag set.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Remove unsupported bits from all CPU models

The following CPU features were never supported by neither TCG or KVM,
so they are useless on the CPU model definitions, today:

 * CPUID_DTS (DS)
 * CPUID_HT
 * CPUID_TM
 * CPUID_PBE
 * CPUID_EXT_DTES64
 * CPUID_EXT_DSCPL
 * CPUID_EXT_EST
 * CPUID_EXT_TM2
 * CPUID_EXT_XTPR
 * CPUID_EXT_PDCM
 * CPUID_SVM_LBRV

As using "enforce" mode is the only way to ensure guest ABI doesn't
change when moving to a different host, we should make "enforce" mode
the default or at least encourage management software to always use it.

In turn, to make "enforce" usable, we need CPU models that work without
always requiring some features to be explicitly disabled. This patch
removes the above features from all CPU model definitions.

We won't need any machine-type compat code for those changes, because it
is impossible to have existing VMs with those features enabled.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Don't enable nested VMX by default

TCG doesn't support VMX, and nested VMX is not enabled by default in the
KVM kernel module.

So, there's no reason to have VMX enabled by default on the core2duo and
coreduo CPU models, today. Even the newer Intel CPU model definitions
don't have it enabled.

In this case, we need machine-type compat code, as people may be running
the older machine-types on hosts that had VMX nesting enabled.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Disable SVM by default in KVM mode

Make SVM be disabled by default on all CPU models when in KVM mode.
Nested SVM is enabled by default in the KVM kernel module, but it is
probably less stable than nested VMX (which is already disabled by
default).

Add a new compat function, x86_cpu_compat_kvm_no_autodisable(), to keep
compatibility on previous machine-types.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Merge remote-tracking branch 'remotes/afaerber/tags/qom-cpu-for-peter' into staging

QOM CPUState and X86CPU

* Cleanups for -cpu ...,enforce

* remotes/afaerber/tags/qom-cpu-for-peter:
  target-i386: Disable SVM by default in KVM mode
  target-i386: Don't enable nested VMX by default
  target-i386: Remove unsupported bits from all CPU models
  target-i386: Disable CPUID_ACPI by default in KVM mode
  target-i386: Rename KVM auto-feature-enable compat function
  pc: Create pc_compat_2_1() functions

Conflicts:
	hw/i386/pc_piix.c
	hw/i386/pc_q35.c
[PMM: Fixed minor textual conflicts]

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>