Re: [qom-cpu PATCH 3/3] target-i386: Don't enable nested VMX by default

[Paolo Bonzini <pbonzini@redhat.com>]

Il 18/06/2014 21:55, Eduardo Habkost ha scritto:
> TCG doesn't support VMX, and nested VMX is not enabled by default on 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>
> ---
>  hw/i386/pc_piix.c | 2 ++
>  hw/i386/pc_q35.c  | 2 ++
>  target-i386/cpu.c | 8 ++++----
>  3 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index a48e263..61882d5 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -267,6 +267,8 @@ static void pc_init_pci(MachineState *machine)
>  static void pc_compat_2_0(MachineState *machine)
>  {
>      smbios_legacy_mode = true;
> +    x86_cpu_compat_set_features("coreduo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
> +    x86_cpu_compat_set_features("core2duo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
>  }
>
>  static void pc_compat_1_7(MachineState *machine)
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index b3c02c1..3949267 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -245,6 +245,8 @@ static void pc_q35_init(MachineState *machine)
>  static void pc_compat_2_0(MachineState *machine)
>  {
>      smbios_legacy_mode = true;
> +    x86_cpu_compat_set_features("coreduo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
> +    x86_cpu_compat_set_features("core2duo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
>  }
>
>  static void pc_compat_1_7(MachineState *machine)
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 2f32d29..6bd44e1 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -719,10 +719,10 @@ static X86CPUDefinition builtin_x86_defs[] = {
>              CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA |
>              CPUID_PSE36 | CPUID_VME | CPUID_ACPI | CPUID_SS,
>          /* Missing: CPUID_EXT_DTES64, CPUID_EXT_DSCPL, CPUID_EXT_EST,
> -         * CPUID_EXT_TM2, CPUID_EXT_XTPR, CPUID_EXT_PDCM */
> +         * CPUID_EXT_TM2, CPUID_EXT_XTPR, CPUID_EXT_PDCM, CPUID_EXT_VMX */
>          .features[FEAT_1_ECX] =
>              CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_SSSE3 |
> -            CPUID_EXT_VMX | CPUID_EXT_CX16,
> +            CPUID_EXT_CX16,
>          .features[FEAT_8000_0001_EDX] =
>              CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
>          .features[FEAT_8000_0001_ECX] =
> @@ -803,9 +803,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
>              CPUID_MTRR | CPUID_CLFLUSH | CPUID_MCA | CPUID_ACPI |
>              CPUID_SS,
>          /* Missing: CPUID_EXT_EST, CPUID_EXT_TM2 , CPUID_EXT_XTPR,
> -         * CPUID_EXT_PDCM */
> +         * CPUID_EXT_PDCM, CPUID_EXT_VMX */
>          .features[FEAT_1_ECX] =
> -            CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_VMX,
> +            CPUID_EXT_SSE3 | CPUID_EXT_MONITOR,
>          .features[FEAT_8000_0001_EDX] =
>              CPUID_EXT2_NX,
>          .xlevel = 0x80000008,
>

Could you please do the same for SVM, perhaps with the exception of 
qemu64?  Nested SVM is enabled by default upstream, but right now it is 
probably less stable than nested VMX.

Paolo