Re: [PATCH qom-cpu 04/11] target-i386: kvm: Enable all supported KVM features for -cpu host

Gleb Natapov
2013-01-06T13:52:07Z

On Fri, Jan 04, 2013 at 08:01:05PM -0200, Eduardo Habkost wrote:
> When using -cpu host, we don't need to use the kvm_default_features
> variable, as the user is explicitly asking QEMU to enable all feature
> supported by the host.
>
> This changes the kvm_cpu_fill_host() code to use GET_SUPPORTED_CPUID to
> initialize the kvm_features field, so we get all host KVM features
> enabled.
>
> This will also allow use to properly check/enforce KVM features inside
> kvm_check_features_against_host() later. For example, we will be able to
> make this:
>
> $ qemu-system-x86_64 -cpu ...,+kvm_pv_eoi,enforce
>
> refuse to start if kvm_pv_eoi is not supported by the host (after we fix
> kvm_check_features_against_host() to check KVM flags as well).
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>

> ---
> Changes v2:
> - Coding style (indentation) fix
>
> Cc: Gleb Natapov <gleb@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> Cc: kvm@vger.kernel.org
> ---
> target-i386/cpu.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index c49a97c..e916ae0 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -911,6 +911,8 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> /* Other KVM-specific feature fields: */
> x86_cpu_def->svm_features =
> kvm_arch_get_supported_cpuid(s, 0x8000000A, 0, R_EDX);
> + x86_cpu_def->kvm_features =
> + kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
>
> #endif /* CONFIG_KVM */
> }
> --
> 1.7.11.7

--
Gleb.