Re: [libvirt] [PATCH qom-cpu 03/11] target-i386: kvm: -cpu host: Use GET_SUPPORTED_CPUID for SVM features
On Fri, Jan 04, 2013 at 08:01:04PM -0200, Eduardo Habkost wrote: The existing -cpu host code simply set every bit inside svm_features (initializing it to -1), and that makes it impossible to make the enforce/check options work properly when the user asks for SVM features explicitly in the command-line. So, instead of initializing svm_features to -1, use GET_SUPPORTED_CPUID to fill only the bits that are supported by the host (just like we do for all other CPUID feature words inside kvm_cpu_fill_host()). This will keep the existing behavior (as filter_features_for_kvm() already uses GET_SUPPORTED_CPUID to filter svm_features), but will allow us to properly check for KVM features inside kvm_check_features_against_host() later. For example, we will be able to make this: $ qemu-system-x86_64 -cpu ...,+pfthreshold,enforce refuse to start if the SVM pfthreshold feature is not supported by the host (after we fix kvm_check_features_against_host() to check SVM flags as well). Signed-off-by: Eduardo Habkost ehabk...@redhat.com Reviewed-by: Gleb Natapov g...@redhat.com --- Changes v2: - Coding style (indentation) fix Cc: Gleb Natapov g...@redhat.com Cc: Marcelo Tosatti mtosa...@redhat.com Cc: Joerg Roedel j...@8bytes.org Cc: k...@vger.kernel.org --- target-i386/cpu.c | 11 --- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index c83a566..c49a97c 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -908,13 +908,10 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def) } } -/* - * Every SVM feature requires emulation support in KVM - so we can't just - * read the host features here. KVM might even support SVM features not - * available on the host hardware. Just set all bits and mask out the - * unsupported ones later. - */ -x86_cpu_def-svm_features = -1; +/* Other KVM-specific feature fields: */ +x86_cpu_def-svm_features = +kvm_arch_get_supported_cpuid(s, 0x800A, 0, R_EDX); + #endif /* CONFIG_KVM */ } -- 1.7.11.7 -- Gleb. -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[libvirt] [PATCH qom-cpu 03/11] target-i386: kvm: -cpu host: Use GET_SUPPORTED_CPUID for SVM features
The existing -cpu host code simply set every bit inside svm_features (initializing it to -1), and that makes it impossible to make the enforce/check options work properly when the user asks for SVM features explicitly in the command-line. So, instead of initializing svm_features to -1, use GET_SUPPORTED_CPUID to fill only the bits that are supported by the host (just like we do for all other CPUID feature words inside kvm_cpu_fill_host()). This will keep the existing behavior (as filter_features_for_kvm() already uses GET_SUPPORTED_CPUID to filter svm_features), but will allow us to properly check for KVM features inside kvm_check_features_against_host() later. For example, we will be able to make this: $ qemu-system-x86_64 -cpu ...,+pfthreshold,enforce refuse to start if the SVM pfthreshold feature is not supported by the host (after we fix kvm_check_features_against_host() to check SVM flags as well). Signed-off-by: Eduardo Habkost ehabk...@redhat.com --- Changes v2: - Coding style (indentation) fix Cc: Gleb Natapov g...@redhat.com Cc: Marcelo Tosatti mtosa...@redhat.com Cc: Joerg Roedel j...@8bytes.org Cc: k...@vger.kernel.org --- target-i386/cpu.c | 11 --- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index c83a566..c49a97c 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -908,13 +908,10 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def) } } -/* - * Every SVM feature requires emulation support in KVM - so we can't just - * read the host features here. KVM might even support SVM features not - * available on the host hardware. Just set all bits and mask out the - * unsupported ones later. - */ -x86_cpu_def-svm_features = -1; +/* Other KVM-specific feature fields: */ +x86_cpu_def-svm_features = +kvm_arch_get_supported_cpuid(s, 0x800A, 0, R_EDX); + #endif /* CONFIG_KVM */ } -- 1.7.11.7 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
