On Thu, Nov 16, 2023 at 02:31:05PM +0100, Jan Beulich wrote:
> ... or we fail to enable the functionality on the BSP for other reasons.
> The only place where hardware announcing the feature is recorded is the
> raw CPU policy/featureset.
>
> Inspired by
> https://lore.kernel.org/all/20230921114940.957141-1-pbonz...@redhat.com/.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
Acked-by: Roger Pau Monné <roger....@citrix.com>
>
> --- a/xen/arch/x86/hvm/svm/svm.c
> +++ b/xen/arch/x86/hvm/svm/svm.c
> @@ -2543,6 +2543,7 @@ const struct hvm_function_table * __init
>
> if ( _svm_cpu_up(true) )
> {
> + setup_clear_cpu_cap(X86_FEATURE_SVM);
> printk("SVM: failed to initialise.\n");
> return NULL;
> }
> --- a/xen/arch/x86/hvm/vmx/vmcs.c
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
> @@ -2163,6 +2163,23 @@ int __init vmx_vmcs_init(void)
>
> if ( !ret )
> register_keyhandler('v', vmcs_dump, "dump VT-x VMCSs", 1);
> + else
> + {
> + setup_clear_cpu_cap(X86_FEATURE_VMX);
> +
> + /*
> + * _vmx_vcpu_up() may have made it past feature identification.
> + * Make sure all dependent features are off as well.
> + */
> + vmx_basic_msr = 0;
> + vmx_pin_based_exec_control = 0;
> + vmx_cpu_based_exec_control = 0;
> + vmx_secondary_exec_control = 0;
> + vmx_vmexit_control = 0;
> + vmx_vmentry_control = 0;
> + vmx_ept_vpid_cap = 0;
> + vmx_vmfunc = 0;
Are there really any usages of those variables if VMX is disabled in
CPUID?
Thanks, Roger.
