[Xen-devel] [PATCH 02/16] VMX: don't unconditionally set the tsc_scaling.setup hook

["Jan Beulich" <JBeulich@xxxxxxxx>]

Instead of checking hvm_tsc_scaling_supported inside the hook function,
install the hook only when setting state such that said predicate
becomes true.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1283,7 +1283,7 @@ static void vmx_handle_cd(struct vcpu *v
 
 static void vmx_setup_tsc_scaling(struct vcpu *v)
 {
-    if ( !hvm_tsc_scaling_supported || v->domain->arch.vtsc )
+    if ( v->domain->arch.vtsc )
         return;
 
     vmx_vmcs_enter(v);
@@ -2346,7 +2346,6 @@ static struct hvm_function_table __initd
     .altp2m_vcpu_emulate_vmfunc = vmx_vcpu_emulate_vmfunc,
     .tsc_scaling = {
         .max_ratio = VMX_TSC_MULTIPLIER_MAX,
-        .setup     = vmx_setup_tsc_scaling,
     },
 };
 
@@ -2486,7 +2485,10 @@ const struct hvm_function_table * __init
     }
 
     if ( cpu_has_vmx_tsc_scaling )
+    {
         vmx_function_table.tsc_scaling.ratio_frac_bits = 48;
+        vmx_function_table.tsc_scaling.setup = vmx_setup_tsc_scaling;
+    }
 
     if ( cpu_has_mpx && cpu_has_vmx_mpx )
     {





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