KVM: x86: Drop explicit @func param from ->set_supported_cpuid()

Drop the explicit @func param from ->set_supported_cpuid() and instead
pull the CPUID function from the relevant entry.  This sets the stage
for hardening guest CPUID updates in future patches, e.g. allows adding
run-time assertions that the CPUID feature being changed is actually
a bit in the referenced CPUID entry.

No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1161,7 +1161,7 @@ struct kvm_x86_ops {
 
 	void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
 
-	void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry);
+	void (*set_supported_cpuid)(struct kvm_cpuid_entry2 *entry);
 
 	bool (*has_wbinvd_exit)(void);
 

arch/x86/kvm/cpuid.c

@@ -784,7 +784,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		break;
 	}
 
-	kvm_x86_ops->set_supported_cpuid(function, entry);
+	kvm_x86_ops->set_supported_cpuid(entry);
 
 	r = 0;
 

arch/x86/kvm/svm.c

@@ -6035,9 +6035,9 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
 
 #define F feature_bit
 
-static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
+static void svm_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 {
-	switch (func) {
+	switch (entry->function) {
 	case 0x80000001:
 		if (nested)
 			entry->ecx |= (1 << 2); /* Set SVM bit */

arch/x86/kvm/vmx/vmx.c

@@ -7128,9 +7128,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	}
 }
 
-static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
+static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 {
-	if (func == 1 && nested)
+	if (entry->function == 1 && nested)
 		entry->ecx |= feature_bit(VMX);
 }