KVM: x86: Add callback to let modules decide over some supported cpuid bits

This patch adds the get_supported_cpuid callback to
kvm_x86_ops. It will be used in do_cpuid_ent to delegate the
decission about some supported cpuid bits to the
architecture modules.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

(Cherry-picked from commit d4330ef2)

arch/x86/include/asm/kvm_host.h

@@ -541,6 +541,8 @@ struct kvm_x86_ops {
 	int (*get_lpage_level)(void);
 	bool (*rdtscp_supported)(void);
 
+	void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry);
+
 	const struct trace_print_flags *exit_reasons_str;
 };
 

arch/x86/kvm/svm.c

@@ -2907,6 +2907,10 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
 {
 }
 
+static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
+{
+}
+
 static const struct trace_print_flags svm_exit_reasons_str[] = {
 	{ SVM_EXIT_READ_CR0,           		"read_cr0" },
 	{ SVM_EXIT_READ_CR3,	      		"read_cr3" },
@@ -3051,6 +3055,8 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.cpuid_update = svm_cpuid_update,
 
 	.rdtscp_supported = svm_rdtscp_supported,
+
+	.set_supported_cpuid = svm_set_supported_cpuid,
 };
 
 static int __init svm_init(void)

arch/x86/kvm/vmx.c

@@ -4115,6 +4115,10 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	}
 }
 
+static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
+{
+}
+
 static struct kvm_x86_ops vmx_x86_ops = {
 	.cpu_has_kvm_support = cpu_has_kvm_support,
 	.disabled_by_bios = vmx_disabled_by_bios,
@@ -4186,6 +4190,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.cpuid_update = vmx_cpuid_update,
 
 	.rdtscp_supported = vmx_rdtscp_supported,
+
+	.set_supported_cpuid = vmx_set_supported_cpuid,
 };
 
 static int __init vmx_init(void)

arch/x86/kvm/x86.c

@@ -1917,6 +1917,9 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		entry->ecx &= kvm_supported_word6_x86_features;
 		break;
 	}
+
+	kvm_x86_ops->set_supported_cpuid(function, entry);
+
 	put_cpu();
 }