KVM: x86: Rename gb_page_enable() to get_lpage_level() in kvm_x86_ops

Then the callback can provide the maximum supported large page level, which
is more flexible.

Also move the gb page support into x86_64 specific.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -528,7 +528,7 @@ struct kvm_x86_ops {
 	int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
 	int (*get_tdp_level)(void);
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
-	bool (*gb_page_enable)(void);
+	int (*get_lpage_level)(void);
 	bool (*rdtscp_supported)(void);
 
 	const struct trace_print_flags *exit_reasons_str;

arch/x86/kvm/svm.c

@@ -2911,9 +2911,9 @@ static const struct trace_print_flags svm_exit_reasons_str[] = {
 	{ -1, NULL }
 };
 
-static bool svm_gb_page_enable(void)
+static int svm_get_lpage_level(void)
 {
-	return true;
+	return PT_PDPE_LEVEL;
 }
 
 static bool svm_rdtscp_supported(void)
@@ -2986,7 +2986,7 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.get_mt_mask = svm_get_mt_mask,
 
 	.exit_reasons_str = svm_exit_reasons_str,
-	.gb_page_enable = svm_gb_page_enable,
+	.get_lpage_level = svm_get_lpage_level,
 
 	.cpuid_update = svm_cpuid_update,
 

arch/x86/kvm/vmx.c

@@ -4036,9 +4036,9 @@ static const struct trace_print_flags vmx_exit_reasons_str[] = {
 
 #undef _ER
 
-static bool vmx_gb_page_enable(void)
+static int vmx_get_lpage_level(void)
 {
-	return false;
+	return PT_DIRECTORY_LEVEL;
 }
 
 static inline u32 bit(int bitno)
@@ -4131,7 +4131,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.get_mt_mask = vmx_get_mt_mask,
 
 	.exit_reasons_str = vmx_exit_reasons_str,
-	.gb_page_enable = vmx_gb_page_enable,
+	.get_lpage_level = vmx_get_lpage_level,
 
 	.cpuid_update = vmx_cpuid_update,
 

arch/x86/kvm/x86.c

@@ -1641,10 +1641,12 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 			 u32 index, int *nent, int maxnent)
 {
 	unsigned f_nx = is_efer_nx() ? F(NX) : 0;
-	unsigned f_gbpages = kvm_x86_ops->gb_page_enable() ? F(GBPAGES) : 0;
 #ifdef CONFIG_X86_64
+	unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
+				? F(GBPAGES) : 0;
 	unsigned f_lm = F(LM);
 #else
+	unsigned f_gbpages = 0;
 	unsigned f_lm = 0;
 #endif
 	unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;