[RFC PATCH 14/27] KVM: x86: Add a helper to init multiple feature bits based on raw CPUID

[Binbin Wu <binbin.wu@linux.intel.com>]

Add kvm_cpu_cap_check_and_init_mf() to initialize KVM-only CPUID leafs
whose allowed feature bits needs to be intersected with the raw host
CPUID value for CPUID paranoid verification.

Use it instead of kvm_cpu_cap_init() to avoid adding new X86 feature bit
definitions in the common x86 header.

Move raw_cpuid_get() to cpuid.h since kvm_cpu_cap_check_and_init_mf()
will be called in vendor module.

Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
---
 arch/x86/kvm/cpuid.c | 23 -----------------------
 arch/x86/kvm/cpuid.h | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 78d8f89d6079..3bd9608770a9 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -672,29 +672,6 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)
-{
-	struct kvm_cpuid_entry2 entry;
-	u32 base;
-
-	/*
-	 * KVM only supports features defined by Intel (0x0), AMD (0x80000000),
-	 * and Centaur (0xc0000000).  WARN if a feature for new vendor base is
-	 * defined, as this and other code would need to be updated.
-	 */
-	base = cpuid.function & 0xffff0000;
-	if (WARN_ON_ONCE(base && base != 0x80000000 && base != 0xc0000000))
-		return 0;
-
-	if (cpuid_eax(base) < cpuid.function)
-		return 0;
-
-	cpuid_count(cpuid.function, cpuid.index,
-		    &entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
-
-	return *__cpuid_entry_get_reg(&entry, cpuid.reg);
-}
-
 /*
  * For kernel-defined leafs, mask KVM's supported feature set with the kernel's
  * capabilities as well as raw CPUID.  For KVM-defined leafs, consult only raw
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index ea8ff5210e4a..0b90344a8b98 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -259,6 +259,29 @@ static __always_inline void kvm_cpu_cap_check_and_set(unsigned int x86_feature,
 		kvm_cpu_cap_set(x86_feature, overlay_mask);
 }
 
+static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)
+{
+	struct kvm_cpuid_entry2 entry;
+	u32 base;
+
+	/*
+	 * KVM only supports features defined by Intel (0x0), AMD (0x80000000),
+	 * and Centaur (0xc0000000).  WARN if a feature for new vendor base is
+	 * defined, as this and other code would need to be updated.
+	 */
+	base = cpuid.function & 0xffff0000;
+	if (WARN_ON_ONCE(base && base != 0x80000000 && base != 0xc0000000))
+		return 0;
+
+	if (cpuid_eax(base) < cpuid.function)
+		return 0;
+
+	cpuid_count(cpuid.function, cpuid.index,
+		    &entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
+
+	return *__cpuid_entry_get_reg(&entry, cpuid.reg);
+}
+
 static __always_inline void kvm_cpu_cap_init_mf(u32 leaf, u32 features, u32 overlay_mask)
 {
 	WARN_ON_ONCE(!kvm_is_configuring_cpu_caps);
@@ -270,6 +293,16 @@ static __always_inline void kvm_cpu_cap_init_mf(u32 leaf, u32 features, u32 over
 	}
 }
 
+static __always_inline void kvm_cpu_cap_check_and_init_mf(u32 leaf, u32 features, u32 overlay_mask)
+{
+	reverse_cpuid_check(leaf);
+	/* This function is used for kvm only cpuid leafs. */
+	BUILD_BUG_ON(leaf < NCAPINTS);
+	features &= raw_cpuid_get(reverse_cpuid[leaf]);
+
+	kvm_cpu_cap_init_mf(leaf, features, overlay_mask);
+}
+
 static __always_inline bool guest_pv_has(struct kvm_vcpu *vcpu,
 					 unsigned int kvm_feature)
 {
-- 
2.46.0