KVM: x86: Add a helper to check kernel support when setting cpu cap

Add a helper, kvm_cpu_cap_check_and_set(), to query boot_cpu_has() as
part of setting a KVM cpu capability.  VMX in particular has a number of
features that are dependent on both a VMCS capability and kernel
support.

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>

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 13374f8..fd29b64 100644 (file)
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -282,4 +282,10 @@ static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
        kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
 }
 
+static __always_inline void kvm_cpu_cap_check_and_set(unsigned int x86_feature)
+{
+       if (boot_cpu_has(x86_feature))
+               kvm_cpu_cap_set(x86_feature);
+}
+
 #endif

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 30e1745..997a471 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1377,8 +1377,7 @@ static __init void svm_set_cpu_caps(void)
 
        /* CPUID 0x8000000A */
        /* Support next_rip if host supports it */
-       if (boot_cpu_has(X86_FEATURE_NRIPS))
-               kvm_cpu_cap_set(X86_FEATURE_NRIPS);
+       kvm_cpu_cap_check_and_set(X86_FEATURE_NRIPS);
 
        if (npt_enabled)
                kvm_cpu_cap_set(X86_FEATURE_NPT);

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b686609..16a32d3 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7149,18 +7149,16 @@ static __init void vmx_set_cpu_caps(void)
                kvm_cpu_cap_set(X86_FEATURE_VMX);
 
        /* CPUID 0x7 */
-       if (boot_cpu_has(X86_FEATURE_MPX) && kvm_mpx_supported())
-               kvm_cpu_cap_set(X86_FEATURE_MPX);
-       if (boot_cpu_has(X86_FEATURE_INVPCID) && cpu_has_vmx_invpcid())
-               kvm_cpu_cap_set(X86_FEATURE_INVPCID);
-       if (boot_cpu_has(X86_FEATURE_INTEL_PT) &&
-           vmx_pt_mode_is_host_guest())
-               kvm_cpu_cap_set(X86_FEATURE_INTEL_PT);
+       if (kvm_mpx_supported())
+               kvm_cpu_cap_check_and_set(X86_FEATURE_MPX);
+       if (cpu_has_vmx_invpcid())
+               kvm_cpu_cap_check_and_set(X86_FEATURE_INVPCID);
+       if (vmx_pt_mode_is_host_guest())
+               kvm_cpu_cap_check_and_set(X86_FEATURE_INTEL_PT);
 
        /* PKU is not yet implemented for shadow paging. */
-       if (enable_ept && boot_cpu_has(X86_FEATURE_PKU) &&
-           boot_cpu_has(X86_FEATURE_OSPKE))
-               kvm_cpu_cap_set(X86_FEATURE_PKU);
+       if (enable_ept && boot_cpu_has(X86_FEATURE_OSPKE))
+               kvm_cpu_cap_check_and_set(X86_FEATURE_PKU);
 
        /* CPUID 0xD.1 */
        if (!vmx_xsaves_supported())